HUGH M. SMITH CRUISE 21 



Summary Cruise Report 



The cruise began August 4 and was completed August 25, 1953, 

 with the occupation of 69 stations whose location is shown in figure 25. 

 All of these were hydrographic stations with sampling depths to 500 m. 

 except 23 and 33, which were trawl stations. Three duplicate sets of 

 four stations were occupied in Kaiwi Channel, but only stations 28, 29, 

 30, and 3 1 of these are used in the analysis in order to provide better 

 continuity in time. Station 5 was occupied on August 6 and station 65 

 on August 24, so that the survey region was covered in 18 days. 



Other observations included 200-m. oblique plankton tows and 

 bathythermograph and GEK observations at each station and at 20-mile 

 intervals. Four daily synoptic weather observations were made and 

 passed on to the U. S. Weather Bureau. 



Meteorological Conditions 



Typical trade wind weather was encountered during the cruise. 

 The overall average air temperature was 77.3 F. On the windward side 

 the average was 76.6 F. and on the leeward side 77.8 F. The lowest 

 tennperature of 75. 1 F, was encountered at station 9 and the highest, 

 81 F. , at station 32 in the immediate lee of Lanai Isleind. Of the winds 

 which were measured on the hydrographic stations, 65 percent were from 

 070° to 090°T. ; 90 percent of the winds came from 050 to 120°T. The 

 winds had an extreme southerly connponent on only two occasions, namely 

 on stations 37 and 38 when the direction was 220 T. and 170 T. , respec- 

 tively. The measured wind speeds were 46 percent between 17 and 21 

 knots, 30 percent between 11 and 16 knots, 12 percent greater than 21 

 knots, and 12 percent less than 11 knots. 



The weather was generally fair except on stations 5 to 8, 37, and 

 46, when showers were encountered. 



Surface Hydrography 



The distribution of the surface temperature, salinity, and density 

 are again discussed separately. Table 4 shows these variables averaged 

 over the quadrants of the survey region together with the extreme values 

 encountered. 



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