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Monthly Outgoing Longwave Radiation

MONTHLY OLR ANOMALY (W/m2)

MONTHLY AVERAGE OLR (with shading in tropics)  (W/m2)

Data:   Outgoing Longwave Radiation ("OLR") anomaly  and observed (watt/m2) on a 2.5 x 2.5 deg. lat/lon grid Base Period for Climatology:  1974-present Data Source:  NCEP, Climate Prediction Center Description Top Plot:  Departure of the monthly OLR from the long term monthly mean in units of Watts/m2.  Negative values imply increased cloudiness and enhanced likelihood of precipitation.  Positive anomalies imply decreased cloudiness/precipitation.  These relationships work best in tropical regions. Bottom Plot:  Observed monthly OLR in units of Watts/m2, contour interval 10.  Green shading in tropical regions indicates areas where the monthly OLR is less than 240 W/m2, a general indicator of precipitation in the tropics.