A197-10
The Configurable Scanning Submillimeter-wave Instrument/Radiometer (CoSSIR): Modernizing Submillimeter Radiometry for Future Cloud Investigations

Tuesday, 15 December 2020: 10:27
Virtual
Ian S Adams1, Rachael Kroodsma1,2, Stephen Joseph Munchak3, Matthew Fritts1 and Lisa Milani1,4, (1)NASA Goddard Space Flight Center, Greenbelt, MD, United States, (2)Earth System Science Interdisciplinary Center, College PARK, MD, United States, (3)NASA Goddard Space Flight Center, Greenbelt, United States, (4)University of Maryland, Earth System Science Interdisciplinary Center (ESSIC), College PARK, United States
Abstract:
CoSSIR is an airborne sensor with a rich development history at NASA Goddard Space Flight Center. In its early incarnations, CoSSIR demonstrated the utility of submillimeter radiometry for observing ice clouds and frozen precipitation during the CRYSTAL FACE and TC4 field campaigns. In addition to pioneering submillimeter sensing of clouds, CoSSIR, and its millimeter-wave sibling CoSMIR, are driven by a unique, configurable pedestal that will support hybrid scan strategies, such as the combined conical and cross-track scanning.

Currently, CoSSIR is undergoing enhancements to enable new science investigations. First, we are completing work on a new, direct drive scanning mechanism which will allow smoother transitions between scan modes. Second, we are updating the receivers to provide new capabilities. We have updated the channel set to include weighting-function-matched bands around the 183.31- and 325-GHz water vapor absorption lines, providing differential snow and cloud ice signals at three atmospheric penetration depths. Additional channels at 170 and 684 GHz complement the range of atmospheric penetration and sensitivity to particle size. All radiometer bands will be dual-polarized, and the improved noise performance will allow more precise polarization measurements at a range of wavelengths compared to the early polarized CoSSIR data at 640 GHz.

CoSSIR’s configurable scanning allows a wide range of scan patterns, many of which were successfully demonstrated with CoSMIR during the first deployment of IMPACTS. Of particular interest is a hybrid of conical imaging and along-track scanning. The latter allows multi-angle views of 2D cloud cross-sections, which we can use to investigate the polarizing effects of clouds and frozen precipitation and link these polarization signatures to hydrometeor properties. To further exploit the along-track, multi-angle geometry, we are developing a computed tomography (CT) algorithm to reconstruct vertical profiles of clouds and frozen precipitation. Work to complete CoSSIR is expected to culminate with a transition to the NASA ER-2 in preparation for observations during the final year of IMPACTS, with CoSMIR data and three-dimensional radiative transfer simulations providing proxy data for development.

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