Meteorology - Precipitation
Obtaining NCEI Station IDs
A map of NCEI Stations can be found here. The Station ID, Name, Location, and Dates can be found by clicking on the map icon. Some stations may not show up until the map is zoomed into that location. It is recommended that you use NCEI Stations that support the 'Normals Daily' Precipitation Dataset, although stations that support the 'Precipitation Hourly' dataset will work as well.
Handling Missing Data
Occasionally, some NCEI Stations will have periods of missing or invalid data. Days with missing data will be indicated in the output time series with values of -9999. However, days with missing data will be excluded for all datasets when calculating statistics. For extreme event aggregation, missing data will be replaced by the mean of the other datasets, or with 0 if the mean is negative.
NCEI Precipitation
The National Centers for Environmental Information (NCEI) provides precipitation data recorded at rain gauge stations. Stations are identified by their Station ID which includes the type of station and the station number. Some stations have been recording data as far back as 1901 to present day. NCEI data are reported in local time zone.
NLDAS Precipitation
The North American Land Data Assimilation System (NLDAS) combines North American radar data and satellite data from CMORPH (https://www.cpc.ncep.noaa.gov/products/janowiak/cmorph_description.html). NLDAS has a one-hour time step on a 0.125-degree grid of North America, with an average time delay of four days for data retrieval. NLDAS has data coverage from January 1, 1979 to the present. NLDAS data are reported in UTC (GMT).
GLDAS Precipitation
The Global Land Data Assimilation System (GLDAS) combines satellite data and ground-based observational data to provide precipitation and other meteorological parameters. GLDAS has a three-hour time step on a global 0.25-degree grid. GLDAS-2.1 provides data coverage from January 1, 2000 to present, with an average time delay of one month for data retrieval. GLDAS data are reported in UTC (GMT).
DAYMET Precipitation
DAYMET is a daily dataset of rain gauge data that has been interpolated and extrapolated. DAYMET uses ground station data with their model algorithm to produce gridded estimates of daily weather parameters. The interpolated spatial resolution is about a 0.009-degree grid over North America. Data is accessible since 1980 to the latest full year. DAYMET discards values for December 31 from leap years to maintain a 365-day year. DAYMET data are reported in UTC (GMT).
PRISM Precipitation
The Parameter-elevation Relationship on Independent Slopes Model (PRISM) is a combined dataset consisting of ground gauge station and RADAR products. The data is on a 4km grid resolution covering the contiguous United States. Data is available from 1981 to present.PRISM data are reported in GMT (UTC).
TRMM Precipitation
The Tropical Rainfall Measuring Mission Multi-Satellite Precipitation Analysis Algorithm (TRMM) provides precipitation estimates in specified TRMM regions from 1998 to 2019. The data is presented in 3-hourly timesteps over a 0.25-degree spatial grid. TRMM data are reported in UTC (GMT).
Temporal Aggregations
The available temporal aggregations are dependent upon the native timestep size of the data source. Possible options include 'daily', for those sources which are not by default daily, and 'monthly'. Aggregated precipitation data are the totals over these time periods and provided in the aggregated timeseries. Monthly aggregations correspond to the calendar month, and require the entire month to be specified in the date time span.