International Satellite Cloud Climatology Project (ISCCP) TOVS in Native Data Format

ISCCP_TOVS_NAT_1 is the International Satellite Cloud Climatology Project (ISCCP) TIROS Operational Vertical Sounder (TOVS) data set in the Native Data Format. It is a daily, global description of the ozone, temperature, and humidity distributions obtained from the analysis of data from the TOVS system. The TOVS data set contents include atmosphere and surface data including temperature structure, water, and ozone abundances obtained from the TOVS product and supplemented by two climatologies. The ISCCP_TOVS_NAT data set contains information concerning the atmospheric temperature and humidity profiles as well as the ozone column abundance. Data collection for this data set is complete.

This data set is composed of 3 types of data files: CLIM MONTHLY, which contains the monthly climatological data obtained from balloon observations; TOVS MONTHLY, which contains the monthly climatological data computed from the daily TOVS values; and TOVS DAILY, which contains the daily composite of the TOVS Sounding Product. The data was collected on a global equal-area grid with the cell area equivalent to 2.5 degrees latitude/longitude at the equator. The grid began at the South Pole with the intersection of the Greenwich meridian (0 deg. longitude) and the South Pole as a cell corner.

The TOVS system flew on the NOAA Operational Polar Orbiting Satellite series. Measurements from the High Resolution Infrared Radiation Sounder (HIRS/2), the Stratospheric Sounding Unit (SSU), and the Microwave Sounding Unit (MSU) were processed by NOAA to produce the TOVS Sounding Product.

ISCCP was the first project of the World Climate Research Program (WCRP), to collect and analyze satellite radiance measurements to infer the global distribution of cloud radiative properties and their diurnal and seasonal variations. These data and analysis products were used to improve the understanding and modeling of the effects of clouds on climate. The ISCCP version of the ice/snow data set included only information concerning fractional coverage. The version actually used in the cloud analysis was changed in two ways: reductions to ice/snow presence and creation of margin zones in the data. The first of these was simply the process of converting the coded parameters in the original data set to code values that indicate only the presence or absence of sea ice and/or snow. The latter process filled in nearby grid cells in the data to indicate proximity to snow or sea ice covered locations. The second change is not included in the archived version of this data.