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Air and water temperatures wind speed and precipitation

Calculation of dry particle deposition, wet deposition, and gas absorptive fluxes of target organic chemicals to the New York New Jersey Harbor Estuary requires knowledge of the air temperatures and wind speeds at the three sites surrounding the estuary (New Brunswick, Sandy Hook, Liberty Science Center), and the mean surface skin temperature of the water body. Figure 27.3 (upper panel) portrays the mean daily air temperatures for the Figure 27.3. Meteorological parameters at the three sampling sites. Upper panel shows temperatures at Liberty Science Center, New Brunswick, and Sandy Hook as well as water surface skin temperatures in Raritan Bay measured by remote sensing. Lower panel shows wind speeds at Liberty Science Center, New Brunswick, and Sandy Hook. Figure 27.3. Meteorological parameters at the three sampling sites. Upper panel shows temperatures at Liberty Science Center, New Brunswick, and Sandy Hook as well as water surface skin temperatures in Raritan Bay measured by...

Effects Of Wind Speed And Direction

Horizontal winds play a significant role in the transport and dilution of pollutants. As wind speed increases, the volume of air moving by a source in a period of time also increases. If the emission rate is relatively constant, a doubling of the wind speed halves the pollutant concentration, as the concentration is an inverse function of the wind speed.

Wind Speed

The wind speed is the mean wind speed over the vertical distribution of a plume. However, usually the only wind speed available is that monitored at ground-level meteorological stations. These stations record ambient atmospheric characteristics, usually at the 10-m level, and typically with lower wind speeds than those affecting the plume. These lower speeds are due to the friction caused by the surface as shown in Figure 5.8.9. Therefore, the wind speed power law must be used to convert near-surface wind speed data into a wind speed representative of the conditions at the effective plume height. The wind speed power law equation is as follows where u1 and z1 correspond to the wind speed and vertical height of the wind station, while u2 and z2 pertain to the characteristics at the upper elevation. This formula is empirical, with the exponent derived from observed data. The exponent (p) varies with the type of ambient weather conditions, generally increasing with stability and surface...

Body Weight Speed And Flight Mode

The importance of flight speed for migration is obvious for a given time airborne, a faster bird can cover a greater distance. The flight speeds of birds have often been measured using a car or aeroplane travelling alongside, or by using radar to track the movements of particular flocks or individuals (Bruderer & Boldt 2001). Measures taken from a vehicle or airplane cannot be corrected for wind effects, and are often of doubtful accuracy, so are of limited value. Radar measures can be obtained specifically for birds on migration and can be corrected to allow for wind speed, but do not always provide a reliable identification of species. Other values used for comparative purposes are the theoretical flight speeds calculated from aerodynamic principles on the basis of body mass, wingspan and wing area (Pennycuick 1969). The main findings to emerge from all these various sources of

Flapping And Soaring Flight

Soaring-gliding flight is not confined to landbirds. Many seabirds make use of up-currents formed either as the wind is deflected off waves (equivalent to slope soaring), or as a wave of 'swell' displaces air upwards as it moves over the sea surface. This method is effective even at times with little wind, providing there are waves or swell to displace the air upwards. Some seabirds also use 'dynamic soaring', which depends partly on wind speed being slowed by the sea surface, an effect which is lessened with height up to about 16 m. The bird first climbs into the wind, then makes a high leeward turn, gaining distance by gliding with the wind whilst losing height. After making a low turn in the trough of a wave, it starts the cycle again. A bird could also make use of discontinuities in wind flow near the sea surface, as it flies first behind a wave crest and then emerges for a time into the unobstructed wind. At this moment, the bird tilts its body so that the temporary gust strikes...

Dry Deposition of Particles to Water Surfaces

Transport of particles to water surfaces by dry deposition is more complicated than the transport to terrestrial surfaces. This complication is brought about by the fact that water is a smooth surface with intermittent wave action. The waves create bursting bubbles and spray formation which make the modeling of dry deposition to water a very difficult task. The situation is complicated by high humidity near the water surface, the temperature difference between air and water, and movement of water surface. Wind speeds tend to be higher over water than over nearby land.

Changes in conditions with altitude

As they ascend from ground level, migrating birds face progressively changing conditions. Wind speed increases, while air density, oxygen availability and temperature decline. Once birds break through the cloud layer, however, they can escape from mist, rain and snow. Wind has a major influence on the height above ground at which birds fly, for it can change in direction as well as strength, affecting the choice of cruising height. This is most strikingly demonstrated by the trade winds, which give way higher up to the anti-trades blowing in the opposite direction. This situation allows birds to find following winds in both autumn and spring, providing they fly at an appropriate height. In southern Israel, for example, the wind shear associated with the shift from trade to anti-trade winds fluctuates roughly around 1.5 km above sea level. Correspondingly, birds studied by radar flew mainly below this level in autumn, and mainly above it in spring, when some reached heights of 5-9 km...

Transpiration and Evaporation

Transpiration (water that passes through vascular plants to the atmosphere) is an important parameter in wetland plant studies because it represents the interaction between a wetland's hydrologic regime and its vegetation. Transpiration is the only component of the water budget that is dependent entirely upon plants. Estimates of transpiration are often combined with evaporation (water that vaporizes directly from the water or soil) this measure is known as evapotranspiration (ET). When water supplies are not limiting, meteorological factors tend to control rates of ET. The rate of evapotranspiration is affected by solar radiation, wind speed and turbulence, available soil moisture, and relative humidity. Rates vary with the difference in vapor pressure at the water surface or leaf surface and the vapor pressure of the atmosphere. As the vapor pressure of the water or leaf surface increases relative to the atmosphere (due to solar energy or increases in temperature, for example), ET...

Model Uses for Differing Biological Control Approaches

These biological control approaches are not, however, without risk, and modeling has also been used to address this issue. A fungal pathogen Chondrostereum purpureum was proposed as an inundative biological control agent for the perennial weed Prunus serotina Ehrh. in forests. Though the pathogen could be applied in a targeted fashion to only the pest trees by formulating it into a mycoherbicide spray, the fungus subsequently produces basidiospores that could disperse and infect nontarget plants, necessitating an analysis of risk. This involved the development of a stratified model to describe spore fluxes for differing layers and showed the significant effect of wind speed and consequent risk of dispersal of inoculum from a treated patch of forest and into commercially valuable Prunus spp. crops.

Scale and two views of the loss of plant water to the atmosphere

There are two very different ways in which we can analyze and explain the loss of water from plants to the atmosphere. Plant physiologists going back at least to Brown and Escombe in 1900 have emphasized the way in which the behavior of the stomata determines the rate at which a leaf loses water. It now seems obvious that it is the frequency and aperture of pores in an otherwise mainly waterproof surface that will control the rate at which water diffuses from a leaf to the outside atmosphere. But micrometero-logists take a quite different viewpoint, focusing on vegetation as a whole rather than on the single stoma, leaf or plant. Their approach emphasizes that water will be lost by evaporation only if there is latent heat available for this evaporation. This may be from solar radiation received directly by the transpiring leaves or as 'advective' energy, i.e. heat received as solar radiation elsewhere but transported in moving air. The micrometeorologists have developed formulae for...

Calculation Of Flight Ranges

Birds often migrate more cheaply in natural than in experimental situations. The average heart rate (reflecting metabolic rate) of four naturally migrating Barnacle Geese Branta leucopsis over the whole journey was 253 beats per minute, which is only half the mean rate recorded from Barnacle Geese trained to fly behind a truck, and 65 of that recorded from Barnacle Geese trained to fly in a wind generator (Butler et al. 2003). Moreover, in the naturally migrating birds, heartbeat (as an index of metabolic rate) declined during the course of a journey from 315 beats per minute to 225 beats per minute, paralleling the loss in body weight as fuel was used (Butler et al. 2003).

