Data: CAMS monthly surface air temperature anomaly
on a 2.0 x 2.0 deg. lat/lon grid
Climatology: University of East Anglia 0.5 x 0.5 deg. lat./lon. gridded surface temperature.
Base Period: 1961-1990
Data Source: NCEP, Climate Prediction Center
Description:
For each of the past 3 months (the last month is shown
on plot) monthly temperatures are first ranked by percentiles. (If
a given month is in the 0th percentile its the coldest in the base period
while the 100th percentile indicates the warmest.) Next, for each
gridpoint, a count is made of the number of times in the past 3 months
that the temperature was in at least in the top tercile (top third of historicalvalues) or in the bottom tercile (bottom third of historical values).
percentile. In the count, months with temperatures in the middle tercile
(middle 1/3 of observed values) are ignored.
On the plot, yellow and orange shading indicates that
2 of the past 3, and 3 of the past 3 months were at or above top tercile,
respectively. Light and dark blue shading indicate areas where temperatures
were in the bottom tercile for 2 of the past 3, and 3 of the past 3
months, respectively.
The temperature data is based on station observations. The period used for computing
the percentiles is 1961-1990. "CAMS" is an acronym for the "Climate
Anomaly Monitoring System" in use at the Climate Prediction Center (CPC)
at the US National Centers for Environmental Prediction (NCEP). |
