Title :
Comparison of ERS Tandem Phase Scatterometer and SAR derived wind speed
Author :
Furevik, Birgitte R. ; Korsbakken, Erik
Author_Institution :
Nansen Environ. & Remote Sensing Center, Bergen, Norway
Abstract :
A validation of wind retrieval by synthetic aperture radar (SAR) has been performed by comparing wind speed estimated from European Remote Sensing Satellite (ERS)-2 SAR with ERS-1 Wind Scatterometer (WSC) measurements, both using the CMODIF2 algorithm. This was possible by using data north of 63°N during the Tandem Phase of the ERS satellites. The WSC and SAR coverage overlapped with a time difference in the data acquisition of only 30 minutes. The WSC has a grid size of 25 km×25 km. 145 sub-images of 25 km×25 km collocated at the WSC wind vectors were extracted from the SAR images and used in the study. The SAR derived wind speed values from these sub-images are within ±2 m/s from the WSC wind speed values and the root-mean-square error is less than 0.5. This is a good correlation considering that ±2 m/s is also the accuracy of the WSC retrieved wind speed. The SAR is observed to underestimate the WSC wind speed with 0.5 m/s. This suggests that (i) the SAR backscatter measurements is not directly comparable to the WSC measurements due to differences in calibration, or (ii) the CMODIF2 needs a correction in its dependence on incidence angle. Their results confirm the usefulness of the SAR derived wind field down to a spatial resolution of 200 m×200 m, provided that external information on wind direction is available
Keywords :
atmospheric techniques; meteorological radar; remote sensing by radar; spaceborne radar; synthetic aperture radar; wind; CMODIF2 algorithm; ERS; ERS-1; ERS-2; SAR; Tandem Phase; Tandem Phase Scatterometer; incidence angle; marine atmosphere; measurement technique; meteorological radar; radar remote sensing; radar scatterometry; retrieval; spaceborne radar; synthetic aperture radar; wind; wind speed; Backscatter; Data acquisition; Data mining; Performance evaluation; Radar measurements; Remote sensing; Satellites; Synthetic aperture radar; Velocity measurement; Wind speed;
Conference_Titel :
Geoscience and Remote Sensing Symposium, 1999. IGARSS '99 Proceedings. IEEE 1999 International
Conference_Location :
Hamburg
Print_ISBN :
0-7803-5207-6
DOI :
10.1109/IGARSS.1999.772043