Jayaraman Srinivasan

Jayaraman Srinivasan
Indian Institute of Science | IISC · Divecha Centre for Climate Change

Phd(stanford)

About

211
Publications
56,415
Reads
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5,410
Citations
Introduction
My current research is on modelling the retreat of glaciers and understanding how monsoons changed in the past
Additional affiliations
March 1993 - March 1995
NASA
Position
  • Senior Resident Resrach Associate
Description
  • worked on earth radiation budget experiment
June 1975 - December 1982
Indian Institute of Technology Kanpur
Position
  • Professor (Assistant)

Publications

Publications (211)
Article
Full-text available
Vertically integrated eastward moisture flux at 70° E over the Arabian Sea (Q) is the dominant factor that drives seasonal Indian summer monsoon rainfall (ISMR). Yet, the nature of this relationship depends on the phase of El-Nino Southern Oscillation (ENSO). The conversion efficiency of Q to rainfall is twice as high during the El-Nino years than...
Article
Full-text available
Plain Language Summary Modern observations suggest that the upwelling along the western boundary of the Arabian Sea is primarily controlled by the strength of the low‐level jet (LLJ). The strength of the LLJ and the Indian summer monsoon rainfall are also positively correlated. Hence, proxies of upwelling have been used to infer the variations in t...
Conference Paper
Full-text available
Modern observations suggest a positive correlation between Indian summer monsoon rainfall and coastal upwelling along the western boundary of the Arabian Sea. It was assumed that this relation is valid in climates of the past and has been the basis of several monsoon reconstructions. Such reconstructions indicate that monsoon increases when local s...
Article
Precipitation is one of the integral components of the global hydrological cycle. Accurate estimation of precipitation is vital for numerous applications ranging from hydrology to climatology. Following the launch of the Global Precipitation Measurement (GPM) Core Observatory, the Integrated Multi-satellite Retrievals for GPM (IMERG) precipitation...
Conference Paper
Full-text available
Monsoons were traditionally considered to be land-based systems. Recent definitions of monsoons based on either the seasonal reversal of winds or the local summer precipitation accounting for more than 50% of the annual precipitation suggests that monsoon domains extend over oceanic regions as well. The concept of global monsoon combines all the mo...
Conference Paper
Full-text available
Proxies of monsoons indicate a nearly synchronous fluctuation across northern monsoon domains on orbital timescales. Using a transient climate simulation, we have shown that precipitation evolves differently over tropical land and ocean. During the deglacial (22 ka to 11 ka) precipitation over land and ocean are in phase, whereas they are out of ph...
Article
Full-text available
Various proxies suggest a nearly in-phase variation of monsoons with local summer insolation. Oceanic proxies of monsoons document a more complex response. Climate model simulations also indicate that the response is different over land and ocean. Here using a transient simulation by a climate model over the last 22,000 years we have unraveled the...
Conference Paper
Full-text available
In the paleo literature, the emphasis has been on the role of insolation in driving monsoons on orbital timescales, but not on the role of feedbacks internal to the climate system. Here, using the energetics framework, we have underscored the effect of water vapor on the Indian summer monsoon over the last 22,000 years in transient climate simulati...
Article
Geostationary satellites offer the possibility of producing high-frequency time series irradiance datasets, covering a large geographical area. Here, we derive half-hourly global irradiance (GHI) at 4 km spatial resolution from visible channel radiance of INSAT-3D satellite using a semi-empirical model and validate it against 19 ground stations ove...
Article
Full-text available
To predict how monsoons will evolve in the 21st century, we need to understand how they have changed in the past. In paleoclimate literature, the major focus has been on the role of solar forcing on monsoons but not on the amplification by feedbacks internal to the climate system. Here we have used the results from a transient climate simulation to...
Presentation
Full-text available
Substantial evidence from proxies suggests that monsoon variations in the past are due to insolation. Our model-based study indicates, however, that surface energy fluxes and the vertical stability of the atmosphere can be dominant. We have used a simple diagnostic based on the energetics of monsoon, to understand the precipitation response to prec...
Chapter
India’s high population density, large spatial and temporal variability in rainfall, and high poverty rates make it particularly vulnerable to the impacts of climate change. This chapter provides a baseline of knowledge on evidence and impacts. More frequent episodes of extreme rainfall, longer dry spells, higher sea levels, and heat waves are expe...
Article
The wind speed forecast by a weather forecast model (with a resolution of 3 km) has been used to identify regions with high wind speed in Karnataka. The correlation between daily wind speed predicted by the model and the measured wind speed at three stations in Karnataka has been shown to be high. Based on this model, new locations have been sugges...
