CALIPSO was launched into a sun-synchronous orbit on April 28, 2006, where it joined the A-Train constellation of four other Earth-orbiting satellites: Aqua, Aura, CloudSat and Parasol. The primary objective of CALIPSO's three-year mission is to make a global survey of the vertical structure of clouds and aerosols and their physical properties.
CALIPSO comprises three instruments, the Cloud-Aerosol LIdar with Orthogonal Polarization (CALIOP), the Imaging Infrared Radiometer (IIR), and the Wide Field Camera (WFC). CALIOP is a two-wavelength, polarization-sensitive lidar that provides information about the composition of clouds, the abundance and sizes of aerosols, and the altitudes of cloud and aerosol layers. The IIR measures outgoing radiation at three wavelengths in the thermal infrared window (8.65 mm, 10.6 mm, and 12.0 mm) to determine cloud emissivity and particle size. The high resolution, nadir-viewing WFC images the region around the lidar and IIR measurements in a single spectral channel (645 nm), which is matched to Band 1 of the MODIS instrument on the Aqua satellite in the A-Train, to provide context for the data from the other instruments.
CALIPSO produces Level 1 and Level 2 archived science data products. The Level 1 data include:
- lidar calibrated and geo-located profiles for the day and night portions of the orbit, with associated browse imagery
- IIR geo-located, calibrated radiances registered to a 1 km grid centered on the lidar track
- WFC geo-located radiances at 125 m and 1 km resolution for the daytime portion of each orbit
Level 2 products include:
- a cloud layer product with horizontal resolutions of 1/3 km, 1 km and 5 km which includes cloud height, thickness, backscatter, extinction, ice/water phase, emissivity, and ice particle size
- an aerosol layer product at 5 km horizontal resolution which includes height, thickness, optical depth, and integrated attenuated backscatter
- an aerosol profile product with a horizontal resolution of 40 km and vertical resolution of 120 m up to 30.1 km, which includes backscatter, extinction, and depolarization profile data
- a cloud profile product with 5 km horizontal resolution and 60 m vertical resolution up to 20.2 km, which includes backscatter, depolarization, and extinction profile data and ice water content
- IIR Level 2 cloud emissivity and particle size in 1 km pixels, with a 70 km swath width co-located to the lidar track
The latter three products are new in the release of data planned for the fourth quarter of 2007. In that release the entire CALIPSO data stream is being reprocessed with revised algorithms to update the data values and add new parameters in the existing data sets.
The ASDC provides access to CALIPSO data tools including a suite of read software written in ITT Visual Information Solutions' Interactive Data Language (IDL) and the HDFView software from the HDF Group for exploring the files and writing out parameters. The ASDC has also developed a new visual data fusion tool which provides geo-located display of CALIPSO data files in conjunction with data from other satellite instruments, such MODIS, OMI, PARASOL and TES, which are flying in the A-Train formation with CALIPSO.
The ASDC provides data access, services and tools for over 35 projects in the discipline areas of Earth's radiation budget, clouds, aerosols and tropospheric chemistry. Additional information is available from the ASDC web site, http://eosweb.larc.nasa.gov.
Supplementary URL: http://eosweb.larc.nasa.gov