Gravity Wave Signatures
and Properties in AMSU-A Data
Introduction
The Advanced Microwave Sounding Unit-A (AMSU-A) is a passive nadir-viewing microwave instrument on NOAA operational satellites. Compared to MLS, AMSU-A has advantages for better horizontal coverage with cross-track scanning and for a longer data record. There are four AMSU instruments currently in orbit: three on NOAA N15 (since May 1998), N16 (since September 2000) and N17 (since June 2002) satellites, and one on NASA Aqua satellite. AMSU-A frequency channels cover altitudes between the surface to ~2 hPa. Detailed descriptions on this instrument can be found in http://www2.ncdc.noaa.gov/docs/klm
AMSU-A radiance fluctuations induced by gravity waves are often weak or comparable to the instrument noise as the FOV (field-of-view) averaging reduces small-scale wave amplitudes significantly. Advances in microwave remote sensing, however, now enable the detection of these weak wave signals. In order to obtain reliable gravity wave signals, instrument radiance error is the first thing we need to understand and characterize. We have developed some useful methods to quantify the AMSU-A instrument noise, which allow us to extract weak variances induced by gravity waves
More AMSU Maps
SH during June-August 2003
MLS-AMSU comparison for SH winter
December 2002-January 2003
Jet streak event during 19-21 Januray 2003
Mountain waves over Scandinavia
Mountain waves over Japan
Gravity Waves in the Northern Hemisphere in January 2003
Lee waves over Andes
Time Series
The U. S. East Coast and North Atlantic in January 2003