Peter John Webster

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We examined the number of tropical cyclones and cyclone days as well as tropical cyclone intensity over the past 35 years, in an environment of increasing sea surface temperature. A large increase was seen in the number and proportion of hurricanes reaching categories 4 and 5. The largest increase occurred in the North Pacific, Indian, and Southwest Pacific(More)
1 Program in Atmospheric and oceanic Sciences, University Colorado, Boulder. 2 Center for Atmospheric Sciences, National Autonomous University of Mexico, Mexico City. 3European Center for Medium-Range Weather Forecasts, Reading, England, United Kingdom. 4 Center for Ocean-Land-Atmopshere Studies, Calverton, Maryland. 5Department of Atmospheric Sciences,(More)
Convectively coupled equatorial waves, as previously detected in studies of wavenumber-frequency spectra of tropical clouds, are studied in more detail. Composite dynamical structures of the waves are obtained using linear regression between selectively filtered satellite-observed outgoing longwave radiation (OLR) data, and various fields from a global(More)
Two distinctly different forms of tropical Pacific Ocean warming are shown to have substantially different impacts on the frequency and tracks of North Atlantic tropical cyclones. The eastern Pacific warming (EPW) is identical to that of the conventional El Niño, whereas the central Pacific warming (CPW) has maximum temperature anomalies located near the(More)
From the analysis of surface, upper-air, and satellite observations it is suggested that the hydrological cycle associated with the Madden–Julian oscillation acts in the mode of a self-regulating oscillator. The regulation occurs as a feedback between hydrological processes in the atmosphere; radiation processes; and the dynamical movement of air over the(More)
The structure of the mean precipitation of the south Asian monsoon is spatially complex. Embedded in a broad precipitation maximum extending eastward from 70°E to the northwest tropical Pacific Ocean are strong local maxima to the west of the Western Ghats mountain range of India, in Cambodia extending into the eastern China Sea, and over the eastern(More)
The summertime intraseasonal oscillation (ISO) is an important component of the south Asian monsoon. Lagged regressions of intraseasonally filtered (25–80 days) outgoing longwave radiation (OLR) reveal that centers of convection move both northward and eastward from the central equatorial Indian Ocean subsequent to the initiation of an ISO. Eastward(More)
The authors examine relationships between Indian Ocean sea surface temperature (SST) variability and the variability of the Indian monsoon, including analysis of potential long-lead predictions of Indian rainfall by regional SST and the influence of ENSO and decadal variability on the stability of the relationships. Using monthly gridded (48 3 48) SST data(More)