General Wind Pattern 



The wind pattern {table 3) over the Islands was influenced by two low 

 pressure systems which developed in the area to the west. The first, December 7 

 to 10, did not pass over the islands. The second, which first appeared on the 

 U. 3. Weather Bureau map of December 15, moved in over the islands and persisted 

 until the end of the cruise. As a result of these lows, the winds were more 

 southerly than normal for December (table IJ. When they are transformed into cur- 

 rent direction by the 45° cum sole rule, the inferred currents are 10° to 80° to 

 the right of the 290°T average indicated by the Pilot Chart. 



As mentioned above, during the process of checking the reliability of 

 the winds computed from the synoptic charts (USUB) these winds were compared to 

 the observed winds recorded in the bathythermograph logs. The results were rather 

 startling and it at first appeared that the computed winds were unreliable. How- 

 ever, because of excellent agreement between computed and observed winds in the 

 upwind area and the fact that almost all of the BT observations were in the lee of 

 Hawaii, it has been suggested that the variance was the result of the "barrier" 

 effect of the high mountains of the island (Saul Price, U3WB, personal communica- 

 tion). Data from this and subsequent cruises are now being analyzed to determine 

 the nature of the effect. 



Dynamic Topography and Geostrophic Currents 



The dynamic heights are shown in figure 2 and the geopotential topography 

 in figure 3- The dotted lines in the vicinity of station 1 represent extrapolated 

 values necessary because of bottle failures below 600 m. at station 1 and are in- 

 tended merely to indicate the direction of flow. The heights are based on the 

 rather dubious assumption that the height of the 700-decibar (m.) surface at sta- 

 tion 1 is the mean of the heights at stations 2 and 8. This method was used be- 

 cause the extrapolated values of salinity and temperature at station 1 provided 

 extremely large dynamic heights, indicating currents of up to 1.6 K:nots In the 

 surface layers. The actual currents were probably somev.here between those indi- 

 cated by the contour in the figures and those indicated by the extrapolated temper- 

 atures and salinities. 



The geopotential topography shows an extremely well-developed cyclonic^/ 

 eddy. At the surface it was centered at station 6, but it shifted towards the 

 island with depth, being centered at station 7 below the lOO-decibar surface. The 

 cross sections (fig. 2, panel B) show that it was still evident dovm to the 500- 

 decibar surface at station 7. 



The most striking feature of the velocity field was the persistence of 

 the surface velocities down to the 300-decibar surface in the southern part of the 

 eddy. The velocities at the surface were almost uniform, except for slight maxima 

 of about 0.8 knots (40 cm/sec) between stations 11 and 14. The velocities around 

 the eddy decreased with depth, as expected, except in the vicinity of station 2, 

 where velocities of 0.7 knot (35 cm/sec) were still indicated at the 300-decibar 

 surface. 



Temperatures 



The temperature cross sections (fig. 4) were constructed from bathythermo- 

 graph observations. 



The general distribution of temperature followed the pattern that was in- 

 ferred from the geostrophic currents. I.e., the isotherms show doming in the center 



^ In the northern hemisphere, flow which curves to the left (counterclock- 

 wise), when facing downstream, is cyclonic, and flovj which curves to the right 

 (clockwise) is anti-cyclonic (Holmboe et al. 1946, p. 191). A cyclonic eddy is 

 characterized by a depression in the geopotential topography at its center, and an 

 anti-cyclonic eddy by a doming. 



