Difference between revisions of "CHIRPS FAQ"

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 +
==Is there a CHIRPS website?==
 +
Yes: https://chc.ucsb.edu/data/chirps
  
−
CHIRPS FAQ's
+
==Where can I get CHIRPS data?==
 +
===Via a web browser===
 +
http://data.chc.ucsb.edu/products/CHIRPS-2.0/
  
−
'''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?'''
+
==Climate Hazards Center landing page for all our public data is,==
−
      Chirps is produced at 0.05 x 0.05 degree spatial resolution
+
    http://data.chc.ucsb.edu/
−
      For daily Africa data we also provide a 2.5 x 2.5 degree spatial resolution product
 
  
−
'''What are the spatial domain available for CHIRPS?'''
+
===Via anonymous ftp===
−
      Global        50N-50S, 180E-180W @0.05 deg resolution = maps 7200x2000 pixels
+
  ftp ftp.chc.ucsb.edu
−
      Africa        40N-40S  20E-55W  @0.05 deg resolution = maps 1500x1600 pixels
+
username: anonymous
−
      CAmer-Carib    efdfdffgggerg1234 346y
+
password: your_email_address
 +
cd  /pub/org/chg/products/CHIRPS-2.0/
  
−
'''What are the time steps available for CHIRPS?'''
+
===DOI links===
−
      pentad
+
CHIRPSv2.0: http://chc.ucsb.edu/data/chirps/ #Points to data webpage, see [https://data.chc.ucsb.edu/products/CHIRPS-2.0/ Data section] for download
−
      dekad
 
−
      monthly
 
−
      daily  (for Africa)
 
  
−
'''What are the file formats available for CHIRPS?'''
+
==What is the spatial resolution of CHIRPS?==
−
      .tif
+
*Chirps is produced at 0.05 x 0.05 degree spatial resolution.
−
      .bil
+
*For daily Africa data we also provide a 0.25 x 0.25 degree spatial resolution product.
  
−
'''What units is CHIRPS in?'''
+
==What are the spatial domain available for CHIRPS?==
−
       Total mm for given time step, mm/pentad, mm/month, etc.
+
*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
 +
*WHem          50N-50S, 125W- 34W  @0.05 deg resolution = maps 1820 x 2000 pixels
  
−
'''What value is used for Bad Values?'''
+
==What are the time steps available for CHIRPS?==
−
      -9999  
+
*daily
 +
*[[#How does CHIRPS define a pentad?| pentad]]
 +
*[[#How does CHIRPS define a dekad?| dekad]]
 +
*monthly
 +
*2-monthly
 +
*3-monthly
 +
*annual
 +
   
 +
===How does CHIRPS define a pentad?===
 +
*6 pentads = 1 calendar month. Each of first 5 pentads in a month have 5 days. The last pentad contains all the days from the 26th to the end of the month.
  
−
'''What is the latency of the CHIRPS product?'''
+
===How does CHIRPS define a dekad?===
−
      There is a rapid, gts-only, CHIRPS available 2 days after the end of a pentad
+
*A dekad = sum of 2 pentads. There are 3 dekads in a calendar month.
−
      Final CHIRPS (all station data) is available sometime after the 15th of the following month.  
 
  
−
'''What is the temporal range for CHIRPS?'''
+
==What are the file formats available for CHIRPS?==
−
      CHIRPS is available from 1981 to near-real time
+
*.tif
−
      The first couple of years are of lesser quality due to large gaps in the B1 IR data for that time period.  
+
*.bil
−
      People using CHIRPS for hydrological modeling may choose to start later than 1981.
+
*.netcdf
  
−
'''Who do I contact with CHIRPS questions?'''
+
==What units is CHIRPS in?==
−
      Pete Peterson
+
Total mm for given time step, mm/pentad, mm/month, etc.
−
      pete@geog.ucsb.edu
 
  
−
'''How was CHIRPS funded?'''
+
==What value is used for Bad Values?==
 +
-9999.
  
−
'''Who uses CHIRPS?'''
+
==What is the latency of the CHIRPS product?==
 +
*There is a rapid (GTS and Mexico only) CHIRPS available 2 days after the end of a pentad.
 +
*Final CHIRPS (all station data) is available sometime in the third week of the following month.
  
−
'''How good is CHIRPS?'''
+
==What is the temporal range for CHIRPS?==
−
      It depends on the questions you are asking.
+
CHIRPS is available from 1981 to near-real time.
−
      For Seasonal Drought monitoring and Trend Analysis, CHIRPS is very good compared with other rainfall datasets.
 
