All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 134 28 6
PDF Downloads 30 10 0

A Comparison of ERBE and AVHRR Longwave Flux Estimates

Arnold Gruber
Search for other papers by Arnold Gruber in
Current site
Google Scholar
PubMed
Close
,
Robert Ellingson
Search for other papers by Robert Ellingson in
Current site
Google Scholar
PubMed
Close
,
Philip Ardanuy
Search for other papers by Philip Ardanuy in
Current site
Google Scholar
PubMed
Close
,
Mitchell Weiss
Search for other papers by Mitchell Weiss in
Current site
Google Scholar
PubMed
Close
,
S. K. Yang
Search for other papers by S. K. Yang in
Current site
Google Scholar
PubMed
Close
, and
Sung Nam Oh
Search for other papers by Sung Nam Oh in
Current site
Google Scholar
PubMed
Close
Restricted access

Comparisons have been made between estimates of the outgoing longwave radiation (OLR) at the top of the atmosphere derived from narrowband Advanced Very High Resolution Radiometer (AVHRR) and broadband Earth Radiation Budget Experiment (ERBE) scanning instruments. Four months of measurements are considered: April, July, and October 1985 and January 1986. Instantaneous comparisons (i.e., collocated in space and time) are considered.

In the former, regional, zonal, and global analyses are performed using collocated and coincident OLR estimates on a 2.5° latitude-longitude scale. In general, the two datasets are found to be in reasonably good agreement, with the mean state and fundamental variability in time and space captured by the two sets of measurements. However, systematic biases are observed between the two datasets, particularly over the subtropical oceans, the daytime deserts, and over snow-covered surfaces at the high latitudes. The monthly global bias between the two datasets (ERBE minus AVHRR) is between −1 and 2 Wm−2 during daytime, and between 4 and 7 Wm−2 during nighttime, while the rms differences range between 12 (June) and 15 (January) Wm−2.

Radiative transfer simulations show that these systematic errors may be attributed to limitations in the single-channel narrowband to broadband algorithm. Even though the results may be globally unbiased, regional biases result where particularly persistent conditions (e.g., trade wind inversion, subsidence over deserts) prevail.

*Office of Research and Applications, National Environmental Satellite, Data, and Information Services, National Oceanic and Atmospheric Administration, Washington, D.C.

+Cooperative Institute for Climate Studies, University of Maryland, College Park, Maryland.

**Research and Data Systems Corporation, Greenbelt, Maryland

++Systems Engineering Research Institute, Korean Institute of Science and Technology, Taejeon, Korea.

Corresponding author address: Dr. Arnold Gruber, Office of Research and Applications, NESDIS/NOAA, Washington, DC 20233.

Comparisons have been made between estimates of the outgoing longwave radiation (OLR) at the top of the atmosphere derived from narrowband Advanced Very High Resolution Radiometer (AVHRR) and broadband Earth Radiation Budget Experiment (ERBE) scanning instruments. Four months of measurements are considered: April, July, and October 1985 and January 1986. Instantaneous comparisons (i.e., collocated in space and time) are considered.

In the former, regional, zonal, and global analyses are performed using collocated and coincident OLR estimates on a 2.5° latitude-longitude scale. In general, the two datasets are found to be in reasonably good agreement, with the mean state and fundamental variability in time and space captured by the two sets of measurements. However, systematic biases are observed between the two datasets, particularly over the subtropical oceans, the daytime deserts, and over snow-covered surfaces at the high latitudes. The monthly global bias between the two datasets (ERBE minus AVHRR) is between −1 and 2 Wm−2 during daytime, and between 4 and 7 Wm−2 during nighttime, while the rms differences range between 12 (June) and 15 (January) Wm−2.

Radiative transfer simulations show that these systematic errors may be attributed to limitations in the single-channel narrowband to broadband algorithm. Even though the results may be globally unbiased, regional biases result where particularly persistent conditions (e.g., trade wind inversion, subsidence over deserts) prevail.

*Office of Research and Applications, National Environmental Satellite, Data, and Information Services, National Oceanic and Atmospheric Administration, Washington, D.C.

+Cooperative Institute for Climate Studies, University of Maryland, College Park, Maryland.

**Research and Data Systems Corporation, Greenbelt, Maryland

++Systems Engineering Research Institute, Korean Institute of Science and Technology, Taejeon, Korea.

Corresponding author address: Dr. Arnold Gruber, Office of Research and Applications, NESDIS/NOAA, Washington, DC 20233.
Save