2A.5
In-situ Measurements of the Air-Sea Interface During Hurricane Fabian
Eric J. Terrill, SIO/Univ. of California, La Jolla,, CA; and W. K. Melville
Measurements of the air-sea interface in very high sea states present a difficult challenge for both remote sensing techniques and in-situ moored or shipboard instrumentation. While the satellite-based remote-sensing techniques generally lose accuracy in high sea-states due to a lack of understanding of the physics of the parameter that is measured and inverted (ie. microwave scattering, EM bias, passive microwave), in-situ measurements are difficult due to the environmental loading placed on the instrumentation and survivability of moorings. Shipboard instrumentation in high sea-states is either too costly for long-term measurements or presents a danger to the personnel onboard the vessel. With significant effort and cost, moorings and surface buoys can be designed to withstand the rigors of the sea-surface during these conditions. However, the statistical nature of very high wind events such as hurricanes, typhoons, and large winter storms requires that moorings be deployed over long periods of time in order to raise the probability of the instrumentation being in the right place and at the right time. The recent improvement of synoptic, predictive models of storm events now presents the opportunity for adaptively sampling the upper ocean during storms through strategic placement of light-weight, low-cost instrumentation in the path of incoming storm events. As part of the ONR sponsored CBLAST experiment, we have developed an air-deployed instrument capable of profiling the upper ocean during hurricane conditions. The CBLAST hurricane float is based upon the proven SOLO (Sounding Oceanographic Lagrangian Observer) float technology which has been applied to the challenges of measuring global ocean climate state. We have implemented several modifications to this instrumentation to make it suitable for hurricane missions including a modified mission that includes profiling 200m of the water column as well as a hover mode which places the float 30-70m below the sea-surface during the storms. The instrument has a number of additional sensors that are integrated into the system to allow remote measurement of the air-sea interface while in this hover mode including measurements of the underwater sound field which depends the intensity of surface wave breaking and rainfall, and the direct measurement of ocean surface waves. Two CBLAST floats were deployed into the path of Hurricane Fabian during the 2003 hurricane season using C130J aircraft by the AFR 53rd Weather Research Squadron. We present early results from the analysis of these unique data sets obtained during the storm. .
Session 2A, CBLAST II
Monday, 3 May 2004, 10:45 AM-12:00 PM, Le Jardin Room
Previous paper