Mission Summary
20030902I1 Aircraft 43RF
CBLAST mission
into Hurricane Fabian 2003

Scientific Crew (49RF)
Lead ScientistMike Black
Radar ScientistRob Rogers
Sonde ScientistChris Landsea
AXBT ScientistEric Uhlhorn
CBLAST ScientistJeff French
CBLAST ScientistJim Laswell

Mission Plan :

The plane will leave St.Croix at 10:30 AM AST and fly a two-plane CBLAST butterfly pattern at 8,000 and 5,000 feet with stepped descents between rainbands and return to St.Croix at 7:30 PM AST.

Mission Summary :

The flight left St. Croix, USVI at 10:55 AM AST and recovered at 8:15 PM AST at St. Croix, USVI. The aircraft executed the CBLAST two-plane butterfly pattern with 60 naut.mile legs covering the northern and western sections of the storm. Due to the lateness of the day only one co-ordinated stair-step pattern was executed 50 n.mi. east of the eye between rainbands.

The AOC and HRD crews and the CBLAST PI's were able to fly the multisonde sequence and also the stair-step descent for the first time in high winds and gain a familiarity with the plan and a strong comfort level with being able to carry it out in a major hurricane. Only one stepped descent pattern was conducted, but it was in surface winds of 25-30 m/s (50-60 kt), a first and a huge accomplishment.

The BAT probe and CIP probe functioned flawlessly as did the fast response temperature sensors, side and down looking radiometer, the IRGA and LICOR, which measured fast response humidity. Also the HRD SFMR and UMASS SFMR functioned flawlessly and were used by NHC's new HWIND program being transitioned to operations by the JHT project. The fully functional HRD SFMR was thanks to recent intense calibration and programing efforts by AOC engineers, Eric Uhlhorn from HRD and Pro Sensing Engineering. This resulted in real time surface wind analyses that showed a 50% larger storm and gale force wind area than the previous analysis without SFMR data. So for the first time in recorded history, we should have reliable heat, moisture and momentum flux measurements in 25-30 m/s winds together with the bulk surface measurments needed to begin to develop a new parameterization.

The CBLAST high wind team is functioning like a well-oiled machine now with all facets of the effort at max throttle: AOC flight crews, maintenance, engineers and technicians, flight directors, Air Force Reserve flight crews and support personnel, Aero riggers, oceanography component PI's Eric Terrill, Eric D'Asaro and Peter Niiler, HRD scientists and staff, Ocean Winds project personnel, etc, etc.

Upwind 170 2500 203745 204920
Downwind 355 1200 205113 205635
Upwind 165 800 210000 210731
Downwind 345 600 210912 211420
Upwind 155 400 211700 212435
Downwind 330 200 212700 213038
Outward 75 2500 213500 214406
Inward 255 1200 214620 215200
Outward 70 900 215400 215948

Problems :

A huge effort by 43RF engineers and technicians brought several instruments to readiness today that were not working at the beginning of the day. Chief among these was the CIP probe which had malfunctioned on the ferry flight to St. Croix yesterday. Both aircraft experienced failures during the flight of their aircraft GPS dropsonde systems. It was only thanks to one such monumental effort by the AOC engineers and technicians that snatched victory from the jaws of defeat. Extensive loiter time was required by the aircraft to allow AOC engineers and technicians time to conduct in-flight repairs of the system. One such loiter for two hours inside the eye resulted in a huge bonus as a unique eyewall evolution took place and recorded for the first time by the tail Doppler radars. Four eyewall penetrations were accomplished in a CAT 4 hurricane with sequences of 8 dropsondes deployed, a huge victory considering the mission almost had to be aborted. The failed receiver will be repaired tomorrow.

The aircraft had to depart without Ed Walsh and the SRA due to four cancelled flights for Ed in his effort to transit from Boulder to St. Croix. As luck would have it, Ed was waving goodbye to the P-3s as his flight finally arrived and the P-3's were taxiing for takeoff. So there were no wave data gathered on todays flight as the Scripps laser altimeter also did not function well, mainly due to the higher altitude that had to be flown. The flight altitudes were required to be higher than nominal; raised from 5,000 and 8,000 ft to 8,000 ft and 12, 000 ft , due to the intensity of the storm. This would have resulted in a loss of the SRA data even if Ed had been there. Additionally, data was lost from the UMASS IWRAP system, which was unable to see the surface from the higher altitudes due to precipitation attenuation and the fact that not enough range gates were available, although a unique partial IWRAP data set was acquired.

Mission Data :

One minute listing

Flight Data

Flight track

Temperature and Moisture

Wind and Altitude

Flight track start

Flight track detail

Flight track detail

Flight track detail

Flight track end

Future Plans :

The storm is still a CAT 4 and still within easy reach of St. Croix. So tomorrow we will conduct a flight focusing on the stair step flux measurements in two different quadrants, this time hopefully with the SRA and Scripps wave measurements and begin to develop a data base of stepped descents in high winds.

Tomorrow will also be a very exciting day as we plan to launch all the CBLAST drifting buoys and floats from the Air Force WC-130J across the anticipated storm position for 24 hours hence, i.e. Thursday afternoon, 2 pm AST. The flight is scheduled to take off from Keesler at 11 am CDT and land in the evening at St. Croix. Chief Robert Lee is in transit from St Croix to Keesler this evening and will participate with other squadron DO's in the deployment. All Scripps minimet boxes arrived Keesler today as did the fourth APL Lagrangian float. Eric Terrill and 3 Aero riggers arrived Keesler this afternoon and have begun rigging the Scripps platforms. They will work through the night to have the rigged platforms ready for securing in the aircraft by morning. The two Scripps ARGO/SOLO floats are scheduled to arrive Keesler tomorrow morning at 9 am and will be immediatly rigged and loaded on the aircraft. Final drop coordinates will be relayed to the 53rd by 9 am EDT, 8 am CDT.

Following the buoy deployments, the NOAA WP-3D's will conduct their 3rd CBLAST flight focusing on the 12 sonde sequence and in providing the data necessary for the flux estimates in 100+ kt winds via budget estimation methods. this effort is being made possible thanks to the assistence of the 53rd detachment in St. Croix assisting in the acuisition of needed GPS sondes.

Peter Black
HRD Field Program Director

Return to Mission page.