Soil Organic Matter Decomposition And Respiration

The net ecosystem exchange (NEE) rate of CO2 represents the balance of gross primary productivity and respiration in an ecosystem. The eddy covariance technique is used to measure the NEE. The covariance between fluctuations in vertical wind velocity and CO2 mixing ratio across the interface between the atmosphere and a plant canopy is measured at a flux tower (Baldocchi, 2003). Although flux tower data represent point measurements with a footprint of typically 1 X 1 km they can be used to validate models and to spatialize biospheric fluxes at the regional scale (Papale and Valentini, 2003).

Aerial and satellite surveys

The advantage of these new systems is that large areas can be surveyed at one time. Considerable skill goes into the design of the sensors and the interpretation of the resulting data. The data that such systems can collect are restricted mainly to surface waters and concerns the temperature, colour, roughness and average slope of the sea surface. From these four basic measurements various characteristics can be derived. Perhaps the best known is an estimate of the chlorphyll content of the water which is related to primary production. This is derived from the colour of the surface waters and allows the production of monthly maps of primary productivity throughout the world's oceans. Other applications include investigating ocean currents from the surface slope deriving wind speed from surface roughness using temperature patterns to help predict events such as El Ni o (see Section 1.3.6) and to provide information regarding boundaries of water masses and mixing processes and...

Types of Climate Models

There are several types of models used at present for climate research (see also Table 1). The most complex and realistic climate models are the so-called coupled general circulation models (GCMs) of the atmosphere and the ocean. These models are based on the most comprehensive set of dynamical and thermodynamical equations and they describe a large set of relevant processes in the ocean and the atmosphere. The name 'general circulation' reflects the fact that these models, unlike more simple models, simulate three-dimensional circulation of the atmosphere (wind speed) and the ocean (current velocity). Climate GCMs originated from the weather prediction models and some models can be used both for weather and climate predictions. The main difference is how the models are used. The weather prediction is aimed on simulations of temporal development of individual weather systems, such as cyclones and anticyclones. Due to chaotic nature of weathers, an accurate prediction of meteorological...

Communication and the Environment

All habitats modify signals during transmission. Signals are both attenuated and degraded, that is, signal energy is absorbed and signal details are distorted by the environment. Often degradation will limit the effective range of a signal before attenuation - it is a common personal experience to know that someone at a distance has said something, but to be unable to understand the words the signal has been detected but the detailed information it contains cannot be discerned. Habitats can be thought of as imposing selection pressures on the form of signals and as a result most signals are adapted to some degree to their transmission environment. For example, birds found in open habitats (e.g., grassland) tend to sing songs with rapid temporal patterning (the songs contain more trills than whistles) and with a wide frequency range. By contrast, woodland bird songs tend to have more low frequency whistles than high frequency trills. This difference contributes to minimizing the effect...

Write a paragraph or two about the natures disasters and read it to the class

Tornadoes form in severe thunderstorms. Extreme temperature and pressure contrasts between the surface and upper troposphere generate very strong updrafts of air. Pressure at the center of a tornado funnel falls to about 900 mb. Wind speeds increase sharply with altitude. The difference in wind speed between the ground and higher levels begins a horizontal rolling motion in the air. The strong updraft of air shifts the rotating air into a vertical position high above the ground. The conditions causing a tornado last only a few minutes, then the funnel dissipates and drops any debris being carried. Other tornadoes may form from the base of the same cloud, however, producing a stop and go progress across the land.

Tropical cyclones and hurricanes

The hurricanes with which Americans are familiar are one of a group of tropical weather systems known collectively as tropical cyclones. The official definition of such systems is that wind speeds average over 115 kph for at least one minute. They are called hurricanes in the western Atlantic, typhoons in the western North Pacific and simple cyclones in the Bay of Bengal and Northern Australia. Tropical cyclones are the most dramatic of a series of tropical weather systems that may develop from less to more intense storms. Tropical storms have average wind speed between 60 and 115 kph, tropical depressions have wind speeds up to 60 kph. The destructive nature of tropical cyclones and storms led to attempts to monitor and modify them. Weather satellites

Apparent Nonstop Seacrossings

Autumn migrations of Brent Geese Branta bernicla over the Pacific Ocean from Izembek Lagoon, Alaska, to Baja California, Mexico, were studied in the same way (Dau 1992). Observers at both sites documented departures and arrivals in three different years, estimating times en route to be 60, 60 and 95 hours respectively, which implied average speeds of 1992, 1992 and 1344 km per 24-hour day (or of 83, 83 and 56 km per hour) over the 5000 km journey. Variability in mean route times between years was associated mainly with differences in wind speed and directions, and possibly also with times spent resting on the sea. This migration is also energetically costly, with birds of both sexes losing an estimated one-third of their total pre-departure body weights during the 2-4 day journey. On a somewhat shorter journey, Canada Geese Branta canadensis minima were estimated to take 48 hours to fly 2800 km over the sea from the Alaska peninsula to the Klamath Basin in Oregon, averaging 1392 km...

Lessons from Coastal Bird IBMs and Future Developments

Which span multiple bird generations. These factors have simplified the development of coastal bird IBMs and their use in advising policy, and so the next step is to identify species that share some or all of these characteristics. Marine ducks, such as the common scoter and common eider Somateria mollissima, feed on similar, bottom-dwelling prey as do inter-tidally feeding shorebirds, and the extent of their feeding habitat changes through the tidal cycle as water depth changes. An IBM has recently been developed to predict the effect of habitat loss and disturbance from wind farms on common scoter wintering in the Irish Sea (Kaiser et al., 2005). Seed-feeding farmland birds have relatively simple diets and the abundance and food value of seeds can be quantified. These birds have considerably declined in recent decades, thought in several species to be associated with over-winter food shortages caused by change in agricultural practices (Robinson and Sutherland, 2002). IBMs can...

Supply of COT Layer Conductances

The total leaf resistance for water vapor transfer, rw, is largely composed of two components that are in series the boundary layer resistance, ra, and the stomatal resistance, rs. The boundary layer is the thin layer of air adjacent to the leaf that is modified by the leaf (Fig. 6 in Chapter 4A on the plant's energy balance). Turbulence is greatly reduced there, and transport is largely via diffusion. Its limit is commonly defined as the point at which the properties of the air are 99 of the values in ambient air. The boundary layer resistance can be estimated by measuring the rate of evaporation from a water-saturated piece of filter paper of exactly the same shape and size as that of the leaf. Conditions that affect the boundary layer, such as wind speed, should be identical to those during measurements of the leaf resistance. The stomatal resistance for water vapor transfer (rs) can now be Under most conditions, the stomatal conductance is considerably less than the boundary layer...

Detecting Interactions

Many of the techniques designed to increase the quantity or quality of resources for human use rely on alterations in environmental conditions as a mechanism to alter species interactions and, therefore, change species composition. For example, removal of forest canopies generates large changes in several environmental parameters at the soil surface, light and wind speed increase and diurnal temperature fluctuations become more pronounced. These and other changes in the physical environment tend to favor recruitment of species that are short lived, fast growing, and high in photosynthetic tissue at the expense of species that are long lived, slow growing, and high in structural tissue. The resulting suite of early successional species provides excellent habitat for some game species (e.g., white-tailed deer) compared with dense, closed-canopied forests. Conversely, many plant and animal species are found primarily in old forest stands with closed canopies, and the distribution and...

