FEDERAL CLIMATE COMPLEX GLOBAL SURFACE SUMMARY OF DAY DATA VERSION 7 (OVER 8000 WORLDWIDE STATIONS) 10/07/2006 The most recent global summary of day data are now located here: ftp://ftp.ncdc.noaa.gov/pub/data/gsod/ -- updated daily with the latest data. This directory/folder (globalsod) will be phased out, and is no longer updated. ******************************************************************** SPECIAL NOTES CONCERNING ON-LINE DATA Data for some countries may not be available through this system. The data summaries provided here are based on data exchanged under the World Meteorological Organization (WMO) World Weather Watch Program according to WMO Resolution 40 (Cg-XII). This allows WMO member countries to place restrictions on the use or re-export of their data for commercial purposes outside of the receiving country. Those countries' data summaries and products which are available here are intended for free and unrestricted use in research, education, and other non-commercial activities. However, for non-U.S. locations' data, the data or any derived product shall not be provided to other users or be used for the re-export of commercial services. To determine off-line availability of any country's data, please contact NCDC--ncdc.orders@noaa.gov, 828-271-4800. Please email ncdc.info@noaa.gov if you have any other questions. As described below, the data are available via: WWW -- http://www.ncdc.noaa.gov and FTP -- ftp.ncdc.noaa.gov and...the WWW system includes INTERACTIVE VISUALIZATION of the data which allows for graphing and selection of data by station and element. ******************************************************************** OVERVIEW The following is a description of the global surface summary of day data produced by the National Climatic Data Center (NCDC) in Asheville, NC. The data used in building these daily summaries are obtained from the USAF Climatology Center, located in the Federal Climate Complex with NCDC. The latest week of the daily summary data is placed on line by NCDC for easy access and download by outside users, and is normally available a few days after the end of the data week. The online data files begin with January 1994, and are now at the Version 7 software level for January 2005 forward. Data provided off-line (eg, order by phone) for any requested period (eg, pre-1994) are strictly Version 6. Over 8000 stations' data are typically available. They are accessible through our WWW server (http://www.ncdc.noaa.gov) or through direct ftp connection. Other periods of the summary of day data (up to 20 years or more) can be obtained off-line from NCDC. Also, the data can be displayed in graphical form using the climate visualization software on our WWW server. This allows the user to select the country and station(s) of interest, and quickly display the element(s) chosen. The daily elements included in the dataset (as available from each station) are: Mean temperature (.1 Fahrenheit) Mean dew point (.1 Fahrenheit) Mean sea level pressure (.1 mb) Mean station pressure (.1 mb) Mean visibility (.1 miles) Mean wind speed (.1 knots) Maximum sustained wind speed (.1 knots) Maximum wind gust (.1 knots) Maximum temperature (.1 Fahrenheit) Minimum temperature (.1 Fahrenheit) Precipitation amount (.01 inches) Snow depth (.1 inches) Indicator for occurrence of: Fog Rain or Drizzle Snow or Ice Pellets Hail Thunder Tornado/Funnel Cloud The latest week is also available in metric units. For details on the contents of the dataset, see the format documentation shown below. The data are available via WWW: http://www.ncdc.noaa.gov/cgi-bin/res40.pl?page=gsod.html. Also...by direct internet-ftp: a) Enter: open ftp.ncdc.noaa.gov b) Login is: ftp c) Password is: your email address d) You are now logged onto a UNIX workstation. Enter 'help' if you'd like a list of available commands. e) To move to the correct subdirectory, enter: cd /pub/data/globalsod The files included in this subdirectory are: Data Files-- all-1994.tar - All 1994 monthly files (compressed) in one tar file. all-1995.tar - All 1995 monthly files (compressed) in one tar file. etc, etc - For each annual volume. data.txt - The global data file for the latest week - usually about 7 mb of data. The latest week's data will also appear as the name of the dates (e.g., january-0106-2001.txt). data.txt.Z - Compressed 'data.txt' file - usually about 1 mb of data. data-metric.txt - Metric version of the 'data.txt' file. data-metric.txt.Z - Metric version of the 'data.txt.Z' file. Previous months' data files - These are identified by their name, such as 'march-94.txt' Previous weeks' data files - These are identified by their name, such as 'january-0106-2001.txt' Monthly files through 2000, weekly files thereafter, in directories by year. Informational/Utility Files-- inven.txt - An inventory by station and WMO block of data.txt. country-list.txt - A list showing the station number range for each country. stnlist-sorted.txt - A station list to be used with the data files --shows the names and locations for each station number. data-selection-program.for - A Fortran program (source code) for selecting data by station or country. data-selection-program.exe - MSDOS-compiled version of program--will work on most PC's. User must have downloaded the 'stnlist.txt' file + at least one of the monthly data files. Data files should be named as 