Radiation energy balance

Photochemical reactors UV Mass and radiation energy balances Braun et al. (1993)... 

Here, after some general remarks, we demonstrate the boundary and geometry effects in terms of a thin gas between two parallel plates. First, reconsider the radiation energy balance given by Eq. (10.22). The one-dimensional cartesian form of this balance, obtained with the help of Eq. (10.29), is... 

FIGURE 7 Terrestrial radiation energy balance. Overall solar energy flux is340 W/m. [From Manahan, S. E. (1984). Environmental Chemistry, 4th ed., Willard Grant Press, Boston. Reproduced by permission.]... 

Heat Transfer in Rotary Kilns. Heat transfer in rotary kilns occurs by conduction, convection, and radiation. In a highly simplified model, the treatment of radiation can be explained by applying a one-dimensional furnace approximation (19). The gas is assumed to be in plug flow the absorptivity, a, and emissivity, S, of the gas are assumed equal (a = e ) and the presence of water in the soHds is taken into account. Energy balances are performed on both the gas and soHd streams. Parallel or countercurrent kilns can be specified. 

The role of atmospheric CO2 in the greenhouse effect. Carbon dioxide is transparent to incoming sunlight, but it absorbs and re-emits a significant amount of the infrared radiation emitted by the Earth. This alters Earth s energy balance, raising its average temperature. 

The Planetary Energy Balance [3] of Incoming Solar (340 W/m2) minus Reflected (101 W/m2) minus Radiated (238 W/m2) = 1 W/m2. This excess energy warms the oceans and melts glaciers and ice sheets. The GHG component is 2 W/m2. The amount of heat required to melt enough ice to raise sea level 1 m is about 12 Watt-years (averaged over the planet)—energy that could be accumulated in 12 years if the planet is out of balance by 1 W/m2 per year. 

A more complete energy balance will be used that includes transport by conduction, convection, and radiation. The new energy balance equation over a small volume element takes the form... 

The preceding calculation of the thermal energy balance of a planet neglected any absorption of radiation by molecules within the atmosphere. Radiation trapping in the infrared by molecules such as CO2 and H20 provides an additional mechanism for raising the surface temperature - the greenhouse effect. The local temperature of a planet can then be enhanced over its black body temperature by the atmosphere. 

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. 

Program DAV10 is an 18 reservoir energy balance climate using the long wave radiation formulation of Kuhn et al. (1989) in LWFLUX Albedo formulation of Thompson and Barron in SWALSEDO with land and sea ice. 

I also applied the revised computational method to calculate zonally averaged temperature as a function of latitude. I introduced an energy balance climate model, which calculates surface temperature for absorbed solar energy, emitted planetary radiation, and the transport of heat between... 

If more solar energy is absorbed than infrared radiation emitted, the earth would warm and a new equilibrium would appear. But, if the earth had more clouds, it would reflect more solar radiation and absorb less. This would have a cooling effect on the planet, lowering the amount of infrared radiation that is escaping to space to balance the lower amount of absorbed solar energy. The earth s radiant energy balance today is 240 watts per square meter. 

This energy balance also assumes that the absorbtivity and emissivity ofthe target surface are nominally equal and for simplicity are considered as one. The view factor associated with the re-radiation from the target to the surroundings has been assumed to be one for simplicity. This assumption will lead to higher estimated temperatures, particularly as the fire encompasses more ofthe field of view of the target. 

ZONE TEMPERATURE ENERGY BALANCE SPECIES PRESENT EMirnro RADIATION MAIN EVENTS IN ZONE... 

An energy balance on the particle yields heat generated by reaction = heat lost by conduction + heat lost by radiation... 

FIGURE 1.9 Global average mean radiation and energy balance per unit of earth s surface [adapted with permission from IPCC (1996) with numbers from Kiehl and Trenberth (1997)]. 

FIGURE 14.50 Schematic of energy balance in warm pool in western Pacific Ocean used to deduce the net effect of clouds on solar radiation. All numbers are given in W m2 (adapted from Ramanathan et at., 1995). 

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