Temperature affects albedo

In addition to biogeochemical cycles (discussed in Section 6.5), the hydrosphere is a major component of many physical cycles, with climate among the most prominent. Water affects the solar radiation budget through albedo (primarily clouds and ice/snow), the terrestrial radiation budget as a strong absorber of terrestrial emissions, and global temperature distribution as the primary transporter of heat in the ocean and atmosphere. 

Dry air rising in the atmosphere has to expand as the pressure in the atmosphere decreases. This pV work decreases the temperature in a regular way, known as the adiabatic lapse rate, Td, which for the Earth is of order 9.8 Kkm-1. As the temperature decreases, condensable vapours begin to form and the work required for the expansion is used up in the latent heat of condensation of the vapour. In this case, the lapse rate for a condensable vapour, the saturated adiabatic lapse rate, is different. At a specific altitude the environmental lapse rate for a given parcel of air with a given humidity reaches a temperature that is the same as the saturated adiabatic lapse rate, when water condenses and clouds form Clouds in turn affect the albedo and the effective temperature of the planet. Convection of hot, wet (containing condensable vapour) air produces weather and precipitation. This initiates the water cycle in the atmosphere. Similar calculations may be performed for all gases, and cloud layers may be predicted in all atmospheres. 

Next to the temperature gradient inside the snowpack, an important driving force for snow metamorphism is wind, that lifts, transports and redeposits snow crystals, changing snowpack mass and density " and deposits aerosols inside the snowpack.Wind and temperature are climatic variables that determine metamorphism and snowpack physical properties such as albedo and heat conductivity. These properties affect the energy balance of the snow-atmosphere and of the soil-snow interfaces, which in turn affect climate. 

The grain growth almost always observed during metamorphism results in a decrease in snow SSA. The rate of decrease greatly affects snow albedo and e-folding depth, considered over large spatial and temporal scales. The initial decrease is very fast, with a factor of 2 decrease in I to 2 days. Experimental and field studies have quantified the rate of decrease of snow SSA as a function of temperature and temperature gradient." In all cases, the best empirical fit of SSA decay plots was of the form ... 

The ice sheets of the Earth are also affecting the global climate because they increase the albedo of the Earth (i.e., the fraction of sunlight that is reflected into space) and thereby lower the average global temperature. The present albedo of the Earth is 39%... 

The constraint between polar cell temperature and albedo can be enforced by letting 0.2 be a fimction of T2. This is feedback, in the sense that the output, T2, of the linear system affects one of the parameters, 2- Th simplest model is... 

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