The upcoming implementation of version 12 of the NCEP Global Ensemble Forecast System (GEFSv12) will be accompanied by a 20-year reanalysis and reforecast. The reanalysis uses a reduced-resolution approximation of the operational global data assimilation system to produce reanalyses with statistical characteristics that approximate those of the real-time system. The reanalyses are used primarily for reforecast initialization. The primary reforecast data spans the period 2000-2020. Every day during this period there were 5-member reforecasts computed to +16 days lead time, and once per week an 11-member ensemble was computed to +35 days lead. These reforecasts will be used for the statistical calibration of precipitation/temperature/freezing level for hydrologic forecasts, for 6-10 and 8-14 day forecasts, and in the future for a broader range of postprocessed products including National Blend of Models precipitation inputs, week 2 fire weather forecasts, and weeks 3-4 S2S forecasts including Atlantic hurricane cyclone energy.
To facilitate research across the enterprise, approximately 200 fields from the reanalysis and reforecast data will be made available on NOAA disk servers and at Amazon Web Services via the NOAA Big Data Program.
The seminar will provide more details on the reanalysis/reforecast, review their statistical characteristics, and will briefly discuss the anticipated future GEFSv13 reanalysis/reforecast, which we envision will utilize a weakly coupled data assimilation system and which may be computed using cloud resources.
