This web page provides access and information to the time series (annual maximum and partial duration) used in precipitation frequency analysis in NOAA Atlas 14 Volumes.
The annual maximum series (AMS) for a station was constructed by extracting the highest precipitation amount for a particular duration in each successive water year of record. The amounts provided are constrained amounts; they were converted to unconstrained values before use in frequency analysis. The partial duration series (PDS) is a listing of the N (number of years of record) greatest observed precipitation depths for a given duration at a station, regardless of how many occurred in the same year.
Starting with Volume 4, only annual maximum series are available for download; PDS-based frequency estimates were derived from AMS data.
Starting with Volume 6, AMS are also available for download for sub-hourly durations.
For more information about water year definition, AMS and PDS data and their use in precipitation frequency analysis, and conversion from constrained to unconstrained amounts please visit the corresponding NOAA Atlas 14 document for that Volume.
Also of interest may be the AMS trend analysis; see Appendix A.3 of the corresponding NOAA Atlas 14 document for more information.