Aug. 31, 1998: (this is the
twelfth 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.)
A campaign to make the most extensive set of hurricane measurements
is already a phenomenal success even though it is only halfway
through its flight time.
"The Bonnie data set is just incredible," said Robbie
Hood, the mission scientist for the third Convection and Moisture
Experiment (CAMEX-3). "Now we're really pumped. We'd like
to work with Danielle as much as we did Bonnie so we can see
the difference between two hurricanes. That will show us why
is one big and why is one small."
While hurricanes have been probed by aircraft since the 1940s
and monitored by satellites since the 1960s, this is the first
coordinated campaign to measure a hurricane's growth with aircraft
at low, medium, and high altitudes.
It brings to bear a range of modern instruments - including
lasers, advanced radar, lightning sensors - on the aircraft and
on board the Tropical Rainfall Measuring Mission (TRMM), launched
in November 1997.
NOAA officials estimate that improved forecasting can be worth
million dollars a mile. That is, every mile of coastline that
does not have to be alerted avoids a million dollars in lost
economic productivity. (Because of a hurricane's power, forecasters
will over-warn rather than risk letting people be caught off
guard.)
CAMEX-3 was designed to study
the factors involved in how strong a hurricane grows. The campaign,
directed by NASA's Global Hydrology and Climate Center in Huntsville,
Alabama, involves two NASA aircraft - a converted spy plane and
a refitted jetliner - plus hurricane researchers from the National
Oceanic and Atmospheric Administration (NOAA) and the U.S. Air
Force's 53rd Weather Reconnaissance Squadron, the Hurricane Hunters.
It also combines some activities with the NASA Texas-Florida
Underflight (TEFLUN-B) campaign that measures a thunderstorm's
environment and conditions from aircraft and the surface simultaneously
as the TRMM satellite passes overhead. |
Coming full circle with hurricanes
One of the ironies of flying through a hurricane is that it
can be smooth sailing. At 7.6 to 10.6 km (25,000-35,000 ft),
scientists aboard NASA's DC-8 Airborne Laboratory could have
been on an ordinary flight.
"It
was so smooth that it was hard to imagine what people on the
ground were going through," said mission scientist Robbie
Hood (left).
"I had really mixed emotions about that. We were happy to
catch it, but then you always wonder what's happening to the
people below."
Actually, Hood knows all too well.
Her first experience with a hurricane was at age 13 in 1969
when Hurricane Camille smashed through the Gulf Coast and claimed
256 lives. Hood was living in Picayune, Miss., 80 km (50 mi)
inland.
"Hurricane Camille was such an intense storm that the
eye was still well formed and came right over our house,"
Hood said. "It pretty much tore up the entire coastline,
but even 50 miles inland it devastated that little town we were
living in - a lot of houses were torn up and trees downed."
She also lived in Missouri in Tornado Alley, "So that's
where I got my interest in hurricanes and severe weather."
Her interest was in remote sensing - observing with instruments
aboard satellites and aircraft - and that work brought Hood full
circle to the Global Hydrology and Climate Center in Huntsville,
Al., where she develops instruments and methods to study storms
by satellite. |
Of
course, the easy part is getting the hardware and people together.
The hard part is waiting for nature to cooperate.
Left:
Bonnie's eye
wall as seen by the Airborne Rain Mapping Radar (ARMAR) on
DC-8, Aug. 23.
"I was worried before we ever left as to whether we would
have a hurricane at all," Hood said, "would we get
out there on time, how many times we could go through it."
Check below for the CAMEX-3
schedule to date, and a list of aircraft
and satellites.
Then Hurricane Bonnie formed in the mid-Atlantic Ocean and
for a while was headed right for Patrick Air Force Base, Fla.,
where the CAMEX team is based. For several days the team arrived
at work with their suitcases, anticipating orders to evacuate
to Warner Robbins AFB, Ga.
Bonnie did more than cooperate - it veered towards the Outer
Banks of North Carolina at the last moment and even posed for
pictures. |
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"On Wednesday [Aug. 26]
when we went out to study it when it was making landfall, we
were afraid we were going to miss it," Hood explained. "And
when we got up there, it was already at least an hour ahead of
its forecast position. But once we got there it was like it stopped
to wait on us. We noticed while we were flying through it, the
center of the eye was not moving that much, and for the last
part of the flight it was pretty much sitting still. It was just
eerie - it was just waiting on us.
"This was just cosmic. There are three TRMM [satellite]
overpasses, and we've got all these airplanes, and this thing
was just sitting here, just waiting on us. I don't know if we'll
ever be able to catch another one that perfectly."
In all, the CAMEX-3 team made four sets of coordinated flights
involving NASA, NOAA, and Air Force aircraft. The first set,
on Aug. 21, was a synoptic flight, measuring conditions that
would determine Bonnie's growth as it moved westward. On Aug.
23 and 24, the teams flew through and over the eye, the central,
open structure that is the focus of a hurricane's motion and
energy. Finally, on Aug. 26, the team probed Bonnie as it hit
the North Carolina shore.
