Fourteen Years of Aerosol Optical Depth Measurements at the SGP CF

Joseph Michalsky DOC/NOAA/OAR/ESRL
Connor Flynn Pacific Northwest National Laboratory
Gary Hodges NOAA/ESRL/GMD & CU-Boulder/CIRES
Jim Schlemmer No Affiliation
Fred Denn Science Systems and Applications, Inc./NASA
Annette Koontz Pacific Northwest National Laboratory
Stephen Schwartz Brookhaven National Laboratory

Category: Aerosols

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Daily-averaged aerosol optical depth at 500 and 870 nm over the SGP central facility

Aerosol optical depth (AOD) has been measured at the Atmospheric Radiation Measurement (ARM) Climate Research Facility (ACRF0 Central Facility (CF) near Lamont, Oklahoma, since the fall of 1992. Most of the data presented are from the multi-filter rotating shadowband radiometer (MFRSR), however, as many as four simultaneous AOD measurements have been made routinely at the site including sun-pointing sunradiometry. Comparisons are shown. The early part of this 16-year record had a disturbed stratosphere with residual Mt. Pinatubo aerosols, followed by the cleanest stratosphere in decades. As such the last 13 years of the record reflect changes that have occurred predominantly in the troposphere. The field calibration technique used at Southern Great Plains (SGP) is compared to Langley calibrations from Mauna Loa Observatory. AODs are calculated when the sun’s elevation is greater than 9º. A modified cloud-screening technique increases the number of daily-averaged AODs retrieved annually to about 240 days compared to 175 days when a more conservative method was employed in earlier studies. This more inclusive data set produces what is believed to be a better representation of the true aerosol climate at the SGP.

This poster will be displayed at ARM Science Team Meeting.