Humidity Sounder for Brazil


The Humidity Sounder for Brazil was an instrument launched on NASA's Earth Observing System satellite Aqua launched in May 2002. It was a four-channel passive microwave radiometer, with one channel at 150 GHz and three channels at 183 GHz. It was very similar in design to the AMSU-B instrument, except it lacked the 89 GHz surface sounding channel. It was intended to study profiles of atmospheric water vapor and provide improved input data to the cloud-clearing algorithms in the Unified AIRS Retrieval Suite, but the scan mirror motor failed on February 5, 2003. It worked with the Atmospheric Infrared Sounder and AMSU-A to form the AIRS Sounding Suite.
HSB was manufactured by Matra Marconi Space, Limited, in the United Kingdom under a contract with the Brazilian National Institute for Space Research.

Instrument characteristics

Table 1: Radiometric characteristics of the HSB
Channel NumberAMSU-B
Channel Number		Frequency
Bandwidth
Instrument Sensitivity
NEDT
11689.9 ± 0.9DELETEDDELETED
217150 ± 0.940000.68
318183.31 ± 1.002x5000.57
419183.31 ± 3.002x10000.39
520183.31 ± 7.002x20000.30

History

HSB stopped scanning suddenly and without warning over the Pacific Ocean February 5, 2003 at 21:39 UTC. The most likely cause is an electrical failure in the scan electronics. By design AMSU-B and therefore HSB had very limited hardware redundancy and software update capability.