Debasis Sengupta

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The space-time evolution of the ocean and atmosphere associated with 1998-2000 monsoon intraseasonal oscillations (ISO) in the Indian Ocean and west Pacific is studied using validated sea surface temperature (SST) and surface wind speed from the Tropical Rainfall Measuring Mission (TRMM) Microwave Imager, and satellite outgoing longwave radiation. Monsoon(More)
In competing risks data, missing failure types (causes) is a very common phenomenon. In this work, we consider a general missing pattern in which, if a failure type is not observed, one observes a set of possible types containing the true type, along with the failure time. We first consider maximum likelihood estimation with missing-at-random assumption via(More)
We address the problem of detecting a weak signal known except for amplitude in incompletely characterized colored nonGaussian noise. The problem is formulated as a test of composite hypotheses using parametric models for the statistical behavior of the noise. A generalized likelihood ratio test (GLRT) is employed. We show that for a symmetric noise(More)
[1] The seasonal cycle and intraseasonal variability of the National Centers for Environmental Prediction/National Center for Atmospheric Research (NCEP) reanalysis surface winds over the Indian Ocean (IO) are assessed by comparing them with in situ surface observations from two moored buoys and winds from the SeaWinds scatterometer on the QuikSCAT(More)
Observed upper ocean currents south of Sri Lanka exhibit large, irregular fluctuations with periods of days to weeks. An ocean model driven by daily surface winds is able to reproduce the observed fluctuations. We find from model experiments that low frequency (30-50 day) intraseasonal variability (ISV) arises when Rossby waves radiated from the eastern(More)
[1] The zonal wind in the equatorial Indian Ocean (EqIO) is westerly almost throughout the year. It has a strong semiannual cycle and drives the spring and fall Wyrtki jets. In addition, high resolution daily satellite winds show ‘‘westerly wind bursts’’ lasting 10–40 days, associated with atmospheric convection in the eastern EqIO. These bursts have the(More)