The Polar-orbiting Operational Environmental Satellite (POES) series offers the advantage of daily global coverage, by making nearly polar orbits 14 times per day approximately 520 miles above the surface of the Earth. The Earth's rotation allows the satellite to see a different view with each orbit, and each satellite provides two complete views of a location around the world each day. The POES constellation of weather satellites is a joint effort between the National Oceanic and Atmospheric Administration (NOAA) and the European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT). The Advanced Very High Resolution Radiometer (AVHRR) is a cross-track scanning system with five spectral bands having a resolution of 1.1 km and a frequency of earth scans twice per day (usually 0230 and 1430 local solar time) on NOAA and EUMETSAT satellites. There are three data types produced from the NOAA POES AVHRR. The Global Area Coverage (GAC) data set is reduced resolution image data that is processed onboard the satellite taking only one line out of every three and averaging every four of five adjacent samples along the scan line; the Local Area Coverage (LAC) data set is recorded onboard at original resolution (1.1 km) for part of an orbit and later transmitted to earth; and the High Resolution Picture Transmission (HRPT) is real-time downlink data. The EUMETSAT MetOp satellite series, initially launched on October 19, 2006, produces the same three data types as well as a fourth data type, Global Full Resolution Area Coverage (FRAC 1.1 km). The MetOp polar orbiting operational meteorological satellite system is the European contribution to the Initial Joint Polar-Orbiting Operational Satellite System (IJPS). AVHRR data provide opportunities for studying and monitoring vegetation conditions in ecosystems including forests, tundra and grasslands. Applications include agricultural assessment, land cover mapping, producing image maps of large areas such as countries or continents, and tracking regional and continental snow cover. AVHRR data are also used to retrieve various geophysical parameters such as sea surface temperatures and energy budget data.

This data set consists of daily visible-band (VIS) imagery and infrared-band (IR) imagery derived from the Environmental Sciences Service Administration (ESSA) satellites, the Improved TIROS Operational System 1 (ITOS 1) satellite, and the the National Oceanic and Atmospheric Administration (NOAA) satellites covering December 1966 through March 1978 (IR data begins in December 1972). The data set was created by scanning the analog imagery from these satellites held in the NOAA National Centers for Environmental Information (NCEI) physical archives in Asheville, NC. Images on 35 mm film, glossy prints, or paper halftone prints were scanned, processed, and then converted to NetCDF format.

The High-Resolution Infrared Radiation Sounder (HIRS) of intersatellite calibrated channel 12 brightness temperature product is a gridded global monthly time series product spanning from 1979 to the most current full month, updated monthly. Among the twenty channels in the HIRS instrument, channel 12 measures upper tropospheric water vapor. Multiple polar orbiting satellites in the NOAA Polar-orbiting Operational Environmental Satellite (POES) and MetOp series have carried HIRS instruments. Due to the independence in calibration of the individual HIRS instruments, biases exist between satellites. Examination of the intersatellite biases shows that the biases are scene brightness temperature dependent. These HIRS channel 12 measurements from the NOAA POES and MetOp series are calibrated to a baseline satellite based on intersatellite bias correction data. The dataset is provided as monthly mean 2.5x2.5 degree latitude/longitude in netcdf format. This CDR is key to understanding water vapor feedback climatology and has been used to study long-term water vapor variability, to evaluate climate models, and to study large-scale atmospheric circulations.

The High-Resolution Infrared Radiation Sounder (HIRS) of intersatellite calibrated channel 12 brightness temperature product is a gridded global monthly time series product spanning from 1979 to the most current full month, updated monthly. Among the twenty channels in the HIRS instrument, channel 12 measures upper tropospheric water vapor. Multiple polar orbiting satellites in the NOAA Polar-orbiting Operational Environmental Satellite (POES) and MetOp series have carried HIRS instruments. Due to the independence in calibration of the individual HIRS instruments, biases exist between satellites. Examination of the intersatellite biases shows that the biases are scene brightness temperature dependent. These HIRS channel 12 measurements from the NOAA POES and MetOp series are calibrated to a baseline satellite based on intersatellite bias correction data. The dataset is provided as monthly mean 2.5x2.5 degree latitude/longitude in netcdf format. This CDR is key to understanding water vapor feedback climatology and has been used to study long-term water vapor variability, to evaluate climate models, and to study large-scale atmospheric circulations.

This NOAA Climate Data Record (CDR) contains the AVHRR Polar Pathfinder (APP) product. APP is a fundamental CDR comprised of calibrated and navigated AVHRR channel data (reflectances and brightness temperatures), viewing and illumination geometry (sensor scan angle, solar zenith angle, and sun-sensor relative azimuth angle), Universal Coordinated Time (UTC) of the data acquisition, and a surface type mask. The data are twice daily composites of up to 23 orbits on a 5 km Equal-Area Scalable Earth (EASE)-Grid twice daily over both poles, the Arctic and Antarctic, from 1982 to the present. The daily APP composites are centered on local solar times of 14:00 (high sun, but could be nighttime for some polar areas in winter) and 04:00 for the Arctic or 02:00 for the Antarctic. The APP covers the north polar region (Arctic) from 48.4 degrees northward, and the south polar region (Antarctic) from -53.2 degrees southward. The update to version 2 of the APP FCDR was updated calibration coefficients for AVHRR GAC visible channels over the entire period.