Summer dryness due to an increase of atmospheric CO2 concentration
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To investigate the hydrologic changes of climate in response to an increase of CO2-concentration in the atmosphere, the results from numerical experiments with three climate models are analyzed and compared with each other. All three models consist of an atmospheric general circulation model and a simple mixed layer ocean with a horizontally uniform heat capacity. The first model has a limited computational domain and simple geography with a flat land surface. The second model has a global computational domain with realistic geography. The third model is identical to the second model except that it has a higher computational resolution. In each numerical experiment, the CO2-induced change of climate is evaluated based upon a comparison between the two climates of a model with normal and four times the normal concentration of carbon dioxide in air.
It is noted that the zonal mean value of soil moisture in summer reduces significantly in two separate zones of middle and high latitudes in response to the increase of the CO2-concentration in air. This CO2-induced summer dryness results not only from the earlier ending of the snowmelt season, but also from the earlier occurrence of the spring to summer reduction in rainfall rate. The former effect is particularly important in high latitudes, whereas the latter effect becomes important in middle latitudes. Other statistically significant changes include large increases in both soil moisture and runoff rate in high latitudes of a model during most of the annual cycle with the exception of the summer season. The penetration of moisture-rich, warm air into high latitudes is responsible for these increases.
KeywordsSoil Moisture High Latitude Computational Domain General Circulation Model Summer Dryness
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- Bryan, K.: 1969, ‘Climate and the Ocean Circulation: III. The Ocean Model’,Monthly Weather Rev. 97, 806.Google Scholar
- Gordon, T. and Stern, B.: 1974, ‘The GARP Programme on Numerical Experimentation’, Report No. 7, 46.Google Scholar
- Hayashi, Y.: 1982, ‘Confidence Intervals of a Climatic Signal’, Submitted toJ. Atmos. Sci. Google Scholar
- Hering, W. S. and Borden, T.R. Jr.: 1965, ‘Mean Distribution of Ozone Density over North America’, 1963–1964. Environmental Research Papers, No. 162, U.S. Air Force Cambridge Research Lab., Hanscom Field, Mass., 19 pp.Google Scholar
- Hoskins, J. J. and Simmons, A. J.: 1975, ‘A Multi-Layer Spectral Model and the Semi-Implicit Method’,Quart. J. Roy. Meteor. Soc. 104, 91.Google Scholar
- Lvovitch, M. I. and Ovtchinnikov, S. P.: 1964, ‘Physical-Geographical Atlas of the World (in Russian)’, Academy of Sciences, U.S.S.R., and Department of Geodesy and Cartography, State Geodetic Commission, Moscow. (See p. 61).Google Scholar
- Manabe, S.: 1969a, ‘Climate and Ocean Circulation. I. The Atmospheric Circulation and the Hydrology of the Earth's Surface’.Monthly Weather Rev. 97, 739.Google Scholar
- Manabe, S. and Holloway, J. L. Jr.: 1975, ‘The Seasonal Variation of the Hydrologic Cycle as Simulated by a Global Model of the Atmosphere’,J. Geophys. Res. 80, 1617.Google Scholar
- Manabe, S., Hahn, D. G., and Holloway, J. L.: 1979, ‘Climate Simulation with GFDL Spectral Models of the Atmosphere’, GARP Publication Series No. 22, Vol. 1, 41–94. World Meteorological Organization, Geneva, Switzerland.Google Scholar
- Manabe, S. and Stouffer, R. J.: 1980, ‘Sensitivity of a Global Climate Model to an Increase of CO2-concentration in the Atmosphere’,J. Geophys. Res. 85, 5529.Google Scholar
- Manabe, S., Smagorinsky, J., and Strickler, R. F.: 1965, ‘Simulated Climatology of a General Circulation Model with a Hydrologic Cycle’,Monthly Weather Rev. 93, 769.Google Scholar
- Möller, F.: 1951, ‘Quarterly Charts of Rainfall for the Whole Earth’, (in German),Petermanns. Geograph. Mitt. 95, 1.Google Scholar
- Panofsky, H. A. and Brier, G. W.: 1965, ‘Some Applications of Statistics to Meteorology’, The Pennsylvania State University, State College, Pa.Google Scholar
- Posey, J. W. and Clapp, P. F.: 1964, ‘Global Distribution of Normal Surface Albedo’,Geofisica Internationale 4, 33.Google Scholar
- Rodgers, C. D. and Walshaw, C. D.: 1966, ‘The Computation of Infrared Cooling Rate in Planetary Atmospheres’,Quart. J. Roy. Met. Soc. 92, 67.Google Scholar
- Sasamori, T., London, J., and Hoyt, D. V.: 1972, ‘Radiation Budget of Southern Hemisphere’,Meteorological Monographs, Vol.13, No. 35, (Meteorology of the Southern Hemisphere, by C. W. Newton (ed.)), American Meteorological Society, Boston, Mass.Google Scholar
- Stone, H. M. and Manabe, S.: 1968, ‘Comparison Among Various Numerical Models Designed for Computing Infrared Cooling’,Monthly Weather Rev. 96, 735.Google Scholar