HR: 0800h
AN: A41B-0427    [Abstracts]
TI: Selection of Data for Langley Derived Top Atmosphere Reference Values at a Turbid and Humid Coastal Site.
AU: * Denn, F M
EM: frederickmdenn@nasa.gov
AF: Science System and Applications, Inc., 1 Enterprise Parkway, Hampton, VA 23693, United States
AB: The motivation for this work is to preform in situ calibrations of a Multi Filter Rotating Shadow-band Radiometer (MFRSR) at a turbid and humid ocean site, thus eliminating the need to remove it from service for calibration. In pursuit of this goal, a method of selecting data used to preform Langley top of atmosphere (TOA) extrapolations, with relatively constant total optical depth (TOD) is presented. The TOA values, in this case voltages, can be used to derive atmospheric extinction values, and thus atmospheric column densities of various constituents. The data used is this study were collected at the Mauna Loa Observatory (MLO), Hawaii and at the Clouds and the Earth's Radiant Energy System (CERES) Ocean Validation Experiment (COVE) site located 20km off the Virginia, USA coast. MLO is an ideal site for this kind of work, hence the data collected there are used as a reference data set. A set of selection criteria, which select for Langley extrapolation periods, of constant TOD, are applied to the data. The resulting TOA values obtained at COVE are compared to those for MLO. The data were collected using a single MFRSR deployed first at MLO, then at COVE, again at MLO and, finally COVE. The COVE data are shown to have merit for the 500, 615, 673, and 870nm wavelengths but not for the 415 and 940nm wavelengths. Depending on the wavelength, differences in TOA voltages can be as little as 1% (673nm channel) to as much as 30% (940nm channel). This method can be applied to other sun photometers.
DE: 3359 Radiative processes
SC: Atmospheric Sciences [A]
MN: 2007 Fall Meeting