TY  - JOUR
A1  - Asgarimehr, Milad
A1  - Zavorotny, Valery
A1  - Wickert, Jens
A1  - Reich, Sebastian
T1  - Can GNSS Reflectometry Detect Precipitation Over Oceans?
JF  - Geophysical research letters
N2  - For the first time, a rain signature in Global Navigation Satellite System Reflectometry (GNSS-R) observations is demonstrated. Based on the argument that the forward quasi-specular scattering relies upon surface gravity waves with lengths larger than several wavelengths of the reflected signal, a commonly made conclusion is that the scatterometric GNSS-R measurements are not sensitive to the surface small-scale roughness generated by raindrops impinging on the ocean surface. On the contrary, this study presents an evidence that the bistatic radar cross section sigma(0) derived from TechDemoSat-1 data is reduced due to rain at weak winds, lower than approximate to 6 m/s. The decrease is as large as approximate to 0.7 dB at the wind speed of 3 m/s due to a precipitation of 0-2 mm/hr. The simulations based on the recently published scattering theory provide a plausible explanation for this phenomenon which potentially enables the GNSS-R technique to detect precipitation over oceans at low winds.
KW  - GNSS Reflectometry
KW  - rain detection
KW  - rain splash
KW  - TDS-1
KW  - ocean surface
KW  - electromagnetic scattering
Y1  - 2018
U6  - https://doi.org/10.1029/2018GL079708
SN  - 0094-8276
SN  - 1944-8007
VL  - 45
IS  - 22
SP  - 12585
EP  - 12592
PB  - American Geophysical Union
CY  - Washington
ER  -