Modis (or Multi-angle Imaging SpectroRadiometer) is a satellite remote sensing instrument that is flown aboard the Terra and Aqua satellites. The instrument observes Earth at multiple angles simultaneously, providing scientists with critical information about our planet’s surface, atmosphere, and biosphere. Modis has revolutionized our understanding of Earth systems and processes, providing insights into topics as diverse as global vegetation health, atmospheric aerosols from volcanic eruptions, and sea surface temperature variability.
The Modis instrument was built by NASA’s Goddard Space Flight Center in Greenbelt, Maryland, USA. The instrument’s primary mirror is 2.45 meters in diameter – about the size of a double door refrigerator – and weighs approximately 1600 kilograms. The telescope uses 26 mirrors to reflect sunlight onto six separate detectors; each detector is sensitive to different wavelengths of light. This allows Modis to measure visible light (including near-infrared and shortwave-infrared), thermal-infrared, and water vapor content in the atmosphere. In total, Modis can measure more than 30 different atmospheric properties and land surface characteristics.
Modis observations are essential for a number of applications related to weather forecasting, climate monitoring, disaster response, and ecosystem management. For example:
– Meteorologists use data from Modis to improve short-term forecasts of hurricanes and other severe storms.
– Climatologists use data from Modis to monitor long-term trends in global climate variables such as sea surface temperature and vegetation health index.
– Wildfire managers use data from Modis to track active fires and map burned areas for post-fire rehabilitation efforts.
– Land managers use data from Modis to assess drought conditions or map invasive species distributions