[mmaimcal]DOE RFP 183 GHz

[Simon Radford]

Dave Woody passed this along to me. 


c. A Passive Microwave Radiometer for Measurements of
Low Concentrations of Atmospheric Water Vapor - Arid
arctic regions are important to the global radiation
budget, as they allow surface cooling by direct
radiation to space. This radiative transfer between
the surface, the atmosphere, and space is
predominantly affected by the amount of water vapor
present. Current instrumentation for measuring
atmospheric water vapor uses microwave technology at
22 GHz, but this wavelength lacks the sensitivity to
measure the low concentrations of water vapor in the
Arctic. The energy emitted from the 183 GHz water
vapor line is much stronger than that emitted from the
22 GHz line, offering a higher signal for low water
vapor values. Therefore, grant applications are sought
to develop a 183 GHz radiometer for continuous
unattended determination of the column and/or vertical
distribution of tropospheric water vapor in the
Arctic. The radiometer should also be applicable to
the measurement of atmospheric water vapor variation
at high latitudes.

Current millimeter wave radiometers are expensive and
typically not suited to harsh environments; therefore,
proposed approaches should be affordable, robust, and
have a reliable and accurate automated calibration
capability. An absolute accuracy of 1 Kelvin is highly
desirable. Also, the system should be capable of
determining the pressure-broadened 183 GHz line shape
intensity from near line center to approximately 16
GHz from line center with sufficient spectral
resolution to adequately retrieve profile information
from this spectral interval. Phase I should determine
the optimum frequency ensemble for arctic climates and
demonstrate the feasibility of a fieldworthy
instrument design, including a calibration system,
using brassboard or other prototype construction.
Phase II should produce a turnkey fieldworthy
instrument system as deliverable, including software
that returns column integrated or water vapor profiles
in engineering units.

http://sbir.er.doe.gov/sbir/Solicitations/FY%202002/BER.htm#T41