Winter Cloud Experiment

Project Description
The Winter Cloud Experiment (WINCE) took place from January 23
to February 13, 1997. During WINCE, an instrumented NASA ER-2
high altitude research aircraft will be flown to learn more
about detecting clouds from space in winter conditions. WINCE
will provide important data with which scientists can improve
cloud detection for future satellite instruments such as the
MODerate resolution Imaging Spectroradiometer (MODIS). This NASA
research instrument, scheduled for launch in mid-1998 as part of
Mission to Planet Earth, will assess earth climate trends of
which clouds are such an important component.

WINCE is jointly hosted by the University of Wisconsin's Space
Science Engineering Center and the 115 Fighter Wing, Wisconsin
Air National Guard, at Truax Field which will provide necessary
faciliites for supporting the NASA ER-2 research aircraft
operations. Madison-based Persoft is providing communications
equipment to facilitate remote data transfer to and from SSEC
computers, about 5 miles away from Truax Field. Persoft
specializes in PC-to-host software and wireless network
connectivity solutions.

UW scientists Steve Ackerman, William Smith and Paul Menzel will
head the scientific analysis of the data set, along with NASA
scientists Dorothy Hall, Jim Spinhirne and Jim Wang of the
Goddard Space Flight Center near Washington, DC. Their research
findings will be applied to cloud detection algorithms for the
MODIS and other future satellite instruments. "The high altitude
nature of the ER-2 (20 km or 65000 feet) is a key element of
WINCE. It allows our instruments to make cloud measurements much
as they would from a satellite platform. That makes it possible
for us to improve our cloud detection capability before the
satellite is ever launched," says Ackerman.

During WINCE, multispectral radiometric measurements of clouds
and the earth will be made by the MODIS Airborne Simulator
(MAS), the High-resolution Interferometer Sounder (HIS) and the
Microwave Imaging Radiometer (MIR) remote sensing instruments
on the ER-2. The measurements combine observations of the
microwave, infrared, and visible energy from clouds, atmosphere
and earth into a single measurement that can be used to analyze
the physical mechanisms important for weather prediction and
climate change. Signatures of clouds over snow-covered ground
are revealed using reflectance and temperature data derived
from these measurements. "In a visible image, both clouds and
snow-covered terrain are highly reflective, so they're hard to
tell apart," Paul Menzel explained. "In the infrared, cold
clouds and cold terrain emit roughly the same thermal
energy. Only with multispectral imaging can we hope to separate
clouds from snow and ice-covered terrain." Cloud height
measurements f! rom the Cloud Lidar System (CLS) onboard the
ER-2 can verify the position and thickness of clouds in the
radiometric data. That data, when combined with the radiometric
measurements, allows UW scientists to examine the underlying
signature of the cloud itself.

Science Objectives:

1. Cloud detection/properties over snow/ice background
2. Snow detection
3. MAS/HIS absolute calibration comparison
4. SSEC ground-based instrumentation overflight
5. ADEOS underflights

For more information, link to

[Summary provided by WINCE]