select the beginning of the observation 199719981999200020012002 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec 123456 789101112 131415161718 192021222324 252627282930 31 select the end of the observation: 199719981999200020012002 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec 123456 789101112 131415161718 192021222324 252627282930 31 select an Node Node A Node B select an interval of averaging 1 hour 3 hour average 6 hour average 12 hour average daily average select a type of averaging forward average required for plots: select a variable Pressure Salinity Temperature Conductivity Sound velocity or