Simulating midday all-slope surface temperatures along a climatic-latitudinal transect during cloudless summer conditions

Two physically-models of solar radiation transmission and of a steady-state slope energy budget have been coupled. Using climatic observational inputs, averaged in 10-deg latitude bands, a systematic examination was made of changing surface temperatures and differences between surface and air temperatures as functions of varying slope angles (0 to 90 deg) and orientations (south-, west-, and north-facing). Along a latitudinal transect of the east coast of the Americas (northern hemisphere), two contrasting landscapes were examined: barren and grassy. No simple relationship was discovered among the factors regarding shortwave and longwave radiative absorption, components of the energy budget, and surface temperature trends, yet the response of temperatures on a latitudinal basis was systematic and orderly. Characteristically, a great diversity existed among surface temperatures of different slopes and orientations at any particular latitude. Such diversity was accentuated in the higher latitudes. The findings were assumed general enough to encompass most of the possible contrasts encountered in a real-world north-south transect.Dr. O'Rourke is currently a Visiting Scholar at UCLA from Litton Systems, Inc., Data Systems Division.