ERBE OLR and Cloud Type by Split Window
Inoue, T.(a) and Ackerman, S.A.(b), Meteorological Research Institute (a), University of Wisconsin (b)
Twelfth Atmospheric Radiation Measurement (ARM) Science Team Meeting
Using collocated ERBE and split window/AVHRR on board NOAA-9, we studied the relationship between cloud type and OLR. NOAA operational OLR estimation is based on flux equivalent temperature defined by the narrow band TBB. We found the relationship between ERBE OLR and brightness temperature (TBB) was different depending on cloud type classified by the split window. The brightness temperature difference between the split window (BTD) is a good indicator of water vapor amount and cloud optical properties. Therefore, we use the TBB and BTD to determine the regression relationship between the cloud type and ERBE OLR. The overall rms difference between the split window method and ERBE OLR is 6.7 Wm-2. The rms difference is better than the NOAA operational method that shows the rms difference is 10.9 Wm-2. The improvement is significant for clear region and low-level stratocumulus region in comparison with NOAA operational method. Although our method is worse than HIRS multi-channel estimation method that indicates the rms difference of 5 W m-2 (Ellingson et al., 1994), however, it can be applied to the geostationary satellite data that provide us the OLR data with high temporal resolution and regardless of daytime and nighttime.
Note: This is the poster abstract presented at the meeting; an extended version was not provided by the author(s).