Management Implications

Monitoring internal wave formation and wind velocity may be particularly important to estuarine-dependent species that develop on the continental shelf. Concurrently monitoring both larval supply and postsettlement mortality is necessary to fully understand recruitment dynamics only by doing so did it become apparent that early postsettlement mortality rather than larval supply was the bottleneck in blue crab populations, even though postlarvae had to cross the shelf to reach the estuary. Blue crabs prefer to settle in submerged vegetation, and packing more recruits into this limited area leads to very highly postsettlement mortality from cannibalization (Pile et al., 1996 Heck, Coen, and Morgan, 2001). The connection between larval transport, larval supply, settlement, and recruitment into adult populations will become clearer as concurrent monitoring of benthic and pelagic phases of the life cycle continue and our understanding of coastal transport processes improves.

Determination of Crop ET Plant Water Use in Agroecosystems Using Climate Variables

Where ETc is the crop ET (crop water use) in units of water depth (inches d-1, cm d-1, or mm d-1), ETref (ETo or ETr) is the reference ET in unit ofwater depth (inches d-1, cmd-1, or mmd-1) as calculated from the basic weather variables (solar radiation, air temperature, wind speed, and relative humidity) measured with a weather station in reference conditions. where ETref is the standardized reference ET (mm d-1 or mmh- ), A is the slope of saturation vapor pressure versus air temperature curve (kPa C- ), Rn is the calculated net radiation at the crop surface (MJm-2d-1 for 24-h time steps or MJ m-2 h-1 for hourly time steps), G is the heat flux density at the soil surface (zero for 24-h time steps or MJm-2h-1 for hourly time steps), Tis the mean daily or hourly air temperature at 1.5-2.5 m height ( C), U2 is the mean daily or hourly wind speed at 2 m height (ms-1), es is the saturation vapor pressure (kPa), ea is the actual vapor pressure (kPa), es - ea is the vapor pressure deficit...

Using Fuzzy Models in Spatial Simulation

Grid data cells are more convenient for modeling approaches. An equally spaced grid cell is better suited to make simulation of fluxes with this data model. These simulations are, for example, important for wind or water erosion modeling. A fuzzy model needs continuous data as inputs. (An approximation with a discrete set with many members is also OK.) The spatial information is split into different information layers (maps) each containing a grid. A fuzz modeling approach usually needs two or three maps as inputs to calculate an output grid. The grids store information like soil quality, elevation data, land-use data, etc. Other data of this type are distances, such as between grid cells and points (nesting places for birds, location of wind energy plant, etc.) or between grid cells and linear features (roads, rivers, etc.). Another important example involving continuous data demonstrates the use of the so-called moving-window technique, which calculates

Simulation of Habitat Quality of the Lesser Spotted Eagle

The output of the part of the model on nutrition is an input for the calculation on habitat quality. The next input is the distance to the breeding places. These places are located in a forest. To evaluate a potential breeding habitat the mean distance to the forest can be used. The last input includes the endangerment caused by wind energy plants. The lesser spotted eagle will avoid areas around wind energy plants. In this sense wind energy plants can shrink the hunting area of the bird. These three inputs are put in a new fuzzy model. The result is the habitat quality of the area. With such a

The Effect Of Landscape And Vegetation

By careful site planning and screening with fences, trees and hedges the amount of wind reaching the building envelope can be much reduced. If the average wind speed around a building is reduced by 1 m s, this alone can reduce the energy requirements for space heating by 3 . In the Norwegian coastal town of Kristian-sund, where the average wind speed is 22 km h (Beaufort scale 4), the loss of heat for an unscreened building through infiltration is 40 greater than for a screened building.

Fates and Effects Physics and Mixing

Water movement and mixing are driven by the effects of wind and tide on coastal lagoons. The basic hydrodynamics of coastal systems are well represented by physics-based simulation models of various kinds. A number of two- and three-dimensional (2D and 3D) models now exist (both research tools and commercially available products) which can adequately represent wind-induced wave patterns and currents, tidal exchanges and circulation, and changes in surface elevations due to tides and winds. (For an introduction to a variety of models, see www.estuary-guide.net toolbox or www.smig.usgs.gov models by Delft Hydraulics at www.wldelft.nl and DHI www.dhigroup.com ) Input data required are basic meteorological data wind speed and direction, plus solar insolation, and a detailed knowledge of the morphometry and bathymetry of the lagoon in question. Based on the conservation of mass and momentum and various turbulence closure schemes, it is possible to adequately model and predict both velocity...

Variation in a complex odorous environment

The release of volatiles from both plants and hosts, as well as the responsiveness of the parasitoids, will strongly depend on the phenotypic and genotypic variation at all trophic levels. Furthermore, the plume released, and the behavior of the parasitoids will directly be affected by abiotic factors such as wind speed, temperature, or air pressure. However, most studies examining the response of parasitoids to volatiles have been carried out under controlled laboratory conditions where the majority of factors mentioned have been

LAI as a Descriptor of Canopy Structure

The vertical distribution of LAI in mixed canopies reflects the functional abilities of species or leaves (shade, air humidity, and temperature tolerance). LAI controls both within- and below-canopy microclimate, determines and controls rainfall, snow and deposition interception, radiation extinction, wind velocity slackening, light quality and quantity below the canopy, and hence influences the living conditions of fungi, plants, insects, macro- and micro-fauna communities.

Factors Influencing Microclimatic Regimes in Dead Wood

Microclimate varies spatially and temporally (Boddy, 1984, 1986) over a range of scales. At the forest scale two important microclimatic gradients are evident a horizontal gradient from forest interior to forest edge, clearcut or natural canopy gap and a vertical gradient from forest floor to canopy. Forest interiors and lower levels in stands tend to have higher air humidity, lower wind speed, lower maximum and higher minimum temperatures compared to gaps, forest edges and open land, and gradients run from stable to variable microclimatic conditions (e.g. Chen et al, 1993 Morecroft et al, 1998 Ritter et al, 2005). Microclimatic stress is hence low in wood decomposing on the forest floor in closed forests, while fungi in dead wood in the canopy or on the floor of exposed forest edges are subject to stressful conditions. In addition, environmental conditions vary vastly between functional sapwood (with its high water content and low aeration), dysfunctional sapwood and heartwood (both...

Organism Microclimate Interactions

Therefore, when making measurements of microcli-matic factors such as air temperature, wind speed, and surface temperature, it is important to consider how these factors are translated into factors such as body temperature, as well as to consider both the direct and indirect effects of body temperature on organismal physiology and ecology.

Methods Of Oil Spill Control

Several factors need to be vectorially combined to define the oil spill spreading pattern. The current will drift the unrestrained oil at about the same velocity as the water. Wind adds a component of about 3-4 of the wind velocity, and natural spreading acts concentrically to disperse the slick. This is initially caused by the oil's hydrostatic head balanced by the oil's inertia. Typically, for an impulsive 500-2,500,000 gal spill of 0.9 specific gravity (SG) oil, this acts for about 1 4-1 hr until the oil reaches about 4in thickness and a 500-3,000 ft diameter. At this point, pressure spreading is primarily balanced by viscous drag in the underlying water, and the slick diameter grows at about 300 ft hr. As the gravity head decreases, the net surface tension spreading pressure (water to air-oil to air-oil to water), usually about 20 dynes per centimeter, continues to disperse the oil until typically a 0.01-0.001 in thickness is reached.

