New Value-Added Product Provides Tropospheric Temperature Measurements

 
Published: 4 February 2013

Sample output from the RLPROFTEMP VAP showing four selected months. Results are shown for (a) January 2009, (b) April 2009, (c) July 2009, and (d) October 2009.
Temperature is one of the most fundamental atmospheric state variables and is crucial to the understanding of many meteorological processes. The Raman lidars at the ARM Climate Research Facility Southern Great Plains (SGP) and Tropical Western Pacific (TWP) Darwin sites are currently the only ARM active remote sensing instruments capable of profiling temperature through much of the troposphere.

Temperature measurements are made possible using the rotational Raman (RR) technique. This technique uses two detection channels that sense Raman-shifted backscatter arising from rotational energy state transitions in atmospheric N2 and O2 molecules due to excitation at the laser wavelength of 354.7 nm. These detection channels use very narrow-bandwidth interference filters to measure the energy content in two different bands of the rotational spectrum. The ratio of the signals from these two detection channels is temperature-sensitive.

The Raman Lidar Profiles-Temperature (RLPROFTEMP) value-added product (VAP) processes the signals from the RR channels and provides calibrated profiles of atmospheric temperature from ~200 m AGL to 15 km AGL at temporal resolutions of 10 and 60 minutes. Results are generated for the SGP Raman lidar and the TWP-Darwin Raman lidar results are being finalized.

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