Error estimates of spaceborne passive microwave retrievals of cloud liquid water over land
- Colorado State Univ., Fort Collins, CO (United States). Cooperative Inst. for Research in the Atmosphere
Cloud liquid water path (LWP) retrievals from the Special Sensor Microwave/Imager (SSM/I) and surface microwave radiometers are compared over land to assess the errors in selected satellite methods. These techniques require surface emissivity composites created from SSM/I and infrared (IR) data. Two different physical methods are tested: a single-channel (SC) approach; and a normalized polarization difference (NPD) approach. Comparisons were made at four sites in Oklahoma and Kansas over an 1-month period. The 85.5-GHz NPD method was the most accurate and robust under most conditions. An error analysis shows that the method`s random errors are dominated by uncertainties in the surface emissivity and instrument noise. Since the SC method is more prone to systematic errors (such as surface emissivity errors caused by rain events), it initially compared poorly to the ground observations. After filtering for rain events, the comparisons improved. Overall, the root mean square (rms) errors ranged from 0.12 to 0.14 kg m{sup {minus}2}, suggesting these methods can provide, at best, three categories of cloud LWP. It is anticipated that the techniques and strategies developed in this study, and prior related studies, to analyze passive microwave data will be requisite for maximizing the information content of future instruments.
- Sponsoring Organization:
- USDOE Office of Energy Research, Washington, DC (United States); Department of Defense, Washington, DC (United States)
- OSTI ID:
- 355579
- Journal Information:
- IEEE Transactions on Geoscience and Remote Sensing, Vol. 37, Issue 2Pt1; Other Information: PBD: Mar 1999
- Country of Publication:
- United States
- Language:
- English
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