Title: Tropospheric Water Vapor and Cloud ICE (TWICE) Millimeter-wave to Terahertz Radiometer Instrument for 6U-Class Nanosatellites
Presenting Author: Steven C. Reising
Organization: Colorado State University
Co-Author(s): Pekka Kangaslahti, Erich Schlecht, Sharmila Padmanabhan, Jonathan Jiang, Richard Cofield, Nacer Chahat, and Shannon Brown; NASA/Caltech Jet Propulsion Laboratory; Xavier Bosch-Lluis, Mehmet Ogut and Yuriy Goncharenko; Colorado State University William Deal, Alex Zamora, Kevin Leon, Sean Shih and Gerry Mei; Northrop Grumman Corporation.

Abstract:
Ice clouds, covering more than 33% of Earth’s surface, substantially modulate Earth’s climate. They play a significant role in the hydrologic cycle by affecting precipitation, atmospheric structure and cloud dynamics. Many ice cloud properties, such as ice water content, cloud fraction and cloud top height, have been observed globally from satellites. However, global measurements of ice particle size distribution (IPSD) along with associated water vapor and temperature profiles in the upper troposphere/lower stratosphere (UTLS) are critically needed. Such global measurements would improve ice cloud microphysics parameterization, precipitation forecasting, more accurate quantification of cloud radiative effects, and more accurate cloud and ice retrievals from remote sensing measurements.

To address this unmet need, a collaborative team involving Colorado State University, Caltech Jet Propulsion Laboratory and Northrop Grumman Corporation is in the process of development and fabrication of the Tropospheric Water and Cloud ICE (TWICE) radiometer instrument. TWICE is designed to meet size, mass, power consumption and downlink data rate requirements for deployment aboard a 6U-Class nanosatellite. TWICE is advancing the state of the art of spaceborne millimeter-wave to terahertz radiometers by transitioning from Schottky mixer-based front ends to MMIC low-noise amplifier front ends, substantially reducing the radiometer’s mass, volume and power consumption. Based on 25-nm InP HEMT MMIC technology, JPL and Northrop Grumman have fabricated and tested new designs for low-noise amplifiers (118-670 GHz) and related front-end components for spectrometer channels. The TWICE instrument will measure three window frequencies from 240 GHz to 670 GHz, with dual-polarization capability at the highest frequency, to provide IPSD and total ice water content. In addition, 12 sounding channels near three absorption lines at 118.75 GHz, 183.31 GHz and 380.20 GHz will provide temperature and water vapor atmospheric profiles in the UTLS in the presence of ice clouds.