  
−
'''How do I reference CHIRPS in publications?'''
+
==Who do I contact with CHIRPS questions?==
−
      Funk, C.C., Peterson, P.J., Landsfeld, M.F., Pedreros, D.H., Verdin, J.P.,
+
[[User:Pete| Pete Peterson]]
−
      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.
+
[mailto:pete@geog.ucsb.edu pete@geog.ucsb.edu]
−
      Geological Survey Data Series 832, 4 p.
+
 
 +
 
 +
==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).
 +
 
 +
You can access EWX [https://ewx3.chc.ucsb.edu/ewx/index.html here].
 +
*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 number of stations changes with time. It is pretty significant in some areas.
 +
 
 +
==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 [ftp://chg-data-out.chc.ucsb.edu/pub/org/chg/people/AGU-Fall.2014.presentations/AGU.2014.pete_peterson.final.pptx]
 +
 
 +
==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. http://pubs.usgs.gov/ds/832/
 +
 
 +
==Is there a copy of the paper online?==
 +
Yes.
 +
*[http://tinyurl.com/chg-chirps/docs/USGS-DS832.CHIRPS.pdf CHG-local source ]
 +
*[http://pubs.usgs.gov/ds/832/ USGS website ]
 +
 
 +
==What's on the agenda for future CHIRPS?==
 +
*extend CHIRPS above 50 degrees North
 +
*aquire more station data
 +
*redo the CHPclim to include more station data and avoid tiling artifacts
 +
*include an additive step to the blending
 +
*consider re-prioritorizing fGTS above fGSOD
 +
*have CHIRPS v2.0 ingested into Google Earth Engine. (https://earthengine.google.org)
 +
*Snippets = The ability to embed the latest CHIRPS image into your web page. (http://ewx.geog.ucsb.edu/ewx-snippets/)
 +
 
 +
 
 +
==What are some of the changes in version 2.0?==
 +
*Since v1.8 we have added many new stations around the world. In particular, 400 in Peru, 1,200 across Africa from Sharon Nicholson, 11,000 in Brazil, over 1,000 in Mexico (Conagua), 76 from Southern Africa, 500 in Russia, 250 in Central Asia and 400 across Central America. In addition we have topped off data from several African countries. The Conagua stations are available in near-real time and will directly improve our preliminary CHIRPS product.
 +
*Daily data now available for the Globe
 +
*NetCDF format added
 +
*Replaced erroneous stations in Tanzania
 +
*Expanded diagnostics, stations by Country plots, EWX rchecks, station comparison/*badness* plots, station density maps, pentad and monthly png's of excluded stations,

Latest revision as of 07:54, 18 September 2023

Is there a CHIRPS website?

Yes: https://chc.ucsb.edu/data/chirps

Where can I get CHIRPS data?

Via a web browser

http://data.chc.ucsb.edu/products/CHIRPS-2.0/


Climate Hazards Center landing page for all our public data is,

   http://data.chc.ucsb.edu/

Via anonymous ftp

ftp ftp.chc.ucsb.edu
username: anonymous 
password: your_email_address
cd  /pub/org/chg/products/CHIRPS-2.0/

DOI links

CHIRPSv2.0: http://chc.ucsb.edu/data/chirps/ #Points to data webpage, see Data section for download

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
  • WHem 50N-50S, 125W- 34W @0.05 deg resolution = maps 1820 x 2000 pixels

What are the time steps available for CHIRPS?

How does CHIRPS define a pentad?

  • 6 pentads = 1 calendar month. Each of first 5 pentads in a month have 5 days. The last pentad contains all the days from the 26th to the end of the month.

How does CHIRPS define a dekad?

  • A dekad = sum of 2 pentads. There are 3 dekads in a calendar month.

What are the file formats available for CHIRPS?

  • .tif
  • .bil
  • .netcdf

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 and Mexico only) CHIRPS available 2 days after the end of a pentad.
  • Final CHIRPS (all station data) is available sometime in the third week of the following month.

What is the temporal range for CHIRPS?

CHIRPS is available from 1981 to near-real time.

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).

You can access EWX here.

  • 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 number of stations changes with time. It is pretty significant in some areas.

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 [1]

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. http://pubs.usgs.gov/ds/832/

Is there a copy of the paper online?

Yes.

What's on the agenda for future CHIRPS?

  • extend CHIRPS above 50 degrees North
  • aquire more station data
  • redo the CHPclim to include more station data and avoid tiling artifacts
  • include an additive step to the blending
  • consider re-prioritorizing fGTS above fGSOD
  • have CHIRPS v2.0 ingested into Google Earth Engine. (https://earthengine.google.org)
  • Snippets = The ability to embed the latest CHIRPS image into your web page. (http://ewx.geog.ucsb.edu/ewx-snippets/)


What are some of the changes in version 2.0?

  • Since v1.8 we have added many new stations around the world. In particular, 400 in Peru, 1,200 across Africa from Sharon Nicholson, 11,000 in Brazil, over 1,000 in Mexico (Conagua), 76 from Southern Africa, 500 in Russia, 250 in Central Asia and 400 across Central America. In addition we have topped off data from several African countries. The Conagua stations are available in near-real time and will directly improve our preliminary CHIRPS product.
  • Daily data now available for the Globe
  • NetCDF format added
  • Replaced erroneous stations in Tanzania
  • Expanded diagnostics, stations by Country plots, EWX rchecks, station comparison/*badness* plots, station density maps, pentad and monthly png's of excluded stations,
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