CW3E 1-km 1-hourly Meteorological Forcing on NWM Grid

Summary

As part of data infrastructure building by the Hydrology Team at the Center for Western Weather and Water Extremes (CW3E), a meteorological forcing engine is developed to produce long-term (1979 to near real time), high-resolution (1-km, 1-hourly), and national-scale (CONUS) forcing data to support research and applications in hydrologic modeling and forecasting. The configuration of this forcing data product is set up to serve the demanding needs at the center, for example, to build near-real-time (NRT) forecasting system for various regions and to perform large scale modeling research for the National Water Model (NWM) (both its current generation WRF-Hydro and its NextGen) in collaboration with the CIROH consortium. See CONUS 1-km Water Monitor & Forecast page for an example of application of this data product.

Data Sources

1. NLDAS-2 meteorological forcing
2. HRRR surface analysis fields
3. Stage-IV precipitation
   • Real-time version 
   • Archive version (after 10-day lookback)
4. PRISM precipitation and temperature
   • Provisional version
   • Recent History version
   • Historical Past version
5. MRMS precipitation (to be implemented)
6. CW3E West-WRF Forecast (forecast time horizon only)

Product Types

For the purpose of hydrologic modeling and forecasting, we set up a couple of time horizons: retrospective, near-real-time (NRT), short-range forecast, and seasonal forecast (Figure 2). The forcing data in the retrospective period is fairly stable - to be revised for bug fixes and other quality improvements, and the forcing data in the NRT period would be subject to frequent updates. Given the space limitations, we make two streams of data products available to the public:

1. Retrospective product
   • 1979-01-01 to ~7 month behind real time
   • updated monthly
   • precipitation based on Stage IV (2002-) and NLDAS-2 (1979-2001) and matched against PRISM at daily (1981-) and monthly level (1979-1980)
   • temperature based on NLDAS-2 and matched against PRISM at daily (1981-) and monthly level (1979-1980)
   • data within recent 7 months may be provided but matched against PRISM Provisional (less stable - will be eventually replaced by PRISM Recent History)
2. Near-Real-Time (NRT) product
   • most recent few years, up to the current day
   • updated daily
   • precipitation based on Stage IV (Real-time and Archive) and NLDAS-2 (gap-filling)
   • other fields based on NLDAS-2 and HRRR

Data Format

All the forcing data is in NetCDF format and follows the CF convention, thus most NetCDF-capable software will be able to read the data and interpret the meta information (e.g., time stamp, grid/projection settings). The naming of forcing variables and the units/sign definition all follow the WRF-Hydro convention such that the files can be read directly by the WRF-Hydro model. See the table for the list of 8 variables.

The data is 1-hourly and labeled in UTC time. Following NCEP conventions, the precipitation is the mean flux in the previous hour, for example, precipitation value time labeled at 12 UTC is the mean between 11 UTC and 12 UTC.

The data is in Lambert Conformal Conic (LCC) projection at 1-km resolution.

Download

Both the retrospective and NRT forcing products are hosted on Globus:

• Retrospective product: https://app.globus.org/file-manager?origin_id=0351632c-c1f7-4885-8125-0a19290791ff&origin_path=%2F  
• NRT product: https://app.globus.org/file-manager?origin_id=1620b36c-6d83-45d1-8673-5143f09ac5d8&origin_path=%2F 

Known Issues

Striping noise in Stage IV hourly data over CNRFC

Among the input datasets, the NCEP Stage IV data started to have striping noise problems as of July 2020 in its hour data over the CNRFC region. Cumulative values at 6-hourly intervals or longer were not affected by this problem. The cause of this issue was assumed to be a buggy 6-hourly to 1-hourly temporal disaggregation procedure performed at NCEP. No fixes have been applied at NCEP so far. A temporary workaround is being developed to redo the temporal disaggregation using the NSSL MRMS (e.g., multisensor pass 1).

Lack of observation data outside of US border

No significant number of Canadian or Mexican observations exist in the input data products, causing abrupt changes across the borders. An ongoing effort is trying to blend in the Canadian Precipitation Analysis System (CaPA) data.

More Information

Please visit the product website at https://www.reachhydro.org/home/records/1-km-conus-forcing/.