Article
Full-text available
In the shortwave solar spectrum (\(0.25{-}5~\upmu \hbox {m}\)), radiation is affected by the change in various aerosol properties and also by water vapour and other gas molecules. The presence of a variety of aerosols over the Bay of Bengal (BoB) during different seasons results in a change in aerosol properties, including the aerosol layer height....
Article
Rain gauges are considered the most accurate method to estimate rainfall and are used as the “ground truth” for a wide variety of applications. The spatial density of rain gauges varies substantially and hence influences the accuracy of gridded gauge-based rainfall products. The temporal changes in rain gauge density over a region introduce conside...
Article
Full-text available
The changes in Earth's precession have an impact on the tropical precipitation. This has been attributed to the changes in seasonal solar radiation at the top of the atmosphere. The primary mechanism that has been proposed is the change in thermal gradient between the two hemispheres. This may be adequate to understand the zonal mean changes, but c...
Article
Full-text available
Single scattering albedo (SSA) represents a unique identification of aerosol type and can be a determinant factor in the estimation of aerosol radiative forcing. However, SSA retrievals are highly uncertain due to cloud contamination and aerosol composition. The recent improvement in the SSA retrieval algorithm has combined the superior cloud-maski...
Article
This study derives the ice water path of the atmospheric column from the microwave sounder SAPHIR onboard Megha-Tropiques. SAPHIR (Sondeur Atmosphérique du Profil d’Humidité Intertropicale par Radiométrie) is a cross-track, multichannel microwave humidity sounder with six channels ranging from 183.3 ± 0.2 to 183.3 ± 11 GHz near the 183.31 GHz water...
Book
This book focuses on the development of physical parameterization over the last 2 to 3 decades and provides a roadmap for its future development. It covers important physical processes: convection, clouds, radiation, land-surface, and the orographic effect. The improvement of numerical models for predicting weather and climate at a variety of place...
Article
The South Asian summer monsoon has been suggested to be influenced by atmospheric aerosols, and this influence can be the result of either local or remote emissions. We have used the Hadley Centre Global Environment Model Version 3 (HadGEM3) coupled atmosphere-ocean climate model to investigate for the first time the centennial-scale South Asian pr...
Article
Full-text available
The changes in Earth's precession have an impact on tropical precipitation. These changes have been ascribed to the changes in solar radiation at the top of the atmosphere, but this cannot explain the variations in precipitation over oceans. Using energy and moisture budget equations we have shown that the surface energy fluxes, as well as vertical...
Article
Full-text available
Single scattering albedo (SSA) represents a unique identification of aerosol type and aerosol radiative forcing. However, SSA retrievals are highly uncertain due cloud contamination and aerosol composition. Recent improvement in the SSA retrieval algorithm has combined the superior cloud masking technique of Moderate Resolution Imaging Spectroradio...
Poster
The changes in Earth’s precession have an impact on tropical precipitation. Speleothem records show that, the intensity of monsoon is directly proportional to insolation on orbtial timescales. However, model based studies suggest that, while this is true over land, precipitation over tropical oceans are in general, inversely related to insolation....
Article
Full-text available
Recent studies have shown that the shallow meridional circulation (SMC) coexists with the deep circulation in the marine ITCZ. The SMC has been assumed to be forced by strong meridional gradients of Sea Surface Temperature (SST) which affect the atmosphere under hydrostatic balance. In this paper, we present a new viewpoint that the shallow meridio...
Article
Full-text available
The history of glacier length fluctuations serves as a reliable indicator of the past climate. In this paper, a numerical flowline model has been used to study the relationship between length variations of Chhota Shigri glacier and local climate since 1876. The simulated front positions of Chhota Shigri glacier are in agreement with those observed....
Article
Full-text available
The inter-tropical convergence zones (ITCZ) form closer to the equator during equinoxes while they form well away from the equator during the boreal summer. A simple three-way balance between the pressure gradients, Coriolis force and effective Rayleigh friction has been classically used to diagnose the location of maximum boundary layer convergenc...
Article
The SAPHIR sensor onboard Megha-Tropiques (MT) measures the earth emitted radiation at frequencies near the water vapor absorption band. SAPHIR operates in six frequencies ranging from 183±0.1 to 183±11 GHz. These frequencies have been used to retrieve cloud ice water path (IWP) at a very high resolution. A method to retrieve IWP over the Indian oc...
Article
The performance of solar photovoltaic modules mounted on the rooftop of a rail coach of The Indian Railways is reported here. The focus of this experiment was to quantify the reduction in diesel consumption of the end-on generation system that powers the electrical load in the new generation coaches. A coach retrofitted with two flexible solar phot...
Article
Full-text available
About 70% of total electricity generation in India in 2015–16 came from thermal power plants that burn coal1. Further, coal power plants still dominate the planned power capacity additions under the 12th and 13th five-year plans2. The coal-based thermal power plants are considered to be least expensive and more reliable in the present electricity g...
Article
Full-text available
The Himalayan glaciers feed major Asian river systems sustaining the lives of more than 800 million people. Though the rates of retreat of individual glaciers are uncertain, on the whole the Himalayan glaciers have been losing mass at an increasing rate over the past few decades. With the changing climate, glaciers will continue to shrink and the r...
Article
The Megha-Tropiques, an Indo-French satellite carries onboard a microwave sounder, SAPHIR, and a microwave radiometer, MADRAS, along with two other instruments. Being a GPM constellation satellite MT-MADRAS was an important sensor to study the convective clouds and rainfall. Due to the non-functioning of MADRAS, the possibility of detection and est...
Poster
Volcanoes were one of the major forcing agents during the last millennium. We have used the CMIP5 MPI-ESM’s past1000 experiment to examine the variability of Indian monsoon. Global annual mean precipitation reduces after a major volcanic eruption. The Indonesian monsoon was most affected during those years. The Indian Monsoon does not show any sign...
Article
Full-text available
The tropical easterly jet (TEJ) is a prominent atmospheric circulation feature observed during the Asian summer monsoon. It is generally assumed that sensible heating over the Tibetan Plateau directly influences the location of the TEJ. However, other studies have suggested the importance of latent heating in determining the jet location. In this p...
Article
Full-text available
Tracking systems, that continually orient photovoltaic (PV) panels towards the Sun, are expected to increase the power output from the PV panels. Tremendous amount of research is being done and funds are being spent in order to increase the efficiency of PV cells to generate more power. We report the performance of two almost identical PV systems;...
Article
Full-text available
The Tropical Easterly Jet (TEJ) is a prominent atmospheric circulation feature observed during the Asian Summer Monsoon (ASM). The simulation of TEJ by the Community Atmosphere Model, version 3.1 (CAM-3.1) has been discussed in detail. Although the simulated TEJ replicates many observed features of the jet, the jet maximum is located too far to the...
Article
Full-text available
Recent studies, over regions influenced by biomass burning aerosol, have shown that it is possible to define a ‘critical cloud fraction’ (CCF) at which the aerosol direct radiative forcing switch from a cooling to a warming effect. Using 4 years of multi-satellite data analysis, we show that CCF varies with aerosol composition and changed from 0.28...
Article
Full-text available
Awareness for the need of sustainable and eco-friendly mobility has been increasing and various innovations are taking place in this regard. A study was carried out to assess the feasibility of installing solar photovoltaic (PV) modules atop train coaches. Most long-distance trains having LHB coaches do not have self-generating systems, thus making...
Article
This is a transient two-dimensional numerical study of double-diffusive salt fingers in a two-layer heat-salt system for a wide range of initial density stability ratio (R ρ0) and thermal Rayleigh numbers (Ra T ∼103 − 1011). Salt fingers have been studied for several decades now, but several perplexing features of this rich and complex system remai...
Article
The impact of heating by black carbon aerosols on Indian summer monsoon has remained inconclusive. Some investigators have predicted that black carbon aerosols reduce monsoon rainfall while others have argued that it will increase monsoon rainfall. These conclusions have been based on local influence of aerosols on the radiative fluxes. The impact...
Article
Full-text available
We estimate the distribution of ice thickness for a Himalayan glacier using surface velocities, slope and the ice flow law. Surface velocities over Gangotri Glacier were estimated using sub-pixel correlation of Landsat TM and ETM+ imagery. Velocities range from ~14–85 m a–1 in the accumulation region to ~20–30 m a–1 near the snout. Depth profiles w...
Conference Paper
Full-text available
The Bay of Bengal shows a unique feature during boreal summer in the tropics. The Sea surface temperatures (SST) in the basin is found to have a weak gradient in the northern hemisphere and a strong gradient in the southern hemisphere. There are two favorable locations for the ITCZ, one near equator (5 • S) and other off-equator (15 • N). In this p...
Conference Paper
Full-text available
The glaciers in the third pole are being extensively debated in scientific and public forums, as changes in their distribution can significantly affect the availability of water in many rivers originating in the region. The rate of mass loss across the third pole varies from −0.21 ± 0.10 m.yr−1.w.e (Eastern Himalayas) to −0.41 ± 0.11 m.yr−1.w.e (We...
