MIMIC-TPW: Seamless advective blending of total precipitable water retrievals from polar orbiting satellites

We describe a novel data blending technique that combines separate swaths of microwave observations from polar orbiting satellites in order to create near-seamless hourly imagery of total precipitable water (TPW) over the oceans. MIMIC-TPW was originally developed as an experimental, real-time visualization tool utilizing microwave-derived moisture fields to follow the development and progression of cyclone-spawning easterly waves and the cyclone-impeding Saharan Air Layer in the North Atlantic Ocean.

The process of advective blending is well suited to the task of tracking TPW, which can normally be treated as a quasi-conservative tracer over time scales of greater than 20 hours. Because the microwave satellite constellation usually retrieves oceanic TPW more frequently than 20 hours, we can use model winds to advect TPW between orbital overpasses with high accuracy. The resulting synthetic image product is much like a composite geostationary image, with only minor artifacts. Animations of sequential images create smooth and coherent depictions of moisture transport that have been promoted by operational weather analysts. We will also discuss the possible application of this technique to other quasi-conservative quantities retrieved by polar orbiting satellites.

We will present the method of producing this derived product as well as the results of validation; sensitivity studies; and case studies showing the utility of this product for tropical cyclone forecasting, observation of atmospheric rivers, and the tracking of major dust events.