USCRN/USRCRN FTP MONTHLY STREAM

NCDC provides ftp access to data from the U.S. Climate Reference Network / U.S.
Regional Climate Reference Network (USCRN/USRCRN) via anonymous ftp at the address:

        ftp://ftp.ncdc.noaa.gov/pub/data/uscrn/products/monthly01

That directory contains a collection of ASCII files named according to the following
convention:

        CRNM01TT-${station_name}.txt

where
               TT = 2-character file format number (currently 02)
  ${station_name} = Unique station name (state location vector) with spaces replaced
                    by underscores (e.g. AZ_Tucson_11_W)

Also contained in the monthly01 directory are important announcements relating to
the Monthly01 product.  Please be sure to review these announcements before using
any product data.

Each file contains fixed-column formatted lines, each of which represents one
month's observation data from one station.  The format of each line is as follows:

    cols 1 -- 5 [5 chars] WBANNO
        The station WBAN number.

    cols 7 -- 12 [6 chars] LST_YRMO
        The Local Standard Time (LST) year/month of the observation.

    cols 14 -- 19 [6 chars] CRX_VN_MONTHLY
        The version number of the station datalogger program that was in 
        effect at the end of the month.

    cols 21 -- 29 [9 chars] PRECISE_LONGITUDE
        Station longitude, using WGS-84, with a precision of 4 decimal places.

    cols 31 -- 39 [9 chars] PRECISE_LATITUDE
        Station latitude, using WGS-84, with a precision of 4 decimal places.

    cols 41 -- 47 [7 chars] T_MONTHLY_MAX
        The maximum air temperature, in degrees C, for the month.  This maximum 
        is calculated as the average of all available day-maximums.  To be 
        valid there must be less than 4 consecutive day maximums missing, 
        and no more than 5 total day maximums missing.

    cols 49 -- 55 [7 chars] T_MONTHLY_MIN
        The minimum air temperature, in degrees C, for the month.  This minimum 
        is calculated as the average of all available day-minimums.  To be 
        valid there must be less than 4 consecutive day minimums missing, 
        and no more than 5 total day minimums missing.

    cols 57 -- 63 [7 chars] T_MONTHLY_MEAN
        The mean temperature, in degrees C, calculated using the typical 
        historical approach of (T_MONTHLY_MAX + T_MONTHLY_MIN) / 2

    cols 65 -- 71 [7 chars] T_MONTHLY_AVG
        The average air temperature, in degrees C, for the month.  This average 
        is calculated using all available day-averages, each derived from 
        24 one-hour averages.  To be valid there must be less than 4 consecutive 
        day averages missing, and no more than 5 total day averages missing.

    cols 73 -- 79 [7 chars] P_MONTHLY_CALC
        The total amount of precipitation, in mm, recorded during the month. 
         To be valid there must be precipitation records for at least 97% 
        of the hours in the month.

    cols 81 -- 87 [7 chars] SOLRAD_MONTHLY_AVG
        The average daily total solar energy received, in MJ/meter^2, during 
        the month. This value is calculated as the average of daily total 
        solar radiation.  To be valid there must be less than 4 consecutive 
        day maximums missing, and no more than 5 total day maximums missing.

    cols 89 -- 89 [1 chars] SUR_TEMP_MONTHLY_TYPE
        Type of surface tempearture measurement.  'R' to denote raw surface 
        temperature measurements, 'C' to denote corrected surface temperature 
        measurements, and 'U' when unknown.

    cols 91 -- 97 [7 chars] SUR_TEMP_MONTHLY_MAX
        The maximum surface temperature, in degrees C, for the month.  This 
        maximum is calculated as the average of all available 10-second daily 
        maximums.  To be valid there must be less than 4 consecutive day 
        maximums missing, and no more than 5 total day maximums missing.

    cols 99 -- 105 [7 chars] SUR_TEMP_MONTHLY_MIN
        The minimum surface temperature, in degrees C, for the month.  This 
        minimum is calculated as the average of all available 10-second daily 
        minimums.  To be valid there must be less than 4 consecutive day 
        minimums missing, and no more than 5 total day minimums missing.

    cols 107 -- 113 [7 chars] SUR_TEMP_MONTHLY_AVG
        The average surface temperature, in degrees C, for the month.  This 
        average is calculated as the average of all available day-averages. 
         To be valid there must be less than 4 consecutive day averages missing, 
        and no more than 5 total day averages missing.
IMPORTANT NOTES:

 1. All fields are separated from adjacent fields by at least one space.

 2. Leading zeros are omitted.

 3. Missing data are indicated by the value -9999 (or -9999.0).

 4. There are no quality flags for these derived quantities. When the raw 
    data are flagged as erroneous, these derived values are not 
    calculated, and are instead reported as missing. So these fields may 
    be assumed to always be good (unflagged) data, except when they are 
    reported as missing.