NCAR Aircraft's Premiere:  The (Arctic) Big Chill

The newest addition to the NCAR-operated aircraft fleet soared off to 
Fairbanks, Alaska, last week on its first assignment after a 400-day (and 
often night) overhaul that left the Research Aviation Facility (RAF) staff 
exhausted but proud.  The Lockheed-built C-130 is scrutinizing clouds 
and sea ice on the coast of the Beaufort Sea north of Canada for BASE 
(Beaufort and Arctic Seas Experiment) as the darkening polar winter 
grips the region during September and October.  NSF, which owns the C-
130, is funding BASE, along with Canada's Atmospheric Environment 
Service and the Institute for Ocean Sciences.  The Canadian Convair 580 
will complement the C-130's observations of the experiment's focus area, 
the mouth of the Mackenzie River at the eastern edge of the Northwest 
Territories.

Referring to the aircraft's extensive makeover, RAF manager Larry Radke 
comments, "NCAR has never done anything quite like this in the facility.  
This is the first time we didn't hire out the work."   For example, Beech 
Aircraft remodeled the King Air and the Navy revamped the Electra's tail 
for the Electra Doppler radar.  "We threw all of our resources including 
our spare change into the project," explains Larry.  "We sold the 
Sabreliner and leased the King Air to Hong Kong to raise money for the 
C-130."  Driven by a rigid deadline and a tight budget, Larry set half the 
facility to work on the C-130.   "The job itself was a whole lot like writing 
a symphony by committee," says Larry.  Many of the staff worked long 
days and weekends as the departure date crept steadily closer.   

Converting the former Navy communications plane into a research 
aircraftÑone that would accommodate passengers as well as 
instrumentsÑmeant starting from scratch.  Besides mounting special 
racks and pods, installing 11 kilometers of electrical wire, and cutting a 
hole in the belly of the plane, the overhaul team also added the basicsÑa 
toilet and a galley.  "This is no 747," comments RAF associate scientist 
Krista Laursen, who will be onboard for many of the ten-hour flights 
throughout the six weeks of the experiment.   "It's loud and has tiny 
windows."  RAF aeronautical engineer Diana Rogers elaborates:  "We 
installed a quiet room and that helped a lot, but you still need ear 
protection to ride in it comfortably."

Krista will operate one of BASE's two special instruments, a multichannel 
cloud radiometer (MCR), which will measure optical cloud thickness, 
particle size, cloud top temperatures, liquid water, and ice.  The MCR 
hangs out of the right wing pod and must be filled with liquid nitrogen 
before take-off each day to keep its operating temperature at a frigid 
Ð70¡C.  

Julie Haggerty, assistant project manager, will spend her flight time in 
front of an onboard video screen monitoring real-time data from a 
microwave radiometer that scans sea ice through a hole in the plane's 
floor.  Microwave emissions reveal the age of the ice through differences 
in brightness.  Other on-board instruments include three video cameras 
pointed in different directions; a hand-held positioning device provided 
by the University NAVSTAR Consortium; a gust probe on the aircraft's 
nose; and basic temperature, pressure, and humidity sensors.  When 
Krista's cloud radiometer is operating, the C-130 will be cruising around 
nine kilometers above the ground.  For Julie's microwave radiometer, the 
plane will drop to about 2.5 km.

BASE offers a double challenge for pilots Michael Heiting and Lowell 
Genzlinger, since both the airplane and the region are unfamiliar.  An 
emergency landing would mean guiding the plane to safety on slick ice 
with ordinary wheels rather than landing skis.  In preparation for such an 
emergency, the crew is equipped with down parkas, wind pants, sleeping 
bags, food for three days, and protection against polar bears, which have 
been known to aggressively stalk and eat humans.

In spite of possible danger and extreme cold (temperatures could sink to 
Ð20¡C before the team heads home), project manager Bruce Morley, a 
veteran of research experiments in Antarctica and Greenland, says "I 
think it will be fun.  We want to observe the region's autumn-winter 
transition as the Beaufort Sea freezes and the liquid water in clouds turns 
to ice."

Principal investigator Judy Curry of the University of Colorado's 
Department of Aerospace Engineering Sciences and the Program in 
Atmospheric and Oceanic Sciences expects BASE to provide ground-
truth data on the interaction between sea ice and weather along the 
Beaufort coast.  The Arctic is important because global climate models 
with doubled carbon dioxide show the greatest climate warming (up to 
15¡C in winter) in the far north, but these predictions are questionable 
because of scanty information about key factors such as radiation and 
clouds.  

"The C-130 is essential to the experiment," says Judy.  "Getting the aircraft 
ready on time required a heroic effort by NCAR.  We didn't have any 
leeway because we're tied up with the Canadian effort and also we 
needed to catch this autumnal freeze-up period."  --Anatta