Christopher Velden and Kurt Brueske
University of Wisconsin - Cooperative Institute for Meteorological Satellite Studies
ABSTRACT
The new Advanced Microwave Sounding Unit (AMSU) was launched in 1998 on board the NOAA-15 polar-orbiting satellite. This instrument package carries microwave sounding channels that can be used to remotely sense thermal structures and anomalies, even in the presence of cirrus cloud. One of the unique meteorological features associated with hurricanes is an upper-level warm core structure. This thermal anomaly intensifies with storm strength as secondary circulations drive a warm descending branch of air to mid levels in the eye. As will be shown in the presentation, this warm anomaly is depicted quite well in AMSU observations.
It will be shown in a case study of Atlantic Hurricane Danielle that the warm anomaly signature precedes storm genesis, strengthens as Danielle develops into a hurricane, and dissipates in the mid-levels at the time NHC was declaring Danielle extratropical. It is hypothesized that the AMSU could be an important method of observing the evolution of the warm core signature and alerting forecasters to hurricane genesis, strength, and the loss of tropical characteristics.
Finally, a new retrieval method is outlined which corrects AMSU-A radiance values in the hurricane warm core region due to resolution limitations. The corrected values are entered into a retrieval package and used to estimate storm strength by hydrostatic calculations.
Suggested session: 5) New Technology
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