Groisman, P. Y., E. L. Genikhovich, R. S. Bradley and B. M. Ilyin,
1997: Assessing surface-atmosphere interactions using former Soviet
Union standard meteorological network data. Part II: Cloud and Snow Cover
Effects. Journal of Climate, 10, 2184.
Groisman and Genikhovich developed a method to obtain direct estimates
of surface turbulent heat fluxes. The authors now apply it to the territory
of the former Soviet Union using the 3-/6-h data of 257 stations for the
past several decades to assess the sensitivity of sensible heat flux to
cloud and snow cover. This property was quantified for bare soil landscapes
over the entire country. During the day, the presence of clouds is associated
with low values of sensible heat flux from the surface to the atmosphere.
At night (and during the day in winter in high latitudes), the sign of
the effect is different, but because the direction of sensible heat flux
is also different (from the atmosphere to the surface), the presence of
clouds again reduces the turbulent heat exchange between the bare soil
and the atmosphere. The estimates of "overall cloud effect" on summer sensible
heat flux are compared with similar estimates from five general circulation
models to assess the abilities of these GCMs to reproduce the response
of this flux to cloud cover change. Snow on the ground is associated with
temperature depression When the effect of this depression is excluded,
the presence of snow on the ground is generally associated with less water
vapor in the lower troposphere under clear-sky conditions, while the evaporation
rate and sensible heat flux are higher than average.