Scores of modeling studies have shown that increasing greenhouse gases in the atmosphere impact the global hydrologic cycle. A stronger tropical hydrological cycle is predicted with enhanced patterns in precipitation distributions and increasing episodes of intense precipitation and droughts. Our investigation attempts to examine trends in the observations using satellite data products such as GPCP precipitation and ISCCP cloud and radiation. Specifically, two aspects of evolving trends in the tropical hydrological cycle over the last 20-30 years are examined: one involving precipitation distributions associated with large-scale circulations, in which I will show the intensification of tropical precipitation in the rising regions of the Walker and Hadley circulations and weakening over the sinking regions of the associated overturning circulations – the “Rich-Get-Richer” phenomena. I will also show evidence of the Hadley cell expansion and widening tropical belt in recent decades manifested in the tropical hydrological cycle using GPCP precipitation and ISCCP cloud and radiation data products. In the second part of the talk, I will show trend analysis of precipitation associated with tropical cyclones in global oceans that reflect trends in extreme events in the hydrological cycle.
Branch Seminar Series Coordinators:Lazaros.Oraiopoulos@nasa.govCharles.K.Gatebe@nasa.gov