Remote Sensing Systems (RSS) Analysis of MSU and AMSU Data, Version 3.3: Monthly Brightness Temperature

The Microwave Sounding Units (MSU) operating on NOAA polar-orbiting platforms have been the principal sources of satellite temperature profiles for the past two decades. The MSUs are cross-track scanners with measurements of microwave radiance in four channels ranging from 50.3 to 57.95 GHz on the lower shoulder of the Oxygen absorption band. These four channels measure the atmospheric temperature in four thick layers spanning the surface through the stratosphere.

A series of follow-on instruments, the Advanced Microwave Sounding Units (AMSUs), began operation in 1998 with the intent of extending microwave sounding measurements into the foreseeable future. The AMSU instruments are similar to the MSUs, but they make measurements using a larger number of channels, thus sampling the atmosphere in a larger number of layers. By using the AMSU channels that most closely match the channels in the MSU instruments, it can be continued to extend the climate-quality dataset.

Remote Sensing Systems (RSS), in collaboration with Dian Seidel of the NOAA Air Resources Laboratory, is funded by the NOAA Climate and Global Change Program to perform an end-to-end analysis of the tropospheric and stratospheric data from the MSU and AMSU series of microwave sounders. The scientists working on the microwave sounding data are Carl Mears and Frank Wentz at Remote Sensing Systems. So far, they have merged the Channel 2 and 4 brightness temperature data from the nine MSU instruments, and Channel 3 brightness temperature data from NOAA-10, NOAA-11, NOAA-12, and NOAA-14, instruments into single brightness temperature datasets for each channel. The merging process requires careful adjustment of the MSU observations to account for drifts caused by orbital decay and changes in local observing time. Then, intersatellite offsets and errors caused by changes in the temperature of the calibration sources are precisely determined. Significant drifts in Channel 3 data from NOAA-6 and NOAA-9 made it impossible to accurately extend the analysis to times before December 1986 for this channel.

The brightness temperature for each channel corresponds to an average temperature of the atmosphere averaged over that channel's weighting function. For each channel, the brightness temperature can be thought of as the averaged temperature over a thick atmospheric layer.

MSU and AMSU "Channels":
TLT= Temperature Lower Troposphere MSU 2 and AMSU 5
TMT=Temperature Middle Troposphere MSU 2 and AMSU 5
TTS=Temperature Troposphere / Stratosphere MSU 3 and AMSU 7
TLS=Temperature Lower Stratosphere MSU 4 and AMSU 9
TTT=Temperature Total Troposphere MSU 2,4 and AMSU 5,9

Reference:
Carl A. Mears and Frank J. Wentz. "Construction of climate-quality atmospheric temperature records from the MSU and AMSU microwave sounders", submitted to the Journal of Atmospheric and Oceanic Technology, May 2008.

Carl A. Mears, Matthias Schabel, Frank J. Wentz. "A reanalysis of the MSU Channel 2 Tropospheric Temperature Record", Journal of Climate, Volume 16, pg. 3650-3664, November, 2003.

Variables
Channel TLS Monthly Brightness Temperature (degK)
Channel TLS Monthly Brightness Temperature Anomaly (degK)
Channel TLT Monthly Brightness Temperature (degK)
Channel TLT Monthly Brightness Temperature Anomaly (degK)
Channel TMT Monthly Brightness Temperature (degK)
Channel TMT Monthly Brightness Temperature Anomaly (degK)
Channel TTS Monthly Brightness Temperature (degK)
Channel TTS Monthly Brightness Temperature Anomaly (degK)
Channel TTT Monthly Brightness Temperature (degK)
Channel TTT Monthly Brightness Temperature Anomaly (degK)
ZonalGlobal by 2.5 deg
MeridionalGlobal by 2.5 deg
VerticalLower Troposphere, Middle Troposphere, Lower Stratosphere, Troposphere / Stratosphere  
Temporal Dec 1978 to Aug 2014 (All except TTS) by 1 month(s)
Jan 1987 to Aug 2014 (TTS) by 1 month(s)
Static?no
Volume 18MB per variable
Serverpublic:
Sourcehttp://www.remss.com/measurements/upper-air-temperature 
Acquired Mar 23, 2011 (Updated Oct 2014)
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