CHIRPS-GEFS | Climate Hazards Center

CHIRPS-GEFS is a bias-corrected and downscaled version of NCEP Global Ensemble Forecast System (GEFS) version 12 precipitation forecasts made to be spatially compatible with Climate Hazards Center InfraRed Precipitation with Stations (CHIRPS) data. The CHIRPS-GEFS data set provides next 5-day to 15-day precipitation forecasts, updated daily, at a spatial resolution of ~5 km across the globe.

CHIRPS-compatible GEFS precipitation forecasts for anticipating flood and drought hazards

CHIRPS-GEFS unites key precipitation observation and forecast resources to support more streamlined situation assessments and hazards early warning. CHIRPS-GEFS forecasts are provided with compatible spatial characteristics and statistical distributions that facilitate their “inter-operation” with CHIRPS. This supports users producing timely impact assessments of forecast rainfall amounts and anomalies, as well as potential changes to agro-climatological or hydrological situations that are being monitored with CHIRPS data. Please find a more detailed overview below.

For comments or inquiries, please contact Marty Landsfeld at marty.landsfeld@ucsb.edu

CHIRPS-GEFS Forecasts

Daily 5-day, 10-day, 15-day Forecasts

5-day

Total Image Data

Anomaly Image Data

10-day

Total Image Data

Anomaly Image Data

15-day

Total Image Data

Anomaly Image Data

Dekadal Forecasts

First (5-8 day lead)

Total & Anomaly Data

Last (0-day lead)

Total & Anomaly Data

Daily Forecasts

Daily

Total Data

In blending CHIRPS and real-time GEFS forecasts, a quantile-matching procedure modifies the GEFS forecast precipitation amount to be consistent with the local historical CHIRPS record. The procedure identifies how the forecast amount ranks historically, compared to historical GEFS forecasts from 2000 to present. Using that rank-based percentile, an amount corresponding to the same percentile of the CHIRPS data distribution is identified. The new forecast thus retains important information from the GEFS, including the advanced weather forecasting ability of the GEFS version 12 system and the historical extremity of the current forecast, while also now aligning with the CHIRPS’s high-quality 5-km resolution climatology and CHIRPS historical variance.

Operational CHIRPS-GEFS data are a bias-corrected 0.05-degree version of the 0.25-degree resolution Day 1 to 10 and 0.5-degree resolution Day 11 to Day 16 GEFS real-time 00 UTC ensemble mean forecasts for total precipitation. The data used in the quantile-matching procedure are 16-day GEFS version 12 ensemble mean “reforecasts” for 2000 to 2019, real-time ensemble mean forecasts from October 2020, and CHIRPS version 2.0 historical precipitation. The GEFSv12 FV3 Phase II “reforecast” data are produced by NCEP/EMC and are described in Guan et al., 2019 (link to pdf here). More information on the GEFS is available here.

Accessing CHIRPS-GEFS

CHIRPS-GEFS data and images are available through several online interfaces.

Data Update Schedule: 5-day, 10-day, and 15-day CHIRPS-GEFS are updated daily. Dekads and pentads periods are updated on the first day of each period (every ~5 to 10 days).

CHIRPS-GEFS Data Repository

Forecast data are provided for several time periods to support users. The table above provides links to the latest forecasts and to the historical data archive for most time periods, in GeoTIFF format (0.05-degree, 50N to 50S, 180W to 180E). All data is available here.

5-day, 10-day, 15-day CHIRPS-GEFS: January 2000 to December 2019 and October 2020 to present. In addition to precipitation totals (mm), anomalies (mm) and standardized precipitation index (Z scores) are available for download. These are computed using all available data.

Dekads CHIRPS-GEFS: October 2020 to present. Dekads correspond to the calendar dates 1-10, 11-20, and 21-end of each month. The “First” dekad forecast is produced 16 days before the last day of the dekad, corresponding to the first opportunity to do so using the GEFS 16-day forecast. The “Last” dekad forecast is produced on the 1st, 11th, and 21st day of each month. The “Last” forecast is preferred, due to the GEFS being initialized with closer-to-actual conditions.

Pentads CHIRPS-GEFS: October 2020 to present. Pentads correspond to the calendar dates 1-5, 6-10, 11-15, 16-20, 21-25, and 26-end of each month. All are updated on the 1st, 6th, 11th, 16th, 21st, 26th of each month. Similar to the dekad forecasts, the “First,” “Second,” and “Last” names correspond to the first, second, and last time that a forecast is produced for the pentad of interest.

Code used to generate CHIRPS-GEFS is available here.

Early Warning Explorer (EWX)

In the CHC EWX and USGS EWX viewers, users can view the CHIRPS-GEFS and other data, including precipitation from several products, MODIS land surface temperature, eMODIS NDVI, modeled evapotranspiration and soil moisture, and more.

As explained here, these EWX viewers provide historical time-series for a variety of regions, such as administrative zones, crop zones, and hydrologic catchment basins. In the USGS EWX viewer, CHIRPS-GEFS pentad forecasts are appended to CHIRPS time-series.

How to cite this data

This page is the registered CHIRPS-GEFS data repository. The assigned DataCite DOI is doi:10.15780/G2PH2M.

Please cite CHIRPS-GEFS data as: CHIRPS-GEFS Precipitation Forecasts https://doi.org/10.15780/G2PH2M (2021). Data was accessed on [DATE].

Harrison, L., Landsfeld, M., Husak, G. et al. Advancing early warning capabilities with CHIRPS-compatible NCEP GEFS precipitation forecasts. Sci Data 9, 375 (2022). https://doi.org/10.1038/s41597-022-01468-2

CHIRPS-GEFS in Action

CHIRPS-GEFS is used in CHC Early Estimates, a data and map resource for monitoring seasonal precipitation and agro-climatological hotspots. The CHC Early Estimates Recent Rainfall Monitor and Seasonal Rainfall Monitor show rainfall accumulations for recent time periods based on the CHIRPS final and preliminary data. The “+ Forecast” version includes the CHIRPS-GEFS 15-day forecast.

Monthly GEOGLAM Crop Monitor for Early Warning bulletins. CHIRPS-GEFS are used for evaluating rainfall conditions and for highlighting areas of concern in Regional Outlooks.

A partnership with the Ethiopian National Meteorological Agency (NMA) results in a dekadally-updated bulletin highlighting the current conditions by blending CHIRPS with data from the NMA’s private station network. Outlooks in these reports use CHIRPS-GEFS forecasts and historical rainfall.

CHIRPS-GEFS has potential for flood early warning, with an example shown here: Blending CHIRPS Data and GEFS Forecasts for an Enhanced Rainfall Forecast Product

Examples of CHIRPS-GEFS in early warning for the March-to-May 2019 Eastern Horn drought, including generation of combined forecast seasonal rainfall scenarios.

A video presentation of Dr. Chris Funk showcasing a number of products for southern Africa is available on the CHC YouTube channel here.

Examples of CHIRPS-GEFS incorporated in operational monitoring of the 2018/19 growing season over Southern Africa can be found here.

CHIRPS-GEFS, and other data available through the Early Warning Explorer, have been featured in Tanzania Ministry of Agriculture National Food Security bulletins.

SERVIR’s ClimateSERV portal has featured CHIRPS-GEFS data. ClimateSERV tools include user-defined boundaries for spatial data extraction and historical time series.

CHIRPS-GEFS is in the public domain, as registered with Creative Commons, and is under a Creative Commons Attribution 4.0 International License. To the extent possible under the law, Marty Landsfeld has waived all copyright and related or neighboring rights to CHIRPS-GEFS. This work is published from: the United States.