| Model ID: | M00044 | ||||||
| Model Name: | The CMOD5 Geophysical Model Function | ||||||
| Encoders: |
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| Key words: | NRCS, C-band Microwave radar | ||||||
| Model Type: | Empirical Model | ||||||
| Latest Modified: | 2012/6/12 0:00:00 | ||||||
| Submission Date: | 2005/9/13 0:00:00 | ||||||
| Abstract: | The model computes C-band VV/HH Normalized Radar Cross Section (NRCS) for a specified incidence angle, radar azimuth angle, wind direction, and wind speed according to the CMOD5 geophysical model function | ||||||
| Equation: |
| 1 |
Name: theta
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Parameter type: double
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Physic Entity: incidence angle，deg
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| 2 |
Name: phi_radar
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Parameter type: double
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Physic Entity: radar illumination azimuth angle relative to north, deg
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| 3 |
Name: phi_wind
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Parameter type: double
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Physic Entity: wind direction relative to north，deg
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| 4 |
Name: spd_wind
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Parameter type: double
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Physic Entity: wind speed，m/s
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| 5 |
Name: Sigma0
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Parameter type: double
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Physic Entity: VV and HH normalized radar cross-section,dB
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| Title: | A Systematic Comparison of the Effect of Polarization Ratio Models on Sea Surface Wind Retrieval From C-Band Synthetic Aperture Radar | |||||||||||||||
| Authors: |
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| Cited by: | IEEE JOURNAL OF SELECTED TOPICS IN APPLIED EARTH OBSERVATIONS AND REMOTE SENSING | |||||||||||||||
| Abstract: | Geophysical model functions (GMFs) for deriving sea surface wind from C-band synthetic aperture radar (SAR) are usually developed and well validated for VV-polarized data, e.g., CMOD5. For wind retrievals from HH-polarization data acquired by some SAR satellites, e.g., RADARSAT-1, part of RADARSAT-2 and ENVISAT ASAR, various Polarization Ratio (PR) models are used to convert normalized radar cross sections (NRCS) from HH to VV polarizations before a GMF is applied. In this study, 116 dual-polarization (VV and HH) C-band ENVISAT Advanced SAR (ASAR) Alternating Polarization (AP) mode images are collected to analyze the behavior of different empirical and theoretical PR models in SAR HH wind retrieval. A new PR model is also developed by analyzing ENVISAT ASAR AP data. SAR HH winds from CMOD5+PR models are validated against SAR VV winds from CMOD5 only. Results show that the proposed new PR model in conjunction with the CMOD5 GMF can constitute promising hybrid GMFs for wind speed retrievals with HH-polarized ENVISAT ASAR images. |
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