HAMSR is a microwave temperature and humidity sounder instrument that looks at the microwave spectrum. Typically, it is flown at the bottom part of an aircraft where it can look straight down from the air to the ground, right through the atmosphere. HAMSR is a self-calibrating cross-track scanning instrument. Its scan mirror makes a full revolution in little more than 1 second. During that period, it obtains a number of overlapping spatial samples of the atmospheric scene below and several view of two internal calibration targets. From an altitude of 20 km, its field of view about 40 km wide on the ground.
The direct measurements are brightness temperatures for each field of view in 25 channels over 3 spectral bands. Additional information on measurements includes:
- Coverage from surface to flight altitude (<100 mb)
- ~ 2 km vertical resolution
- ~ 2 km horizontal resolution (at nadir, at the surface)
- ~ 40 km wide swath (at the surface)
- 8 channels in the 50-GHz band: primary T-sounding
- 10 channels in 118-GHz band: secondary T-sounding
- 7 channels in 183-GHz band: q- sounding
Current data products from HAMSR include calibrated brightness temperatures and soon will also have retrieved T & q profiles. Research products for rain rates and convective intensity are being developed. Data collected during field campaigns that HAMSR participated in are available at the Global Hydrology Resource Center.