Cloud cover

R is hydrogen, alkenyl, or alkyne. In remote tropospheric air where NO concentrations ate sometimes quite low, HO2 radicals can react with ozone (HO2 + O3 — HO + 2 O2) and result in net ozone destmction rather than formation. The ambient ozone concentration depends on cloud cover, time of day and year, and geographical location. 

Solar Evaporation. Recovery of salts by solar evaporation (1 3) is favored in hot dry climates. Solar evaporation is also used in temperate 2ones where evaporation exceeds rainfall and in areas where seasons of hot and dry weather occur. Other factors (4,5) affecting solar pond selection are wind, humidity, cloud cover, and land terrain. 

Introduction Gas dispersion (or vapor dispersion) is used to determine the consequences of a release of a toxic or flammable material. Typically, the calculations provide an estimate of the area affected and the average vapor concentrations expected. In order to make this determination, one must know the release rate of the gas (or the total quantity released) and the atmospheric conditions (wind speed, time of day, cloud cover). 

Wind speed, m/s Day radiation intensity Night cloud cover ... 

SUN ANGLE, SPECTRUM, INTENSITY-AS ALTERED BY CLOUD COVER AND ATMOSPHERE... 

Amount, tenths, one coded alphanumeric character Type, one coded alphanumeric character Height, hundreds of feet, three alphanumeric characters Amount of opaque cloud cover, tenths, one alphanumeric character"... 

Numerous analyses of data routinely collected in the United States have been performed by the U.S. National Climatic Center, results of these analyses are available at reasonable cost. The joint frequency of Pasquill stability class, wind direction class (primarily to 16 compass points), and wind speed class (in six classes) has been determined for various periods of record for over 200 observation stations in the United States from either hourly or 3-hourly data. A computer program called STAR (STability ARray) estimates the Pasquill class from the elevation of the sun (approximated from the hour and time of year), wind speed, cloud cover, and ceiling height. STAR output for seasons and the entire period of record can be obtained from the Center. Table 21-2 is similar in format to the standard output. This table gives the frequencies for D stability, based on a total of 100 for all stabilities. 

Clouds cover roughly two-thirds of our earth s surface and play an important role in influencing global climate by affecting the radiation budget. Cirrus clouds are one example of a cloud type whose optical properties are not accurately known. Cirrus clouds form in the upper troposphere and are composed almost exclusively of non-spherical ice crystal particles. The impact of cloud coverage on dispersion of pollution in the atmosphere is an area of great concern and intensive study. 

The vertical temperature gradient (the lapse rate) is usually not monitored by routine meteorological observation, and it, too, must be approximated from estimates of solar insolation, solar angle, and differential heating due to uneven cloud cover. For purposes of diffusion analyses, the lapse rate is usually approximated by a constant. 

Identify potential blast sources. Data provided by the literature (Sadee et al. 1976/ 1977 Gugan 1978 Robert and Pritchard 1982) identified potential blast sources. The plot plan in Figure 7.4 shows that the cloud covered a substantial area the oxidation and caprolactam plants (indicated in Figure 7.4 as Section 7 and 27) and also the more-or-less open area toward the hydrogen plant. 

Consequently, the potential explosive power of the rest of the cloud, covering a more-or-less open area, can be expressed as a fuel-air charge of... 

Climatic conditions such as cloud cover, wind speed,... 

Note that there are many other applications of detectors in an astronomical observatory, including detectors that are used for active optics, site monitoring (seeing, cloud cover), surveillance and safety monitoring. 

How well do GCMs simulate the spatial variability of climatic change Today s GCMs utilize data grids that partition the atmosphere into cells, each covering an area about the size of Colorado. A mean state of the atmosphere (temperature, humidity, cloud cover, for example) is computed for each cell. Consequently, any ou ut statistics (the prediction) has a lower spatial resolution (more genei ized, less detailed) than the real atmosphere is likely to manifest. 

On the average, the air over roughly half of the Earth s surface has an upward velocity and half has a downward velocity. This frontal activity (Section 7.5.3) and the interactions of marine air with the cold ocean surface result in about half of the Earth being covered by clouds and half being clear. As will be discussed in Chapter 17, this large fractional cloud cover is extremely important to the Earth s climate because it controls the planetary albedo (reflectivity). 

