The influence of surface roughness of deserts on the July circulation
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The influence of low surface roughness of deserts on the July circulation is examined by employing numerical simulations with a GLAS GCM. Two identical sets of simulations were made with the model starting from the initial state of the atmosphere based on the NMC analysis of observations for June 15, at OOZ for the years 1979 and 1980. The first set, called the Control, had land surface roughness set to 45 cm, everywhere. The second set called the Experiment, had surface roughness set to 0.02 cm for deserts, but 45 cm everywhere else on land. All other prescribed boundary conditions were the same in both runs.
A comparative analysis of these simulations showed that the rainfall in the Sahara desert was reduced significantly in both Experiments as compared to the corresponding Controls; the ITCZ (inter-tropical convergence zone) moved southward, to about 14° N, which is close to its observed location at about 10° N. This was primarily caused by the relative moisture divergence from the smoother Sahara. In other deserts, which anyway had little rainfall in the July simulation of the Control run, there was virtually no change. The differences in regional heat and moisture budgets, particularly for the Sahara desert, are significant as compared to the sample standard deviation for a set of three July simulations (i.e., Control runs for three different initial conditions). In a third simulation, in which the surface roughness was changed over all land, similar results were obtained in the Sahara desert region.
The study reveals the influence of low surface-roughness of deserts on the July rainfall. For the Sahara desert, this influence is comparable to that of an increase in surface albedo. In nature, formation of deserts leads to reduction of surface roughness as the vegetation perishes and soil erosion ensues. It is inferred that the smoothness of land then causes reduction in rainfall and further promotes desertification.
- Anthes, R. A. (1984) Enhancement of Convective Precipitation by Mesoscale Variations in Vegetative Covering in Semiarid Regions. J. Climate and Appl. Meterorol. 23: pp. 541-554
- Arakawa A.: 1972, ‘Design of the UCLA General Circulation Model, Numerical Simulation of Weather and Climate’, Tech. Rep. No. 7, Dep. Meteorol., UCLA.
- Arakawa, A., Lamb, V. R. (1977) Computational Design of the Basic Dynamical Processes of the UCLA General Circulation Model. Academic Press, New York
- Bhumralkar, C. M. (1973) An Observational and Theoretical Study of Atmospheric Flow Over a Heated Island: Part I. Monthly Weather Rev. 10: pp. 719-730
- Carson, D. J. and Sangster A. B.: (1981), ‘The Influence of Land-surface Albedo and Soil moisture on General Circulation Model Simulations’, in I. D. Rutherford (ed.), GARP/CRP: Research Activities in Atmospheric and Oceanic Modelling, Numerical Experimentation Programm, Report No. 2, pp. 5.14–5.21.
- Charney, J. G. (1975) Dynamics of Deserts and Drought in the Sahel. Quart. J. Roy. Meteorol. Soc. 101: pp. 193-202
- Charney, J. G., Quirk, W. J., Chow, S. H., Kornfield, J. (1977) A Comparative Study of the Effects of Albedo Change on Drought in Semi-arid Regions. J. Atmos. Sci. 34: pp. 1366-1385
- Chervin, R. M. (1979) “‘Response of the NCAR General Circulation Model to Changed Land Surface Albedo”’, Report of the JOC Study Conference on Climate Models: Performance, Intercomparison and Sensitivity Studies. GARP Publ. Series, No. 22 Vol. 1: pp. 563-81
- Davies, J. A., Allen, C. D. (1973) Equilibrium, Potential and Actual Evaporation from Cropped Surfaces in Southern Ontario. J. Appl. Meteorol. 12: pp. 649-657
- Deardorff, J. W. (1972) Parameterization of the Planetary Boundary Layer for use in General Circulation Models. Monthly Weather Rev. 100: pp. 93-106
- Fennessy, M. J., Sud, Y. C. (1983) A Study of the Influence of Soil Moisture on Future Precipitation. Laboratory for Atmospheric Sciences, Goddard Space Flight Center, Greenbelt, MD 20771
- Halem, M., Shukla, J., Mintz, Y., Wu, M. L., Godbole, R., Herman, G., Sud, Y. (1979) Comparisons of Observed Seasonal Climate Features with a Winter and Summer Numerical Simulation produced with the GLAS General Circulation Model. WMO, Geneva, Switzerland
- Henderson-Sellers, A., Wilson, M. F. (1983) Surface albedo Data for Climate Modelling. Rev. Geo. and Space Phys. 21: pp. 1743-1778
- Hoffert, M. I., Sud, Y. C. (1976) Similarity Theory of the Buoyantly-interactive Planetary Boundary Layer with Entrainment. J. Atmos. Sci. 33: pp. 2136-2151
- Idso, S. B., Deardorff, J. W. (1978) Comments on the Effect of Variable Surface Albedo on the Atmospheric Circulation in Desert Regions. J. Appli. Meteorol. 17: pp. 560
- Jaeger, L. (1976) Monatskarten des Niederschlags fur die ganze Erde. Im Selbstverlag des Deutschen Wetterdienstes, Offenbach, W. Germany
- Lettau, H. (1969) Note on Aerodynamic-roughness Parameter Estimation on the Basis of Roughness Element Description. J. Appl. Meteorol. 8: pp. 828-32
- Lorenz, E. N. (1960) Energy and Numerical Weather Prediction. Tellus 12: pp. 364-373
- Malkus, J. S. (1963) Tropical Rain Induced by a Small Natural Heat Source. J. Appl. Meteorol. 2: pp. 547
- Mintz, Y. The Sensitivity of Numerically Simulate Climates to Landsurface Boundary Conditions. In: Houghton, J. T. eds. (1984) The Global Climate. Cambridge University Press, London, pp. 70-105
- Namias, J.: 1959, ‘Persistence of Mid-tropospheric Circulation between adjacent Months and Seasons, in the Atmosphere and the Sea in Motion’, (Rossby memorial Volume) B. Bolin (ed.), pp. 240–248.
