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Ashok, Karumuri
- South Asian Subtropical Low-Level Jet:Influence on Regional Hydrology and Aerosol Optical Depth
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PDF Views:90
Authors
Affiliations
1 National Centre for Earth Science Studies, Akkulam, Thiruvananthapuram 695 011, IN
2 University of Hyderabad, Central University P.O., Prof. C.R. Rao Road, Gachibowli, Hyderabad 500 046, IN
1 National Centre for Earth Science Studies, Akkulam, Thiruvananthapuram 695 011, IN
2 University of Hyderabad, Central University P.O., Prof. C.R. Rao Road, Gachibowli, Hyderabad 500 046, IN
Source
Current Science, Vol 117, No 5 (2019), Pagination: 852-858Abstract
A 38-year high-resolution wind climatology shows a consistent occurrence of hitherto unreported South Asian subtropical low-level jets (SASLLJs) over the 31°–35°N and 60°–62°E latitude–longitude region, occurring throughout the year are the northerly LLJs (NLLJs) and southerly LLJs (SLLJs). The NLLJ is persistent mostly during the monsoon season. The NLLJ is frequent, unlike the SLLJ. The synoptic heat low in South Asia (62°–66°E and 27°–32°N) and the anticyclone over Turkmenistan (40°–50°N and 50°– 60°E) are critical in inducing the NLLJ. Regional topography permits direct mid-latitude air intrusion into the subtropical region. Importantly, we find that the NLLJ results in enhancing the transportation of dust to the Indian subcontinent and the northern part of the Arabian Sea due to wind blows. Long-term NLLJ intensity displays waning trend because of the weakening of pressure gradients between the heat low in South Asia and over Turkmenistan.Keywords
Aerosol Optical Depth, Low-Level Jet, Regional Hydrology, Rainfall.Full Text
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- The Past Climate of the Indian Region as Seen from the Modelling World
Abstract Views :214 |
PDF Views:84
Authors
Affiliations
1 Centre for Earth, Ocean and Atmospheric Sciences, University of Hyderabad, Hyderabad 500 046, IN
1 Centre for Earth, Ocean and Atmospheric Sciences, University of Hyderabad, Hyderabad 500 046, IN
Source
Current Science, Vol 119, No 2 (2020), Pagination: 316-327Abstract
Proxy-reconstruction studies suggest several waxing and waning epochs of the Indian summer monsoon (ISM) since Last Glacial Maximum (LGM; j21 kyr BP). These fluctuations in the ISM are attributed to several internal and external factors. The few available past climate modelling studies for various epochs also support the results from the reconstruction studies for India. Our results, based on an analysis of five CMIP5-PMIP3 simulations for the periods of LGM, Mid-Holocene (MH; j6 kyr BP), last-millennium and historical period (CE 1901–1999) indicate that the ISM rainfall was lowest during the LGM, and strongest during the MH. The simulations, relative to the historical time period, suggest highest low-level convergence over the Indian region during MH and lowest during LGM. These slow changes in large-scale circulation patterns resulted in relatively highest simulated ISM rainfall during the MH, and lowest in the LGM.Keywords
Indian Summer Monsoon, Last Glacial Minimum, Mid-Holocene, Last Millennium, Past Climate Modelling, PMIP3 Simulations.Full Text