Title: Tropospheric Water and Cloud ICE (TWICE) Instrument Development for CubeSat Deployment
Presenting Author: Steven Reising
Organization: Colorado State University

Co-Author(s): Pekka Kangaslahti, Eric Schlecht, Sharmila Padmanabhan, Richard Cofield, Jonathan Jiang, and Shannon T. Brown, JPL; William Deal, Northrop Grumman Corporation; Xavier Bosch-Lluis and Mehmet Ogut, Colorado State University

Abstract:
The new Tropospheric Water and Cloud ICE (TWICE) instrument will provide critically needed measurements of water vapor and cloud ice in the upper troposphere at a variety of local times, providing data not currently available from microwave sensors in sun-synchronous orbits. Such global measurements will enable more accurate cloud and moisture simulations in global circulation models, improving both climate predictions and uncertainty characterization. In addition, this capability will address the need for measurements of cloud ice particle size distribution and water content in both clean and polluted environments to investigate the effect of aerosol pollution on cloud properties and climate. This is particularly important since the uncertainty in the aerosol effect on climate is at least four times as great as the uncertainty in greenhouse gas effects. Finally, the TWICE instrument will provide humidity and temperature profiles covering most of the troposphere in nearly all weather conditions.

The TWICE instrument will advance the state of the art of submillimeter-wave radiometers by transitioning from Schottky mixer-based front ends to InP HEMT MMIC low-noise amplifier front ends, thereby substantially reducing the mass, volume and power consumption of space-borne radiometers. New low-noise amplifiers and front-ends based on InP HEMT MMIC technology up to 670 GHz are being designed and fabricated for the TWICE instrument by JPL and Northrop Grumman. These technology developments will greatly enhance the suitability of these instruments for deployment on small satellite platforms in general, and on CubeSats in particular. The TWICE instrument will provide millimeter- and submillimeter-wave radiometer channels from 118 GHz to 670 GHz, including three window frequencies to perform ice particle sizing and determine total ice water content, as well as sounding channels near three absorption lines for water vapor and temperature sounding, particularly in the upper troposphere in the presence of ice clouds.