Reconciliation of Surface and Profiler Winds at ISS Sites

Abstract

Integrated Sounding Systems (ISSs), which combine surface-based, balloon-borne, and radar observation capabilities, were deployed for the first time during the Intensive Observing Period (IOP) of the recent Coupled Ocean?Atmosphere Response Experiment. This note addresses efforts to synthesize the data from these disparate platforms as well as avenues for future research that were opened in the process. The collaborative nature of the ISSs led to the application of different processing methods to the surface winds than were used with the winds measured by 915-MHz wind profilers. A new set of ship-based surface winds that are more directly analogous to the profiler winds has been developed. The statistical properties of these ?AL-processed ISS surface winds? are shown to be similar to those of the land-based ISS surface winds, to the low-level profiler winds, and to surface winds measured at nearby buoys. A method of combining the surface and profiler winds from an ISS into one coherent dataset is also presented here; it involves assuming a logarithmic wind profile over a surface layer whose depth is invariant over the course of the IOP. While there are some obvious oversimplifications to this method, it is the most sophisticated option available from currently collected ISS data, it is more physically reasonable than a simple linear interpolation between the surface and higher-altitude winds, and it yields wind profiles that are acceptable for many applications. Both of these new datasets are now available to the community. The process of combining the two sets of measurements not only led to a reconsideration of the postprocessing of the shipboard surface winds but also led to renewed interest in the effects of sea clutter on profiler winds. Further work is now under way in the profiler community to address the issue of sea clutter on ship-based and near-sea profiler installations.