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Monthly Surface Air Temperature Persistence

This map shows, over the course of the three previous months, the number of months in which monthly surface air temperature was in the bottom or top tercile of the climatological distribution.

For each of the previous three months (the last of the three months is labeled on the plot), monthly temperature is first ranked by percentiles with respect to the 1981-2010 climatology for each calendar month of the year (the 0th percentile represents the coolest temperature for that month of the year in the climatological base period, while the 100th percentile indicates the warmest). Next, for each gridpoint, a count is made of the number of months in the previous thress months that the temperature was in the bottom or the top tercile of the climatological distribution. The bottom tercile is the lowest one-third of the climatological distribution (below the 33.33rd percentile), and the top tercile is the highest one-third of the climatological distribution (above the 66.67th percentile). In the count, months with temperature in the middle tercile are ignored.

On the map, light and dark blue shading indicates that 2 of the previous 3, and 3 of the previous 3 months had temperatures in the bottom tercile, respectively. Lighter and darker red shading on the plot indicates where temperature was in the top tercile for 2 of the previous 3 months, and 3 of the previous 3 months, respectively.

The data used in this map are from the NOAA Climate Prediction Center's GHCN-CAMS gridded temperature data set. "GHCN" is an acronym for the "Global Historical Climatology Network" of station data, and "CAMS" is an acronym for the "Climate Anomaly Monitoring System" in use at the Climate Prediction Center (CPC).

Dataset Documentation

Monthly Surface Air Temperature Persistence
Data GHCN-CAMS gridded monthly surface air temperatures at 0.5° lat/lon spatial resolution
Data Source NCEP (National Centers for Environmental Prediction), CPC (Climate Prediction Center)
Analysis Counts of months with temperature in the highest and lowest monthly temperature terciles based upon the 1981-2010 base period.

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