This map shows an animation of the month-to-month change in monthly climatological precipitation (in mm/month) through the course of the year based on CAMS-OPI data using the 1991-2020 base period.
On the map, the difference in precipitation is displayed as precipitation in the later month minus precipitation in the earlier month. Green shading indicates that precipitation has increased from one month to the next, and brown shading indicates that precipitation has decreased. Contours are drawn at +/- 10, 25, 50, 100, 150, 200, 250 mm/month. The time label on the map displays the date of the middle day of the earlier month followed by a dash and the date of the middle day of the later month.
"CAMS" is an acronym for the "Climate Anomaly Monitoring System" in use at the Climate Prediction Center (CPC) at the U. S. National Centers for Environmental Prediction (NCEP). "OPI" stands for "Outgoing longwave radiation Precipitation Index" (the satellite precipitation estimates are based on emitted longwave radiation observed by polar-orbiting satellite.)
Contact help@iri.columbia.edu with any technical questions or problems with this Map Room.