Title: Characteristics of Bay of Bengal Monsoon Depressions in the 21st Century

Journal Article · · Geophysical Research Letters
ORCiD logo [1]; ORCiD logo [1]; ORCiD logo [2]; ORCiD logo [3];  [3];  [4]; ORCiD logo [1]
  1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  2. Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
  3. Indian Institute of Technology Bombay, Mumbai (India)
  4. Univ. of Reading, Reading (United Kingdom)
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Here, we show that 21st century increase in radiative forcing does not significantly impact the frequency of South Asian summer monsoon depressions (MDs) or their trajectories in the Coupled Model Intercomparison Project Phase 5 general circulation models (GCMs). A significant relationship exists between the climatological occurrences of MDs and the strength of the background upper (lower) tropospheric meridional (zonal) winds and tropospheric moisture in the core genesis region of MDs. Likewise, there is a strong relationship between the strength of the meridional tropospheric temperature gradient in the GCMs and the trajectories of MDs over land. While monsoon dynamics progressively weakens in the future, atmospheric moisture exhibits a strong increase, limiting the impact of changes in dynamics on the frequency of MDs. Moreover, the weakening of meridional tropospheric temperature gradient in the future is substantially weaker than its inherent underestimation in the GCMs. Our results also indicate that future increases in the extreme wet events are dominated by nondepression day occurrences, which may render the monsoon extremes less predictable in the future.

Research Organization:
Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States); Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States). Oak Ridge Leadership Computing Facility (OLCF)
Sponsoring Organization:
USDOE; USDOE Office of Science (SC), Biological and Environmental Research (BER) (SC-23)
Grant/Contract Number:
AC05-00OR22725; AC05-76RL01830
OSTI ID:
1474867
Journal Information:
Geophysical Research Letters, Journal Name: Geophysical Research Letters Journal Issue: 13 Vol. 45; ISSN 0094-8276
Publisher:
American Geophysical UnionCopyright Statement
Country of Publication:
United States
Language:
English

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Cited By (2)

Regional Climate Response of Middle Eastern, African, and South Asian Monsoon Regions to Explosive Volcanism and ENSO Forcing journal July 2019
Tropical Lows in Southern Africa: Tracks, Rainfall Contributions, and the Role of ENSO journal November 2019

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54 ENVIRONMENTAL SCIENCES
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