Gathering the data
Although the scientists are halfway through the flight campaign,
they have hardly begun the important work of CAMEX-3: analyzing
the data. And they have plenty.
"This
experiment is going to produce a ton of papers," Hood said.
"Most of the instrumentation's been doing really well,"
she continued, "especially the landfall case. At one point
we lowered our altitude on the DC-8 to fly between cloud layers.
It was an excellent mission for MACAWS, the Multicenter Airborne
Coherent Atmospheric Wind Sensor."
Above:
The MACAWS team checks
data during a test flight just before Bonnie formed. photo
credit: Bill Ingalls/NASA
MACAWS aims at laser into the clear air and measures the light
reflected back by aerosols in the atmosphere. Like measuring
the speed of a star, the red shift - or blue shift - tells the
speed of the aerosol relative to the aircraft. Subtracting the
aircraft's speed yields the true wind speeds across wide, clear
sections between the storm's cloud decks. Such measurements are
difficult to obtain unless you fly right through every spot in
the storm.
"MACAWS was seeing all kinds of wind structures"
in the middle of Bonnie, Hood said. "I was talking with
Dr. Jeff Rothermel [of NASA/Marshall Space Flight Center, the
principal investigator] Thursday and he's really excited about
the data set he collected."
The other laser instrument is the Lidar Atmospheric Sensing
Experiment (LASE) from NASA's Langley Research Center. It measures
moisture and aerosol content, crucial factors in how strong a
storm will become.
"The LASE people had a pretty good mission, too. They
wanted to sample the moisture of the inflow region as it's coming
inside the storm. We think we captured that" when they flew
in between the cloud decks at 7.6 km (25,000 ft.). |
"Bonnie was just in the right place at the right time
the whole time we were working it. My only regret is that I wish
we could have worked it yesterday, too. We really thought it
was going to go overland, and that it was going to die out."
Then the team rested, although they might have flown again
on Aug. 27 had they known that Bonnie - unexpectedly - would
veer back out to sea and pick up energy again.
"To have gotten one hurricane and worked it four times
is just phenomenal to me," Hood said. "We still have
about half of our flight hours to go, so we can work another
one at least three or four times."
Some of that attention will
go to Danielle, now expected to hook around to the north and
not even make landfall. Danielle is more compact and less energetic
than Bonnie. The CAMEX-3 team flew two missions over the weekend.
On Saturday, the Citation II flew a convection study with a TRMM
overflight. The DC-8 completed a successful vortex motion and
evolution flight through Danielle and peppered Danielle with
40 dropsondes. On Sunday, DC-8 had another successful vortex
motion and evolution inflow flight on Hurricane Danielle. Monday
will be a no-fly day for the team, in preparation for flights
on Tuesday.
During the Bonnie study, the team had "excellent coordination"
in having one NOAA WP-3D Orion on the first eye wall flight,
and both Orions plus an Air Force WC-130 Hercules on the second
eye wall penetration for a total of five aircraft.
It was during the second eye wall flight that Bonnie pulled
yet another surprise - snow in August.
"Right along the eye wall this big dome cloud had come
up and it was shooting ice crystals or snow up and it was falling
on top of the DC-8," Hood explained. |
"The eye wall was trying to redefine itself. Traditional
theory is that you have an eye here, and the new eye wall is
forming out here, and it will eventually squeeze in and overpower
the original eye wall. If it has a greater wind speed than the
original eye wall, if it moves in faster, it will increase the
wind even more through conservation of momentum, and it makes
the wind even more powerful."
What we saw, on all three days, was the traditional eye wall,
and then this outer eye wall, and the wind speeds were greater
in the outer eye wall, but it pretty much stayed in the same
place. The inner eye wall was going through all kinds of fluctuations."
The team also noticed that the eye wall location radioed up
by the NOAA Orion crews did not match the location that the DC-8
crew was observing.
"A lot of times we found the eye at our altitude was
displaced, one way or the other from what was seen at the lower
altitudes. What I was amazed about was how fast it was doing
that. We would go out of the eye and come back a half an hour
later and the thing would be shifted this way or that way."
Right, Above: Color
and thermal images of part of Bonnie as seen by the Multispectral
Atmospheric Mapping Sensor (MAMS) on ER-2, Aug. 23.
"For
me all this is brand new, because I've never flown through a
hurricane. But people like Ed Zipser, who know a lot more about
hurricanes, were a lot more surprised by what we were seeing."
More surprises my lie ahead. With only half of the flight
time used, the CAMEX-3 team is planning how they will investigate
Danielle, and whether to hoard some of the hours for the hurricanes
that may form later. The CAMEX-3 campaign is scheduled to run
through Sept. 23.
