CHIRPS Reality Checks - Revision history

Harrison: /* April 2026 */

2026-05-15T19:22:23Z

April 2026

Harrison: /* April 2026 */

2026-05-15T17:30:02Z

April 2026

Harrison: /* April 2026 */

2026-05-15T17:26:04Z

April 2026

Harrison: /* April 2026 */

2026-05-15T17:24:56Z

April 2026

Harrison: /* April 2026 */

2026-05-15T17:24:00Z

April 2026

Harrison: /* April 2026 */

2026-05-15T17:10:30Z

April 2026

Harrison: /* March 2026 */

2026-05-15T17:10:00Z

March 2026

Harrison: /* March 2026 */

2026-04-10T23:37:08Z

March 2026

Harrison: /* March 2026 */

2026-04-10T23:34:35Z

March 2026

Harrison: /* March 2026 */

2026-04-10T23:27:21Z

March 2026

@@ Line 30: / Line 30: @@
 '''CHIRPS v2: Final versus Prelim''' This [https://data.chc.ucsb.edu/products/CHIRPS/v3.0/diagnostics/chirps_minus_prelim/v2/archive/Difference_global_202604.png map] shows the difference between Prelim data and Final data, for April 2026 CHIRPS v2. This [https://data.chc.ucsb.edu/products/CHIRPS/v3.0/diagnostics/chirps_minus_prelim/v2/archive/PercentDifference_global_202604.png map] shows the ratio of values.
-''' Data notes: New SSOD station archive''' This month CHIRPS began blending station reports from the Synoptic Summary of the Day (SSOD), a new source that is intended to replace the Global Summary of the Day (GSOD). The GSOD archive ended in August 2025. Like other global sources, and some regional sources, we put through an automated quality control that screens for false zeros and blend the QCed data (fSSOD) into CHIRPS v3 Final. Currently, for April 2026 CHIRPS v3 data, the SSOD reports are in eleven countries, and this number is expected to increase.
+''' Data notes: New SSOD station archive''' This month CHIRPS began blending station reports from the Synoptic Summary of the Day (SSOD), a new source that is intended to replace the Global Summary of the Day (GSOD). The GSOD archive ended in August 2025. Like other global sources, and some regional sources, we put SSOD through an automated quality control step that screens for false zeros, then we blend the QCed data (fSSOD) into CHIRPS v3 Final. Currently, for April 2026 CHIRPS v3 data, the SSOD reports are in eleven countries, and this number is expected to increase.
 '''Data notes: Eurasia''' CHIRP v3 and CHIRPS v3 again underestimated precipitation in the region around eastern Europe to central Asia, including in western Russia, Ukraine, northern Turkiye, Kazakhastan, based on stations. The very low CHIRP values and blending algorithm resulted in the stations, though included, having little ability to raise CHIRPS v3 values. This is an issue that has been seen before during this time of year in CHIRP/S v3. e.g. December 2025.

@@ Line 29: / Line 29: @@
 '''CHIRPS v2: Final versus Prelim''' This [https://data.chc.ucsb.edu/products/CHIRPS/v3.0/diagnostics/chirps_minus_prelim/v2/archive/Difference_global_202604.png map] shows the difference between Prelim data and Final data, for April 2026 CHIRPS v2. This [https://data.chc.ucsb.edu/products/CHIRPS/v3.0/diagnostics/chirps_minus_prelim/v2/archive/PercentDifference_global_202604.png map] shows the ratio of values.
 ''' Data notes: New SSOD station archive''' This month CHIRPS began blending station reports from the Synoptic Summary of the Day (SSOD), a new source that is intended to replace the Global Summary of the Day (GSOD). The GSOD archive ended in August 2025. Like other global sources, and some regional sources, we put through an automated quality control that screens for false zeros and blend the QCed data (fSSOD) into CHIRPS v3 Final. Currently, for April 2026 CHIRPS v3 data, the SSOD reports are in eleven countries, and this number is expected to increase.
 '''Data notes: Eurasia''' CHIRP v3 and CHIRPS v3 again underestimated precipitation in the region around eastern Europe to central Asia, including in western Russia, Ukraine, northern Turkiye, Kazakhastan, based on stations. The very low CHIRP values and blending algorithm resulted in the stations, though included, having little ability to raise CHIRPS v3 values. This is an issue that has been seen before during this time of year in CHIRP/S v3. e.g. December 2025.
 '''Europe''' CHIRP (without stations) indicated fairly above-average conditions for April. However, stations (and several news reports) indicate April conditions were actually quite dry. The contrast between CHIRP and CHIRPS is notably in Germany, where extensive station reporting is available. A similar, albeit less dramatic, example can be seen in Portugal and Spain.
 '''United States''' CHIRP v3 (satellite-only subset of CHIRPS) outperfromed IMERG Late in rainfall estimation over the central United States, across the region from Illinois to Arkansas. IMERG underestimated rainfall, while the CHIRP estimates closely matched station reports. Over the northern Sierra Nevada mountain range in California, CHIRP v3 underestimated precipitation, and the blending of stations brought CHIRPS v3 values close to reported values in that area.
 '''Rchecks plots''' This was one of the top two wettest Aprils on record for Haiti, South America, and the Great Lakes region. There were notable differences this month between CHIRP (satellite-only) and CHIRPS (with station data), particularly across Europe. Consistent with this, the global-average CHIRP–CHIRPS difference ranked among the three largest April discrepancies in the historical record. See the 'Data notes: Eurasia' entry above for more information on this. Plots are available [https://data.chc.ucsb.edu/products/CHIRPS/v3.0/diagnostics/rchecks/monthly_compares/?C=M&O=D here].

