Near-surface wind speed retrieval from space-based, multi-angle imaging of ocean sun glint patterns
✍ Scribed by David Fox; Enrique Gonzalez; Ralph Kahn; John Martonchik
- Book ID
- 104091766
- Publisher
- Elsevier Science
- Year
- 2007
- Tongue
- English
- Weight
- 1012 KB
- Volume
- 107
- Category
- Article
- ISSN
- 0034-4257
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✦ Synopsis
The relationship between the MISR multi-angle observations of sun glint pattern width over ocean and the near-surface wind speed is explored. With this relationship, we develop an algorithm that can constrain the standard, wind-driven glint/white cap model that defines the ocean-surface boundary condition in MISR aerosol retrievals. The key geometric factor determining wind retrieval quality is the angular distance between the reflection vector and the closest MISR multi-angle observationthe minimum Sun Glint Angle (SGA).
MISR-retrieved winds are within 2.4 m/s of buoy-measured values for minimum SGA below about 15°for the 38 cases studied, and usually better than 1.1 m/s, except one for which the wind speed was extremely low. For minimum SGA above about 15°, MISR angular glint pattern reflectance sampling is not adequate to perform wind retrievals. An ambiguity in the retrieval that can occur for minimum SGA greater than 6°or 7°is resolved by the minimum observed absolute reflectance. We also confirm the high accuracy of the Cox-Munk ocean surface reflectance model, used to analyze the glint pattern dependence on wind speed. The wind-retrieval method could be used in an operational multi-angle aerosol retrieval algorithm to dynamically constrain the ocean surface boundary condition when glint pattern angular sampling is adequate.