Studying Clouds Over India’s Ganges Valley

Summary

DOE’s Atmospheric Radiation Measurement (ARM) Climate Research Facility is a multi-platform national scientific user facility that supports research for addressing the major uncertainties of climate models—clouds and aerosols—with heavily instrumented fixed research sites in Oklahoma, Alaska, and the tropical Western Pacific. It also provides mobile and aerial measurement platforms to support research at key sites around the world. This week, through an intergovernmental agreement with India, an ARM mobile facility began operating at the Aryabhatta Research Institute of Observational Sciences (ARIES) in India for the Ganges Valley Aerosol Experiment (or GVAX). Measurements obtained during the nine-month field study will enable scientists to study how aerosols—small particles like dust and soot—in the air affect the formation of clouds and whether they increase or decrease the amount of precipitation that falls from them. Their findings will be used to improve computer models that simulate Earth’s climate system. Some studies suggest that haze over the Ganges Valley region will increase temperature and pressure, which could draw moisture from the ocean and intensify seasonal monsoons. Other studies indicate the increased heat will cause clouds to dry up. To refine these possibilities, data are needed that span both the summer and winter monsoon seasons. This is the first large-scale field study that the United States or any other country has conducted in India that is related to environmental and climate issues. This collaborative experiment, in addition to DOE and the Indian government, involves NOAA, NSF, and the Navy.