Mission Summary
20080721I1 Aircraft 43RF
3-D Doppler Winds Operational Mission
Tropical Storm Dolly flight 2008

Scientific Crew (43RF)
Lead ScientistRob Rogers
Doppler ScientistJohn Gamache
AXBT ScientistPaul Leighton
Dropsonde ScientistKathryn Sellwood

Flight Crew (43RF)
PilotsMark Nelson
Carl Newman
Flight DirectorJack Parrish
NavigatorJoe Bishop
Flt. Eng.Dewie Floyd
Data TechTerry Lynch
Jeff Smith
Elec. TechDamon SanSouci

Mission Plan :

This was a combination EMC 3-D Doppler winds/TPC fix mission with an AXBT module for HRD into Tropical Storm Dolly. The plan called for the aircraft to fly a butterfly pattern at 8000 ft altitude, setting up an IP 120 nm northeast of the center (Fig. 1) . On the northwest side, the pattern would add three legs to sample ocean features in the Gulf of Mexico. We would drop 12 evenly-spaced AXBT' s on those legs, coincident with GPS drops for the turn points of those legs, plus the midpoint of the radial legs. The flight would also attempt to drop AXBT's at the points coincident with the BT drop points from the previous night's flight. If there were clear air in daylight and surface winds > 50 kt, the banked SFMR maneuvers would be attempted again.

Mission Summary :

Takeoff from Tampa was at 2023 UTC. Dolly was a broad circulation in the northern Bay of Campeche (Fig. 2) , after having traversed the northern tip of the Yucatan peninsula the night before. There was an area of cold cloud tops on the northwest side of the circulation center and a broad band spiraling out from the center on the east and southeast side (Fig. 3) . Limited deep convection near the center of circulation was evident, with isolated areas of 85-91 GHz brightness temperatures < 150°K on the east and northeast sides of the storm (Fig. 4).

The actual flight track is shown in Fig. 5. In addition to the butterfly pattern mentioned in the mission brief, the aircraft executed the additional three legs to sample warm and cold-core rings in the Gulf of Mexico. Flight-level winds (Fig. 5b) showed that the circulation was better-organized than the previous day. Peak flight-level and surface winds of 50 kt were located on the northwest side of the storm, with a very asymmetric wind distribution persisting (e.g., 30 kt on the southeast side). The wind field was very broad on the northwest side, indicating that a distinct inner core had not yet developed. Dropsonde winds (Fig. 6) show that the circulation was shallow, not clearly extending up to 700 hPa. AXBT's were dropped in a line on the northwest side of the flight track (Fig. 7). In addition, four AXBT's were dropped at or near (within approximately 10-20 km) the drop locations from the previous P-3 flight. These should provide an opportunity to measure local changes in ocean temperature and mixed-layer structure during the passage of a tropical storm. Additionally, on the final inbound leg, from west to east, we encountered a line of isolated convective cells about 150 km west of the storm center. Given reports from a G-IV flight that dry air was observed to the west of the storm (Fig. 8a), we decided to release a series of drops (Fig. 8b), spaced about 10 km apart, in an attempt to sample across possible arc clouds.

Overall the mission was successful. We accomplished the tasked objectives (fix for TPC, radar sampling for EMC), and we flew the AXBT and possible arc cloud module for HRD. The storm was very broad, but better organized than the previous day. Despite this improvement in organization, however, the storm intensified little. Estimated minimum sea-level pressure on the first and third center passes remained at 998 hPa. The peak SFMR-measured wind was 45-50 kt. The storm did remain asymmetric, with limited deep convection. It appeared to still be encountering some westerly vertical shear today.

Problems :

There were no problems today. There was a total of 17 GPS sondes dropped and 18 AXBT's dropped. All GPS sondes worked; one AXBT failed.

Robert Rogers

Mission Data

1 second data file | NetCDF data file

Flight Data

Flight track

Temperature and Moisture

Wind and Atlitude

Flight track detail

Page last updated August 4, 2008
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