The sea state of the Beaufort and Chukchi seas is controlled by the wind forcing and the amount of ice-free water available to generate surface waves. Clear trends in the annual duration of the open water season and in the extent of the seasonal sea ice minimum suggest that the sea state should be increasing, independent of changes in the wind forcing. Wave model hindcasts from four selected years spanning recent conditions are consistent with this expectation. In particular, larger waves are more common in years with less summer sea ice and/or a longer open water season, and peak wave periods are generally longer. The increase in wave energy may affect both the coastal zones and the remaining summer ice pack, as well as delay the autumn ice-edge advance. However, trends in the amount of wave energy impinging on the ice-edge are inconclusive, and the associated processes, especially in the autumn period of new ice formation, have yet to be well-described by in situ observations. There is an implicit trend and evidence for increasing wave energy along the coast of northern Alaska, and this coastal signal is corroborated by satellite altimeter estimates of wave energy

Recent studies show the promising ability of cross-polarization synthetic aperture radar (SAR) for high-wind-speed monitoring. However, no dual-polarization (dual-pol) geophysical model functions (GMFs) have thus far been established. In this paper, we first address the difference between dual-pol and quad-pol VH radar returns with respect to wind speed and show the necessity of having a VH dual-pol GMF for ScanSAR images, for remote sensing of mesoscale wind processes, such as hurricanes. By collocating VH dual-pol RADARSAT-2 SAR measurements with in situ buoy winds, a VH dual-pol GMF was developed after introducing a denoise procedure to increase the signal-to-noise ratio for SAR measurements. Study results suggest that the VH dual-pol radar returns have a linear monotonic piecewise increasing dependence on wind speed, with decreasing scatter in high winds. Successful application of the GMF to high-wind-speed retrieval for hurricane Gustav in 2008 suggests that VH mode SAR images do not exhibit signal saturation or the speed ambiguity problem that affects copolarization SAR images for high-wind-speed retrieval. This result supports the potential future application of VH dual-pol SAR images to hurricane monitoring.

A new method to measure ocean wave slope spectra using fully polarimetric synthetic aperture radar (POLSAR) data was developed without the need for a complex hydrodynamic modulation transform function. There is no explicit use of a hydrodynamic modulation transfer function. This function is not clearly known and is based on hydrodynamic assumptions. The method is different from those developed by Schuler and colleagues or Pottier but complements their methods. The results estimated from NASA Jet Propulsion Laboratory (JPL) Airborne Synthetic Aperture Radar (AIRSAR) C-band polarimetric SAR data show that the ocean wavelength, wave direction, and significant wave height are in agreement with buoy measurements. The proposed method can be employed by future satellite missions such as RADARSAT-2.

A new algorithm for hurricane wind retrieval is developed based on the primary characteristics of hurricane processes. By assuming constant wind speeds and equal‐distant wind directions in three neighboring sub‐image blocks of any specific concentric circle around the hurricane eye, both wind speed and wind direction are resolved without any external information. To evaluate the accuracy of the new algorithm, a Radarsat‐1 synthetic aperture radar image of hurricane Isabel is studied. The retrieved wind speed is compared with QuikSCAT scatterometer winds and in situ winds. Good consistency is shown. Since the new algorithm doesn't rely on any external wind information, fine resolution wind structures can be retrieved without adding errors due to linear interpolation of the externally‐derived coarse‐resolution wind direction.

Under strong ocean surface wind conditions, the normalized radar cross section of synthetic aperture radar (SAR) is dampened at certain incident angles, compared with the signals under moderate winds. This causes a wind speed ambiguity problem in wind speed retrievals from SAR, because two solutions may exist for each backscattered signal. This study shows that the problem is ubiquitous in the images acquired by operational space‐borne SAR sensors. Moreover, the problem is more severe for the near range and range travelling winds. To remove this ambiguity, a method was developed based on characteristics of the hurricane wind structure. A SAR image of Hurricane Rita (2005) was analysed to demonstrate the wind speed ambiguity problem and the method to improve the wind speed retrievals. Our conclusions suggest that a speed ambiguity removal algorithm must be used for wind retrievals from SAR in intense storms and hurricanes.