NORMALIZED 380-nm IRRADIANCES

Daily data have been low-pass filtered (3-day triangular). Gaps in the data record occur during instrument servicing and recalibration.

Values near one indicate mostly clear sky in the afternoon, and values less than one result from cloudy conditions. Inferred dates of the onset of monsoon season (approximate) are:

day 190 (July 10) in 1997;

day 185 (July 5) in 1998;

and day 170 (June 19) in 1999.

Note also the "false start" during the week of May 25, 1999.

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