A5066395508- Climate variability and models
- Meteorological Phenomena and Simulations
- Tropical and Extratropical Cyclones Research
- Oceanographic and Atmospheric Processes
- Atmospheric aerosols and clouds
- Hydrology and Drought Analysis
- Precipitation Measurement and Analysis
- Climate change impacts on agriculture
- Ocean Waves and Remote Sensing
- Ionosphere and magnetosphere dynamics
- Atmospheric chemistry and aerosols
- Plant Water Relations and Carbon Dynamics
- Dust and Plasma Wave Phenomena
- Atmospheric Ozone and Climate
- Hydrological Forecasting Using AI
- Aeolian processes and effects
- Lightning and Electromagnetic Phenomena
- Atmospheric and Environmental Gas Dynamics
- Magnetic confinement fusion research
- Cryospheric studies and observations
- Nonlinear Waves and Solitons
- Marine and coastal ecosystems
- Remote Sensing and Land Use
- Solar and Space Plasma Dynamics
- Solar Radiation and Photovoltaics
Cotton University
2017-2024
Indian Institute of Science Education and Research Pune
2015-2018
Indian Institute of Science Bangalore
2000-2016
Indian Institute of Tropical Meteorology
2006-2015
University of Victoria
2014
NSF National Center for Atmospheric Research
2011
George Mason University
2011
East Carolina University
2011
Iowa State University
2011
Swedish Meteorological and Hydrological Institute
2011
How and to what extent the intraseasonal oscillations (ISOs) influence seasonal mean its interannual variability of Indian summer monsoon is investigated using 42-yr (1956–97) daily circulation data from National Centers for Environmental Prediction–National Center Atmospheric Research 40-Year Reanalysis satellite-derived outgoing longwave radiation period 1974–97. Based on zonal winds at 850 hPa over Bay Bengal, a criterion devised define "active" "break" conditions. The underlying spatial...
Empirical evidence is presented to support a hypothesis that the interdecadal variation of Indian summer monsoon and tropical SST are parts coupled ocean–atmosphere mode. The rainfall (IMR) strongly correlated with variations various indices El Niño–Southern Oscillation (ENSO). It also shown interannual variances both IMR ENSO vary in phase follow common variation. However, correlation between eastern Pacific or Southern index (SOI) on timescale does not oscillation. spatial patterns sea...
A link between the Atlantic Multidecadal Oscillation (AMO) and multidecadal variability of Indian summer monsoon rainfall is unraveled a long sought physical mechanism linking climate has been identified. The AMO produces persistent weakening (strengthening) meridional gradient tropospheric temperature (TT) by setting up negative (positive) TT anomaly over Eurasia during northern late summer/autumn resulting in early (late) withdrawal south west decrease (increase) seasonal rainfall. On...
Abstract A broad‐scale circulation index representing the interannual variability of Indian summer monsoon is proposed and shown to be well correlated with precipitation in region. Using monthly analysis based on merging rain‐gauge data satellite estimates for period 1979‐96, it that seasonal time‐scales coherent over a large region covering continent as north Bay Bengal parts south China. new index, termed Extended Monsoon Rainfall (EIMR), defined averaged 70°E–110°E, 10°N–30°N. EIMR...
Abstract The concept of an interannually varying Indian summer monsoon season is introduced here, considering that the duration primary driving monsoon—the large‐scale meridional gradient deep tropospheric heat source—may vary from one year to another. Onset (withdrawal) defined as day when source shifts south north (north south). This physical principle leads a new thermodynamic index seasonal mean monsoon. While traditional measure rainfall, averaged 1 June 30 September, indicates...
Active and break phases of the Indian summer monsoon are characterized by enhancement decrease precipitation over trough region. Using genesis data low pressure systems (LPS) circulation for period 1954 to 1993, it is shown that frequency occurrence LPS nearly 3.5 times higher in active phase as compared phase. In addition, tracks these synoptic also strongly spatially clustered along during monsoon. The enhanced (decreased) (break) due modulation meridional shear zonal winds cyclonic...
Being an integral effect of sub‐seasonal rain spells over the season, seasonal mean south Asian monsoon (SAM) rainfall could be affected by change in length rainy season (LRS). An objective definition duration SAM has, however, been lacking. Here we show that meridional gradient tropospheric temperature (ΔTT) region controls LRS and defines season. It is further shown ENSO induces decreased regulating LRS. The atmospheric response to tropical sea surface (SST) Pacific during evolving El Niño...
The potential predictability of the Indian summer monsoon due to slowly varying sea surface temperature (SST) forcing is examined. Factors responsible for limiting are also investigated. Three multiyear simulations with R30 version Geophysical Fluid Dynamics Laboratory's climate model carried out this purpose. mean simulated by realistic including precipitation over continent. interannual variability large-scale component such as "monsoon shear index" and its teleconnection Pacific SST well...
Abstract The quasi‐biweekly mode (QBM) and the 30–60 day are two major intraseasonal oscillations (ISOs) in tropics. QBM is known to have a influence determining active break conditions of Indian monsoon during northern summer. A westward‐propagating equatorial Rossby wave with period influences Australian winter. Universality between summer winter established through analysis daily circulation convection data for 10 years. It shown that mean spatial structure resembles gravest meridional...
The representation of tropical convection remains a serious challenge to the skillfulness our weather and climate prediction systems. To address this challenge, World Climate Research Programme (WCRP) Observing System Predictability Experiment (THORPEX) Weather (WWRP) are conducting joint research activity consisting focus period approach along with an integrated framework tailored exploit vast amounts existing observations, expanding computational resources, development new, high-resolution...
Abstract Factors responsible for limited predictability of the Asian summer monsoon (ASM) are investigated within a conceptual framework predictability. Predictability seasonal mean depends on interannual variability (IAV) annual cycle (MAC) and is determined by relative contribution predictable “external” component IAV compared to unpredictable “internal” IAV. Contributions slow processes such as those involving air–sea interactions associated with El Niño–Southern Oscillation (ENSO) or...
Flash floods associated with extreme rain events are a major hydrological disaster in the northeast Indian (NEI) region because of unique topographic features as well increased frequency occurrence such events. Knowledge spatiotemporal distribution these and an understanding factors responsible for them, therefore, would be immensely useful appropriate preparedness. Using daily rainfall data from 15 stations over 32 years (1975–2006), it is shown that largest not during premonsoon...
Abstract In an attempt to unravel the interactions between cloud microphysics and dynamics that make shallow clouds precipitate heavily in this region, some unique observations of rain microphysical parameters are presented here from two stations, Pune Mahabaleshwar, one each on lee windward sides, respectively, Western Ghat (WG) mountains peninsular India. To elucidate microphysics, we used raindrop size distribution (DSD) by fitting three parameter Gamma functions observed spectra. Over...