Hurricane research team stays busy
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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.
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 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.
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 firstname.lastname@example.org.
CAMEX Series Headlines
August 12: Overview CAMEX story , describes the program in detail.
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.
- km - kilometer (1 km = 0.62 smi = 0.54 nmi)
- km/h - kilometers per hour
- mi, or smi - miles (statute miles; 1 smi = 0.87 nmi = 1.61 km)
mph - (statute) miles per hour
- nmi - nautical miles (1 nmi = 1.15 smi= 1.85 km)
- kts - knots (nautical miles per hour)
- Standard International Units:
- English (or US) units:
- Nautical units:
|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.