National Weather Service United States Department of Commerce

CHPS Forcing Team

In the summer of 2008, the CHPS Acceleration Team (CAT) made the strategic decision that areal data forcings will be provided to FEWS (Flood Event Warning System) in the form of gridded fields. Furthermore, these fields will be generated external to the FEWS environment. Gridded data elements to be considered, for both the observed and forecast time domain, are:

    1) Precipitation
    2) Temperature
    3) Freezing Level
    4) Potential evapo-transpiration

Existing functionality within FEWS will be used to spatially integrate these external gridded fields into mean areal values using a combination of defined basin boundaries and specified elevation breaks.

A CHPS Forcings teams was formed to plan and manage the approach for generating these grids and ultimately ensuring their proper use in the FEWS model operations. The team is composed of members from each of the four CAT RFCS, and members from OHD/HSMB (Hydrologic Science and Modeling Branch) and OCWWS/HSD (Hydrologic Services Division). The team is led by the OHD/HSEB (Hydrologic Software Engineering Branch). The four CAT RFCs are ABRFC, CNRFC, NERFC, NWRFC.

The team has conducted near-weekly conference calls, beginning in November 2008. The minutes of these conferences are provided via the below links.

The key issues being considered by the team are the methods used to generate each of the grids and the form of the grids (spatial resolution, grid projection, data format). The applications used for generating the grids include baseline applications such as GFE and MPE/DQC, and local applications. For BOC-1 (Baseline Operating Capabilities, for CAT sites), it has been decided that the grids will be provided to FEWS in GRIB1 format. Grid transformation utilities are being planned, so the grids may be first generated in different forms. A matrix is provided below which shows the methods and grid forms to be used for each RFC, and for each forcing.

The immediate, primary goal of the team is to ensure generation of the grids and proper use of the grids within the FEWS operations for BOC-1. BOC-2 involves implementation of CHPS at the remaining nine RFCs. The methods and overall approach used in BOC-1 will be evaluated and possibly modified for the BOC-2 phase.

[Back to main CHPS web page]

Main Link Categories:
Home | HL | OHD | NWS