select the beginning of the observation 199719981999 2000 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec 123456 789101112 131415161718 192021222324 252627282930 31 select the end of the observation: 199719981999 2000 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec 123456 789101112 131415161718 192021222324 252627282930 31 Node A Node B select an interval of averaging 1 minute 10 minute average 20 minute average 30 minute average 1 hour average 3 hour average 6 hour average 24 hour average select a type of averaging centered average forward average select a way of viewing data Download the data Due to the large amount of data involved in profile data, we strongly recommend that for prompt response a short time selection (< 3 months) be used for each request. From 08/01/97 to 02/20/98, bin size is 0.25 m; after that, bin size is 1.0 m . To be consistent, the contour and time series plots do not extend over different bin sizes.