can be made that will lead to better estimates of heat and momentum 

 flux with a resultant improvement in the Naval environmental pre- 

 diction programs. 



Initial efforts have been towards building up an instrumentation 

 capability in this field and testing sensor systems at an air -water 

 interface. Because of the somewhat easier instrumentation problem, 

 the temperature field has been first to be investigated. It also 

 gives some information about the velocity field since the statistics 

 of the near-passive, scalar temperature field can be expected to be 

 similar in important ways to the statistics of the fluid-distorting 

 velocity field. 



This paper is a report of some of our first measurements of the 

 temperature field over a wind-generated wave surface. 



INSTRUMENTATION 



The temperature measurements were made with micro-bead thermistors 

 (VECO 41A401C) 0.005 in. in diameter. Their resistance at 25 C is 

 10,000 ohms. Their time constant in dry air was measured to be better 

 than 0.1 sec. The thermistors were used as one arm of a DC operated 

 Wheatstone bridge. 



Waves were measured with a two-wire resistance wave gauge. The 

 probe wires were Silbraze rods 1/16 of an inch in diameter and sepa- 

 rated by 3/4 of an inch. 



Mean wind speed was measured with a Casella cup anemometer. The 

 data were collected on an Ampex CP 100 analog tape recorder at a 

 speed of 1-7/8 ips using the FM record/reproduce system. 



The sensors were mounted on a chassis made of pipe (Fig. 1). One 

 thermistor was mounted on a styrofoam float shaped like a hemisphere. 

 The float followed the vertical wave motion along a stretched wire 

 through its center. A second thermistor was mounted on a steel rod 

 at a fixed height. 



The wave gauge was clamped to the frame so as to be as near as 

 possible to the float and placed directly downstream of it. 



The cup anemometer was bolted to the frame about 1 meter above 

 the water surface. 



FIELD PROGRAM 



The measurements were made over Roberts Lake (Fig. 2) in Seaside, 

 California. Roberts Lake is small - 1200 ft. long, 600 ft. wide and 

 6 ft. deep. However, it is convenient to the School, provides wind 

 generated waves and illustrates some of the processes likely to be 



378 



