Retrieval of vertical wind profiles during monsoon from satellite observedwinds over the Indian Ocean using complex EOF analysis

The aim of this paper is to study the feasibility of deriving vertical wind profiles from current satellite observations. With this aim, we carried ou t complex empirical orthogonal function (CEOF) analysis of a large number o f radiosonde observations of wind profiles over the Indian Ocean during the monsoon months. It has been found that the first two CEOFs explain 67% of the total variance in wind fields. While the first principal component is w ell correlated with the winds at 850 mb (r = 0.80), the second one is highl y correlated with winds at 200 mb (r = 0.89). This analysis formed the basi s of a retrieval algorithm which ensures the retrieval of vertical profiles of winds using satellite tracked cloud motion vector winds. Under the assu mption that accurate measurements of wind are available at the above mentio ned levels, the r.m.s. error of retrieval of each component of wind is esti mated to range between 2 ms(-1) and 6 ms(-1) at different levels, which is much less than the natural variance of winds at these levels. For a better visualization of retrieval, we have provided retrieved and true wind profil es side by side for four typical synoptic conditions during the monsoon sea son.