@@ Line 32: / Line 32: @@
 '''Cambodia''' This month, with the inclusion of the new SSOD station dataset in the CHIRPS v3 blending process, Cambodia gained four new stations in CHIRPS v3 Final. This is helpful as this is the oblu source with stations located in Cambodia. In the SSOD archive there is metadata for 23 stations, though only these 4 stations had available reports to blend into CHIRPS.
-''' CHIRPS notes: New SSOD station archive''' This month CHIRPS began blending station reports from the Synoptic Summary of the Day (SSOD), a new source that is intended to replace the Global Summary of the Day (GSOD). The GSOD archive ended in August 2025. Like other global sources, and some regional sources, we put through an automated quality control that screens for false zeros and blend the QCed data (fSSOD) into CHIRPS v3 Final. Currently, for April 2026 CHIRPS v3 data, the SSOD reports are in eleven countries, and this number is expected to increase.
+''' Data notes: New SSOD station archive''' This month CHIRPS began blending station reports from the Synoptic Summary of the Day (SSOD), a new source that is intended to replace the Global Summary of the Day (GSOD). The GSOD archive ended in August 2025. Like other global sources, and some regional sources, we put through an automated quality control that screens for false zeros and blend the QCed data (fSSOD) into CHIRPS v3 Final. Currently, for April 2026 CHIRPS v3 data, the SSOD reports are in eleven countries, and this number is expected to increase.
-'''CHIRPS notes: Eurasia''' CHIRP v3 and CHIRPS v3 again underestimated precipitation in the region around eastern Europe to central Asia, including in western Russia, Ukraine, northern Turkiye, Kazakhastan, based on stations. The very low CHIRP values and blending algorithm resulted in the stations, though included, having little ability to raise CHIRPS v3 values. This is an issue that has been seen before during this time of year in CHIRP/S v3.
+'''Data notes: Eurasia''' CHIRP v3 and CHIRPS v3 again underestimated precipitation in the region around eastern Europe to central Asia, including in western Russia, Ukraine, northern Turkiye, Kazakhastan, based on stations. The very low CHIRP values and blending algorithm resulted in the stations, though included, having little ability to raise CHIRPS v3 values. This is an issue that has been seen before during this time of year in CHIRP/S v3. e.g. December 2025.
 '''Europe''' CHIRP (without stations) indicated fairly above-average conditions for April. However, stations (and several news reports) indicate April conditions were actually quite dry. The contrast between CHIRP and CHIRPS is notably in Germany, where extensive station reporting is available. A similar, albeit less dramatic, example can be seen in Portugal and Spain.
@@ Line 40: / Line 40: @@
 '''United States''' CHIRP v3 (satellite-only subset of CHIRPS) outperfromed IMERG Late in rainfall estimation over the central United States, across the region from Illinois to Arkansas. IMERG underestimated rainfall, while the CHIRP estimates closely matched station reports. Over the northern Sierra Nevada mountain range in California, CHIRP v3 underestimated precipitation, and the blending of stations brought CHIRPS v3 values close to reported values in that area.
-'''Rchecks plots''' This was one of the top two wettest Aprils on record for Haiti, South America, and the Great Lakes region. There were notable differences this month between CHIRP (satellite-only) and CHIRPS (with station data), particularly across Europe. Consistent with this, the global-average CHIRP–CHIRPS difference ranked among the three largest April discrepancies in the historical record. See the 'CHIRPS notes: Eurasia' entry above for more information on this. Plots are available [https://data.chc.ucsb.edu/products/CHIRPS/v3.0/diagnostics/rchecks/monthly_compares/?C=M&O=D here].
+'''Rchecks plots''' This was one of the top two wettest Aprils on record for Haiti, South America, and the Great Lakes region. There were notable differences this month between CHIRP (satellite-only) and CHIRPS (with station data), particularly across Europe. Consistent with this, the global-average CHIRP–CHIRPS difference ranked among the three largest April discrepancies in the historical record. See the 'Data notes: Eurasia' entry above for more information on this. Plots are available [https://data.chc.ucsb.edu/products/CHIRPS/v3.0/diagnostics/rchecks/monthly_compares/?C=M&O=D here].
 === March 2026 ===

