SUMMARY OF COAST FLIGHT 19 and 20

COAST Flight 19 was flown on August 19, 2001. This flight covered the Big Box from south to north. AXBTs were deployed as follows:

Line 2: 6 AXBTs
Line 4: 6 AXBTs
Line 6: 7 AXBTs
Line 8: 7 AXBTs

We modified the flight slightly to accomodate a longer east-west line, on which we obtained a vertical section of atmospheric variables. We flew this additional line ("Line 9") in place of Line 3. Line 9 was flown at the latitude of the Newport NDBC buoy, 44 37 North, and extended westward from the shoreline for about 70 nm. The line was flown at the very end of Flight 19, about 1900 PDT. COAST Flight 20 was flown the next day, August 20, at about 0730 PDT, and meteorological measurements were again made on Line 9. Together with the Line 9 measurements from the preceding evening, the diurnal variation in the atmosphere could be assessed. We had planned to fly an additional flight on the evening of August 20 to capture another evening meteorological section, but the changes due to the approaching low from the Gulf of Alaska had already begun, and we felt that the conditions would be dominated by that synoptic system as opposed to diurnal variations. Thus, we elected not to fly.

On Flight 19 over the Big Box, measurements were made of: SST, subsurface ocean temperature, and upper-ocean color; atmospheric temperature, humidity and horizontal winds. The SST field showed a change from our previous flight on August 13, with a more extensive cool water region. The separated upwelling jet over Heceta Bank was apparent in the SST field. We overflew both ships while they were in the jet on Line 3. We made several passes over the Thompson at different altitudes to gather color and SST calibration data.

The atmosphere during both flights showed no temperature inversion below 1,000m; however, the northerly winds had a very nice jet structure, especially near the coast. Maximum jet winds were about 25-30 knots at about 300m height. The jet-max speeds decreased westward from the coast to be closer to 15 knots over the outer Big Box. Surface winds throughout the BB were about 15 knots on Flight 19 and closer to 10 knots on Flight 20 (along Line 9).

Data products will be available from http://www.marine.unc.edu/cool/COAST or they may be retrieved from the real-time results or 4-days-plus results areas. All of these are buttons off of the main COAST site.

Submitted by:
John Bane
August 20, 2001