The Dependence of Sea-Surface Microwave Emission on Wind Speed, Frequency, Incidence Angle, and Polarzation over the Frequency Range from 1 to 40 GHz

AMSR-E advanced wind speed retrieval algorithm and its application to marine weather systems

“…At -2 < t о < 12°C the variations of T Boc H (11) do not exceed 0.3 K and as the first assumption can be considered as a constant equal to 67.1 K. Minimum T Boc ≈ 66.9 K is observed at t о ≈ 4°C. Accurate values can be derived by a formula: Dependence of ΔT Boc H (11,W) (the sea surface emissivity) on W is nonlinear that follows from analysis of experimental data [4,[12][13][14][15][16][17]. Microwave measurements were carried out from ground, airplane and satellite platforms at different frequencies at vertical and horizontal polarization at the broad range of the incidence angles and wind speed.…”

“…Microwave measurements were carried out from ground, airplane and satellite platforms at different frequencies at vertical and horizontal polarization at the broad range of the incidence angles and wind speed. The sensitivity of T Boc V,H ( ) and V,H ( ) to the sea surface wind speed changes with W. Estimates of these dependencies and the suggested approximating functions vary significantly [5,6,[13][14][15][16][17]. In particular, wind speed sensitivity ΔT Boc H (11,W)/ΔW determined by analysis of the AMSR-E measurements was ≈ 1 K/(m/s) [5,6] as opposite to the estimates 0.5-0.6 K/(m/s) [13,14].…”

“…The sensitivity of T Boc V,H ( ) and V,H ( ) to the sea surface wind speed changes with W. Estimates of these dependencies and the suggested approximating functions vary significantly [5,6,[13][14][15][16][17]. In particular, wind speed sensitivity ΔT Boc H (11,W)/ΔW determined by analysis of the AMSR-E measurements was ≈ 1 K/(m/s) [5,6] as opposite to the estimates 0.5-0.6 K/(m/s) [13,14]. The higher values of the wind speed sensitivity were also derived by processing data acquired by a stepped frequency microwave radiometer operating at = 5-8 GHz during several flights in the areas gale winds [17].…”

Polarization signature from the FengYun-3 Microwave Humidity Sounder

“…It is well known that microwave radiation emitted from oceans in the low frequency range, from 6 GHz to 37 GHz, exhibits an obvious difference between vertical and horizontal polarization states (Wilheit, 1979;Sasaki et al, 1987;Ruf, 1998;Rosenkranz, 1992). Generally speaking, for microwave radiation over calm ocean surfaces under clear-sky conditions, brightness temperature at vertical polarization increases and that at horizontal polarization decreases with incident angle from nadir until it reaches Brewster's angle (also known as the polarization angle).…”

Application of reflected Global Navigation Satellite System (GNSS-R) signals in the estimation of sea roughness effects in microwave radiometry

“…L-band brightness temperature has long been studied for the remote sensing of SSS [1][2] through the use of this principle. Brightness temperature, however, is also strongly dependent on the surface roughness [3] [4] and this dependence must be removed or corrected first, to retrieve This research was supported by NASA grant NNX08A087G, "Comparison of GNSS-R Ocean Roughness Measurements with Radiometric and Scattering Models at L-band and S-band", Justin Voo was supported by the NASA Earth and Space Science Fellowship (NESSF) Program grant NNX07A049H to conduct a portion of this work at the Jet Propulsion Laboratory. The work described in this paper that was performed by the Jet Propulsion Laboratory, California Institute of Technology, was carried out under a contract with the National Aeronautics and Space Administration.…”