README FILE FOR THE U.S. HISTORICAL CLIMATOLOGY NETWORK (U.S. HCN) MONTHLY DATA Version 2.5 -------------------------------------------------------------------------------- -------------------------------------------------------------------------------- I. CONTENTS OF http://cdiac.ess-dive.lbl.gov/ftp/ushcn_v2.5_monthly ushcn2014_FLs_52i_tmax.gz: GZIP-compressed file of bias-adjusted mean monthly maximum temperatures (with estimates for missing values) ushcn2014_FLs_52i_tmin.gz: GZIP-compressed file of bias-adjusted mean monthly minimum temperatures (with estimates for missing values) ushcn2014_FLs_52i_tavg.gz: GZIP-compressed file of the average of bias- adjusted mean monthly maximum and minimum temperatures (with estimates for missing values) ushcn2014_FLs_52i_prcp.gz: GZIP-compressed file of total monthly precipitation (UNADJUSTED, but with estimates for missing values) ushcn2014_FLs_tob_tmax.gz: GZIP-compressed file of mean monthly maximum temperatures adjusted only for the time of observation bias ushcn2014_FLs_tob_tmin.gz: GZIP-compressed file of mean monthly minimum temperatures adjusted only for the time of observation bias ushcn2014_FLs_tob_tavg.gz: GZIP-compressed file of the average of mean monthly maximum and minimum temperatures adjusted only for the time of observation bias ushcn2014_raw_tmax.gz: GZIP-compressed file of unadjusted mean monthly maximum temperatures ushcn2014_raw_tmin.gz: GZIP-compressed file of unadjusted mean monthly minimum temperatures ushcn2014_raw_tavg.gz: GZIP-compressed file of the average of un- adjusted mean monthly maximum and minimum temperatures ushcn2014_raw_prcp.gz: GZIP-compressed file of unadjusted total monthly precipitation ushcn-stations.txt: List of U.S. HCN stations and their coordinates readme.txt: This file -------------------------------------------------------------------------------- -------------------------------------------------------------------------------- II. FORMAT OF THE DATA FILES Each data file contains data for all USHCN stations for one of the four meteorological variables Tmax, Tmin, Tavg, or precipitation. Temperature values are given in tenths of degrees Fahrenheit (e.g., 725 indicates 72.5F) and precipitation amounts are given in hundredths of inches (e.g., 468 indicates 4.68"). Each record (line) in the files contains one year of 12 monthly values plus an annual value. The values on each line include the following: ------------------------------ Variable Columns Type ------------------------------ STAID 1-11 Character YEAR 13-16 Integer VALUE1 18-22 Integer DMFLAG1 23 Character QCFLAG1 24 Character DSFLAG1 25 Character VALUE2 27-31 Integer DMFLAG2 32 Character QCFLAG2 33 Character DSFLAG2 34 Character . . . . . . . . . VALUE13 126-130 Integer DMFLAG13 131 Character QCFLAG13 132 Character DSFLAG13 133 Character ------------------------------ These variables have the following definitions: STAID is the station identification code, containing country code ('US' for all USHCN stations, network code ('H' for Historical Climatology Network), columns 4-11='00'+6-digit Cooperative Observer ID number See "ushcn-stations.txt" for a complete list of stations and their metadata. YEAR is the 4-digit year of the record. VALUE1 is the value for January in the year of record; in tenths of degrees Fahrenheit for temperature (e.g., 725 indicates 72.5F) and hundredths of inches for precipitation (e.g., 468 indicates 4.68"). Missing data values are filled with "-9999". DMFLAG1 is the data measurement flag for January in the year of record: Blank = no measurement information is applicable; A - H = applying only to the relatively small number of values assigned using v1.0 of the USHCN database, indicates the number of days missing (1 to 8) in calculation of monthly mean temperature; a - i = applying to version 2.5 USHCN data values (the vast majority), the number of days missing (1 to 9) in calculation of monthly mean temperature; E = if QCFLAG and DSFLAG are both blank, 'E' indicates the data value is an estimate from surrounding values; no original value is available; I = applying only to the relatively small number of values assigned using v1.0 of the USHCN database, indicates that the data value is interpolated using surrounding stations' values; . = applying only to the relatively small number of values assigned using v1.0 of the USHCN database, indicates that the data value has been estimated; QCFLAG1 is the quality