The Tomorrow.io Weather Constellation: Current Status and On-Orbit Performance

Tomorrow.io aims to revolutionize the commercial/private weather partnership by launching a low-Earth-orbit (LEO) constellation of microwave sounders and radars. The sounders represent the latest generation of the TROPICS (Time-Resolved Observations of Precipitation structure and storm Intensity with a Constellation of Smallsats) instrument design, featuring an operationalized payload with improved onboard calibration and digital signal processing capabilities. They measure twelve channels between 91 and 204 GHz near oxygen and water vapor absorption lines in order to provide temperature and humidity profiles. The Ka-band radars conduct narrow single-beam scans using a 1.2 m parabolic reflector and are specialized for precipitation retrievals.

The first eight satellites have already launched, and we anticipate fourteen satellites in orbit by early 2026. At that point, the constellation will provide global sub-hourly revisit rates coupled with low data latencies. A variety of sun-synchronous and inclined orbits act to fill LEO gaps and observation content complements NOAA / NASA / EUMETSAT missions. These observations provide considerable benefit for operational nowcasting and numerical weather prediction needs alongside time-insensitive applications such as reanalyses or inter-calibration / validation.

In this talk, we provide an overview of instrument capabilities and on-orbit performance. We will discuss instrument calibration and geolocation accuracies. Following this, we describe available L0/L1/L2 products (e.g. uncalibrated and inter-calibrated brightness temperatures, temperature and humidity profile products, precipitation retrieval products) and show evaluation results. Examples will be drawn from overpasses of interesting weather events including tropical cyclones, frontal systems, and atmospheric rivers.