Radiation, solar, cloud cover

Atmospheric conditions (temperature, pressure, wind speed, humidity, solar radiation and cloud cover) ... 

Surface Wind Speed at 10 m (m s ) Solar Radiation" Nighttime Cloud Cover Fraction ... 

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. 

The parameter classification after Klug is determined by six stability classes (with the German abbreviation AK for Ausbreitungsklasse), reaching from extreme stable (AK I) to extreme labile TAK V). In the Turner stability scheme AK 5 denotes extreme stable, AK 2 extreme labile, see table 2. An estimate of the stability can be made from synoptical observations of solar radiation, cloud cover and wind velocity /14/. With the parameters after Klug equation (3.4) becomes... 

Surface wind speed at 10 m (m sec" ) Solar radiation Night-time Cloud cover fraction ... 

The ambient atmosphere at the mobile instrument site in Hoboken, N.J. contained up to 4 pphm of H2O2 on a day with high solar radiation and apparent photochemical smog formation. Hydrogen peroxide was observed between 12 00 A.M. and 2 00 P.M. On days when solar radiation was low because of cloud cover, no H2O2 was observed. 

In addition, cloud cover is known to partially block solar radiation. Thus, mountain forests subject to cloud immersion may suffer from insufficient photosynthetically active radiation (PAR) during the growing season at certain elevations where condensation of water vapor to cloud aggregation stage is greatest. For example, forest around Whiteface Mt, New York State, growing at 1050 m asl may be immersed in clouds for 10% of the year, but 35% of the time at 1350 m asl (Miller et al., 1993). Whether the trend is maintained at higher altitude until the treeline is reached, or is also applicable to other latitudes is unlikely as mountain climates vary widely. 

This irradience or insolation (a term that is a shortened version of incoming solar radiation ) figure is used to size photovoltaic systems. Of course the amount of incoming solar radiation depends on a number of factors such as cloud cover, moisture, and particulate concentration in the atmosphere. Each geographic region has its particular climate characteristics to be considered when calculating the number of panels required for the photovoltaic fuel cell system. 

Clouds The discussion of solar UV variability in proceeding paragraphs has assumed cloud free conditions. However, in most parts of the world this is the exception, usually there are either broken cloud fields or a more or less homogeneous cloud cover. In general, clouds reduce solar radiation, but the amount of reduction is extremely variable due to the variable nature of clouds. For the estimation of the effect of clouds on solar irradiance, the most important par-... 

Diamond et al. [127] have estimated UVR doses in wetlands using this approach. Typical UVR doses were estimated by first generating maximal solar radiation doses for each day using a radiative transfer model, SBDART [113]. The model produced values for the full spectrum of solar radiation, from 280 to 700 nm, for cloudless conditions. These maximal values were then modified based on cloud cover effect estimates from 30 yr of historical solar radiation data (National Renewable Energy Laboratory, Department of Energy http //rredc.nrel.gov/solar/). The values derived in this procedure were estimated daily terrestrial, spectral (2 nm increments from 280 to 700 nm) solar radiation doses. Water column doses were then derived from absorption coefficients and spectral attenuation data described by Peterson et al. [128]. Although the focus of this effort was to characterize risk of UV-B radiation effects in amphibians, the procedure is directly applicable to phototoxicity, and the resulting UV-A radiation and spectral doses could be directly incorporated into calculation of possible effects. 

In the outdoor chamber, the solar spectrum varies with cloud cover and solar zenith angle and the distribution of the radiation is difficult to model. 

The effect of an increase in the extent of cloud cover on the atmospheric heat balance was numerically studied by Schneider (1972). He took into account the variation of the planetary albedo as well as the decrease of the infrared radiation loss. Schneider found that a more extensive cloud cover produces a temperature drop at low and midlatitudes if the height, thickness and albedo of the clouds remain unchanged. In contrast, over polar regions, where the intensity of incoming solar radiation is low and the surface albedo is great, an increase in the extent of cloud cover leads to a temperature rise in the surface air. 

Incoming Solar Radiation Cloud Cover Fraction ... 

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