caa a22 4500 469084464 CHVBK 20180323133001.0 cr unu---uuuuu 170328e19921201xx s 000 0 eng 10.1007/BF02677076 doi (NATIONALLICENCE)springer-10.1007/BF02677076 Simulation of desert-scrub growth: A forcing to warmer and more pluvial climate [Elektronische Daten] [Joseph Otterman, Ming-Dah Chou] Desert-fringe vegetation growing over bright, sandy soils reduces the surface albedo from above 0.4 to well below 0.3. Called desert-scrub, these shrubs form a predominantly vertical clumps protruding from the soil-level, thereby significantly increasing the coefficient of turbulent heat transfer from the surface. The impact on global and desert-belt climate of changes in these two surface characteristics was simulated by a multi-layer energy balance model. Evaluated only as a forcing to a further climatic change (that is, without accounting for any possible feedbacks) the results are: if vegetation (such as apparently existed under the warmer climate of 6,000 BP) grows over large areas in the arid, currently bare-soil regions, the annual Northern Hemisphere surface temperature increases by 0.7°C (by 0.6°C in July), the surface temperature over land in the 20-30°N zone increases by 0.9°C in both the annual and the July means, and the land-ocean annual temperature contrast in this zone increases by 0.25°C (0.2°C in July). These results represent the combined influence of the reduction in the surface albedo and of the increase in the coefficient of turbulent heat transfer. In the desert-belt zones, the increase in the transfer coefficient sharply reduces the land temperature and the land-ocean temperature contrast from the values produced by the albedo change alone. This reduction must be attributed to the increased land-to-ocean circulation (which our model does not evaluate explicitly). Considering that a stronger circulation (resulting from land-ocean temperature contrast) generally forces a higher rainfall, the vegetation which emerged in the arid regions during the post-glacial optimum should be considered a significant positive feedback towards a still warmer, and also a more pluvial, climate. Our study may have implications for the 21st century, if the global warming expected from the enhanced greenhouse effects is accompanied by increased precipitation over the continents. Advances in Atmospheric Sciences, 1992 Otterman Joseph Ramat Aviv, Tel Aviv University, Israel aut Chou Ming-Dah NASA / Goddard Space Flight Center, Laboratory for Atmospheres, Code 913, 20771, Greenbelt, MD, U. S. A. aut Advances in Atmospheric Sciences Science Press 9/4(1992-12-01), 441-450 0256-1530 9:4<441 1992 9 376 https://doi.org/10.1007/BF02677076 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF02677076 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Otterman Joseph Ramat Aviv, Tel Aviv University, Israel aut NATIONALLICENCE 700 1- Chou Ming-Dah NASA / Goddard Space Flight Center, Laboratory for Atmospheres, Code 913, 20771, Greenbelt, MD, U. S. A aut NATIONALLICENCE 773 0- Advances in Atmospheric Sciences Science Press 9/4(1992-12-01), 441-450 0256-1530 9:4<441 1992 9 376 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer