A5069287550- Atmospheric aerosols and clouds
- Atmospheric chemistry and aerosols
- Atmospheric Ozone and Climate
- Air Quality and Health Impacts
- Atmospheric and Environmental Gas Dynamics
- Meteorological Phenomena and Simulations
- Air Quality Monitoring and Forecasting
- Climate variability and models
- COVID-19 impact on air quality
- Optical Wireless Communication Technologies
- Aeolian processes and effects
- Cryospheric studies and observations
- Precipitation Measurement and Analysis
- Space exploration and regulation
- Remote Sensing in Agriculture
- Calibration and Measurement Techniques
- Vehicle emissions and performance
- Solar Radiation and Photovoltaics
- Impact of Light on Environment and Health
- Remote Sensing and LiDAR Applications
- Ocean Waves and Remote Sensing
- COVID-19 epidemiological studies
- Computer Graphics and Visualization Techniques
- Music Technology and Sound Studies
- Crystallography and Radiation Phenomena
Indian Institute of Science Bangalore
2015-2024
Goddard Space Flight Center
2008-2009
Indian Academy of Sciences
2006
Scripps Institution of Oceanography
2000-2002
Vikram Sarabhai Space Centre
1996-2000
University of California, San Diego
2000
Every year, from December to April, anthropogenic haze spreads over most of the North Indian Ocean, and South Southeast Asia. The Ocean Experiment (INDOEX) documented this Indo‐Asian at scales ranging individual particles its contribution regional climate forcing. This study integrates multiplatform observations (satellites, aircraft, ships, surface stations, balloons) with one‐ four‐dimensional models derive aerosol forcing resulting direct, semidirect two indirect effects. consisted...
The Indo‐Gangetic Plain (IGP) encompasses a vast area, (accounting for ∼21% of the land area India), which is densely populated (accommodating ∼40% Indian population). Highly growing economy and population over this region results in wide range anthropogenic activities. A large number thermal power plants (most them coal fed) are clustered along region. Despite its importance, detailed investigation aerosols sparse. During an intense field campaign winter 2004, extensive aerosol atmospheric...
Abstract The first regional synthesis of long‐term (back to ~ 25 years at some stations) primary data (from direct measurement) on aerosol optical depth from the ARFINET (network observatories established under Aerosol Radiative Forcing over India (ARFI) project Indian Space Research Organization subcontinent) have revealed a statistically significant increasing trend with seasonal variability. Examining current values turbidity coefficients those reported 50 ago reveals phenomenal nature...
Light-absorbing organic aerosols, known as brown carbon (BrC), counteract the overall cooling effect of aerosols on Earth's climate. The spatial and temporal dynamics their light-absorbing properties are poorly constrained unaccounted for in climate models, because limited ambient observations. We combine isotope forensics (δ13C) with measurements light absorption a conceptual aging model to constrain loss absorptivity (i.e., bleaching) water-soluble BrC (WS-BrC) one world's largest emission...
Abstract Climate change has great significance globally in general and South Asia particular. Here we have used data from a network of 35 aerosol observatories over the Indian region to generate first time regional synthesis using primary estimate trends. On an average, optical depth (AOD) was found increasing at rate 2.3% (of its value 1985) per year more rapidly (~4%) during last decade. If trends continue so, AOD several locations would nearly double approach unity next few decades...
During a comprehensive aerosol field campaign, simultaneous measurements were made of spectral optical depths, black carbon mass concentration (M b ), total t ) and size segregated concentrations over an urban continental location, Bangalore (13° N, 77°E, 960 m msl), in India. Large amounts BC observed; both absolute terms fraction (∼11%) sub‐micron (∼23%) implying significantly low single scatter albedo. The visible depth (τ p was the range 0.24 to 0.45. Estimated surface forcing is as high...
Collocated measurements of the mass concentrations aerosol black carbon (BC) and composite aerosols near surface were carried out along with spectral optical depths (AODs) from a high‐altitude station, Manora Peak in central Himalayas, during comprehensive field campaign December 2004. Despite being pristine location Shivalik Ranges Himalayas having monthly mean AOD (at 500 nm) 0.059 ± 0.033 (typical to this site), total suspended particulate (TSP) concentration was range 15–40 μg m −3 (mean...
We examine the spatio‐temporal characteristics of aerosols in recent years (2000–2003) over Indian region with special emphasis on Indo‐Gangetic basin (northern India) using data from Moderate Resolution Imaging Spectroradiometer (MODIS), Aerosol Robotic Network (AERONET) and Total Ozone Mapping (TOMS). First, we have compared MODIS‐derived aerosol optical depth (AOD) fine‐mode fraction (FMAF ratio AOD to total mode AOD) those AERONET at Kanpur (26.45°N, 80.346°E). It has been found that...
