HR: 0830h
AN: A51E-0734    [PDF]
TI: The Accuracy of Solar Irradiance Calculations Used in Medium Range Forecast Models
AU: * Zamora, R J
EM: robert.j.zamora@noaa.gov
AF: NOAA Environmental Technology Laboratory, 325 Broadway, Boulder, CO 80305 United States
AU: Dutton, E G
EM: ellsworth.g.dutton@noaa.gov
AF: NOAA Climate Monitoring and Diagnostics Laboratory, 325 Broadway, Boulder, CO 80305 United States
AU: Wilczak, J M
EM: james.m.wilczak@noaa.gov
AF: NOAA Environmental Technology Laboratory, 325 Broadway, Boulder, CO 80305 United States
AU: Trainer, M
EM: michael.trainer@noaa.gov
AF: NOAA Aeronomy Laboratory, 325 Broadway, Boulder, CO 80305 United States
AU: McKeen, S A
EM: stuart.a.mckeen@noaa.gov
AF: NOAA Aeronomy Laboratory, 325 Broadway, Boulder, CO 80305 United States
AB: During the 2002 New England Air Quality Study the NOAA Environmental Technology Laboratory (ETL) made radiative transfer observations at the University of New Hampshire, Thompson Farm Air Chemistry Site. We measured upward and downward solar irradiance, upward and downward IR irradiance, and aerosol optical depth at 412, 500, 675 and 862 nm from 18 July through 31 August 2000. We evaluated the solar irradiance forecasts made by both the National Center for Environmental Prediction (NCEP) operational ETA model and the Pennsylvania State University National Center for Atmospheric Research Mesoscale Model 5 (PSU/NCAR/MM5) Air Chemistry Model using the ETL observations. Our observations show that aerosol optical depths exceeding 0.8, accompanied the surface ozone events of 22-23 July and 11-15 August. The comparisons between the solar irradiance observed at Thompson Farm and the ETA and MM5 forecasts for 11-15 August ozone events suggest that the lack of sophisticated aerosol physics in both forecast models can cause the models to produce excessive clear-sky downwelling irradiance. 50-80 W m-2 forecast errors characterize the comparison. Similar comparisons conducted by ETL for Nashville, TN, Houston, TX and the Central Valley of California suggest that the radiative imbalances in models using the Lacis and Hanson solar irradiance parameterization are largest in regions impacted by the aerosols embedded in the East Coast industrial pollution plumes. We will show results that suggest that once the aerosol optical depth exceeds 0.1 the models typically forecast excessive downwelling solar irradiance. We will also present comparisons between JNO2 measured at Thompson farm with the 412 nm sun photometer measurements.
DE: 0300 ATMOSPHERIC COMPOSITION AND STRUCTURE
DE: 0360 Transmission and scattering of radiation
SC: Atmospheric Sciences [A]
MN: 2003 Fall Meeting