Investigation Of Tropical Cyclone Wind Asymmetry From Cross-Polarization Sar Imagery

2020 ◽  
Author(s):  
Xiaofeng Yang ◽  
Sheng Wang ◽  
Kaijun Ren
Keyword(s):  
Tropical Cyclone ◽  
Cross Polarization ◽  
Sar Imagery

Tropical Cyclone Winds and Inflow Angle Asymmetry from SAR Imagery

2021 ◽  
Author(s):  
Guosheng Zhang ◽  
Xiaofeng Li ◽  
William Perrie ◽  
Jun A. Zhang
Keyword(s):  
Tropical Cyclone ◽  
Sar Imagery

scholarly journals Tropical Cyclone Wind Speed Retrieval from Dual-Polarization Sentinel-1 EW Mode Products

2020 ◽  
Vol 37 (9) ◽  
pp. 1713-1724
Author(s):  
Yuan Gao ◽  
Changlong Guan ◽  
Jian Sun ◽  
Lian Xie
Keyword(s):  
Wind Speed ◽  
Tropical Cyclone ◽  
Noise Removal ◽  
Cross Polarization ◽  
High Wind ◽  
Dual Polarization ◽  
High Wind Speed ◽  
Wind Speeds ◽  
Hurricane Wind ◽  
The Cross

AbstractRecent studies indicate that the cross-polarization synthetic aperture radar (SAR) images have the ability of retrieving high wind speed on ocean surface without wind direction input. This study presents a new approach for tropical cyclone (TC) wind speed retrieval utilizing thermal-noise-removed Sentinel-1 dual-polarization (VV + VH) Extra-Wide Swath (EW) Mode products. Based on 20 images of 9 TCs observed in the 2016 and 2018 and SAR-collocated European Centre for Medium-Range Weather Forecasts (ECMWF) fifth-generation reanalysis (ERA5) data and the National Oceanic and Atmospheric Administration (NOAA) Hurricane Research Division’s (HRD) Real-time Hurricane Wind Analysis System (H*Wind) data, a subswath-based geophysical model function (GMF) Sentinel-1 EW Mode Wind Speed Retrieval Model after Noise Removal (S1EW.NR) is developed and validated statistically. TC wind speed is retrieved by using the proposed GMF and the C-band model 5.N (CMOD5.N). The results show that the wind speeds retrieved by the S1EW.NR model are in good agreement with wind references up to 31 m s−1. The correlation coefficient, bias, and standard deviation between the retrieval results and reference wind speeds are 0.74, −0.11, and 3.54 m s−1, respectively. Comparison of the wind speeds retrieved from both channels suggests that the cross-polarized signal is more suitable for high–wind speed retrieval, indicating the promising capability of cross-polarization SAR for TC monitoring.

scholarly journals DETECTION OF MARINE VESSELS BASED ON VARIATION OF DEGREE OF POLARIZATION

2018 ◽  
Vol IV-5 ◽  
pp. 311-316
Author(s):  
G. K. Dashondhi ◽  
K. M. Buddhiraju
Keyword(s):  
Satellite Images ◽  
Speckle Noise ◽  
Vital Role ◽  
Degree Of Polarization ◽  
False Alarms ◽  
Cross Polarization ◽  
Maritime Surveillance ◽  
L Band ◽  
Sar Imagery ◽  
Marine Vessels

<p><strong>Abstract.</strong> For improving security of any country, satellite images are playing vital role. Vessels detection using SAR imagery is one of the primary requirements for maritime surveillance. In this paper, the algorithm used for vessels detection has four parts. The first part includes pre-processing to reduce speckle noise, second part helps in the reduction of cross polarization by real and complex rotation of the coherency matrix, third part derives a new parameter called variation of degree of polarization (VD) and fourth one is a post processing part to connect region and fill gaps using morphological operation. The proposed algorithm is tested on ALOS PALSAR1 (space borne L band) and UAVSAR (Airborne L band) datasets and yielded promising results with a relatively few false alarms.</p>

scholarly journals A Study of the Intensity of Tropical Cyclone Idai Using Dual-Polarization Sentinel-1 Data

2019 ◽  
Vol 11 (23) ◽  
pp. 2837 ◽  
Author(s):  
Peng Yu ◽  
Johnny A. Johannessen ◽  
Xiao-Hai Yan ◽  
Xupu Geng ◽  
Xiaojing Zhong ◽  
...  
Keyword(s):  
Wind Speed ◽  
Tropical Cyclone ◽  
Band Model ◽  
Strong Wind ◽  
Cross Polarization ◽  
Dual Polarization ◽  
Wind Fields ◽  
Polarization Model ◽  
Wind Speeds ◽  
Intense Storm

Monitoring the intensity and size of a tropical cyclone (TC) is a challenging task, and is important for reducing losses of lives and property. In this study, we use Idai, one of the deadliest TCs on record in the Southern Hemisphere, as an example. Dual-polarization synthetic aperture radar (SAR) measurements from the Copernicus Sentinel-1 mission are used to examine the TC structure and intensity. The wind speed is estimated and compared using well known C-band model functions based on calibrated cross-polarization SAR images. Because of the relatively high noise floor of the Sentinel-1 data, wind speeds under 20 m/s from cross-polarization models are ignored and replaced by low to moderate wind speeds retrieved from co-polarization radar signals. Wind fields retrieved from the co- and cross-polarization model results are then merged together to estimate the TC size and the TC fullness scale, a concept related to the wind structure of a storm. Idai has a very strong wind speed and fullness structure, indicating that it was indeed a very intense storm. The approach demonstrates that open and freely available Sentinel-1 SAR data is a unique dataset to estimate the potential destructiveness of similar natural disasters like Idai.

scholarly journals Wind direction retrieval of tropical cyclone from SAR imagery using improved local gradient method

2020 ◽  
Vol 569 ◽  
pp. 012055
Author(s):  
Yan Wang ◽  
Gang Zheng ◽  
Lizhang Zhou ◽  
Zhou Qiu ◽  
Xiaohui Li ◽  
...  
Keyword(s):  
Tropical Cyclone ◽  
Gradient Method ◽  
Wind Direction ◽  
Sar Imagery ◽  
Local Gradient
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