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| Titel |
Sea surface wind field by TerraSAR-X and Tandem-X data |
| VerfasserIn |
Xiaoming Li, Susanne Lehner |
| Konferenz |
EGU General Assembly 2013
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 15 (2013) |
| Datensatznummer |
250078753
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| Zusammenfassung |
| A new Geophysical Model Function (GMF), denoted XMOD2, is developed to retrieve the
sea surface wind field from X-band TerraSAR-X/Tandem-X (TS-X/TD-X) data. In contrary
to the previous XMOD1, XMOD2 is based on a nonlinear GMF, and moreover
it also depicts the difference between upwind and downwind of the sea surface
backscatter. By exploiting 371 collocations, the retrieved TS-X/TD-X sea surface wind
speed U10 by XMOD2 agrees well with in situ buoy measurements with a bias
of 0.39 m/s, an RMSE of 1.52 m/s and a scatter index (SI) of 16.1%. To apply
XMOD2 to TS-X/TD-X data acquired at HH polarization, we verify the X-band
SAR Polarization Ratio (PR) models by comparing the retrieved sea surface wind
speed to in situ buoy measurements as well. Based on 62 collocated pairs, it is
found that by using the Elfouhaily type PR model and XMOD2 yields better U10
retrieval with a bias of -0.27 m/s, an RMSE of 2.06 m/s and a SI of 22.7% than using
the X-PR model which yields a bias of -0.98 m, and RMSE of 2.30 m and a SI of
23.4%.
Several TerraSAR-X and TanDEM-X ScanSAR images are acquired in October, 2012 to
track the Hurricane Sandy. Three of the images are acquired in the open sea, which are
presented in this chapter to demonstrate observations of sea surface wind and wave
extracted from X-band ScanSAR image with high spatial resolution of 17 m in the
hurricane.
In the case of the TerraSAR-X image acquired on October 26, 2012, we analyze the peak
wave direction and length of swell generated by Hurricane Sandy, as well as interaction of
swell with the Abaco Island, Bahamas. In the other two cases, sea surface wind field derived
from the TerraSAR-X and TanDEM-X acquired on October 27 and 28 are presented.
The sea surface wind speed retrieved by the X-band Geophysical Model Function
(GMF) XMOD2 using wind direction derived from SAR images and the NOAA
Hurricane Research Division (HRD) wind analyses are both presented for comparisons.
We also compare the retrieved sea surface wind speed with Stepped Frequency
Microwave Radiometer (SFMR) to quantify effect of rainfall on X-band SAR images. |
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