Coastal Ecosystems and Disturbances

Coastal ecosystems are subject to effluents from neighboring land areas as well as disturbances such as hurricanes. Excessive rainfall over land and river discharge into coastal zones brings an abundance of pollutants and nutrients from agriculture that sometimes cause explosive phytoplankton blooms. Hurricane Isabel made landfall east of Cape Lookout, North Carolina, as a Category 2 (Stafford-Simpson scale) hurricane on 18 September 2003. The storm's center tracked to the northwest, passing west of Chesapeake Bay in the early morning of 19 September. Hurricane Isabel brought the highest storm surge and winds to the region since the Chesapeake-Potomac hurricane of 1933 and Hurricane Hazel in 1954. The storm surge reached a high of 2.7 m, and sustained wind speeds reached about 30 m s with gusts of 40 ms 1. Hurricane Isabel was responsible for physical and biological changes in the Chesapeake Bay on a variety ofspatial and temporal scales. Short-term responses included a reduction of...

Combinations of factors

Damage to forests often results from the combined impact of several factors as in north-west Colorado, where over 10 000 ha of subalpine forest was blown down in 1997 (Kulakowski and Veblen, 2002). The study area, shown in Fig. 9.15, ranges from 2400 to 3400 m (8000-11000 ft) in altitude, and its forests are dominated by lodgepole pine Pinus contorta, quaking aspen Populus tremuloides, Engelmann spruce Picea engelmannii and subalpine fir Abies lasiocarpa. It was concluded that both topographic position and fire history contributed to susceptibility to wind damage. Damage was least in the younger stands, at lower elevations and in areas away from ridges where wind speeds were lower. Stands

Gaseous absorptive deposition

The concepts of air-water exchange and mass transfer of organic chemicals across water surfaces have been described in detail elsewhere (Eisenreich etal., 1997 Liss and Duce, 1997). Diffusive air-water exchange refers to the transfer of chemical across an air-water interface and may be visualized as diffusive transfer of a chemical across near-stagnant layers of 0.1 to 1.0 mm thickness. At low wind speeds, insufficientwind energy exists to mix the air and water films or boundary layers, and a stagnant boundary layer is established (Stagnant Two-Film Model). Higher wind speeds generate more turbulence in the boundary layers, parcels of air and water are forced to the surface, and exchange is dependent on the renewal rate of air and water parcels. In highly turbulent seas, gas exchange is enhanced by breaking waves and bubble ejection. Under turbulence and wind conditions normally occurring in estuaries and lakes, the first two models are most applicable although wind extremes may be...

Nuclear Weapons Tests as a Source

Yields, and the meteorological conditions of temperature, precipitation, wind speed, and direction that vary with altitude. Usually, large particles settle locally, whereas small particles and gases may travel a long distance. There was evidence of long-range transport and fallout of debris from the test when the beta activity was first picked up by the film packaging material at mills of Kodak Research Laboratories in Indiana and Iowa in the summer of 1945. On the other hand, large atmospheric explosions may inject radioactive material into the stratosphere, 10 km or more above the ground, where it could remain in the atmosphere for years and subsequently be distributed globally and eventually deposited into the ground (i.e., global fallout) thereby contaminating the radioactivity level in the ecological environment.

Instability of the Water Surface Bubbles and Sprays

The dramatically strong enhancement of the gas transfer across the interface through the presence of bubbles and sprays is important mainly in the oceanographic context. Breaking waves lead to the development of bubbles as well as sprays into the atmosphere. This results in a significant increase of the actual surface area and a stronger turbulence intensity. Thus, the reaeration rate increases significantly when waves are present. An increase in the transfer velocity up to a factor of 3 to 5 compared to a smooth interface is observed, in particular at high wind speeds ( 5 m s ).

Quantitative Reasoning

The amount of reasoning that goes into an equation varies. Some relations between quantities are based on empirical relations derived completely from data. Some are based on the application of statistics to quantities in situations where some relation is expected on other grounds. An example would be a functional relation used to calculate primary production from wind strength in a coastal zone where wind-driven upwelling brings nutrients upward into the light. Little relation would be expected between wind strength and production by photosynthetic microbes per se. A stronger relation would be expected between production and upwelling-favorable wind stress, which takes into account both wind direction and amount of energy imparted to the water by the wind. Thus an equation to calculate production from wind stress is based on more specific reasoning than an equation based on wind speed alone, in much the same way that the solution to the surfing problem required reasoning about...

Aiacote Top Ten Winner The Plaza At Ppl Center Location Allentown Pennsylvania

Placed within a challenging and constrained site, the design preserves the cultural landscape represented by an existing nineteenth-century summer home, respectfully and adaptively reusing the original house and adding contemporary office, laboratory, and common spaces. The all-electric building relies on renewable energy sources, including a grid-connected and net-metered 26.4-kilowatt photovoltaic array that powers the building's closed-loop, ground-source heat-pump system. A planned on-site wind turbine will likely make the building a net-energy exporter. Icynene spray foam insulates all exterior walls and roof assemblies, creating a technically and ecologically effective air barrier and optimized R-values. Other components reinforce the performance benefits of this extremely secure envelope, including offset-stud framing double- and triple-glazed argon-insulated low-E windows enthalpy wheels that recapture heat and moisture from exhaust air and precondition incoming fresh air and...

Long Distance Seed Dispersal

Recent population and community models show that the entire distribution of dispersal distances, and not only mean dispersal distances, is critical for rates of range expansion, recruitment patterns, genetic structure, metapopulation dynamics, and ultimately for community diversity at different scales. The use of dispersal mechanistic models, and especially those that are spatially explicit, is a promising tool because it provides reliable predictions of standard (local dispersal) as well as nonstandard (long-distance dispersal, LDD) events of seed dispersal, which are especially difficult to capture in nature. For wind-dispersed species, for example, the processes that affect seed dispersal distance are either atmospheric (the spatial and temporal statistics of the wind velocity field (vertical, longitudinal, and

Topdown control See food chain

Tornado A relatively small (about 100 m in diameter) funnel of rapidly rotating air (wind speeds may exceed 300 km h-1) that forms around an intense low-pressure center. It is capable of sweeping up objects from the ground. Tornadoes are accompanied by violent down-drafts.

Charge Your Gadgets the Green

Choosing green portable power chargers and extenders is the ecofriendlier alternative to tapping into the wall outlet to recharge gadgets. What makes these gadgets green Some use solar or wind power to recharge your gadgets. For instance, the Iqua SUN solar Bluetooth headset recharges itself when exposed to daylight, and the HY Mini wind-powered charger can be strapped to your arm or bicycle to recharge your mobile phone, digital camera, or other portable gadget.

Vegetative propagation

Variable A characteristic or property that can posses a range of values. It may be a measured value of an environmental factor, such as wind speed or temperature, or it may represent the number of individuals in a population possessing a particular characteristic, e.g. a particular age or height. Variables are often used to plot graphs showing relationships or dependencies. In this situation, one variable may be fixed (e.g. a location along a transect) or under the control of the experimenter (e.g. time) - this is an independent variable. The other - the property being measured or the rate of reaction - is not controlled, and is a dependent variable.

Photoprotection photoinhibition and photooxidation

Against the background of environmental variability, there may be superimposed variations in the contemporary ambient range of fluctuations, subjecting hitherto supposedly acclimated plank-ters to additional demands of accommodation. Among the most crucial of these is a weakening of the mechanical forcing, either as a result of a sharp reduction in the wind speed or of sharp increase in the photon flux (perhaps as the cloud clears) or, as is often the case, the coincidence of both events. In all these instances, the abrupt shortening of the Monin-Obukhov length is, far from being the net beneficial influence cited above (in Section 3.3.3), potentially highly dangerous. Part of the hitherto entrained population becomes disentrained deep in the water column, where the irradiance is markedly sub-saturating. Another is retained within a new, much shallower, surface circulation, exposed to a much elevated I* value and to a probable excess of radiation in the harmful, high-energy...

