Feasibility Study Report for 3D Cloud Tomography From Space Using Passive Microwave Technologies

Passive microwave (PMW) remote sensing technologies advanced rapidly in the past decade or so, making 3D cloud tomography (CT) increasingly feasible using PMW sensors. However, current 3D-CT study still dominantly concentrated at visible/infrared bands, which works well for thin clouds, but is limited to only outlining thick cloud boundaries. Despite being able to penetrate through thick clouds and to reveal the internal mass distribution, which is critical for precipitation forecast, there is no trade-space study readily available for MW/sub-mm radiometers for 3D-CT. Technology-wise, emerging new technologies can potentially enable hydrometeor profiling through tomography with a single sensor, but a thorough evaluation of feasibility and challenges is still missing.
This feasibility assessment report aims at addressing this gap from both science and technology perspectives. For science, we will use a simulated cloud case to present the trade-space study results focusing on optimal vertical resolution that can be achieved using different combinations of PMW instrument parameters. For technology, we will present our evaluation of candidate architectures, subsystem components, the desired specs, challenges and recommendations for future development directions. For disclaimer, this report is not intended as a comprehensive review, but rather as a starting point to kick-off more studies in this area.