flag for January in the year of record: Blank = no failure of quality control check or could not be evaluated; d = Pairwise Homogenization Algorithm (PHA) has strong evidence that multiple inhomogeneities exist, but are too close to adjust; g = PHA cannot adjust station series previous to a given inhomogeneity because there are too few neighbors to estimate the adjustment (uncommon); DSFLAG1 is the data source flag for January in the year of record: Blank = value was computed from daily available in GHCN-Daily; Not Blank = daily data are not available so the monthly value was obtained from the USHCN version 1 dataset. The possible values are as follows: 1 = NCDC Tape Deck 3220, Summary of the Month Element Digital File; 2 = Means Book - Smithsonian Institute, C.A. Schott (1876, 1881-1931); 3 = Manuscript - Original Records, National Climatic Data Center; 4 = Climatological Data (CD), monthly NCDC publication; 5 = Climate Record Book, as described in History of Climatological Record Books, U.S. Department of Commerce, Weather Bureau, USGPO (1960); 6 = Bulletin W - Summary of the Climatological Data for the United States (by section), F.H. Bigelow, U.S. Weather Bureau (1912); and, Bulletin W - Summary of the Climatological Data for the United States, 2nd Ed.; 7 = Local Climatological Data (LCD), monthly NCDC publication; 8 = State Climatologists, various sources; B = Professor Raymond Bradley - Refer to Climatic Fluctuations of the Western United States During the Period of Instrumental Records, Bradley, et. al., Contribution No. 42, Dept. of Geography and Geology, University of Massachusetts (1982); D = Dr. Henry Diaz, a compilation of data from Bulletin W, LCD, and NCDC Tape Deck 3220 (1983); G = Professor John Griffiths - primarily from Climatological Data. VALUE2 is the value for February in the year of record; DMFLAG2 is the data measurement flag for February in the year of record; QCFLAG2 is the data quality flag for February in the year of record; DSFLAG2 is the data source flag for February in the year of record; . . . VALUE12 is the value for December in the year of record; DMFLAG12 is the data measurement flag for December in the year of record; QCFLAG12 is the data quality flag for December in the year of record; DSFLAG12 is the data source flag for December in the year of record. VALUE13 is the annual value (mean for temperature; total for precipitation); DMFLAG13 is the data measurement flag for the annual value; QCFLAG13 is the data quality flag for the annual value; DSFLAG13 is the data source flag for the annual value. -------------------------------------------------------------------------------- -------------------------------------------------------------------------------- III. FORMAT OF "ushcn-stations.txt" ------------------------------ Variable Columns Type ------------------------------ COOP ID 1-6 Character LATITUDE 8-15 Real LONGITUDE 17-25 Real ELEVATION 27-32 Real STATE 34-35 Character NAME 37-66 Character COMPONENT 1 68-73 Character COMPONENT 2 75-80 Character COMPONENT 3 82-87 Character UTC OFFSET 89-90 Integer ------------------------------ These variables have the following definitions: COOP ID is the U.S. Cooperative Observer Network station identification code. Note that the first two digits in the Coop Id correspond to the state. LATITUDE is latitude of the station (in decimal degrees). LONGITUDE is the longitude of the station (in decimal degrees). ELEVATION is the elevation of the station (in meters, missing = -999.9). STATE is the U.S. postal code for the state. NAME is the name of the station location. COMPONENT 1 is the Coop Id for the first station (in chronologic order) whose records were joined with those of the HCN site to form a longer time series. "------" indicates "not applicable". COMPONENT 2 is the Coop Id for the second station (if applicable) whose records were joined with those of the HCN site to form a longer time series. COMPONENT 3 is the Coop Id for the third station (if applicable) whose records were joined with those of the HCN site to form a longer time series. UTC OFFSET is the time difference between Coordinated Universal Time (UTC) and local standard time at the station (i.e., the number of hours that must be added to local standard time to match UTC). -------------------------------------------------------------------------------- --------------------------------------------------------------------------------