A multiple satellite concept for severe weather monitoring

Kurzfassung

3D wind vectors can be derived from high resolution visible (VIS) and thermal infrared (TIR) stereo images of the drift of clouds and upper troposphere water vapour structure observed by two satellites operated in low Earth orbit (LEO) with identical ground track at a time delay of 200-600 s (TANDEM constellation). Threefold along-track stereos-copy at narrow stereo view angles of +10° and +15° for the VIS/TIR bands will provide high redundancy and sufficient similarity of the observed image texture for automatic image correlation and data evaluation. A ground pixel size of 100 and 200 m for the VIS/TIR bands and one pixel accuracy for image correlation (worst case) will provide a height resolution of 600 and 700 m and a wind resolution of 0.5 and 1.0 m/s for a time gap of only 200 s. The TANDEM can be based on any existing LEO satellite providing cloud and/or water vapour images with daily global coverage. High resolution horizontal wind vectors with stereoscopic height assignment do require stereo observation only for the add-on satellite. However, a TANDEM with two stereo satellites can additionally identify strong vertical displacements on as a new observational input for numerical weather prediction.