NOAA Climate Data Record (CDR) of MSU and AMSU-A Mean Layer Temperatures, UAH Version 6.0

This dataset includes monthly gridded temperature anomalies on a global 2.5 x 2.5 degree grid derived from Microwave Sounding Unit (MSU) and Advanced Microwave Sounding Unit (AMSU) radiance data since December 1978. In addition, there are monthly regional anomalies and monthly mean annual cycle temperatures. All products are derived for four bulk layers of the atmosphere: the Lower Troposphere (TLT), Mid-Troposphere (TMT), Tropopause (TTP) and Lower Stratosphere (TLS). Version 6.0 is the latest UAH version archived at NOAA and is updated monthly. It utilizes the linear calibration equation with hot-target correction for the MSU series (TIROS-N through NOAA-14) rather than other non-linear calibration equations. Gridded values of absolute temperature are calculated from a polynomial fit in the vertical coordinate of all view angle temperatures binned into each grid over a month. The selected temperature is calculated from a prescribed view-angle where it intersects the polynomial fit of the temperature vs. view-angle relationship or each grid. The diurnal adjustment is completely empirical, calculated by comparing a diurnally-drifting spacecraft against one that is not drifting during their overlap comparison period (for a.m. spacecraft, NOAA-15 vs. (non-drifting) AQUA, and for p.m., NOAA-18 vs. (non-drifting) NOAA-19 during 4 years). The calculated diurnal relationship of temperature change vs. time of day is then applied to all drifting satellites. The Lower Troposphere is calculated from a linear combination of TMT, TTP and TLS rather than from a linear combination of view-angles from the single channel (MSU2 or AMSU5) as was done in versions 5.6 and earlier. A new bulk layer centered on the Tropopause was added in version 6.0. These products were converted from the native text file format to netCDF-4 following CF metadata conventions, and they are accompanied by algorithm documentation, data flow diagram and source code for the NOAA CDR Program.