Mechanical stability of slender tree stems 141 The Mechanical Control of Growth

Dense canopy may reduce thigmomorphogenetic responses (e.g., see 42,126 , but see Mitchell 127 ) or induce them when trees are grown in full sunlight 128 . The use of artificial fans to imitate wind loading on trees may be useful for identifying thigmomorphogenetic responses 90 , but provides little information with regard to the natural significance of thigmomorphogenesis. Experiments where forest trees would be subjected to artificial loading by the use of fans, for example to simulate turbulence would require huge facilities (see, e.g., 129,130 ). Recently, a new technique to demonstrate the occurrence of significant thigmomorphogenetic acclimation to wind in natural conditions has been proposed by Moulia and Combes 131 . These authors studied the variability in the difference between staked and free-standing plant canopies over several growing periods in alfalfa (Medicago sativa L.). Moulia and Combes 131 showed that the month-to-month variability in wind speed when winds were...

Laboratory Research On Physiology Migratory Restlessness And Directional Preferences

Recently developed wind tunnels have revealed much about the mechanics and energy needs of bird flight (Pennycuick et al. 1997). A wind tunnel creates a smooth (laminar) air flow in a test section where birds are trained to fly. The artificial wind speed can be adjusted so that, when the bird flies against the wind, it maintains a constant position in an observation section. Low turbulence is important in order to generate a natural situation reflecting flight through nonturbulent air but, if desirable, turbulence can be created by inserting nets or other objects upstream from the test section. Wind tunnels have been used to test flight mechanical theory (Chapter 3), to measure the metabolic costs of flight and to study flight style using high-speed video cameras. To yield meaningful results, especially on energy consumption, birds must be trained in the wind tunnel beforehand, so that they 'feel at home' there, and fly steadily, maintaining constant position against the wind for long...

Empirical Equations for Wind Induced Turbulence

The main parameter affecting gas transfer in a purely wind-driven regime is the shear stress due to the wind field, given by the friction velocity u*a in the air flow over the water surface. This is related to the wind velocity U10 at the standard 10 m level, u*a yCb U10. CD is the quadratic law drag coefficient, CD (0.8 + 0.065 U10) x 10-3, representing an increasing roughness effect due to wave growth with increasing wind speed. As summarized by Chu and Jirka, for low wind speeds, a linear relationship, and for high wind speeds, a quadratic relationship,

Pollination strategies

Sycamore Seed Dispersal Mechanism

Forest plants face a number of problems in respect of pollination, from the sheer size of the larger trees to the still, dark conditions inside a forest hampering pollinators. Trees in northern and temperate forests, especially the conifers, tend to be wind pollinated (anemophilous) but towards the tropics the trend is towards animal pollination, particularly by insects (entomophilous). Wind pollination is often seen as primitive and wasteful of pollen (a single birch catkin can produce 5.5. million pollen grains) and yet is remarkably prevalent. The easy answer would be to say that in northern areas there are fewer insects and higher wind speeds, leaving wind as the best pollen transporter. While this is undoubtedly true, it appears to be so successful due to low species diversity of trees. Wind can transport pollen long distances but is unspecific as to where the pollen goes. In northern areas where forests are dominated by relatively few tree species this is not necessarily a...

Dry Deposition of Particles to Vegetative Canopies

The wind and particle concentration profiles are needed for proper modeling and analysis of dry deposition fluxes and dry deposition velocities. The velocity profiles above the canopy are estimated by analyzing momentum transport dependent on the wind speed, roughness height, and the height of canopy. The shape of the wind and concentration profiles can be used to identify the region with the greatest resistance to air momentum flux and concentration flux, respectively. The transport of particles through the vegetative canopies is governed by the wind speed and particle concentrations. The collection efficiency within the canopy depends on the area available for the collection and the efficiency of the mechanisms which deposit the particle on the receptor. A few models have been developed to describe the deposition velocity to the vegetative surfaces with different approaches to estimate the collection area and collection efficiency of particles within the canopies. Some of these...

Box 21 I Langmuir circulations

The dynamics and dimensions of Langmuir circulation cells are now fairly well known. The circumstances of their formation never arise at all at low wind speeds (U 3-4 m s-1 Scott et al., 1969 Assaf et al., 1971). Spacing of streaks may be as little as 3-6 m apart at these lower wind speeds, when there is an rough correlation between the downwelling depth and the width of the cell (ratio 2.0-2.8). In the open water of large lakes and the sea, where there is little impediment to Langmuir circulation, the distance between the larger streaks (50-100 m) maintains this approximate dimensional proportionality being comparable with that of the mixed depth (Harris and Lott, 1973 Boyce, 1974). The velocity of downwelling (w 2.5 x I0-2 ms-1) is said to be proportional to the wind speed ( 0.8 x I0-2 U) Scott et al., 1969 Faller 1971), but the average velocities of the upwellings and cross-currents are typically less. The representation in Fig. 2.29a is one of a number of such 'snapshots' of...

Wind cold and wave regeneration

Crescent-shaped regeneration waves which move straight downwind appear to result from the death of a single tree or small group of trees, thus exposing a downwind arc of living trees to much higher wind speeds. Indeed, wind speeds in the canopy at the exposed edge of the old forest stand may be over 50 higher than those in the rest of the canopy. While a single crescent might

Ecological problems of understorey plants

Wind speeds are drastically reduced below the woodland canopy, especially when in leaf. In British woodlands the most prominent wind-pollinated herb is the summergreen dog's mercury Mercurialis perennis which flowers early in February and March when wind speeds are relatively high. Most woodland herbs are insect pollinated and face the problem of being found by insects in a dark woodland. The solutions are to flower before the canopy closes (the commonest option), produce pale or white flowers to show up in the gloom (such as wood sanicle Sanicula europaea) or fragrant flowers (such as wood sage Teucrium scorodonia).

Bloodfeeding Behaviour Haematophagy

A general and more comprehensive model of blood-feeding behaviour has four steps (i) the appetitive search (ii) activation and orientation (iii) attraction and (iv) landing and probing. These steps include host location, host acceptance and the initiation of blood feeding. The initiation of any or all of these stages is dependent on endogenous factors, such as the age, host preference, nutritional and reproductive state of the insect, whether or not the insect is crepuscular, nocturnal or diurnal, and their interaction. Exogenous factors, such as temperature, humidity, wind speed, light intensity and the availability of hosts, are also likely to affect the outcome of the blood-meal-seeking process (Fig. 13.1). All the endogenous factors and the insect's response to the exogenous factors may change because of infection by parasites. In addition, vector behaviour may be altered by proxy, i.e. the behaviour of the vector is not altered by direct action on the vector but by action instead...

The Grassland Environment

KS (dominated historically by tallgrass prairie), the annual precipitation is 100 cm. But the way the rainfall is distributed is notably different. At Lawrence, KS, over 60 of the rainfall occurs in the growing season (AprilSeptember), whereas at Washington, DC, the precipitation is uniformly distributed throughout the year. The open nature of grasslands is accompanied by the presence of sustained high wind speeds. Windy conditions increase the evaporation of water from grasslands and this increases water stress in the plants and animals. Another factor that increases water stress is the high input of solar radiation in these open ecosystems. This leads to the convective uplift of moist air and results in intense summer thunderstorms. Rain falling in these intense storms may not be effectively captured by the soil and the subsequent runoff of this water into streams reduces the moisture available to grassland plants and animals. In addition to periods of water stress within the...

