TY - JOUR T1 - GNSS-R nonlocal sea state dependencies: Model and empirical verification A1 - Chen-Zhang,David D. A1 - Ruf,Christopher S. A1 - Ardhuin,Fabrice A1 - Park,Jeonghwan AD - Univ Michigan, Dept Elect & Comp Engn, Ann Arbor, MI 48109 USA. AD - Univ Michigan, Climate & Space Dept, Ann Arbor, MI 48109 USA. AD - Univ Brest, IFREMER, Lab Ocean Phys & Satellite Oceanog, CNRS,IRD, Plouzane, France. AD - Ohio State Univ, Electrosci Lab, Columbus, OH 43212 USA. UR - https://archimer.ifremer.fr/doc/00358/46909/ DO - 10.1002/2016JC012308 KW - waves KW - wind KW - remote sensing N2 - Global Navigation Satellite System Reflectometry (GNSS-R) is an active, bistatic remote sensing technique operating at L-band frequencies. GNSS-R signals scattered from a rough ocean surface are known to interact with longer surface waves than traditional scatterometery and altimetry signals. A revised forward model for GNSS-R measurements is presented which assumes an ocean surface wave spectrum that is forced by other sources than just the local near-surface winds. The model is motivated by recent spaceborne GNSS-R observations that indicate a strong scattering dependence on significant wave height, even after controlling for local wind speed. This behavior is not well represented by the most commonly used GNSS-R scattering model, which features a one-to-one relationship between wind speed and the mean-square-slope of the ocean surface. The revised forward model incorporates a third generation wave model that is skillful at representing long waves, an anchored spectral tail model, and a GNSS-R electromagnetic scattering model. In comparisons with the spaceborne measurements, the new model is much better able to reproduce the empirical behavior. Y1 - 2016/11 PB - Amer Geophysical Union JF - Journal Of Geophysical Research-oceans SN - 2169-9275 VL - 121 IS - 11 SP - 8379 EP - 8394 ID - 46909 ER -