A series of plots of the time variation of various climate system variables.    Select desired field from menu at left.

Data for these analyses was obtained from the US National Centers for Environmental Prediction, Climate Prediction Center.

Aids to interpreting plots:

Definitions

Climatology	The long-term average of a given variable, often the 30-year period 1961-1990.
Anomaly	The difference between the observed value of a variable and its climatological value.
OLR	An abbreviastion for "Outgoing Longwave Radiation".  Anomalies in OLR can be related to cloud cover and precipitation.  Negative OLR anomalies generally indicate increased cloudiness and likelihood of precipitation while positive anomalies imply decreased cloudiness.   The relationship between OLR anomalies and precipitation holds most strongly in tropical regions.
Percentiles	Percentiles represent a ranking of the data over a given base period.  Data in the zeroth percentile have the lowest value in the base period while those at the hundreth percentile have the highest value during the base period.  On some plots the percentiles are displayed from 0 to 1 (the percentiles are divided by 100).