Ganges Valley Aerosol Experiment (GVAX)

13 June 2011 - 31 March 2012

Lead Scientist: V. Rao Kotamarthi

Observatory: AMF, PGH

The Ganges valley region is one of the largest and most rapidly developing sections of the Indian subcontinent. The Ganges River, which provides the region with water needed for sustaining life, is fed primarily by snow and rainfall associated with Indian summer monsoons. Impacts of changes in precipitation patterns, temperature, and the flow of the snow-fed rivers could be immense. Recent satellite-based measurements have indicated that the upper Ganges valley has some of the highest persistently observed aerosol optical depth values. The aerosol layer covers a vast region, extending across the Indo-Gangetic Plain to the Bay of Bengal during the winter and early spring of each year. The persistent winter fog in the region is already a cause of much concern, and several studies have been proposed to understand the economic, scientific, and societal dimensions of this problem. During the INDian Ocean EXperiment (INDOEX) field studies, aerosols from this region were shown to affect cloud formation and monsoon activity over the Indian Ocean. This is one of the few regions showing a trend toward increasing surface dimming and enhanced mid-tropospheric warming. Increasing air pollution over this region could modify the radiative balance through direct, indirect, and semi-indirect effects associated with aerosols. The consequences of aerosols and associated pollution for surface insolation over the Ganges valley and monsoons in particular are not well understood.

The proposed field study was designed for use of 1) the ARM Mobile Facility to measure relevant radiative, cloud, convection, and aerosol optical characteristics over mainland India during an extended period of 12 months; and 2) the G-1 aircraft* and surface sites to measure relevant aerosol chemical, physical, and optical characteristics in the Ganges valley during a period of 8-12 weeks. The aerosols in this region have complex sources, including burning of coal, biomass, and biofuels; automobile emissions; and dust. The extended AMF deployment enabled measurements under different regimes of the climate and aerosol abundance — in the wet monsoon period with low aerosol loading; in the dry, hot summer with aerosols dispersed throughout the atmospheric column; and in the cool, dry winter with aerosols mostly confined to the boundary later and mid troposphere. Each regime, in addition, has its own distinct radiative and atmospheric dynamic drivers. The aircraft operational phase assisted in characterizing the aerosols at times when they have been observed to be at the highest concentrations.

A number of agencies in India collaborated with the proposed field study and provided support in terms of planning, aircraft measurements, and surface sites. The high concentration of aerosols in the upper Ganges valley, together with hypotheses involving several possible mechanisms with direct impacts to the hydrologic cycle of the region, gave researchers a unique opportunity to generate data sets that will be useful both in understanding the processes at work and providing answers regarding the effects of aerosols on climate in a region where the perturbation is the highest.

*As of April 1, 2011, the G-1 no longer participated in this field campaign.

The ARM Mobile Facility (AMF) operated at the ARIES Observatory in Nainital from June 2011 to March 2012.
The ARM Mobile Facility (AMF) operated at the ARIES Observatory in Nainital from June 2011 to March 2012.

Co-Investigators

Richard Coulter
Greg McFarquhar
Sethu Raman

Related Publications

2017

Dumka U, D Kaskaoutis, R Sagar, J Chen, N Singh, and S Tiwari. 2017. "First results from light scattering enhancement factor over central Indian Himalayas during GVAX campaign." Science of The Total Environment, 605-606, 10.1016/j.scitotenv.2017.06.138.

2016

Singh N, R Solanki, N Ojha, RH Janssen, A Pozzer, and SK Dhaka. 2016. "Boundary layer evolution over the central Himalayas from radio wind profiler and model simulations." Atmospheric Chemistry and Physics, 16(16), 10.5194/acp-16-10559-2016.

Krishna Moorthy K, S Satheesh, and V Kotamarthi. 2016. "Evolution of Aerosol Research in India and the RAWEX–GVAX:An Overview." Current Science, 111(1), 10.18520/cs/v111/i1/53-75.

2015

Dumka UC, D Bhattu, SN Tripathi, DG Kaskaoutis, and BL Madhavan. 2015. "Seasonal inhomogeneity in cloud precursors over Gangetic Himalayan region during GVAX campaign." Atmospheric Research, 155, 10.1016/j.atmosres.2014.11.022.