← Older revision		Revision as of 17:24, 15 May 2026
Line 37:		Line 37:

	'''Europe''' CHIRP (without stations) indicated fairly above-average conditions for April. However, stations (and several news reports) indicate April conditions were actually quite dry. The contrast between CHIRP and CHIRPS is notably in Germany, where extensive station reporting is available. A similar, albeit less dramatic, example can be seen in Portugal and Spain.		'''Europe''' CHIRP (without stations) indicated fairly above-average conditions for April. However, stations (and several news reports) indicate April conditions were actually quite dry. The contrast between CHIRP and CHIRPS is notably in Germany, where extensive station reporting is available. A similar, albeit less dramatic, example can be seen in Portugal and Spain.
		+
		+	'''United States''' CHIRP v3 (satellite-only subset of CHIRPS) outperfromed IMERG Late in rainfall estimation over the central United States, across the region from Illinois to Arkansas. IMERG underestimated rainfall, while the CHIRP estimates closely matched station reports. Over the northern Sierra Nevada mountain range in California, CHIRP v3 underestimated precipitation, and the blending of stations brought CHIRPS v3 values close to reported values in that area.

	'''Rchecks plots''' This was one of the top two wettest Aprils on record for Haiti, South America, and the Great Lakes region. There were notable differences this month between CHIRP (satellite-only) and CHIRPS (with station data), particularly across Europe. Consistent with this, the global-average CHIRP–CHIRPS difference ranked among the three largest April discrepancies in the historical record. See the 'CHIRPS notes: Eurasia' entry above for more information on this. Plots are available [https://data.chc.ucsb.edu/products/CHIRPS/v3.0/diagnostics/rchecks/monthly_compares/?C=M&O=D here].		'''Rchecks plots''' This was one of the top two wettest Aprils on record for Haiti, South America, and the Great Lakes region. There were notable differences this month between CHIRP (satellite-only) and CHIRPS (with station data), particularly across Europe. Consistent with this, the global-average CHIRP–CHIRPS difference ranked among the three largest April discrepancies in the historical record. See the 'CHIRPS notes: Eurasia' entry above for more information on this. Plots are available [https://data.chc.ucsb.edu/products/CHIRPS/v3.0/diagnostics/rchecks/monthly_compares/?C=M&O=D here].

@@ Line 29: / Line 29: @@
 '''CHIRPS v2: Final versus Prelim''' This [https://data.chc.ucsb.edu/products/CHIRPS/v3.0/diagnostics/chirps_minus_prelim/v2/archive/Difference_global_202604.png map] shows the difference between Prelim data and Final data, for April 2026 CHIRPS v2. This [https://data.chc.ucsb.edu/products/CHIRPS/v3.0/diagnostics/chirps_minus_prelim/v2/archive/PercentDifference_global_202604.png map] shows the ratio of values.
 '''CHIRPS notes: Eurasia''' CHIRP v3 and CHIRPS v3 again underestimated precipitation in the region around eastern Europe to central Asia, including in western Russia, Ukraine, northern Turkiye, Kazakhastan, based on stations. The very low CHIRP values and blending algorithm resulted in the stations, though included, having little ability to raise CHIRPS v3 values. This is an issue that has been seen before during this time of year in CHIRP/S v3.
 '''Rchecks plots''' This was one of the top two wettest Aprils on record for Haiti, South America, and the Great Lakes region. There were notable differences this month between CHIRP (satellite-only) and CHIRPS (with station data), particularly across Europe. Consistent with this, the global-average CHIRP–CHIRPS difference ranked among the three largest April discrepancies in the historical record. See the 'CHIRPS notes: Eurasia' entry above for more information on this. Plots are available [https://data.chc.ucsb.edu/products/CHIRPS/v3.0/diagnostics/rchecks/monthly_compares/?C=M&O=D here].

