Indian Ocean Experiment

international field experiment

Also known as: INDOEX

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July 20, 2026

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The Indian Ocean Experiment (INDOEX) was an international field experiment that began in the late 1990s. It involved coordinated measurements of air pollution from satellites, aircraft, ships, surface stations, and balloons. The primary focus was to study the "Asian brown cloud," a large atmospheric phenomenon of aerosols like soot and dust that occurs annually over eastern China and southern Asia from November to May.12

This brown cloud is caused by the combustion of fossil fuels and biomass and has been linked to reduced monsoon rainfall, agricultural declines, and respiratory problems. INDOEX observations revealed a significant aerosol formation over South Asia and the northern Indian Ocean, contributing to a dimming of the surface in India and China.12

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Asian brown cloud
…1990s as part of the Indian Ocean Experiment (INDOEX), in which coordinated air pollution measurements were taken from satellites, aircraft, ships, surface stations, and balloons. The INDOEX observations surprised researchers by revealing a large aerosol formation over most of South Asia and the northern Indian Ocean. Because of the effects…
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…1990s as part of the Indian Ocean Experiment (INDOEX), in which coordinated air pollution measurements were taken from satellites, aircraft, ships, surface stations, and balloons. The INDOEX observations surprised researchers by revealing a large aerosol formation over most of South Asia and the northern Indian Ocean. Because of the effects…
Read More

atmospheric brown cloud
…1990s as part of the Indian Ocean Experiment (INDOEX), in which coordinated air pollution measurements were taken from satellites, aircraft, ships, surface stations, and balloons. The INDOEX observations surprised researchers by revealing a large aerosol formation over most of South Asia and the northern Indian Ocean. This “Asian brown cloud”…
Read More
…1990s as part of the Indian Ocean Experiment (INDOEX), in which coordinated air pollution measurements were taken from satellites, aircraft, ships, surface stations, and balloons. The INDOEX observations surprised researchers by revealing a large aerosol formation over most of South Asia and the northern Indian Ocean. This “Asian brown cloud”…
Read More