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Sandy Deserts Negligible Evaporation Q* Q H + Q G. Not terribly high. Instability in afternoon. Very High Surface Temps (despite high albedo) Shallow layer of extremely high instability High winds. Strong heat flux convergence. Lower atmosphere very unstable.
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Sandy Deserts Negligible Evaporation Q* QH + QG Not terribly high Instability in afternoon
Very High Surface Temps (despite high albedo) Shallow layer of extremely high instability High winds Strong heat flux convergence Lower atmosphere very unstable Mirage due to density variation Huge diurnal air temperature range
Snow and Ice Snow and ice permit transmission of some solar radiation
Notice the difference between K and Q* Why ? High Albedo Magnitudes of longwave fluxes are small due to low temperature
Q* = QH + QE + QS + QM Q* = QH + QE + QS + QM - QR Surface Energy Balance for Snow and Ice Rainfall adds heat too Negligible QE (sublimation possible) Q* is negative Percolation and refreezing transfers heat Low heat conduction QM> QS COLD MELTING Condensation at surface is common (snow pack temperature can only rise to 0C) - QE can be important ! Why ? KV>LF QM = LF r QS Convergence or divergence of sensible heat fluxes QM Latent heat storage change due to melting and refreezing
Q* can be negative for nold snow Isothermal snow Surface Radiation Balance for Melting Snow Raise temp Turbulent transfer Latent heat storage change due to melting or freezing (negligible QE, QM and small QS if ‘cold’ snow)
Surface Radiation Balance for Melting Glacier Higher Continual receipt of QH and QE from atmosphere
Surface Radiation Balance for a Lake
Surface Radiation Balance for a Plant Canopy