SHIP'S INFLUENCE ON SURFACE AND RAWINSONDE TEMPERATURES 



DURING BOMEX 



Warren M. Wisner 



National Weather Service Climatologist for Missouri 



Columbia, Missouri 65201 



Abstract . The Barbados Oceanographic and Meteorological 

 Experiment (BOMEX), conducted in the summer of 1969, pro- 

 vided an opportunity to examine the representativeness of 

 data on sea-air interaction processes obtained from a 

 variety of sensors. This paper presents a comparative 

 analysis of observations made from conventional facilities 

 located amidships on five fixed ships with data obtained 

 from instruments mounted on a boom extending forward from 

 the bow of each ship. Results based on temperature re- 

 cordings indicate that the boom measurements probably are 

 more reliable when the relative wind blows off the sea past 

 the boom and then over the ship. When the wind off the sea 

 blows over the ship and then over the boom, however, ship's 

 influence is such that the boom and shipboard instrumenta- 

 tion provide equally reliable measurements. 



1. INTRODUCTION 



The Barbados Oceanographic and Meteorological Experiment (BOMEX) was de- 

 signed for study of the joint behavior and interaction between the atmosphere 

 and the ocean in tropical and subtropical waters through detailed observations 

 in the upper 1,000 m of the ocean and an atmospheric layer more than 6 km 

 thick. The experiment was conducted in the western Atlantic, east of the is- 

 land of Barb ado s_, from May 3 to July 28, 1969. During the first three obser- 

 vation periods - May 3 to May 15, May 24 to June 10, and June 19 to July 2 - 

 observations were made within a 500-km by 500-km area, with five ships occupy- 

 ing fixed positions at the four corners and in the center of the square (see 

 fig. 1). During Period IV - July II to July 28 - the array was extended south- 

 ward for investigation of tropical convective systems (see fig. 2). 



The five fixed ships used as observation platforms were the U.S. Coast and 

 Geodetic Surveyl ships Oaeanographerj Rainier, Mt. Mitchell, and Discoverer 

 and the U.S. Coast Guard cutter Roakaway . The mooring systems designed to 

 maintain the ships at their designated locations failed -- the Mt, Ntitahell's 

 and Rainier 's at the very beginning of Period I, the Roakauay's early in 

 Period II, and the Oaeanographer's and Discoverer's later during the same 

 period. After mooring failure, the ships used various modes of steaming and 

 drifting in an attempt to remain as close as possible to their assigned 

 positions . 



Now the National Ocean Survey. 