@@ Line 24: / Line 24: @@
 ''
 ==R-Checks Monthly Highlights==
 === March 2026 ===

← Older revision		Revision as of 23:37, 10 April 2026
Line 31:		Line 31:

	'''Australia''' The blending of station data was very important for CHIRPS Final estimation of the effect of Cyclone Narelle, which had a [https://www.bom.gov.au/news-and-media/severe-tropical-cyclone-narelles-journey-across-northern-australia "long and historic journey"] across Australia. CHIRP had underestimated precipitation amounts and blended stations corrected this.		'''Australia''' The blending of station data was very important for CHIRPS Final estimation of the effect of Cyclone Narelle, which had a [https://www.bom.gov.au/news-and-media/severe-tropical-cyclone-narelles-journey-across-northern-australia "long and historic journey"] across Australia. CHIRP had underestimated precipitation amounts and blended stations corrected this.
		+
		+	'''Western United States''' Extreme dry March 2026 occurred in the western United States. Stations across California reported near zero precipitation. The situation has led to a snow drought, described as "A March Meltdown: Historically Low Snowpack Melts Across the West, Signaling a Dire Water Supply Situation." According to the [https://www.drought.gov/drought-status-updates/snow-drought-current-conditions-and-impacts-west-2026-04-09 April 2026 NOAA/NIDIS report], "This year, Arizona, Colorado, Idaho, Nevada, New Mexico, Oregon, Utah, and Wyoming all set new record-low April 1 SWE values since SNOTEL monitoring began in the 1980s. California recorded its second-lowest April 1 SWE value. Snow usually accumulates in March, but the record-shattering heat wave coupled with abnormally dry conditions led to rapid and early melting of an already historically low snowpack across most of the West. The exceptions are Washington and parts of Idaho and Montana. California River Basins experienced their driest March on record. The Colorado River Basin (Upper and Lower) experienced its warmest March on record, at 13.7 °F warmer than the normal."

	'''Thailand''' Stations that reported mixed, low and up-to moderate amounts of precipitation across the northern part of Thailand (ranging from 0 mm to ~ 50mm) are higher than low CHIRP3 estimates. The low CHIRP values appear to be influencing CHIRPS Final estimates, largely producing underestimates compared to stations. Current data production steps limit the gains than can occur from station-blending when the satellite-based (CHIRP) estimates are close to zero; Rcheckers would like to see this issue improved in future CHIRPS version development.		'''Thailand''' Stations that reported mixed, low and up-to moderate amounts of precipitation across the northern part of Thailand (ranging from 0 mm to ~ 50mm) are higher than low CHIRP3 estimates. The low CHIRP values appear to be influencing CHIRPS Final estimates, largely producing underestimates compared to stations. Current data production steps limit the gains than can occur from station-blending when the satellite-based (CHIRP) estimates are close to zero; Rcheckers would like to see this issue improved in future CHIRPS version development.

← Older revision		Revision as of 23:34, 10 April 2026
Line 31:		Line 31:

	'''Australia''' The blending of station data was very important for CHIRPS Final estimation of the effect of Cyclone Narelle, which had a [https://www.bom.gov.au/news-and-media/severe-tropical-cyclone-narelles-journey-across-northern-australia "long and historic journey"] across Australia. CHIRP had underestimated precipitation amounts and blended stations corrected this.		'''Australia''' The blending of station data was very important for CHIRPS Final estimation of the effect of Cyclone Narelle, which had a [https://www.bom.gov.au/news-and-media/severe-tropical-cyclone-narelles-journey-across-northern-australia "long and historic journey"] across Australia. CHIRP had underestimated precipitation amounts and blended stations corrected this.
		+
		+	'''Thailand''' Stations that reported mixed, low and up-to moderate amounts of precipitation across the northern part of Thailand (ranging from 0 mm to ~ 50mm) are higher than low CHIRP3 estimates. The low CHIRP values appear to be influencing CHIRPS Final estimates, largely producing underestimates compared to stations. Current data production steps limit the gains than can occur from station-blending when the satellite-based (CHIRP) estimates are close to zero; Rcheckers would like to see this issue improved in future CHIRPS version development.

