Thompson Cruise Report August 12-13
04:00 Local Time (August 14).

Early Sunday morning (August 12) we completed a pump station at CP-1 and started the profiling transect from CP-1 to CP-12. The transect took 29 hours to complete. All systems were on line with only a half hour break to change pump oil half way through the transect. There was a S jet with a core at about 50 km offshore and a N flow of 20 cm/s at the offshore end and at a depth of 100-120 m and deeper. Fluorescence is high in the upper 10-20 m but not as continuously as shown in the SEASOAR August 8. Highest levels are still at 124.6 W, moderate levels inshore and low levls between 124.3 and 124.4. The scatterometer data shows the high density small particles in the surface water and a 5-20 m thick boundary boundary layer of elevated particulate density. There also appears to be an area between CP-4 and CP-5 with elevated scatterometer values (compared to water inshore and offhore) from a depth of 30 m down to the bottom boundary layer.

We returned to CP-11 to do our offshore pump station. Afterwards, we moved to CP-4 and ran a short profiling transect to CP-5 to consider site selection for the 48 h time series. We just completed a midshelf pump station at CP-5, and will repeat the short profiling transect CP-4 to CP-5 before selecting the time series location. At CP-5 surface temperature surface temperature is up to 12.2 C and all of the chl fluorescence is in the upper 10 m. We still have the cold 7.5 C water extending up from the bottom to about 50 m between CP-4 and CP-5. Nitrate levels are about 25 uM and silicate about 35 uM in the bottom (100 m) water here.

Plans for the next 2 days (Aug 14-16) are to complete the second 48 time series to evaluate the tidal cycle, day/night tranisitions for FRRF and phytoplankton pigments, and we will also including sampling every 2 h for POC/PON and DOC/DON. We are hoping the winds pick up, they have been close to 15 kts for the last 12 h.

Pat Wheeler
Chief Scientist, Thompson