Components of Stability

Resistance and resilience are affected by regional species abundance and distribution. Resistance can be compromised by fragmentation, which increases community exposure to external factors. For example, trees in interior forest communities usually are buffered from high temperatures and high wind speeds by surrounding trees and usually have less buttressing than open-grown trees. Fragmentation increases the proportion of trees exposed to high temperatures and wind speeds and thereby vulnerable to moisture stress or toppling (J. Chen et al. 1995, Franklin et al. 1992). Fragmentation also interferes with the adapted abilities of species in the regional pool to recolonize disturbed sites. Species are adapted to levels of dispersal and colonization sufficient to maintain populations within the characteristic habitat matrix of the landscape. If the rate of patch turnover is increased through fragmentation, the colonization rates for many species may be insufficient to provide the...

Pathway of Radionuclides and Transport Processes in the Atmosphere

Where V(x, y, z, t) is a vector of the mean wind velocity, K(Kx, K., Kz) is a diagonal matrix of the turbulent eddy diffusivity, i is the decay coefficient of the ith radionuclide, D(x, y, z, t) is the deposition due to dry and wet removal, and S(x, y, z, t) is the source term including resuspension. Under the assumptions of homogeneous turbulence over a flat terrain in a large diffusion time, the above equation can be simplified to have a Gaussian solution, which serves as a basis for the Gaussian plume model. This Gaussian plume model requires only horizontal wind speed and direction at the release location along with the estimates of atmospheric stability and source term and can be quickly performed to have results of distributions of radioactivity in a gross view. Generally, having a more realistic view, the above equation is numerically solved by difference equation that can take into account the various effects of terrain and spatially varying turbulence and meteorology,...

Exergy A Useful Concept

As mentioned above, there exist several identifiable 'engines of growth' (positive feedback cycles) of which the first, historically, and still one of the most powerful, has been the continuously declining real price of physical resources, especially energy (and power) delivered at a point of use. The tendency of virtually all raw material and fuel costs to decline over time (lumber was the main exception) has been thoroughly documented, especially by economists at Resources For the Future (RFF). The landmark publication in this field was the book Scarcity and Growth (Barnett and Morse 1963), updated by Barnett (1979). The details of historical price series, up to the mid-1960s, can be found in Potter and Christy (1968). The immediate conclusion from those empirical results was that scarcity was not in prospect and was unlikely to inhibit economic growth in the (then) foreseeable future. It is also very likely, however, that increasing availability and declining costs of energy (and...

Disturbances

Disturbances can be characterized by several criteria that determine their effect on various organisms (see Walker and Willig 1999, P. White and Pickett 1985). Disturbance type, such as fire, drought, flood, or storm, determines which ecosystem components will be most affected. Above-ground versus below-ground species or terrestrial versus aquatic species are affected differently by fire versus flood. Intensity is the physical force of the event, whereas severity represents the effect on the ecosystem. A fire or storm of given intensity, based on temperature or wind speed, will affect organisms differently in a grassland versus a forest. Scale is the area affected by the disturbance and determines the rate at which organisms recolonize the interior portions of the disturbed area. Frequency is the mean number of events per time period reliability is measured as the inverse of variability in the time between successive events (recurrence interval). Disturbances vary in intensity and...

Biosphere

Biotic Relating to life, especially describing living components of the environment that through their presence or activities affect the life of organisms in that environment or alter other aspects of the environment. For example, the presence of tall trees in a forest affects abiotic (nonbi-otic) factors such as temperature, light intensity, humidity, and wind speed. The presence of several similar species leads to competition between them for resources such as nutrients and water.

Forecasting weather

The business of weather forecasting begins with the collection of weather data such as temperature, pressure, wind speed, wind direction, cloud forms, and rain. The data are plotted on maps and make it possible to analyze the general atmospheric conditions. The visual models of the weather systems are converted to numerical computer models. In mid-latitudes weather systems such as cyclones with their fronts and anticyclones are the main features of weather maps. They are the basic models that forecasters use to predict the weather after computing the speed, direction, and internal features of each system. Since the continuous flow of data indicates that they are changing, sometimes in unexpected ways, forecasters must continuously update their predictions.

Photosynthesis

Virtually all the organic carbon in our environment, from the carbon in a person's fingernails to the carbon in a plastic pen, was formed by plants from CO2 in the air. The energy for this conversion comes entirely from sunlight. Among the few known exceptions in nature are ecosystems found on the ocean floor and hot springs that obtain their energy from oxidation of reduced inorganic compounds issuing from deep below the ocean floor in hot-water vents. Most human-made sources of energy, such as fossil fuels and weather-driven electric plants (wind and hydroelectric), ultimately come from the sun. Only nuclear, geothermal, and tidal electrical facilities, plus a portion of wind energy driven by Earth's rotation, do not derive their energy from the sun.

Water bottles

This is much less expensive than the use of ships. Instruments can be attached at several depths along a cable below a buoy, including sensors for wave height, sea temperature, current speed and direction, salinity, pressure, pH and oxygen concentration. The surface float can be fitted with instruments for measuring atmospheric conditions such as air temperature, barometric pressure, wind speed and direction. All the collected measurements are recorded in a memory store within the buoy and can be transmitted periodically or on command by radio to shore stations.

Scales Of Air Motion

On the mesoscale and microscale, topographical features critically influence wind flow. Surface variations have an obvious effect on wind velocity and the direction of air flow. Monsoons, sea and land breezes, mountain-valley winds, coastal fogs, windward precipitation systems, and urban heat islands are all examples of the influence of regional and local topography on atmospheric conditions. Mesoscale phenomena occur over hundreds of kilometers microscale phenomena, over areas less than 10 kilometers. For an area, the total effect of these circulations establishes the hourly, daily, and seasonal variation in wind speed and direction. The frequency distribution of wind direction indicates the areas toward which pollutants are most frequently transported.

Wind Rose

Wind speed determines the travel time of a pollutant from its source to a receptor and accounts for the amount of pollutant diffusion in the windward direction. Therefore, the concentration of pollutant at any receptor is inversely proportional to the wind speed. Wind direction determines in what direction a pollutant travels and what receptor is affected at a given time. Wind direction is normally defined by a wind rose, a graphic display of the distribution of wind direction at a location during a defined period. The characteristic patterns can be presented in either tabular or graphic forms. Wind speed is usually measured by an anemometer, which consists of three or four hemispherical cups arranged around a vertical axis. The faster the rotation of the cups, the higher the speed of the wind. A wind vane indicates wind direction. Although wind is three-dimensional in its movement, generally only the horizontal component is denoted because the vertical component is much smaller. A...

Stack Design

Consider the average height at stack elevation, average temperature, average mixing conditions (stability), and average lapse rate. The stack height design must also consider the average height and frequencies of inversions. For emission sources such as generating stations, the ideal stack height should exceed the most frequent inversion height. Also, planners should consider not only the averages of temperature, wind speed, and stability, but also the frequency with which worst-case combinations of these parameters occur.

Stability Classes

In the late 1960s, Pasquill developed a method for classifying atmospheric conditions which was later modified by Gifford (1975), resulting in six stability classes, labeled A through F. The method was based on the amount of incoming solar radiation, cloud cover, and surface wind speed as shown in Table 5.8.1.

Climate

Climate The average pattern of weather at a place, including solar radiation, temperature, humidity, precipitation, wind velocity, and atmospheric pressure. Climate depends on the variation in atmospheric conditions at a location over a period of years. As well as the conditions that might be expected at different times of year, it also encompasses the extremes reached and the frequency of less common weather events. Thus the precise climate of a place Solar radiation drives the atmospheric circulation, which is modified by the cori-olis force (the effect of the Earth's rotation) and topography. Solar radiation varies with latitude at the equator the Sun is overhead, and day length varies little all year round. At the poles the Sun's rays strike the Earth at a considerable angle, so incoming solar radiation is less, and daylength varies from 24-hour daylight in midsummer to 24-hour night in midwinter. Because of the tilt of the Earth's axis, solar radiation at a given site varies...