	'''Rchecks plots''' New March record for the difference between CHIRPS and CHIRP spatial average in [https://data.chc.ucsb.edu/products/CHIRPS/v3.0/diagnostics/rchecks/monthly_compares/chirpsV3.Asia.stats.2026.03.png Asia] and [https://data.chc.ucsb.edu/products/CHIRPS/v3.0/diagnostics/rchecks/monthly_compares/chirpsV3.Latin_Amer.stats.2026.03.png Latin America]. CHIRPS v3 Final data indicates that March 2026 was the wettest March on the 1981-to-present data record for [https://data.chc.ucsb.edu/products/CHIRPS/v3.0/diagnostics/rchecks/monthly_compares/chirpsV3.Haiti.stats.2026.03.png Haiti] and the [https://data.chc.ucsb.edu/products/CHIRPS/v3.0/diagnostics/rchecks/monthly_compares/chirpsV3.Sahel.stats.2026.03.png Sahel]. More plots are available [https://data.chc.ucsb.edu/products/CHIRPS/v3.0/diagnostics/rchecks/monthly_compares/?C=M&O=D here].		'''Rchecks plots''' New March record for the difference between CHIRPS and CHIRP spatial average in [https://data.chc.ucsb.edu/products/CHIRPS/v3.0/diagnostics/rchecks/monthly_compares/chirpsV3.Asia.stats.2026.03.png Asia] and [https://data.chc.ucsb.edu/products/CHIRPS/v3.0/diagnostics/rchecks/monthly_compares/chirpsV3.Latin_Amer.stats.2026.03.png Latin America]. CHIRPS v3 Final data indicates that March 2026 was the wettest March on the 1981-to-present data record for [https://data.chc.ucsb.edu/products/CHIRPS/v3.0/diagnostics/rchecks/monthly_compares/chirpsV3.Haiti.stats.2026.03.png Haiti] and the [https://data.chc.ucsb.edu/products/CHIRPS/v3.0/diagnostics/rchecks/monthly_compares/chirpsV3.Sahel.stats.2026.03.png Sahel]. More plots are available [https://data.chc.ucsb.edu/products/CHIRPS/v3.0/diagnostics/rchecks/monthly_compares/?C=M&O=D here].

@@ Line 25: / Line 25: @@
 ==R-Checks Monthly Highlights==
 === March 2026 ===
 '''CHIRPS v3: Final versus Prelim''' This [https://data.chc.ucsb.edu/products/CHIRPS/v3.0/diagnostics/chirps_minus_prelim/archive/Difference_global_202603.png map] shows the difference between Prelim data and Final data, for March 2026 CHIRPS v3. This [https://data.chc.ucsb.edu/products/CHIRPS/v3.0/diagnostics/chirps_minus_prelim/archive/PercentDifference_global_202603.png map] shows the ratio of values.
 '''CHIRPS v2: Final versus Prelim''' This [https://data.chc.ucsb.edu/products/CHIRPS/v3.0/diagnostics/chirps_minus_prelim/v2/archive/Difference_global_202603.png map] shows the difference between Prelim data and Final data, for March 2026 CHIRPS v2. This [https://data.chc.ucsb.edu/products/CHIRPS/v3.0/diagnostics/chirps_minus_prelim/v2/archive/PercentDifference_global_202603.png map] shows the ratio of values.
 '''Rchecks plots''' New March record for the difference between CHIRPS and CHIRP spatial average in [https://data.chc.ucsb.edu/products/CHIRPS/v3.0/diagnostics/rchecks/monthly_compares/chirpsV3.Asia.stats.2026.03.png Asia] and [https://data.chc.ucsb.edu/products/CHIRPS/v3.0/diagnostics/rchecks/monthly_compares/chirpsV3.Latin_Amer.stats.2026.03.png Latin America]. CHIRPS v3 Final data indicates that March 2026 was the wettest March on the 1981-to-present data record for [https://data.chc.ucsb.edu/products/CHIRPS/v3.0/diagnostics/rchecks/monthly_compares/chirpsV3.Haiti.stats.2026.03.png Haiti] and the [https://data.chc.ucsb.edu/products/CHIRPS/v3.0/diagnostics/rchecks/monthly_compares/chirpsV3.Sahel.stats.2026.03.png Sahel]. More plots are available [https://data.chc.ucsb.edu/products/CHIRPS/v3.0/diagnostics/rchecks/monthly_compares/?C=M&O=D here].
 === February 2026 ===