NOAA Climate Data Record (CDR) of GPS RO-Calibrated AMSU Channel 9 (Temperatures in the Lower Stratosphere,TLS), Version 1.1 (Version Superseded)

**Please note, this dataset has been superseded by a newer version (see below). Users should not use this version except in rare cases (e.g., when reproducing previous studies that used this version).** The Climate Data Records (CDR) for Channel 9 contains Radio Occulation (RO) calibrated brightness temperatures from AMSU-A channel 9 measurements at 57.3 GHz from 2001 through present on a 2.5 degree grid. Data are partitioned into yearly files with monthly variables, where each file contains RO-calibrated channel 9 brightness temperatures from AMSU-A measurements from NOAA-15, 16, 17, 18, 19, NASA AQUA and Metop-A. the NOAA archive of the Level 1b AMSU dataset, and the NASA DAAC archive of the Aqua Level 1B dataset. The RO satellites measure the bending angle of GPS signals as they pass through the atmosphere. Temperature profiles are derived from these GPS bending angles from the COSMIC and CHAMP data from 2001 through present. Calibration coefficients are calculated from coincident measurements of AMSU channel 9 brightness temperatures and corresponding values derived from an AMSU forward model applied to temperature profile measurements from RO temperature profiles. The calibrated AMSU measurements are then combined into gridded monthly values. From these the climatology is calculated using 12 years of data. Anomaly values are then obtained by subtracting this climatology from the monthly values.