SPECTral Radiative Transfer Unified Model (SPECTRUM) - Phase II Prototype

Orbital Micro Systems, Inc. (OMS) will build SPECTral Radiative transfer Unified Model (SPECTRUM), a development platform using multiple Radiative Transfer Models (RTMs) from ultraviolet (UV) to radio frequencies to aid in instrument and algorithm development. OMS created a full SPECTRUM design in Phase I. In Phase I, OMS demonstrated the use of containers to connect RTMs without modifying either the RTM or the SPECTRUM components. This proposal advances SPECTRUM to Phase II. The Phase II objectives are: Build SPECTRUM core infrastructure to run multiple RTMs and algorithms. Populate SPECTRUM with multiple RTMs and algorithms. Create a workbench of tools to support instrument and algorithm development. Four principles drive the SPECTRUM design: 1) Use existing RTMs. 2) No modifications required to integrate RTMs into SPECTRUM. 3) Interchangeable RTMs, satellites, and algorithms. 4) Keep it simple OMS designed SPECTRUM as a modular, document-driven system of containers. Document-driven means communication between SPECTRUM and RTMs will consist entirely of file transfers. A container is a customized, isolated computing environment that holds only those resources, software, and libraries required to run one RTM. Using containers allows a modular SPECTRUM design with interchangeable and replaceable RTMs and algorithms. OMS purposefully created this simple, modular design to minimize the effort required to integrate multiple RTMs into a single system. This allows OMS to focus on integrating RTMs and developing tools rather than building supporting infrastructure. SPECTRUM will consist of five systems: the RTM library, the translator, the workflow, the workbench, and the constituent repository. The translator creates RTM input configuration files from user-selected options and consolidates RTM output into a single file. The workflow orchestrates the execution of RTMs and retrievals. The workbench contains tools to help build and analyze RTMs and associated retrievals. The constituent repository contains physical characteristics, spatial distributions, and vertical profiles of atmospheric constituents. At the end of Phase II, the RTM library will contain 14 RTMs and associated retrieval algorithms. For the Phase II base period, OMS selected RTMs based on a compare and contrast strategy of multiple RTMs covering similar frequency ranges with similar retrieval algorithms. For the Phase II option period, OMS will select RTMs based on an Earth system strategy to couple RTMs for a mix of different physical environments.