IAS Gyan

Daily News Analysis


30th September, 2023 Science and Technology

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  • The CALIPSO mission that analysed climate, weather, and air quality ended on August 1, National Aeronautics and Space Administration (NASA) announced.


  • The Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) mission is a collaborative effort between NASA (National Aeronautics and Space Administration) and CNES (Centre National d'Études Spatiales), the French space agency.
  • Launched in April 2006, CALIPSO is a pioneering Earth-observing satellite mission designed to study the Earth's atmosphere and provide essential data for understanding climate change, atmospheric processes, and air quality.

Mission Objectives

Understanding Clouds and Aerosols:

  • CALIPSO's primary objective is to enhance our understanding of clouds and aerosols (tiny solid and liquid particles suspended in the atmosphere) and their roles in Earth's climate system.

Climate Change Research:

  • CALIPSO aims to provide valuable data for climate change research by monitoring key atmospheric parameters.

Air Quality and Weather Forecasting:

  • The mission contributes to improved air quality assessments and weather forecasting by providing real-time atmospheric data.


Lidar Technology:

  • CALIPSO is equipped with a lidar (light detection and ranging) instrument, known as the CALIOP (Cloud-Aerosol Lidar with Orthogonal Polarization).
  • CALIOP uses laser pulses to measure the altitude and properties of clouds and aerosols with high precision.

Passive Sensors:

  • The satellite also carries passive sensors, including the Imaging Infrared Radiometer (IIR) and the Wide Field Camera (WFC), which provide complementary data on clouds and aerosols.

Operational Details

Sun-Synchronous Orbit:

  • CALIPSO and its partner satellite, CloudSat, operated in a Sun-synchronous orbit, crossing the equator in the early afternoon each day.

Measuring Atmospheric Layers:

  • The satellites measured cloud altitudes and the vertical distribution of various airborne particles, including dust, sea salt, ash, and soot.

Achievements and Discoveries

Global Aerosol Mapping:

  • CALIPSO has produced global aerosol maps, helping scientists understand aerosol distribution, sources, and their impact on climate and air quality.

Cloud-Height Profiles:

  • The mission provides detailed cloud-height profiles, which are essential for improving climate models and weather forecasts.

Volcanic Ash Monitoring:

  • CALIPSO's ability to detect volcanic ash clouds has enhanced aviation safety and provided critical data during volcanic eruptions.

Long-Term Climate Records:

  • CALIPSO has contributed to the creation of long-term climate records that are vital for monitoring trends in atmospheric composition.

International Collaboration

Collaboration with Other Satellites:

  • CALIPSO operates in coordination with other Earth-observing satellites like Aqua and Aura, enhancing the accuracy of atmospheric measurements.

Global Impact:

  • CALIPSO's data is freely available to the international scientific community, promoting global collaboration in climate and atmospheric research.


The CALIPSO mission stands as a remarkable example of international collaboration in space-based Earth science. Its lidar technology and other instruments have provided invaluable insights into our planet's atmosphere, aiding climate research, air quality assessments, and weather forecasting. As CALIPSO continues to operate and collect data, it remains a vital tool in our efforts to comprehend and address the complex challenges posed by climate change and atmospheric processes.


Q.   Discuss the key achievements and contributions of NASA's CALIPSO mission, which concluded in August 2023. How has this satellite mission advanced our understanding of Earth's atmosphere, climate dynamics, and air quality? (250 Words)