Fig. 7-6 Satellite observations of global reflectivity for January 1967-1970. White indicates areas of persistent cloudiness and relatively high precipitation, except for northern Africa where desert surface regions are highly reflective. (From US Air Force and US Department of Commerce (1971). "Global Atlas of Relative Cloud Cover," 1967-1970, Washington.)...

Another family of feedbacks involving biota arise via the process of evapotranspiration in which the rate of water vapor is transferred from the land surface to the atmosphere is mediated by plants. Several consequences have been proposed that include influences of biota on the greenhouse effect of water vapor as well as relative humidity and clouds. Lovelock (1988) suggested that tropical forests might be kept cool by increasing cloud cover in response to higher relative humidity released through enhanced evapotranspiration (via the clouds influences on albedo). Yet another connection arises because tree-covered land has different turbulence properties above it than bare soil, which also influences the cloud cover above. 

If we let Ti be the predictive temperature that we have now, 255 K, we can quickly see what happens if A changes from Ai, to a new value A2. The current albedo of Earth is ca. 0.3, and current fractional cloud cover is ca. 0.5. Ice and snow cover are minimal and most of the Earth is oceans with Aocean 0.1. Forests have forests 0.1 so most of the noncloudy Earth has. A % 0.1. This gives an expression for average cloud albedo ... 

Other data such as light intensity, percentage cloud cover, and soil moisture may also be recorded. The use of meteorological equipment, which can measure critical climatic information such as wind speed (current, maximum and average), humidity, air temperature, and dew-forming point, is preferable in the field. Historic weather data in the form of 10-year averages must be reported and are required for comparison of the trial specific data with the normal weather data. 

There are now doubts as to whether Venus is in fact extremely hostile to life. An audacious theory suggests that the cloud cover in the Venusian atmosphere could have provided a refuge for microbial life forms. As the hot planet lost its oceans, these primitive life forms could have adapted to the dry, acid atmosphere. However, the intensity of the UV radiation is very puzzling. The authors suggest that sulphur allotropes such as Sg act on the one hand as a UV umbrella and on the other as an energy-converting pigment (Schulze-Makuch et al 2004). 

Tompkins A (2002) A prognostic parameterization for the subgrid-scale variability of water vapor and clouds in large-scale models and its use to diagnose cloud cover. J Atmos Sci 59 1917-1942 Turusov V, Rakitsky V, Tomatis L (2002) Dichlorodiphenyltrichloroethane (DDT) ubiquity, persistence, and risks. Environmental Health Perspectives 101 125-128 UNEP (2001) Stockholm convention on persistent organic pollutants. http //chmpopsint/... 

Significant economies of computation are possible in systems that consist of a one-dimensional chain of identical reservoirs. Chapter 7 describes such a system in which there is just one dependent variable. An illustrative example is the climate system and the calculation of zonally averaged temperature as a function of latitude in an energy balance climate model. In such a model, the surface temperature depends on the balance among solar radiation absorbed, planetary radiation emitted to space, and the transport of energy between latitudes. I present routines that calculate the absorption and reflection of incident solar radiation and the emission of long-wave planetary radiation. I show how much of the computational work can be avoided in a system like this because each reservoir is coupled only to its adjacent reservoirs. I use the simulation to explore the sensitivity of seasonally varying temperatures to such aspects of the climate system as snow and ice cover, cloud cover, amount of carbon dioxide in the atmosphere, and land distribution. 

I use the seasonal simulation to explore the sensitivity of this energy balance climate model to such features of the climate system as permanent ice and snow at high latitudes, seasonal ice and snow, cloud cover, carbon dioxide amount, and the distribution of the continents. 

The albedo depends on surface properties—whether ocean, land, or ice—on the presence or absence of clouds, and on the zenith angle of the sun. The formulation I use is based on a detailed study by Thompson and Barron (1981). I have fitted to the results of their theory the analytical expressions contained in subroutine SWALBEDO. Figures 7-2 and 7-3 illustrate the calculated albedos for various conditions Figure 7—2 shows the variation of albedo for clear and cloudy skies over land and ocean as a function of the daily average solar zenith angle, results that were calculated using subroutine SWALBEDO. The temperature was taken to be warm enough to eliminate ice and snow. The most important parameter is cloud cover, because the difference between land and ocean is most marked... 

Fig. 7-3. The albedo as a function of temperature at a solar zenith angle of 75°, comparing clear and cloudy ocean and land. The temperature effect results from the large albedo of ice and snow. The sensitivity is small for cloud-covered land and...

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