Abstract
The estimation of evaporation from the sea surface is not yet achieved adequately by remote sensing techniques, in general. However, for approximate averaged estimates over moderate space and time scales over a specific tropical region, e.g., weekly values over the Indian Ocean as needed in monsoon moisture diagnosis, it may be possible to extrapolate satellite wind and humidity data to the ocean surface and then use bulk aerodynamic parameterization for estimating evaporation. In the present investigation, GOES low-level cloud winds and TIROS-N moisture profiles over the Indian Ocean are extrapolated to the ocean surface. The planetary boundary layer (PBL) wind shear is obtained over different sub-regions and periods during the monsoon season, by reference to objectively analysed fields. These shear values are applied to GOES satellite winds to obtain sea-surface winds. The humidity extrapolation was based on (i) an exponential fit for water vapour density and (ii) a vertical distribution of relative humidity approximately proportional to atmospheric pressure. The exchange coefficient is varied slightly depending on wind speed and boundary-layer stability inferred approximately from TIROS-N sea surface temperatures and temperature profiles. The evaporation estimate as based on these satellite parameters is assessed by comparison with ships' surface observations. Sensible heat exchange is also estimated and assessed. Some inferences based on these estimates are also presented, in relation to monsoon onset and activity.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Ali, M. M., Simon, B., and Desai, P. S.: 1985a, ‘Zonal Wind Stress and Mixed-Layer Slope: A Case Study Using Satellite and Ships' Data in MONEX-79’, paper presented at CATAC Symp., Andhra Univ., March, 1985.
Ali, M. M., Simon, B., and Desai, P. S.: 1985b, ‘Inference of Vertical Motion in the Equatorial Indian Ocean Using Satellite Data in MONEX-79’, paper presented at SCOR Symposium on Vertical Motion in the Equatorial Ocean, Paris, May 6–10, 1985.
Ali, M. M., Desai, P. S., and Hariharan, T. A.: 1985c, ‘Heat Budget and Heat Transport over the Equatorial Indian Ocean’, paper submitted to IAMAP/IAPSO Joint Assembly, Hawaii, August 1985; submitted to Oceanologica Acta.
Bunker, A.: 1976, ‘Computations of Surface Energy Flux and Annual Air-Sea Interaction Cycles of the North Atlantic Ocean’, Mon. Wea. Rev. 104, 1122–1140.
Fleagle, R. F. and Businger, J. A.: 1981, Introduction to Atmospheric Sciences, Academic Press, New York, Fig. 6.6, p. 289.
Large, W. G. and Pond, S.: 1981, ‘Open Ocean Momentum Flux Measurement in Moderate to Strong Winds’, J. Phys. Oceano. 11, 324–336.
Large, W. G. and Pond, S.: 1982, ‘Sensible and Latent Heat Flux Measurement over the Ocean’, J. Phys. Oceano. 12, 464–482.
Liu, W. T.: 1984, ‘Estimation of Latent Heat Flux with Seasat-SMMR: A Case Study in North Atlantic’, in C. Gautier and M. Fieux (eds.), Large-Scale Oceanographic Experiments and Satellites, D. Reidel Publ. Co., Dordrecht, Holland, 207–221.
Manabe, S. and Wetherald, R. T.: 1967, ‘Thermal Equilibrium of the Atmosphere with a Given Distribution of Relative Humidity’, J. Atmos. Sci. 24(3), 241–259.
Narayanan, M. S. and Rao, B. M.: 1981, ‘Detection of Monsoon Inversion by TIROS-N Satellite’, Nature 294, 546–548.
O'Brien, J. J. and Hurlburt, H. E.: 1974, ‘Equatorial Jet in the Indian Ocean: Theory’, Science 184, 1075–77.
Pathak, P. N.: 1982, ‘Comparison of Sea Surface Temperature from TIROS-N and Ships in the Indian Ocean During MONEX (May–July, 1979)’, Remote Sens. Env. 12, 363–369.
Paulson, C. A., Leavitt, E., and Fleagle, R. G.: 1972, ‘Air-Sea Transfer of Momentum, Heat, and Water Determined from Profile Measurement During BOMEX’, J. Phys. Oceano. 2, 487–497.
Sadler, J. C. and Kilonsky, B. J.: 1985, ‘Deriving Surface Winds from Satellite Observations of Low-Level Cloud Motions’, Jour. Climat. Appl. Meteorol. 24(8), 758–769.
Saunders, P.: 1976, ‘On the Uncertainty of Wind Stress Calculations’, J. Mar. Res. 34(2), 155–160.
Shetye, S. R.: 1985, Private communication.
Simon, B., Desai, P. S., Rao, B. M., and Hariharan, T. A.: 1985, ‘Regional Evaporation Estimate from Operational Meteorological Satellites’, Abstract for IAMAP/IAPSO Joint Assembly, Hawaii, August 1985.
Taylor, P. K.: 1984, ‘The Determination of Surface Fluxes of Heat and Water by Satellite Microwave Radiometry and in situ Measurements’, in C. Gautier and M. Fieux (eds.), Large-Scale Oceanographic Experiments and Satellites, D. Reidel Publ. Co., Dordrecht, Holland, pp. 223–246.
Wylie, D. P. and Hinton, B. B.: 1982, ‘A Comparison of Cloud Motion and Ship Wind Observations over the Indian Ocean for the Year of FGGE’, Boundary-Layer Meteorol. 23, 197–208.
Wyrtki, K.: 1973, ‘An Equatorial Jet in the Indian Ocean’, Science 181, 262–264.
Young, J. A., Virji, H., Wylie, D. P., and Lo, C.: 1980, Summer Monsoon Windset from Geostationary Satellite Data, Univ. of Wisconsin Press, Madison, 5.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Simon, B., Desai, P.S. Equatorial Indian Ocean evaporation estimates from operational meteorological satellites and some inferences in the context of monsoon onset and activity. Boundary-Layer Meteorol 37, 37–52 (1986). https://doi.org/10.1007/BF00122755
Revised:
Issue Date:
DOI: https://doi.org/10.1007/BF00122755