Wide‐ranging multi‐platform data from a major field campaign conducted over Indian region was used to estimate the energy absorbed in ten layers of atmosphere. We found that during pre‐monsoon season, most is characterized by elevated aerosol layers. Three‐fold increase extinction coefficient observed at higher atmospheric (>2 km) compared near surface and substantial fraction (as much as 50 70%) optical depth contributed aerosols above (reflecting) clouds. Consequent absorption hence...
The influences of the springtime northern Indian biomass burning are shown for first time over central Himalayas by using three years (2007-2009) surface and space based observations along with a radiative transfer model. Near-surface ozone, black carbon (BC), spectral aerosol optical depths (AODs) meteorological parameters measured at high altitude site Nainital (29.37 degrees N, 79.45 E, 1958 m amsl) located in Himalayas. satellite include MODIS derived fire counts AOD (0.55 mu m), OMI...
[1] First ever in-situ measurements of black carbon (BC) aerosols in the troposphere (up to 9 km) made over central India and resulting atmospheric impact as revealed by environment lapse rate are presented. The altitude distribution BC showed multiple peaks; two surprisingly large peaks, one at ∼4.5 km, another above 8 km. Associated with these, rapid decrease environmental a sharp increase atmosphere stability were observed, probably caused warming layers. This important observation calls...
Abstract The influence of atmospheric aerosols on Earth's radiation budget and hence climate, though well recognized extensively investigated in recent years, remains largely uncertain mainly because the large spatio‐temporal heterogeneity lack data with adequate resolution. To characterize this diversity, a major multi‐platform field campaign ICARB (Integrated Campaign for Aerosols, gases Radiation Budget) was carried out during pre‐monsoon period 2006 over Indian landmass surrounding...
Abstract We examine long‐term trends in the near‐surface black carbon mass concentration, using multiyear primary data obtained from a dense network (ARFINET) of observatories over Indian region. report for first time statistically significant decreasing trend based on this region, at an average rate ~242 ± 53 ng · m −3 year −1 during period 2007–2016. This finding contrasts with generally increasing columnar aerosol optical depth, reported earlier, and steadily anthropogenic activities The...
Results of the studies on characteristics marine aerosol optical depths made in remote regions tropical Indian Ocean using a multiwavelength solar radiometer, taken scientific cruise, are presented. The dependence prevailing winds boundary layer and deck level relative humidity (RH) examined. Aerosol (τ p ) far oceanic with air mass prevailing, general, found to increase nearly exponentially average wind speed ( U as τ =τ o exp( ), where = 0.16 ± 0.04. No association is seen humidity,...
Abstract During the second phase of Arabian Sea Monsoon Experiment (ARMEX-II), extensive measurements spectral aerosol optical depth, mass concentration, and size distribution ambient aerosols as well concentration black carbon (BC) were made onboard a research vessel during intermonsoon period (i.e., when monsoon winds are in transition from northeasterlies to westerlies/southwesterlies) over (AS) adjoining Indian Peninsula. Simultaneous depths (AODs) at different regions landmass. Mean...
Mineral dust is the single largest contributor of natural aerosols over land. Dust exhibit high variability in their radiative effects because composition varies locally. This arises regional distinctiveness soil characteristics as well accumulation other aerosol species, such black carbon, on while airborne. To accurately estimate climate impact dust, spatial and temporal distribution its properties are essential. However, this poorly understood many regions world, including Indian region....
Abstract. In Part 1 of this two-part paper, we present the results extensive and collocated measurements columnar near-surface (in well mixed region) properties atmospheric aerosol particles at a tropical coastal location, Trivandrum (8.55° N; 76.97° E), located close to southwest tip Indian peninsula. These are used evolve average, climatological pictures optical microphysical delineate distinct changes associated with contrasting monsoon seasons as transition from one season other. Our...
Abstract Synergizing satellite remote sensing data with vertical profiles of atmospheric thermodynamics and regional climate model simulations, we investigate the relative importance, transport pathways, seasonality contribution dust from (Thar Desert adjoining arid regions) (southwest Asia northeast Africa) sources over Indian Ocean [i.e., Bay Bengal (BOB)]. We show that while northern BOB contribute more than 50% to total load during southwest monsoon period (June–September),...
<p><strong>Abstract.</strong> The vertical distribution in the physical and chemical properties of submicron aerosol has been characterised across northern India for first time using airborne situ measurements. This study focusses primarily on Indo-Gangetic Plain, a low-lying area north which commonly experiences high mass concentrations prior to monsoon season. Data presented are from UK Facility Airborne Atmospheric Measurements BAe-146 research aircraft that performed...