Left:
Danielle, as seen by the NASA/Goddard SeaWIFS instrument, with
the ground track of the DC-8 Airborne Laboratory overlaid. Hurricane
Bonnie, at the top right of the image, is moving northeast across
the North Atlantic Ocean. The black section to the right is where
data are unavailable because of the satellite's own path and
scnn pattern. (links to 945x1024-pixel,
414K JPG.)
CAMEX-3/TEFLUN-B flight
activities
5 |
ER-2 arrives at Patrick Air Force Base |
6 |
No-fly day |
7 |
No-fly day |
8 |
Shakedown over Andros Island Ground Station. The convective thunderstorm
was exactly below the ER-2 flight track as predicted and we should
have some good data from the flight. |
9 |
No-fly day |
10 |
DC-8 flies from Dryden Flight Research Center to Patrick AFB |
11 |
No-fly day |
12 |
No-fly day |
13 |
TEFLUN B: Deep convection measurements
over Melbourne, Fla., area. The TEFLUN-B ground coordination
flight seems to be a large success. We had all three aircraft
in stacked formation, on coordinated lines, through an active
storm, instruments working well, with a TRMM satellite overpass. |
14 |
No-fly day |
15 |
TEFLUN B: Deep convection measurements
over central Florida |
16 |
No-fly day |
17 |
No-fly day |
18 |
No-fly day |
19 |
No-fly day |
20 |
TEFLUN B: Convection east of Cape
Canaveral. Today's TEFLUN-B mission was highly successful. The
ER-2 was canceled due to high cross winds. The DC-8 and UND Citation
accomplished major goals in the stratiform rain environment while
the TRMM satellite passed overhead. The NASA aircraft are on
alert for a CAMEX-3, tropical storm Bonnie, flight tomorrow.
The UND Citation is on alert for a possible TEFLUN-B mission. |
21 |
CAMEX-3: Tropical Storm Bonnie synoptic
flow measurements. The ER-2 was canceled due to high winds.
The DC-8 did fly a synoptic flow mission on tropical storm Bonnie.
Everything seems to be a success. Patrick AFB is officially on
a HURCON 4 alert. The AF Battle Staff will meet at 1000 tomorrow.
We need to prepare to evacuate the base tomorrow If we are not
forced to evacuate, tomorrow will be a no fly day. Stay tuned. |
22 |
TEFLUN B: Citation II TEFLUN mission
was successful today; the NASA DC-8 and ER-2 had no-fly day.
Patrick AFB issued a HURCON 3 posted at 1300 EDT. Plans are to
perform another Bonnie mission tomorrow with DC-8 and ER-2. If
HURCON 2 is issued, we will have to evacuate the area immediately.
The aircraft will be sent to Warner-Robbins AFB, Macon, GA. |
23 |
CAMEX-3: Hurricane Bonnie eye wall
#1. DC-8 and ER-2 made extremely successful flights over
the eye wall of hurricane Bonnie in coordination with the NOAA
aircraft. They both overflew the Andros Island site on the return
from Bonnie. Monday we will make another flight over hurricane
Bonnie, planning closer coordination with NOAA aircraft Flight
tracks over the hurricane will be similar to the ones flown on
Sunday. |
24 |
CAMEX-3: Hurricane Bonnie eye wall
#2. CAMEX bagged another highly successful overflight of
Hurricane Bonnie in conjunction with the NOAA WP-3 aircraft.
The aircraft will stand down Tuesday, Aug. 25. |
25 |
No-fly day |
26 |
CAMEX-3: Hurricane Bonnie landfall.
Another extremely successful flight day. Both ER-2 and DC-8
overflew Bonnie as it made landfall. There were three TRMM overpasses
during the flight with the earliest overpass almost directly
over the eye wall. Both NOAA Orions also flew coordinated patterns
with the NASA aircraft. Tomorrow will be a no fly day and Friday
a tentative hard down day. We anticipate the earliest opportunity
for a Hurricane Danielle flight on Saturday, 29 August. |
27 |
TEFLUN B: UND Citation II had a
successful flight studying convection over the S-POL site. |
28 |
No-fly day |
29 |
CAMEX-3: Vortex motion and evolution
and moisture inflow measurements of Danielle by DC-8. |
30 |
CAMEX-3: Vortex motion and evolution
and moisture inflow measurements of Danielle by DC-8. |
31 |
No-fly day |
CAMEX-3/TEFLUN-B satellites
|
GOES-8:
Geostationary Operational Environmental Satellite; operated by
NOAA. |
|
NOAA:
Polar-orbit weather satellites; operated by NOAA
(also called Advanced Television Infrared Observational Satellites
[TIROS]). |
|
TRMM: Tropical
Rainfall Measuring Mission; Japanese satellite carrying some
NASA instruments, including mapping radar and a Lightning Imaging
Sensor. |
|
SeaStar:
Commercial satellite, operated by Orbital Sciences Corp. under
contract to NASA, carrying the Sea-viewing Wide Field-of-view
Sensor (SeaWiFS). Not a formal part of CAMEX-3, but its data
are available to investigators. |
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 (this story)
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
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. |
|