The California-Nevada data set is a file of relatively long, relatively high quality time series from selected stations in the Southwest. The 162 stations are all south of 43 N and west of 114 W. The stations were selected from summary of the day (SOD) records from both first order (usually stations located at airports taking hourly observations) and cooperative observation stations (recording one or more daily values). All data were provided through the courtesy of Dr. Kelly Redmond and colleagues from the Western Regional Climate Center (WRCC) in Reno, NV.

 
 
 

The image at the left shows the probability of measureable precipitation at Giant Forest, California, for sample periods of 1 to 30 days throughout the year. This is an example of the type of information available from the Climatological Data Summaries page at the WRCC. The WRCC Climatological Data Summaries page provides station information for general climatology, a pictorial description of the amount of daily data and graphical descriptions of the climate.
 
 
 
 
 

For the California-Nevada dataset, stations were selected primarily for their precipitation records. The map below shows the location of the stations in this dataset. All stations should have good temporal precipitation coverage. The daily maximum and minimum temperatures, while available for most stations, are not available at all stations. Daily snow accumulation records are available for many of the stations. Criteria for selection were length of record, ending year, percentage of "non-missing" records, station elevation and the availability of "better" nearby stations.
 

 
 

The station elevations run from -59 m (Death Valley, 1961:1998) to 2940 m (Ellery Lake, 1948:1998). The elevation distribution is bimodal because of the selection process. The first mode is at sea level. The second is at 800 m. California station elevations cluster toward sea level. The higher the elevation, the fewer stations to choose from. Station elevations above 800 m were given preference over low during the selection process.
 

The earliest station record start date is 1893 and earliest end date is 1974 (both at Yuma, AZ). Most station records start in the 1940's (mean start year is around 1944) and end in the late 1990's (mean EOR or "end of record" is around 1997). The mean record length is 54 years. The longest record length is 99 years (Sacramento, 1900:1998) and the shortest record is 38 years (Death Valley, 1961:1998).
 

Completeness of each station's data is computed using the precipitation records. The mean percentage of "non-missing" records is 98.6% during the main record era (ERA 2, the period from 1948:EOR) and 98.9% during the early era (ERA 1, with 34 stations having at least some records occurring before 1948). The lowest percentages are 86.1% during ERA 2 (Blue Canyon, 1948:1995) and 85.4% during ERA 1 (Los Angeles, 1930:1947). Several stations have 100% data availability.

 View the list of stations and other information such as latitude, longitude, elevation and period of record.

The data set was developed from an existing data set (called the "West 11 set" over the 11 contiguous mountainous Western states of the United States) used in various avenues of research at Climate Research Division, Scripps Institution of Oceanography, University of California, San Diego. [See: Cayan, D.R., K.T. Redmond, and L.G. Riddle, "ENSO and Hydrologic Extremes in the Western United States", Journal of Climate, in press, 1999 for further documentation.] Additional stations were selected from throughout California (on the basis of a summary of monthly precipitation collected by the State of California Department of Water Resources), using the same criteria as above, to increase station density. 

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Format of the dataset:

Note:

1) On station map, "long record" indicates stations with 50+ years of record starting around 1948 or earlier and ending in the 1990's. "Short record" stations have 30 or less years of data and/or end before the 1990's.

2) calnev_station.v1.log - contains station info for stations with data in the file calnev_station.v1.cts
   a) ERA1 = percent of non-missing data from beginning of record
   b) ERA2 = percent of non-missing data from 1948 through end of record.
   c) Elevation is in meters.

3) For cross-matching stations using NCDC, WBAN, WMO and ICAO identifiers, refer to the file called  "weather_station.catalog". The file is located on meteora.ucsd.edu in the /weather/misc directory.
 

Questions:  Larry Riddle, lriddle@ucsd.edu