Gogoi MM, SS Babu, V Jayachandran, KK Moorthy, SK Satheesh, M Naja, and VR Kotamarthi. 2015. "Optical properties and CCN activity of aerosols in a high-altitude Himalayan environment: Results from RAWEX-GVAX." Journal of Geophysical Research: Atmospheres, 120(6), 10.1002/2014jd022966.

2014

Lundquist JK, A Purkayastha, C St. Martin, and R Newsom. 2014. Estimating the wind resource in Uttarakhand: Comparison of dynamic downscaling with Doppler Lidar Wind Measurements. NREL/TP-5000-61103.

2013

Feng Y, V Kotmarthi, and R Coulter. 2013. Modeling Radiative Impact of Aerosols Over South Asia Constrained by Observations of Vertical Distribution. Presented at 4th Atmospheric System Research (ASR) Science Team Meeting. Potomac, MD.

2012

Naja M, N Singh, N Ojha, D Phanikumar, U Dumka, V Pant, S Sahai, P Pant, R Sagar, S Satheesh, KK Moorthy, and VR Kotamarthi. 2012. Vertical Profiling of Meteorological Parameters Using AMF1 in the Central Himalayan Region During GVAX: Implications on Aerosols and Trace Gases Variations. Presented at 3rd Atmospheric System Research (ASR) Science Team Meeting. Arlington, VA.

Dumka U. 2012. Optical Properties of Atmospheric Aerosols over the Ganges Valley Aerosol Experiment Site, ARIES, Nainital. Presented at 3rd Atmospheric System Research (ASR) Science Team Meeting. Arlington, VA.

Kotamarthi VR. 2012. Preliminary Results from the Nainital AMF Study. Presented at 3rd Atmospheric System Research (ASR) Science Team Meeting. Arlington, VA.


View All Related Publications

PGH Data Sources

Name Full Name Browse Data
AERI Atmospheric Emitted Radiance Interferometer Browse Data
AERINF AERI Noise Filtered Browse Data
AIP Aerosol Intensive Properties Browse Data
AOD Aerosol Optical Depth, derived from atmospheric extinction of solar irradiance Browse Data
AOS Aerosol Observing System Browse Data
AOSCCNAVG Aerosol Observing System (AOS): cloud condensation nuclei data, averaged Browse Data
CCN Cloud Condensation Nuclei Particle Counter Browse Data
CEIL Ceilometer Browse Data
CLAP Continuous Light Absorption Photometer Browse Data
CPC Condensation Particle Counter Browse Data
CSPHOT Cimel Sunphotometer Browse Data
DL Doppler Lidar Browse Data
DLPROF Doppler Lidar Profiles Browse Data
ECMWFDIAG European Centre for Medium Range Weather Forecasts Diagnostic Analyses Browse Data
GNDRAD Ground Radiometers on Stand for Upwelling Radiation Browse Data
MET Surface Meteorological Instrumentation Browse Data
MFRSR Multifilter Rotating Shadowband Radiometer Browse Data
MFRSRCLDOD Cloud Optical Properties from MFRSR Using Min Algorithm Browse Data
MPL Micropulse Lidar Browse Data
MWR Microwave Radiometer Browse Data
MWRHF Microwave Radiometer - High Frequency Browse Data
MWRP Microwave Radiometer Profiler Browse Data
MWRRET MWR Retrievals Browse Data
NEPHELOMETER Nephelometer Browse Data
NFOV Narrow Field of View Zenith Radiometer Browse Data
PBLHT Planetary Boundary Layer Height Browse Data
PSAP Particle Soot Absorption Photometer Browse Data
QCRAD Data Quality Assessment for ARM Radiation Data Browse Data
RWP Radar Wind Profiler Browse Data
SASHE Shortwave Array Spectroradiometer-Hemispheric Browse Data
SASZE Shortwave Array Spectroradiometer-Zenith Browse Data
SKYRAD Sky Radiometers on Stand for Downwelling Radiation Browse Data
SONDE Balloon-Borne Sounding System Browse Data
SONDEADJUST Sonde Adjust Browse Data
TSI Total Sky Imager Browse Data