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Evidence for Interannual to Decadal Variations in Hadley and Walker Circulations and Links to Water and Energy FluxesMass and energy transports associated with the Hadley and Walker circulations are important components of the earth s climate system and are strongly linked to hydrologic processes. Interannual to decadal variation in these flows likely signify a combination of natural climate noise as well as a response to anthropgenic forcing. There remains considerable uncertainty in quantifying variations in these flows. Evidence in the surface pressure record supports a weakening of the Walker circulation over the Pacific in recent decades. Conversely the NCEP / NCAR and ERA 40 reanalyses indicate that the Hadley circulation has increased in strength over the last two decades, though these analyses depict significantly different mass circulation changes. Interestingly, the NCEP - II / DOE reanalysis contains essentially no Hadley circulation changes. Most climate model integrations anticipate a weakening of both tropical circulations associated with stronger static stability. Clearly there is much uncertainty not only with the mass transports, but also how they are linked to water and energy balance of the planet through variations in turbulent heat and radiative fluxes and horizontal exports / imports of energy. Here we examine heat and water budget variations from a number of reanalysis products and focus on the linear and nonlinear response of ENSO warm and cold events as opportunities to study budget variations over the past 15-20 years. Our analysis addresses such questions as To what extent do Hadley and Walker Cell variations compensate each other on mass and energy transport? Do static stability adjustments appear to constrain fractional precipitation response vs. fractional water vapor response? We appeal to constraints offered by GPCP precipitation, SSWI ocean evaporation estimates, and ISCCP-FD radiative fluxes, and other satellite data sets to interpret and confirm reanalysis-based diagnostics. Using our findings we also attempt to place in context the recent findings that tropical ocean evaporation increased by order 5% or more during the 1990s, reconciling this with GPCP precipitation variations.
Document ID
20070013776
Acquisition Source
Marshall Space Flight Center
Document Type
Conference Paper
Authors
Robertson, Franklin
(NASA Marshall Space Flight Center Huntsville, AL, United States)
Bosilovich, Michael
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Miller, Timothy
(NASA Marshall Space Flight Center Huntsville, AL, United States)
Date Acquired
August 23, 2013
Publication Date
January 1, 2007
Subject Category
Meteorology And Climatology
Meeting Information
Meeting: 87th Annual AMS Meeting
Location: San Antonio, TX
Country: United States
Start Date: January 14, 2007
End Date: January 18, 2007
Sponsors: American Meteorological Society
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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