CRTM Version 3: New Opportunities for Satellite-based Sensor Simulation

The JCSDA Community Radiative Transfer Model (CRTM) has long stood as a fundamental tool for the assimilation and simulation of radiance data within meteorological and environmental systems. The latest iteration, CRTM v3, represents a significant leap forward in both functionality and adaptability. This presentation provides an overview of the novel features and enhancements incorporated into CRTM v3, with a special focus on its utilization in Joint Effort for Data assimilation Integration (JEDI) and Unified Forward Operator (UFO).

This critical advancement in CRTM v3 enables accurate modeling of polarized light across diverse atmospheric and surface conditions (e.g., clouds, aerosols, snow cover, sea ice, ocean, and land surfaces), creating new and exciting opportunities in remote sensing applications and atmospheric research. By implementing full Stokes polarization, CRTM v3 addresses complex interactions between light and matter, thereby offering more realistic simulations of radiative transfer processes.

A technical highlight of the CRTM v3 release is its ability to read both binary format files and netCDF4 coefficient files, as part of a transition away from binary formats. This mixed capability ensures seamless integration until all legacy coefficients are converted to netCDF4. Furthermore, the addition of space-based radar simulation capabilities has broadened the scope of CRTM's application.

One of the most exciting developments of CRTM v3 is its application in small satellite missions such as TROPICS (Time-Resolved Observations of Precipitation structure and storm Intensity with a Constellation of Smallsats). The new functionalities have proven to be particularly potent in enhancing data assimilation, modeling, and predictive accuracy within smallsat platforms. Practical examples will be provided to elucidate how these updates have contributed to the optimization of smallsat missions.

This talk will also explore real-world case studies showcasing CRTM v3's integration with the JEDI/UFO framework. By detailing the underlying methodologies and presenting examples, we aim to illuminate how CRTM v3's advancements align with modern requirements and stand as a testament to publicly accessible community-driven scientific innovation. The open-source collaborative model of CRTM ensures that there is equitable access for all developers / users to contribute to and utilize the model in their own applications without restrictions.

We will also briefly highlight the future of artificial intelligence methods to further accelerate the computational speed of CRTM -- essential for operational requirements -- while increasing the scientific accuracy of the model.