Averaging Periods

Long-term models use meteorological conditions ranging from a month or season to one or more years. The cli-matological data used in these models are generated from hourly data into joint frequency-distribution tables of wind speed, wind direction, and Pasquill-Gifford stability categories. These data are referred to as stability array (STAR) data sets.

Figure 412

A fourth mechanism of gas movement has been described for Phragmites australis (Armstrong et al. 1992). This mechanism, called Venturi-induced convection, is based on gradients in wind velocity. The dead, hollow, broken shoots and stubbles of P. australis may remain attached to the rhizome for 2 to 3 years. They are closer to the ground than the taller live shoots. The tall shoots are exposed to higher wind velocities and therefore lower external air pressures. Gas concentrations within the tall shoots are lower than within the broken shoots. This creates a pressure gradient in which gases are driven from the area of higher concentration (the broken shoots) into the area of lower concentration (the taller shoots). In effect, air is pulled through the whole plant, including the underground portions, by the deficit in gas pressure in the wind-exposed taller shoots. The pull of air is balanced by air inputs into the broken shoots (Figure 4.14). Models of Venturi-induced convection...

Londons lichens

In the winters of the late nineteenth and twentieth centuries when stationary high pressure systems settled over Western Europe, wind speeds fell and temperature inversions formed. Pollutant concentrations increased and fog became widespread in Britain, with London severely affected by these conditions (Brimblecombe 1987 88 NSCA 2002). The famous smog which began on 5 December 1952 led to the abandonment of La Traviata at Sadler's Wells theatre and death of cattle at Smithfield market, and within 12 hours large numbers of people showed respiratory illnesses. This led to the Clean Air Act of 1956 and Smoke Control Areas. Partly through legislation, social, economic and technological changes, concentrations of sulphur dioxide have fallen from an annual high mean of 350mgm 3 in the 1970s to an annual average across London in 2001 of 3 mgm 3 with no exceedances of the EU objectives for health or vegetation expected (Bell et al. 2004). During peak concentrations, the city of London was so...

Dry weather flow

Dune A ridge or hill of sand typically between 1 and 50 m high deposited there by the wind. Sand dunes usually migrate downwind with time, as sand is picked up by the wind on the windward slope, then dropped as the wind speed decreases when it reaches the downwind side of the dune. Dunes are formed in sandy deserts and along coastlines. Coastal dune systems form important barriers against the sea, protecting land and settlements in the hinterland.

Extinction

Bramwell and Whitfield (1974) speculated that the extinction of Pteranodon could have been caused by climate change, and particularly in average wind speed towards the end of the Cretaceous. This would also have applied to Quetzalcoatlus, Titanopteryx, and Azhdarcho. An increase of only 5ms-1 would have been enough to make conditions impossible for the giant pterosaurs. Such a change could have been caused by global cooling, accompanied by the development of clear temperature differences between the equator and the poles. As Wellnhofer (1991, incorporated in Norman and Wellnhofer 2000) argued, longer periods of the year with higher wind speeds, during which the large pterosaurs were unable to fly, would have reduced their numbers to such an extent that they sank below the critical level at which survival was possible.

Tracking migrants

Leica Vector), the distance to a bird can be measured, and furnishing the instrument with azimuth and elevation scales provide polar coordinates to the bird, which can easily be converted to space coordinates (x, y, z) (Hedenstrom and Alerstam 1996). Multiple registrations of positions allow reconstruction of flight tracks and analysing the data in relation to wind speed and direction at each altitude, the flight speed and direction in relation to the air are obtained (Figure 7.2). The wind profile can be obtained by tracking ascending helium-filled weather balloons using the range finder. If the data are fed directly to a computer the instrument should be referred to as an ornithodolite (Pennycuick 1982).

Fire Weather

Weather refers to the conditions at the time of a fire and largely affects the behavior of the fire. The primary weather variable that most affects fires is wind. At low wind speed, fuel structure plays a critical role in fire spread. Live foliage dissipates heat by losing water and often will not combust until it has been heated sufficiently to drive off water. In the absence of wind this typically requires the presence of dead fuels, which combust more readily and will heat living fuels sufficiently to combust. Fire spread commonly depends upon a sufficient mixture of live and dead fuels in order to sustain the fire. However, under windy conditions this equation changes and wind is capable of carrying heat to living foliage and rapidly spreading fire through mostly living foliage. Wind increases combustion by mixing of oxygen and altering the flame angle so that there is increased heating of fuels ahead of the flaming front. In general, as wind speed increases the role of fuels...

Figure 511

Water pollination shares a number of characteristics with wind pollination. Both anemophily and hydrophily are random abiotic strategies that lack the specificity of biotic pollination. Both have high pollen production and much of the pollen does not contact a stigma. Both anemophilous and hydrophilous species have reduced perianths and high pollen ovule ratios. The pollen exine is reduced and the receptive surface, or stigma, is often enlarged. Anemophily and hydrophily differ in pollen dispersal distances. The pollen dispersal distance of anemophiles is limited by wind speed and the pollen grain's ability to remain airborne. Hydrophiles' pollen dispersal is limited to the water body they inhabit. Pollen that is dispersed to deep or disturbed areas where plants do not live is lost (Les 1988).

Hydropower

Hydrogen economy An idealized economy in which the only fuel is hydrogen, which is burned or oxidized in fuel cells to give electricity directly. The hydrogen could be produced by electrolysis of water, the electricity for this being generated by wind power, water power, or similar renewable sources. Hydrogen fuel would cause no pollution and minimize the emission of greenhouse gases.

Energy inputs

Energy consumption produces significant pollution and involves massive amounts of water consumption. Political tensions over access to traditional energy supplies such as oil already exist and are likely to increase as such supplies dwindle. Unfortunately, the Australian Commonwealth Government places low priority on developing renewable energy sources. Nevertheless, some efforts are being made to promote cogeneration in industry (ibid.). Methane gas from municipal waste is now fueling five power stations in the country, and wind farms have great potential for low-cost power supply (ABS 1994a). Solar energy is especially suitable for Australia's sunny climate. Australia has some of the world's most advanced solar cell technology. Currently, some 10 000 Australian households generate their own electricity by solar energy and 5 per cent of Australian homes have solar water heaters (ibid.). Thus, although Australia's current energy inputs indicate

The butterfly effect

The extreme sensitivity to initial conditions exhibited by a simple non-linear model of fluid convection in the atmosphere.21 Thus, the story goes that if weather systems were chaotic then an almost negligible change in local wind speed in South America, such as that created by a wing flap of a butterfly, may ultimately mean the difference between having a hurricane in the northern hemisphere and not having one. Of course, this sensitivity has nothing to do with butterflies per se, and butterflies do not directly trigger anything it is simply that with chaos, a small difference will always cascade to produce uncorrelated futures (not necessarily bad ones either). The nursery rhyme 'For the want of a nail, the shoe was lost for the want of a shoe the horse was lost . . .' captures some of this contingency.

Mathematical Models

Recent approaches have used mathematical models to quantify heat flux between organisms and the environment using microclimate and climate data. These models play an increasingly vital role in improving our understanding of the biogeography and life history of many organisms, from plants to snails to elk. Climate data that must be collected for the models include air temperature, wind speed, solar radiation, cloud cover, and humidity in the vicinity of the organism in question.

