83rd Annual

Thursday, 13 February 2003
The use of kite observations to study air–sea interaction– controlled atmospheric surface layer profiles during the RED Experiment
Kenneth L. Davidson, NPS, Monterey, CA; and P. S. Guest, D. L. Mabey, P. A. Frederickson, K. D. Anderson, S. M. Doss-Hammel, and D. Tsintikidis
Poster PDF (705.4 kB)
During the RED Experiment conducted off Oahu, Hawaii, in the late summer of 2001, the Naval Postgraduate School (NPS) obtained near-surface scalar profile data from kite-borne sondes flown from a small vessel. These data were obtained simultaneously with microwave propagation measurements along a 26 km over-water path from the Research Platform FLIP to the shore, and optical propagation data obtained along a 10 km path. The purpose of obtaining the kite data was to provide direct measurements of the vertical temperature, humidity and refractivity profiles near the surface in order to determine their effect on microwave and optical propagation and to examine the application of traditional Monin-Obukhov similarity (MOS) theory scaling of near-surface profiles over the ocean.

In this study a brief description of the methods and equipment used to obtain kite profile measurements is presented. Comparisons are made between the directly measured kite profiles and MOS theory predictions based upon mean meteorological measurements obtained at a single height. Significant deviations between observed and predicted profiles were discovered in some cases and the reasons behind these differences will be examined. Both the kite-observed and MOS-predicted refractivity profiles were used to compute propagation loss values, which were then compared to the actual microwave propagation measurements. This provided an opportunity to effectively verify the profiles obtained through different methods and to investigate the causes of differences between observed and predicted profile shapes. Spectral wave data obtained from two buoy platforms and the FLIP will be used to examine any sea-state dependent influences on the near-surface profile observations. Kite measurements obtained off San Clemente Island and in Monterey Bay, California, and off the Virginia coast will also be included in the presentation to expand the variety of environmental and hydrographic conditions included in the study and to illustrate profile differences between warm and cold water areas and wind-wave and swell dominated sea states.

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