Thompson Cruise Report August 14-17

After completing vertical profiling of Line 6 from CP-1 to CP-11 (with pump stations at each end), we ran a 3 day time series between CP-4 and CP-5, August 13-16). We could not maintain position at a fixed location, but with low currents and winds we were able to profile E/W and W/E (both directions) and completed 10 profiling transects (turbulence, optics, chemistry and biosonics) over a three day period. The data show very nice night vertical migration of "large particles" and "small particles" (scatterometer ). During the second two days of this we sampled surface water for pigments and absorption every two hours and surface and bottom water for POC/PON and DOC/DON every two hours and ran 3 twelve depth pump stations. It was an intensive sampling effort by all groups.

On August 16 we first saw a large peak in fluorescence close to CP-5 (greater than 4 v, and later offshale). We intended to map this feature N and S of CP. After several crossings along 44 11.5 we could see that it was a wide band of elevated fluorescence between 124 36 and 124 42 W. This was also apparent in the August 16 SeaWIFS image. After discussions with WECOMA, we worked out a plan for both ships to study this feature (possibly a jet carrying high Chl off the bank).

We deployed two more drifters around noon on August 17 near CP-9. We are now in the process of running four proling transects south of line 6 (CP-line): 44 11.5, 44 6.5, 44 1.5 and 43 56.5 from the inshore side of the high chl band, across the band, and hopefully across the jet. We are running a 9 depth pump station at the midpoint of the high Chl region along each transect. The first transect took 14 h, this included an 8 h profiling transect inshore to offshore), moving south and ADCP offshore to inshore and a pump station in the region of elevated chl. Completing three more transects will take us through August 20.

Submitted at 15:30 August 18 2001
Pat Wheeler, Chief Scientist