Buoyant Convection

Wind shear is indeed the dominant driving mechanism for gas transfer in oceans and lakes with moderate or strong wind speeds. However, there exist many lakes that are topographically sheltered, giving them protection against strong wind (wind speeds below 3 m s ) and limiting their wave generation due to their smaller fetch length when compared to the ocean. Such sheltered lakes are normally characterized by a well-defined thermal structure and undergo diurnal temperature fluctuations due to daytime heating and nighttime cooling. During daytime, the main oxygen supply comes from photosynthetic production in the surface layer and often leads to oversaturation of oxygen concentration. The DO deficit is at its minimum regardless of the wind speed. In contrast, at night, when the water surface is being cooled, the oxygen solubility increases and the DO deficit is maximum. Thus, the most oxygen absorption from the atmosphere occurs during the night. The transfer mechanism at night is aided...

Fire in Grasslands

It is generally recognized that climate, fire, and grazing are three primary factors that are responsible for the origin, maintenance, and structure of the most extensive natural grasslands. These factors are not always independent (i.e., grazing reduces standing crop biomass which can be viewed simply as a fuel for fire, and biomass is also highly dependent upon the amount of precipitation). Historically, fires were a frequent occurrence in most large grasslands. Most grasslands are not harmed by fire, many benefit from fire, and some depend on fire for their existence. When grasses are dormant, the moisture content of the senesced foliage is low and this fine-textured fuel ignites easily and burns rapidly. The characteristic high wind speeds and lack of natural fire breaks in grasslands allow fire to cover large areas quickly. Because fire moves rapidly and much of the fuel is above the ground, temperatures peak rapidly and soil heating into the range that is biological damaging (...

Humaninduced Losses

Gas flares on oilrigs also attract birds on dark foggy nights up to several thousand per night having been killed at individual flares (Lid 1977). The usual numbers are much lower, however, estimated by Bourne (1979) at a few hundreds of birds per rig per year, a small proportion of the numbers passing. Modern wind turbines are known to kill migrants by night or by day, but information is only just beginning to emerge on the scale of these losses (which generally seem small, being estimated at a total of 33 000 birds per year in the USA, US FWS 2002). The greatest losses seem to occur at windfarms situated on narrow migration routes (with many raptors killed in southwest Spain), or near wetlands, which attract large numbers of gulls and other large birds. As these turbines continue to multiply in the years ahead, they could collectively begin to impose a heavier drain on migratory bird populations, perhaps achieving population levels effects, especially on large species with low...

Beaufort scale

The Beaufort scale was devised in 1805 by Sir Francis Beaufort, a captain (later admiral) in the British Royal Navy, to measure the observable effects of wind force at sea. It was later adapted to include effects on land, and wind speed equivalents were officially incorporated in 1926. Sailors and forecasters use the Beaufort scale as a standardised way to rate wind speed. Warnings of potentially dangerous conditions for people in small boats are usually issued at a rating of six on the scale. The Beaufort number is also referred to as a 'Force' number, for example 'Force 10 Gale'. Wind speed km h Wind speed mph

Dune Restoration

Impact of moving grains dislodges other grains, and by surface creep. Sand fences often are erected to trap sand and initiate dune building. Fences may be built using wooden pickets, boards, bamboo, reeds, fabric, or other materials such as branches that deflect and slow the wind. Guidelines for using fences include (1) use fences of 40-50 porosity as they are most efficient in trapping sand, (2) install fences parallel to the shoreline, and (3) a single row of fence is suitable at lower wind speed but double fences may be needed at higher wind speed. As the dune builds, continued sand trapping and dune growth is facilitated by installing additional fences atop the original fence as it becomes buried. Other sources of sand for dune building include dredged material pumped onto the beach and sand pushed up by bulldozers. Frequently, dunes are established too close to the beach which does not allow for the natural ebb and flow of sand between the dune, beach, and offshore sand bar....

Basic Concepts

Although most passive sensors operate in the visible and infrared portions of the EMS, there are also some passive microwave sensors in use that measure a number of parameters such as wind speed, atmospheric and sea surface temperature, soil moisture, rainfall, and atmospheric water vapor.

Plant Noise Survey

And other structures and sound barriers Considering the effect of meterological conditions, such as temperature, barometric pressure, relative humidity, and wind speed and direction on noise levels Mapping significant information such as residential, commercial, or industrial zones population densities special areas (hospitals) and areas of unique noise characteristics

Downwash

Stack-tip downwash occurs when the ambient wind speed is high enough relative to the exit velocity of the plume so that some or all of the plume is pulled into the wake directly downwind of the stack, as shown in Figure 5.8.11. This downwash has two effects on plume rise. First, the pollutants drawn into the stack wake leave the stack region at a lower height than that of the stack and with a lower upward velocity. Second, the downwash increases the plume cross section, which decreases the concentration. To avoid stack-tip downwash, environmental engineers should consider the ratio of emission velocity (vs) to wind speed velocity at the stack height (us) in the stack design. If vs 1.5 us, then the physical stack height should be adjusted by the following equation Wind Speed us -5

Woody material

Populus Tremula Boom

Pioneer birch, will similarly produce a burst of dead wood. Other factors that create dead wood, such as disease, high winds, ice, snow and fire, are less predictable in occurrence. Some of these events produce very large quantities of dead wood such as the New England hurricane of 1938 (Fig. 7.7), the severe windstorm on 12 October 1962 which blew down an estimated 26 million cubic metres of timber in north-western North America and the high winds of 16 October 1987 in southern England which blew over 15 million trees. In the last case, high wind speeds just short of hurricane force were aided by wet soils and a late autumn (trees still had a large 'sail area' of leaves to catch the wind). Despite the external forces governing dead wood production, in some forests there can be a tendency towards seasonality of tree fall due to predictable high winds or the wet season for example, in the tropical forests of Panama, tree fall is maximal in August through to September. Forest fires are...

Atmospheric Cycles

Anthropogenic sources of particles come from a variety of activities, such as the burning of fossil fuels, industrial processes, forest fires, smoking cigarettes, and the wearing away of automobile brake linings. The residence time of these particles, as well as of those from natural sources, varies according to such factors as wind speed, precipitation timing, and height in the atmosphere. Although the concern regarding airborne particles whether anthropogenic or natural is usually related to health, successive volcanic eruptions over a long period of time can produce a shield to solar radiation, reducing the temperature of the earth's surface and thus altering the climate. Concern about gases, however, revolves around their role in global warming, discussed elsewhere in this work.

Giant Rosette Plants

Acaulescent Plants

Implying non-linear behaviour of the system. The role of pubescence has been examined in more detail in Espeletia timotensis in relation to temperature, wind speed and high solar radiation in the p ramo habitat (Meinzer and Goldstein 1985 Schuepp 1993). Pubescence is more effective at high wind speeds. Increased boundary layer thickness due to a coat of hairs hinders exchange between leaf surface and ambient wind, and its primary effect in cool air would be an increase in surface temperature. This may be about 7 0C in the case studied, which is associated with a small increase in transpiration 17 ) due to the effects of leaf temperature on leaf air water vapour pressure difference. In numerical simulations it was shown however, that in contrast an increase of surface temperature of about 7 0 C would result in a doubling of the transpiration rate of non-pubescent leaves. Increased transpiration will have a feed-back on leaf temperature because of the effect of transpirational cooling,...

Ecological niches

Abies Alba Ecology

Temperature, for instance, limits the growth and reproduction of all organisms, but different organisms tolerate different ranges of temperature. This range is one dimension of an organism's ecological niche. Figure 2.2a shows how species of plants vary in this dimension of their niche how they vary in the range of temperatures at which they can survive. But there are many such dimensions of a species' niche - its tolerance of various other conditions (relative humidity, pH, wind speed, water flow and so on) and its need for various resources. Clearly the real niche of a species must be multidimensional.

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