Research Project: Utilizing geostationary satellite observations to develop a next generation ice cloud optical property model in support of JCSDA Community Radiative Transfer Model (CRTM) and JPSS CAL/VAL
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- Saito, Masanori
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SOW As a flagship effort of a multi-agency (NOAA, NASA, Navy and Air Force) Joint Center for Satellite Data Assimilation (JCSDA), the Community Radiative Transfer Model (CRTM) is a powerful and robust tool to facilitate the forward and adjoint radiative transfer simulations involved in satellite remote sensing programs and data assimilation efforts. Although the CRTM is a state-of-the-art radiative transfer package, ice optical property model used in CRTM is obsolete. Ice clouds are ubiquitous in the atmosphere, covering approximately 40% of the tropics and 20% of the globe. These clouds play important roles in the radiative transfer process in the earth-atmosphere coupled system. It is well known that the “equivalent-sphere” model for ice clouds produces significant errors or even misleading results. Progress in developing of more realistic nonspherical ice crystal models has been steady but slow. The existing ice cloud optical property models still suffer various shortcomings, for example, some models lead to inconsistency for applications in the solar and infrared spectral regimes, and some models lacks microphysical consistency in comparison with in situ measurements. In response to this funding opportunity, we propose to develop a next generation ice model in support of the Community Radiative Transfer Model (CRTM) and the improved modeling capability will benefit the CAL/VAL efforts in conjunction with the Joint Polar Satellite System (JPSS).
We will use observations made by the Advanced Baseline Imager (ABI) aboard GOES-16 and GOES 17 with high temporal resolution to first infer the radiative and microphysical properties (specifically, optical thickness and the effective particle size) using both the solar bi-spectral technique (i.e., the Nakajima-King method) and the infrared split window technique with daytime ABI observations while only infrared technique will be used for nighttime retrieval. Furthermore, we will collocate the aforesaid retrievals with collocated CALIOP retrieval. In the proposed retrievals, an ice cloud optical property model must be used. We will test various ice cloud models. The optimal model is the one that will lead to spectral consistency between solar-band and IR-band based retrievals and consistency between passive (ABI based) and active (CALIOP based) retrievals. After an optimal ice cloud model is identified, we will implement it in CRTM. Specifically, the implementation will be conducted for the channels of Cross-track infrared Soundar (CrIS) and Visible Infrared Imaging Radiometer Suite (VIIRS) on JPSS. This effort will support JPSS CAL/VAL effort. We call special attention to the optical ice cloud optical properties generated through the proposed project, which can be directly used to generate the forward look-up tables involved in JPSS-based cloud property retrievals in consistent with the improved CRTM so that data assimilation using CRTM and JPSS cloud products are consistent.
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Cooperative Agreement