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Title: A meridional dipole in premonsoon Bay of Bengal tropical cyclone activity induced by ENSO: TROPICAL CYCLONES, MONSOON AND ENSO

Analysis of Bay of Bengal tropical cyclone (TC) track data for the month of May during 1980-2013 reveals a meridional dipole in TC intensification: TC intensification rates increased in the northern Bay and decreased in the southern Bay. The dipole was driven by an increase in low-level vorticity and atmospheric humidity in the northern Bay, making the environment more favorable for TC intensification, and enhanced vertical wind shear in the southern Bay, tending to reduce TC development. These environmental changes were associated with a strengthening of the monsoon circulation for the month of May, driven by a La Nin˜a-like shift in tropical Pacific SSTs andassociated tropical wave dynamics. Analysis of a suite of climate models fromthe CMIP5 archive for the 150-year historical period shows that most models correctly reproduce the link between ENSO and Bay of Bengal TC activity through the monsoon at interannual timescales. Under the RCP 8.5 scenario the same CMIP5 models produce an El Nin˜o like warming trend in the equatorial Pacific, tending to weaken the monsoon circulation. These results suggest
Authors:
 [1] ;  [2] ;  [2] ;  [3]
  1. Marine Sciences Laboratory, Pacific Northwest National Laboratory, Seattle Washington USA
  2. Atmospheric Sciences and Global Change, Pacific Northwest National Laboratory, Richland Washington USA
  3. Physical Oceanography Division, Atlantic Oceanographic and Meteorological Laboratory, Miami Florida USA
Publication Date:
OSTI Identifier:
1290364
Report Number(s):
PNNL-SA-113075
Journal ID: ISSN 2169-897X; KP1703010
DOE Contract Number:
AC05-76RL01830
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Geophysical Research: Atmospheres; Journal Volume: 121; Journal Issue: 12
Publisher:
American Geophysical Union
Research Org:
Pacific Northwest National Laboratory (PNNL), Richland, WA (US)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English