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Preparing for Danielle

NASA team rests after "quite incredible" work with Bonnie

Aug. 28, 1998:(this is the eleventh 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.)

NASA researchers are taking Thursday and Friday off to rest themselves, recalibrate their instruments, and then plan their research over hurricane Danielle which is gaining power to the east of Florida.

To date the Convection and Moisture Experiment (CAMEX-3) team has made four sets of flights around, through, and over Hurricane Bonnie as part of a major effort to understand how hurricanes intensify and, eventually, to be able to predict what their strength will be.

"This is certainly the most complete data set that we've ever had of a hurricane, any one day would have been the most complete," said Dr. Ed Zipser of Texas A&M University, lead scientist for the Tropical Rainfall Measuring Mission (TRMM) field validation experiment and a major participant in the CAMEX-3 campaign. "But we had three days ... this is quite incredible. And then it was topped off by the TRMM overflights" on Wednesday.

At right: A colorized GOES-8 image shows Bonnie as it staggers northeast into the Atlantic Ocean. (Links to 600x508-pixel, 55KB JPG.)

"We studied the atmosphere in front of this very large hurricane, spent two days flying through Bonnie's eye wall out at sea, and then catch her in a landfall situation," said Robbie Hood, the mission scientist from NASA's Marshall Space Flight Center in Huntsville, Ala. "It was our sheer luck to be able to catch the storm in many different phases. This is a powerful data set that will help NOAA [National Oceanic and Atmospheric Administration] in its predictions of intensity and direction to help save lives and money."

CAMEX operates out of Patrick Air Force Base, Fla., and uses NASA's DC-8 and ER-2 research aircraft in conjunction with NOAA's WP-3D Orion hurricane hunters. In addition, the study uses data from weather satellites and has timed its flights to coincide with observations by the Tropical Rainfall Measuring Mission (TRMM) satellite. Wednesday's flights, for example, matched three passes by TRMM, exactly the sort of coordinated measurements that the team wanted.

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Bonnie's progress is seen in color images from the Sea-viewing Wide Field-of-view Sensor (SeaWiFS) satellite. The images here show Bonnie, from left to right, top to bottom, on Aug. 24 (Monday) through Aug. 27 (Thursday). Each image links to a larger JPG up to 1,000 pixels wide and 200 to 226 KB in size.

The first CAMEX-3 research flight set (DC-8 and ER-2 plus NOAA aircraft) was in the relatively calm weather ahead of Bonnie as the hurricane approached the U.S. coast. This let scientists measure conditions that would affect Bonnie's growth, which they measured with two flight sets through the hurricane and its eye and then one more (Wednesday) as Bonnie waded ashore in North Carolina.

"I think we are in the era of what I hope will be a well-organized national weather research program," Zipser said, "because NASA, NOAA, the [National] Science Foundation, and the university community have shown they can cooperate in a multi-agency, multi-aircraft mission and I think that holds great promise, not just in hurricanes, but all kinds of natural disasters."

The first stage in studying Danielle will be a synoptic flight ahead of the storm to measure winds and other conditions ahead on Saturday.

Weather forecast

Bonnie continued to pummel the Carolina outer banks, but is expected to begin recurving toward the north, albeit along the U.S. coast. On Friday morning it had moved back over the Atlantic and picked up energy, turning itself from a tropical storm back into a hurricane.

Hurricane Danielle, currently at an intensity of 148 km/h (92 mph, 80 kts), is moving nearly due west at 31 km/h (20 mph, 17 kts). Minimum pressure is 993 mb, on the high side for winds of 148 km/h (92 mph, 80 kts). Danielle is fighting shear generated by an upper low to its west, but models forecast this shear to break down, and Danielle should slowly intensify. All models tightly agree on the predicted continued westward track, around the southern flank of a strong 500 mb anticyclone located east of Bermuda. Then the models gradually track Danielle toward the northwest, then north, on a similar track to Bonnie.

Over Florida, weak south-southwest winds prevail over the peninsula. A weak high is projected to build westward across Florida tonight, with the ridge axis initially located over southern Florida. This should keep the area in a southwesterly regime for the next 24-36 hours. Morning soundings at Cape Canaveral and Tampa are dry in the mid-levels, although water vapor imagery shows increasing mid- and upper-level moisture is advecting into the region. Today, the probability of thunderstorms is low as the atmosphere slowly recovers from the dry, subsident environment in the wake of Bonnie. Scattered, short-lived showers are possible along both sea breeze fronts, with the west coast breeze propagating inland through the afternoon. Surface winds will be southwesterly at 19 km/h (12 mph, 10 kts).

Over the next day to two days, look for gradual moistening through the column and slightly increased thunder storm probabilities. The wind regime will be light southerly, changing to a southeasterly regime. Thus the probability of afternoon thunder storms is equally likely inland of both sea breeze fronts. Danielle's 48-hr forecast position is some 500 km (311 mi) north of Hispaniola with an intensity of 176 km/h (109 mph, 95 kts).

Left: NASA/Marshall's Lightning Imaging Sensor observed Hurricane Bonnie as the TRMM spacecraft flew over the storm several times in the last few days. The image at left shows intense lightning as Bonnie nears the North Carolina coast in observations made Thursday. (Links to 756x680-pixel GIF)

For the next 2 to 3 days, Danielle's forecast position by 72 hrs is 28.0 N, 73.5 W, or 650 km (404 mi) east of PAFB, with gentle recurvature toward the northwest, and an intensity of 222 km/h (138 mph, 120 kts).

Finally, for the next 3 to 5 days, thunderstorm activity over the peninsula should again become suppressed over the peninsula as Danielle skirts by us offshore.

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 (this story)
August 31: Quite a Windfall
Hurricane team completes first half of unique science campaign
September 2: Bonnie Cuts a Towering Figure Satellite radar shows mountainous cloud chimney
September 4: Hurricane team studies EarlFour aircraft probe storm
September 10: NASA team awaits next hurricane
September 16: Hurricane season passing its primeThunderstorm 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
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.

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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.

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.

More web links 
  • More Space Science Headlines - NASA research on the web 
  • The Marshall Newsroom - more information on this and other news from the Marshall Space Flight Center 
  • NASA's Earth Science Enterprise Information on Earth Science missions, etc. 
  • Global Hydrology and Climate Center studies the global water cycle and its effect on climate. 
  • National Hurricane Center carries the latest tracking information on tropical storms and hurricanes. It also has lots of historical data and images, including hi-resolution copies of the pictures above of damage by Hurricane Andrew
  • The Public Use of Remote Sensing Data at Goddard Space Flight Center has high-resolution images of Fran (including the original of the image used in this story), Andrew, and other hurricanes and of other events seen from space.