CHIRPS FAQ

CHIRPS FAQ's

Is there a CHIRPS website?

     yes,
     http://chg2.geog.ucsb.edu/data/chirps/index.html

Where can I get CHIRPS data?

     in a browser go to,
     ftp://chg-ftpout.geog.ucsb.edu/pub/org/chg/products/CHIRPS-latest/
     or equivalently,     tinyurl.com/chg-chirps
     .
     via anonymous ftp,
     ftp chg-ftpout.geog.ucsb.edu
     username: anonymous 
     password: your_email_address
     cd  /pub/org/chg/products/CHIRPS-latest/

What is the spatial resolution of CHIRPS?

     Chirps is produced at 0.05 x 0.05 degree spatial resolution
     For daily Africa data we also provide a 0.25 x 0.25 degree spatial resolution product

What are the spatial domain available for CHIRPS?

     Global          50N-50S, 180W-180E   @0.05 deg resolution = maps 7200 x 2000 pixels
     Africa          40N-40S   20W- 55E   @0.05 deg resolution = maps 1500 x 1600 pixels
     CAmer-Carib   23.5N- 6N   93W- 57W   @0.05 deg resolution = maps  720 x  350 pixels 

What are the time steps available for CHIRPS?

     pentad
     dekad
     monthly
     daily   (for Africa)

What are the file formats available for CHIRPS?

     .tif
     .bil

What units is CHIRPS in?

      Total mm for given time step, mm/pentad, mm/month, etc.

What value is used for Bad Values?

     -9999  

What is the latency of the CHIRPS product?

     There is a rapid, gts-only, CHIRPS available 2 days after the end of a pentad
     Final CHIRPS (all station data) is available sometime after the 15th of the following month. 

What is the temporal range for CHIRPS?

     CHIRPS is available from 1981 to near-real time
     The first couple of years are of lesser quality due to large gaps in the B1 IR data for that time period. 
     People using CHIRPS for hydrological modeling may choose to start later than 1981.

Who do I contact with CHIRPS questions?

     Pete Peterson
     pete@geog.ucsb.edu

What is the spatial density of station data used in CHIRPS?

      The closest thing we have available is what we call reality checks 
      we post in EWX (Early Warning Explorer). Take a look here,
      http://chg2.geog.ucsb.edu:8080/EWX/index.html
         on the left open up the Africa tab
              then double click on,  RCHECKS-STNS
      You will have to zoom in to see squares with black dots in the middle.
      These are 10x10 pixel boxes of the station value on top of the CHIRPS field.
      A 'reality check' to see if the stations match the background field.
      You can zoom in on a location then cycle through month/years to see how 
      the # of stations changes with time.  Its pretty significant in some areas.

Also,

      ftp://chg-ftpout.geog.ucsb.edu/pub/org/chg/products/CHIRPS-latest/qc/stations_used/monthly/
      Each file represents a single month of CHIRPS for the Globe.
      There are 5 columns,
      year,month,latitude,longitude,station_used?
      Each file has 52,743 lines representing our total list of anchor stations used in CHIRPS.
      The last column, station_used is
           0   if no station data used for that location/time
           1   if we had station data for that location/time.

How was CHIRPS funded?

      CHIRPS has been supported by funding from
      the U.S. Agency for International Development (USAID)       
      the USAID Famine Early Warning Systems Network (FEWS NET)
      the National Aeronautics and Space Administration (NASA)  and 
      the National Oceanic and Atmospheric Administration (NOAA)

Who uses CHIRPS?

How good is CHIRPS?

     For its intended uses, Seasonal Drought monitoring and Trend Analysis, it is very good, 
     see validation-pptx (under construction)
     For other uses it depends on the questions you are asking. 
     

How do I reference CHIRPS in publications?

     Funk, C.C., Peterson, P.J., Landsfeld, M.F., Pedreros, D.H., Verdin, J.P.,
     Rowland, J.D., Romero, B.E., Husak, G.J., Michaelsen, J.C., and Verdin, A.P., 
     2014, A quasi-global precipitation time series for drought monitoring: U.S.
     Geological Survey Data Series 832, 4 p.

Is there a copy of the paper online?

     yes,
     tinyurl.com/chg-chirps/docs/USGS-DS832.CHIRPS.pdf

What's on the agenda for future CHIRPS?

      redo the CHPclim to include more station data and avoid tiling artifacts
      include fGSOD data from 1981-1999
      include fGTS  data from 1984-1994
      include Peru-ANA station data
      include an additive step to the blending