Hurricane research team stays busy

Team flies 4 missions in 5 days

Sept. 18, 1998: (this is the 17th in a series of stories covering the ongoing CAMEX mission to hunt hurricane data in a way not done since the 50s. Other stories are linked in below.)

As the Convection and Moisture Experiment (CAMEX-3) enters its last week, the science and flight teams have been keeping busy with four days of flights during Sept. 13-17. Yesterday, the DC-8 and ER-2 flights provided an excellent study of good convective lines and large stratiform regions. Today and Saturday are no-fly days and Sunday will be an all-day science meeting.

Right: Views from the GOES-8 and Meteosat-7 weather satellites show Tropical Storm Georges (arrow) early this morning in the mid-Atlantic Ocean. A closer view of Georges is below. (link to 627x312-pixel, 89KB JPG, top, and 600x400-pixel, 73KB JPG, bottom.) Current satellite images are available through the Global Hydrology and Climate Center's Interactive GOES viewer.

From Sunday through Tuesday, the aircraft made one flight for calibration and other tests and two flights for the Texas and Florida Underflight (TEFLUN) campaign supporting the Tropical Rainfall Measuring Mission (TRMM) satellite.

The Sept. 13 mission was designed to sample atmospheric water vapor in the vicinity of Andros Island, Bahamas during clear sky, nighttime conditions. Humidity information was also collected by Andros Island ground-based instrumentation. This mission was a great success thanks to a pocket of clear sky positioned in the target area throughout the flight period. The TRMM satellite also passed over the area during the mission providing an excellent opportunity to compare the aircraft observations with spaceborne counterparts.

The missions flown on Sept. 14-15 were TEFLUN missions flown to sample Florida convection in support of TRMM calibration and validation studies. Only the NASA DC-8 and University of North Dakota Citation were used; the NASA ER-2 could not take off due to significant crosswinds at Patrick Air Force Base.

The mission on the 14th sampled developing and decaying oceanic convection east of Cape Canaveral. The mission on the 15th sampled a more widespread area of rain in central Florida west of Cape Canaveral. Both missions were flown within range of radar located west of Melbourne, Fla. The flight legs through the rain were coordinated with scientists monitoring the rainfall activity at the radar. The UND Citation collected microphysical data describing the cloud and rain particle sizes while the DC-8 sampled the rain using remote sensing instrumentation.

Sign up for our EXPRESS SCIENCE NEWS delivery

A wide variety of rain conditions was sampled. Portions of the missions were also devoted to sampling the humidity and wind environment outside the storm areas. All three of these missions sampled conditions related to the tropical disturbance currently developing in the Gulf of Mexico. The pocket of clear sky sampled in the Andros Island area on Sept. 13 immediately preceded this disturbance as it began to spin to the west. The disturbance then passed slowly over southern Florida and provided the rainfall for the TEFLUN missions on Sept. 14-15. This area of disturbance has proceeded farther to the west into the Gulf of Mexico. Some forecast models are predicting that this disturbance will become Tropical Storm Hermine some time today.

Note: More details are available in the NASA press release describing CAMEX-3. Check back as hurricane season progresses. We will post science updates as the campaign develops. PIX: High resolution scans of 35mm camera photos from the CAMEX-3 campaign are available from Public Affairs Office at NASA headquarters. Please call the NASA Headquarters Photo Department at 202-358-1900, or contact Bill Ingalls at bingalls@hq.nasa.gov. CAMEX Series Headlines August 12: Overview CAMEX story , describes the program in detail. August 13: CAMEX maiden flight , for calibration of TRMM satellite instruments August 14: CAMEX test flights , CAMEX flies over tropical storm weather in successful calibration run August 18: CAMEX aircraft make second flight with TRMM , second calibration run for TRMM August 20: CAMEX may get first chance at a tropical storm , later this week  August 21: Here comes Bonnie! , CAMEX scheduled to fly over T.S. Bonnie  August 22: West by Northwest , CAMEX team may have to evacuate to Georgia  August 24: Eye-to-eye, and Bonnie winks, CAMEX team makes first flight through eye  August 25: Snow in August, Bonnie surprises the hurricane team  August 26: Camera of many colors Hurricane hunters using advanced scanner to peer into storms   August 28: Preparing for Danielle NASA team takes break as Bonnie fades away August 31: Quite a Windfall Hurricane team completes first half of unique science campaign. Includes listing of August flights and aircraft and spacecraft used in CAMEX-3. September 2: Bonnie Cuts a Towering Figure Satellite radar shows mountainous cloud chimney September 4: Hurricane team studies Earl Four aircraft probe storm September 10: NASA team awaits next hurricane September 16: Hurricane season passing its prime Thunderstorm studies continue as a new hurricane candidate wends its way from Africa. September 18: Two new storms brewing for hurricane research team Scientists fly 4 out of 5 days, clear air sampled over the Bahamas, oceanic convection data collected east of Cape Canaveral (this story) September 21:The last hurricane - CAMEX team wrapping up campaign with flights into Georges September 23: Hurricane Georges puts on a light show - CAMEX team treated to purple sprites and weird lightning NCAR has an extensive writeup on the GPS dropsondes used in CAMEX-3 and other atmospheric campaigns. A new study - not related to CAMEX-3 - by the Arizona State University suggests a link between hurricanes in the northwest Atlantic and air pollution.

CAMEX-3 - the third Convection and Moisture Experiment - is an interagency project to measure hurricane dynamics at high altitude, a method never employed before over Atlantic storms. From this, scientists hope to understand better how hurricanes are powered and to improve the tools they use to predict hurricane intensity.

An overview story (Aug. 12, 1998) describes the program in detail. The study is part of NASA's Earth Science enterprise to better understand the total Earth system and the effects of natural and human-induced changes on the global environment. A midterm story (Aug. 31, 1998) reviews the first month of operations and the windfall of data.

Measuring distance and speed

Because meteorology and aeronautics first used modified nautical charts, their data bases are in nautical miles and knots (nautical miles per hour). In these stories, we use Standard International ("metric") units first, and give more familiar measurements in English units and the original measurements in nautical units. Because of rounding and because the wind speeds originally are expressed in knots, km/h speeds to knots may be slightly different from the numbers in the story.

Standard International Units: 

km - kilometer (1 km = 0.62 smi = 0.54 nmi) 

km/h - kilometers per hour 

English (or US) units: 

mi, or smi - miles (statute miles; 1 smi = 0.87 nmi = 1.61 km)
mph - (statute) miles per hour 

Nautical units: 

nmi - nautical miles (1 nmi = 1.15 smi= 1.85 km) 

kts - knots (nautical miles per hour) 

 

Web Links

CAMEX-3 home page contains links to daily flight operations and instrument descriptions. Lightning Imaging Sensor aboard the TRMM satellite observes lightning from above the clouds - and my lead to better warnings on the ground. MACAWS uses the Doppler effect (red and blue shifts) to measure wind velocity. SPARCLE is a Space Shuttle experiment set for 2001 to demonstrate laser wind measurement from space.