Article
During recent years, an increase in the intensity of pre-monsoon tropical cyclones (TC) is observed over the Arabian Sea. The present study suggests this increase is due to epochal variability in the intensity of TCs and is associated with epochal variability in the storm-ambient vertical wind shear and Tropical Cyclone Heat Potential (TCHP). There...
Article
Full-text available
The effect of meridional variation of sea surface temperature (SST) on tropical atmospheric circulation is analyzed using Aqua-planet Experiment (APE) simulations. The meridional SST gradient around the narrow SST peak in CONTROL simulation favours a strong and single equatorial Intertropical Convergence Zone (ITCZ, defined by the maximum of zonall...
Article
Full-text available
The Tropical Easterly Jet (TEJ) is a prominent atmospheric circulation feature observed during the Asian Summer Monsoon. It is generally assumed that Tibet is an essential ingredient in determining the location of the TEJ. However studies have also suggested the importance of latent heating in determining the jet location. The relative importance o...
Article
Full-text available
Himalayan glaciers are being extensively debated in scientific and public forums, as changes in their distribution can significantly affect the availability of water in many rivers originating in the region. The distribution of glaciers can be influenced by mass balance, and most of the glaciers located in the Pir Panjal and Greater Himalayan mount...
Article
ISI Document Delivery No.: 164FG Times Cited: 0 Cited Reference Count: 0 Kidd, Chris Srinivasan, J. Roca, Remy 0 WILEY-BLACKWELL HOBOKEN Q J ROY METEOR SOC SI B
Article
Full-text available
During a series of measurements, simultaneous measurements were made of spectral aerosol optical depths (AOD), black carbon (BC) mass concentration, total and size segregated composite aerosol mass concentrations at the second campus of Indian Institute of Science (IISc), Challakere, Karnataka. Surprisingly, most of the aerosol mass is found in the...
Article
The radiative impact of aerosols is one of the largest sources of uncertainty in estimating anthropogenic climate perturbations. Estimation of the aerosol radiative effects is much more complicated than the radiative impact due to well-mixed greenhouse gases. The majority of aerosol radiative impact assessments made so far are based on models, whic...
Article
Full-text available
Measurements of the spectral aerosol optical depths (AODs) were made over the Arabian Sea, Indian Ocean, Southern Ocean, and Antarctica during a trans-continental cruise experiment conducted during January to April 2006. Our investigations show that AODs (at 500 nm) remain low (≤0.1) and steady in the Southern Indian Ocean (20°S to 40°S). In contra...
Article
Satheesh et al. (2006, hereafter S06) used measurements of surface radiation to quantify changes in irradiance due to aerosols in Bangalore, India. S06 also made model estimates by incorporating aerosol microphysical and optical properties measured simultaneously at the same location into radiation models, using the conventional assumption that aer...
Article
In this study, the authors have investigated the likely future changes in the summer monsoon over the Western Ghats (WG) orographic region of India in response to global warming, using time-slice simulations of an ultra high-resolution global climate model and climate datasets of recent past. The model with approximately 20-km mesh horizontal resol...
Article
Full-text available
This article compares the land use in solar energy technologies with conventional energy sources. This has been done by introducing two parameters called land transformation and land occupation. It has been shown that the land area transformed by solar energy power generation is small compared to hydroelectric power generation, and is comparable wi...
Article
Full-text available
The failure of atmospheric general circulation models (AGCMs) forced by prescribed SST to simulate and predict the interannual variability of Indian/Asian monsoon has been widely attributed to their inability to reproduce the actual sea surface temperature (SST)–rainfall relationship in the warm Indo-Pacific oceans. This assessment is based on a co...
Technical Report
Full-text available
We have studied the dynamics of glaciers using analytical and numerical models. We have developed a numerical ice-flow model based on the formulation of Adhikari and Huybrechts (2009) and used it to gain insight into the processes governing advance/ retreat of glaciers. We have proposed a simple model for estimating advance/retreat on a climate tim...
Article
Precise specification of the vertical distribution of cloud optical properties is important to reduce the uncertainty in quantifying the radiative impacts of clouds. The new global observations of vertical profiles of clouds from the CloudSat mission provide opportunities to describe cloud structures and to improve parameterization of clouds in the...
Article
Full-text available
A megawatt scale grid-connected photovoltaic power plant was commissioned on 27 December 2009 in Yalesandra in Kolar district in Karnataka. The Yalesandra plant is one among more than 20 such Megawatt size solar power plants in India during the past few years. The performance of this plant during its first year of operation has been discussed. The...