readout meter with a well-stirred water bath of 

 a known temperature near that of the ocean's 

 surface. This test determined a correction factor 

 which was the difference between the ART 

 meter readout and the true mercury tempera- 

 ture of the water bath (fig. 6). The tempera- 

 ture correction factor usually remained con- 

 stant, but was checked at intervals of about 1 

 hour. If the difference in readings varied, a 

 malfunction in operation was indicated and 

 corrected. This check verified the correct opera- 

 tion of the infrared detector and measurement 

 section of the ART survey unit. The strip chart 

 recorder was checked for uniform operation by 

 noting the ART temperature meter reading in 

 relation to the position of the recorder pen. The 

 ART meter readings were marked on the rec- 

 order chart, and any shift in the positioning of 

 the recorder pen relative to similar ART meter 

 readings indicated a malfunction. These two in- 

 flight checks were necessary to insure stand- 

 ardization of performance from the ART unit. 



Figure 6 also illustrates the difference be- 

 tween the profile of traces from the ocean sur- 

 face and from a well-mixed water bath. The 

 fine structure in the ocean trace represents the 

 effect of fluctuation in sea surface temperature 

 as the instrument moves over the ocean's sur- 

 face. The fine structure in the bath trace indi- 

 cates the effect of the aircraft's electrical, phys- 

 ical, and sonic interference. In a laboratory 

 environment, the viewing of a temperature- 

 stabilized water bath produces a trace free of 

 fine structure. 



During the flights, calibration temperatures 

 were obtained from sea surface measurements 

 made while the plane was overhead. In the 

 northern area simultaneous, comparative tem- 

 perature observations of the ART and surface 

 bucket cast were made with the UMATILLA 

 (ULV) and COLUMBIA (CRLV) lightvessels; 

 in the central area they were obtained with the 

 SAN FRANCISCO (SFLV) lightvessel. All 

 vessels used surface cast thermometers fur- 

 nished by the National Weather Service. In the 

 southern area simultaneous observations were 

 made with the NURDC (Naval Undersea Re- 

 search and Development Center) Oceanograph- 

 ic Tower off San Diego, Calif. A thermistor 

 was used on the tower to determine surface 

 temperature. Comparisons with 146 simultane- 

 ous sea surface temperatures showed an aver- 



age diflference of 0.35 F° (ART lower) , a range 

 of -1.9 F° to +1.2 F°, and a standard devia- 

 tion of 0.65 F°. 



ART Coastal Charts — Readout and Plotting 



In processing the ART data, the strip chart 

 recorder track was read out, using a calibrated 

 grid adjusted to sea surface temperature ob- 

 served during the simultaneous airborne-sur- 

 face check with one of the lightships or the 

 NURDC tower. From August 1963 to January 

 1966 the recorder track was read out at 30- 

 second intervals, and four observations were 

 averaged to give a 2-minute average tempera- 

 ture. To reduce the amount of time involved 

 in making readouts and averaging calculations, 

 a slide rule-type averaging device was con- 

 structed (fig. 7) and used after January 1966. 

 Comparison of the two averaging techniques 

 yielded differences of less than 0.1 F°. 



Upon return to the U.S. Coast Guard air 

 station the temperatures were coded onto an 

 Airborne Radiation Thermometer Sea Tem- 

 perature (ARTST) (U.S. Navy) message form 

 and transmitted via tape or teletype to U.S. 

 Navy Fleet Numerical Weather Central, Mont- 

 erey, Calif. Later, at the Tiburon Marine Lab- 

 oratory, 2-minute averages were plotted on the 

 aircraft flight track, and contoured charts were 

 drawn from these data. These isotherm charts 

 were issued without charge by the laboratory 

 to interested persons and biological, oceano- 

 graphic, and meteorological laboratories. 



RESULTS 



Monthly Isotherm Charts 



Temperature data in the form of contoured 

 charts, are located in appendix A for each 

 monthly ART survey in the three survey areas. 

 The temperatures shown on the charts are 

 corrected to agree with sea surface tempera- 

 ture measurements obtained from lightships 

 or the (USNURDC) oceanographic tower dur- 

 ing the flights. 



Mean Monthly Isotherm Charts 



Temperature data for the 5-year mean 

 monthly isotherm charts (figs. 8-43) were 

 calculated from each monthly survey by deter- 

 mining the average temperature for each 10- 

 minute (longitude by latitude) area. The mean 