- Nappo, C. J. (1975) Parameterization of Surface Moisture and Evaporation Rate in a Planetary Boundary Layer Model. J. Appl. Meteorol. 14: pp. 289-296
- Posey, J. W. (1964) Global Distribution of Normal Surface Albedo. Geofisica Internacional 4: pp. 33
- Randall, D. A.: 1982, ‘Montly and Seasonal Simulations with the GLAS Climate Model’, Proceedings of the Workshop on Intercomparison of Large-Scale Models used for Extended Range Forecasts of the European Center for Medium Range Weather Forecasts, Reading, England, pp. 107–166.
- Rind, D. (1982) The Influence of Ground Moisture Conditions in North America on Summer Climate as Modelled in the GISS GCM. Monthly Weather Rev. 110: pp. 1487-1494
- Ripley, E. A. (1976) Drought in Sahara: Insufficient Bigeophysical Feedback?. Science 191: pp. 100
- Schickedanz, P. T. (1976) The Effect of Irrigation on Precipitation in the Great Plains. Illinois State Water Survey, University of Illinois, Urbana, Illinois
- Shukla, J., Straus, D., Randall, D. A., Sud, Y., and Marx, L.: 1981, ‘Winter and Summer Simulations with the GLAS Climate Model’, NASA Technical Memorandum 83866, 282 pp.
- Shukla, J., Mintz, Y. (1982) The Influence of Land Surface Evapotranspiration on Earth's Climate. Science 215: pp. 1498-1501
- Shukla, J., Wallace, J. M. (1983) Numerical Simulation of the Atmospheric Response to Equatorial Pacific Sea-surface Temperature Anomalies. J. Atmos. Sci. 40: pp. 1614-1630
- Slade, D. H. (1968) TID-24190 Meteorology and Atomic Energy. Office of Information services AEC, Oakridge, Tenn.
- Soer, G. J. R. (1980) Estimates of Regional Evapotranspiration and Soil Moisture Conditions Using Remotely sensed Crop Surface Temperature. Remote Sensing of Environment 116: pp. 27-44
- Stidd, C. K.: 1968, ‘Local Moisture and Precipitation’, Reprint No. 45A, Center for Water Resources Research, Desert Research Institute, University of Nevada.
- Sud, Y. C., Fennessy, M. J. (1982) A Study of the Influence of Surface Albedo on July Circulation in Semi-Arid Regions using the GLAS GCM. J. Climatol. 2: pp. 105-125
- Sud, Y. C., Fennessy, M. J. (1982) An Observational Data-based Evapotranspiration Function for General Circulation Models. Atmosphere-Ocean 20: pp. 301-316
- Sud, Y. C., Fennessy, M. J. (1984) A Numerical Study of the Influence of Evaporation in Semi-arid Regions on the July Circulation. J. Climatol. 4: pp. 383-98
- Sud, Y. C., Smith, W. E. (1984) Ensemble Formulation of Surface Fluxes and Improvement in Evapotranspiration and Cloud Parameterization in a GCM. Boundary-Layer Meteorol. 29: pp. 185-210
- Sutclife, R. C. (1956) Water Balance and the General Circulation of the Atmosphere. Quart. J. Roy. Meteorol. Soc. 103: pp. 29-46
- Walker, J., Rowntree, P. R. (1979) Effect of Soil-moisture and Rainfall in a Tropical Model. Quart. J. Roy. Meteorol. Soc. 103: pp. 29-46
- Walsh, J. E., Richman, M. B., Allen, D. W. (1982) Spatial Coherence of Monthly Precipitation in the United States. Monthly Weather Rev. 110: pp. 272-286
- Yeh, T. C., Wetherald, R. T., Manabe, S. (1984) The Effect of Soil Moisture on the Short-Term Climate and Hydrology Change — A Numerical Experiment. Monthly Weather Rev. 112: pp. 475-490
- The influence of surface roughness of deserts on the July circulation
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