A Gradient Wind Correction for Surface Pressure Fields Retrieved from Scatterometer Winds

Abstract

Given a field of geostrophic winds and at least one pressure observation, a pressure field can be computed. If the winds are in reality gradient winds, then a correction must be applied to calculate the actual geostrophic winds. Here a method is proposed for including a gradient wind correction in the retrieval of geostrophic winds from Quick Scatterometer (QuikSCAT) surface measurements with a planetary boundary layer model. This correction translates into a better estimate of the corresponding surface pressure fields. The scheme is assessed by comparing these pressure fields to buoy measurements in the Gulf of Alaska and to radiosonde measurements in Hurricane Floyd. The gradient wind correction has a curvature component and a time-dependent component. Their relative magnitude is evaluated.