Large-Scale Changes of Soil Wetness Induced by an Increase in Atmospheric Carbon Dioxide

作者：S. Manabe, R. T. Wetherald · 发表于：Journal of the Atmospheric Sciences · 年份：1987 · DOI：10.1175/1520-0469(1987)044<1211:lscosw>2.0.co;2 · 被引用次数：422 · 研究领域：Atmospheric and Environmental Gas Dynamics、Climate variability and models、Meteorological Phenomena and Simulations

The change in soil wetness in response to an increase of atmospheric concentration of carbon dioxide is investigated by two versions of a climate model which consists of a general circulation model of the atmosphere and a static mixed layer ocean. In the first version of the model, the distribution of cloud cover is specified whereas it is computed in the second version incorporating the interaction among cloud cover, radiative transfer and the atmospheric circulation. The CO2-induced changes of climate and hydrology are evaluated based upon a comparison between two quasi-equilibrium climates of a model with a normal and an above normal concentration of atmospheric carbon dioxide. It is shown that, in response to a doubling (or quadrupling) of atmospheric carbon dioxide, soil moisture is reduced in summer over extensive midcontinental regions of both North America and Eurasia in middle and high latitudes. Based upon the budget analysis of heat and water, the physical mechanisms responsible for the CO2-induced changes of soil moisture are determined for the following four regions: northern Canada, northern Siberia, the Great Plains of North America and southern Europe. It is found that, over northern Canada and northern Siberia, the CO2-induced reduction of soil moisture in summer results from the earlier occurrence of the snowmelt season followed by a period of intense evaporation. Over the Great Plains of North America, the earlier termination of the snowmelt season also con...