The GFMS is a NASA-funded experimental system using real-time TRMM Multi-satellite Precipitation Analysis (TMPA) precipitation information as input to a quasi-global (50°N - 50°S) hydrological runoff and routing model running at 1/8th degree latitude/longitude grid. Flood detection/intensity estimates are based on 13 years of retrospective model runs with TMPA input, with flood thresholds derived for each grid location using routed runoff statistics (95th percentile plus parameters related to basin size). The intensity value is the calculated water depth above the flood threshold. Calculations of streamflow are also shown as well as precipitation totals from the last day, three days and seven days. All the calculations are updated every three hours.
The flood detection algorithm is described in Wu et al. (2012), the flood model in Wang et al., (2011) and the TMPA precipitation data product in Huffman et al. (2010).
References
Wu, H., R. Adler, Y. Tian, Y. Hong, F. Policelli, 2012. Evaluation of Global Flood Detection Using Satellite-based Rainfall and a Hydrological Model. J. Hydromet. (in revision).
Wang, J., Yang, H., Li, L., Gourley, J. J., Sadiq, I. K., Yilmaz, K. K., Adler, R. F., Policelli, F. S., Habib, S., Irwn, D., Limaye, A. S., Korme, T. & Okello, L., 2011. The coupled routing and excess storage (CREST) distributed hydrological model. Hydrol. Sci. J. 56(1), 84.98.
Huffman, G.J., R.F. Adler, D.T. Bolvin, E.J. Nelkin, 2010: The TRMM Multi-satellite Precipitation Analysis (TMPA). Chapter 1 in Satellite Applications for Surface Hydrology, F. Hossain and M. Gebremichael, Eds. Springer Verlag, ISBN: 978-90-481-2914-0, 3-22.