TY  - JOUR
A1  - Asgarimehr, Milad
A1  - Wickert, Jens
A1  - Reich, Sebastian
T1  - TDS-1 GNSS Reflectometry
BT  - Development and Validation of Forward Scattering Winds
JF  - IEEE journal of selected topics in applied earth observations and remote sensing
N2  - This study presents the development and a systematic evaluation study of GNSS reflectometry wind speeds. After establishing a wind speed retrieval algorithm, UK TechDemoSat-1 (TDS-1) derived winds, from May 2015 to July 2017, are compared to the Advanced Scatterometer (ASCAT). ERA-Interim wind fields of the European Centre for Medium-range Weather Forecasts (ECMWF) and in situ observation from Tropical Atmosphere Ocean buoy array in the Pacific are taken as reference. One-year averaged TDS-1 global winds demonstrate small differences with ECMWF in a majority of areas as well as discuss under- and overestimations. The pioneering TDS-1 winds demonstrate a root-mean-squared error (RMSE) and bias of 2.77 and -0.33 m/s, which are comparable to the RMSE and bias derived by ASCAT winds, as large as 2.31 and 0.25 m/s, respectively. Using buoys measurements as reference, RMSE and bias of 2.23 and -0.03 m/s for TDS-1 as well as 1.40 and -0.68 m/s for ASCAT are obtained. Utilizing rain microwave-infrared estimates of the Tropical Rainfall Measuring Mission, rain-affected observation of both ASCAT and TDS-1 are collected and evaluated. Although ASCAT winds show a significant performance degradation resulting in an RMSE and bias of 3.16 and 1.03 m/s, respectively, during rain condition, TDS-1 shows a more reliable performance with an RMSE and bias of 2.94 and -0.21 m/s, respectively, which indicates the promising capability of GNSS forward scattering for wind retrievals during rain. A decrease in TDS-1-derived bistatic radar cross sections during rain events, at weak winds, is also demonstrated.
KW  - Advanced scatterometer (ASCAT)
KW  - European Centre for Medium-Range Weather Forecasts (ECMWF)
KW  - GNSS forward scatterometry
KW  - GNSS reflectometry
KW  - TechDemoSat-1 (TDS-1)
KW  - wind speed
Y1  - 2018
U6  - https://doi.org/10.1109/JSTARS.2018.2873241
SN  - 1939-1404
SN  - 2151-1535
VL  - 11
IS  - 11
SP  - 4534
EP  - 4541
PB  - Inst. of Electr. and Electronics Engineers
CY  - Piscataway
ER  -