'monyr.txt' (eg, 'jun96.txt') on your hard drive. convert-to-metric.for - A Fortran program (source code) for converting any data file from English units to metric units. The program asks for input file name (unit 11) and output file name (unit 21) when executed. convert-to-metric.exe - MSDOS-compiled version of program--will work on most PC's. uncomp.exe - MSDOS utility to uncompress any of the '.Z' files. Just enter 'uncomp filename.ext' to uncompress the file back to ASCII format. readme.txt - A description of the data and its format. special-note.txt - Any special notices about the data. world-stns.gif - A 'gif' file with worldwide surface stations plotted. Most of these stations will have summary of day data. world-stns.ps - A 'postscript' version of the 'gif' file--for an 8.5 x 11-inch copy on a postscript printer. Other files will occasionally appear, such as special reports about recent weather events. All files with a '.txt.Z' extension are compressed versions of the '.txt' file. f) To get a copy of the data description, enter: get readme.txt destination (destination is your output location and name)...e.g.-- get readme.txt c:readme.txt - copies to hard drive c: g) Then, to get a copy of any of the other files, use the same procedure, such as-- get data.txt c:data.txt h) To logoff the system when finished, enter: bye ******************************************************************** DETAILS/FORMAT Global summary of day data for 18 surface meteorological elements are derived from the synoptic/hourly observations contained in USAF DATSAV3 Surface data and Federal Climate Complex Integrated Surface Data (ISD). The data are normally available about 3-4 days after the end of the data week. Historical data are generally available for 1973 to the present, with some stations having data back to before 1930. Generally, data from 1982 (beginning of current synoptic code) to the present are the most complete. For some periods, one or more countries' data may not be available due to data restrictions or communications problems. In deriving the summary of day data, a minimum of 4 observations for the day must be present (allows for stations which report 4 synoptic observations/day). Since the data are converted to constant units (e.g, knots), slight rounding error from the originally reported values may occur (e.g, 9.9 instead of 10.0). The mean daily values described below are based on the hours of operation for the station. For some stations/countries, the visibility will sometimes 'cluster' around a value (such as 10 miles) due to the practice of not reporting visibilities greater than certain distances. The daily extremes and totals--maximum wind gust, precipitation amount, and snow depth--will only appear if the station reports the data sufficiently to provide a valid value. Therefore, these three elements will appear less frequently than other values. Also, these elements are derived from the stations' reports during the day, and may comprise a 24-hour period which includes a portion of the previous day. The data are reported and summarized based on Greenwich Mean Time (GMT, 0000Z - 2359Z) since the original synoptic/hourly data are reported and based on GMT. As for quality control (QC), the input data undergo extensive automated QC to correctly 'decode' as much of the synoptic data as possible, and to eliminate many of the random errors found in the original data. Then, these data are QC'ed further as the summary of day data are derived. However, we expect that a very small % of the errors will remain in the summary of day data. The record length is 132. The data can also be provided on CD, DVD, or paper copy. The data are strictly ASCII, with a mixture of character data, real values, and integer values. Following is the data format: First record--header record of 132 characters. All ensuing records--data records as described below. All 9's in a field (e.g., 99.99 for PRCP) indicates no report or insufficient data. FIELD POSITION TYPE DESCRIPTION STN 1-6 Int. Station number (WMO/DATSAV3 number) for the location. YEAR 9-12 Int. The year. MODA 13-16 Int. The month and day. TEMP 19-24 Real Mean temperature for the day in degrees Fahrenheit to tenths. Missing = 9999.9 (Celsius to tenths for metric version.) Count 26-27 Int. Number of observations used in calculating mean temperature. DEWP 30-35 Real Mean dew point for the day in degrees Fahrenheit to tenths. Missing = 9999.9 (Celsius to tenths for metric version.) Count 37-38 Int. Number of observations used in calculating mean dew point. SLP 41-46 Real Mean sea level pressure for the day in millibars to tenths. Missing = 9999.9 Count 48-49 Int. Number of observations used in calculating mean sea level pressure. STP 52-57 Real Mean station pressure for the day in millibars to tenths. Missing = 9999.9 Count 59-60 Int. Number of observations used in calculating mean station pressure. VISIB 63-67 Real Mean visibility for the day in miles to tenths. Missing = 999.9 (Kilometers to tenths for metric version.) Count 69-70 Int. Number of observations used in calculating mean visibility. WDSP 73-77 Real Mean wind speed for the day in knots to tenths. Missing = 999.9 (Meters/second to tenths for metric version.) Count 79-80 Int. Number of observations used in calculating mean wind speed. MXSPD 83-87 Real Maximum sustained wind speed reported for the day in knots to tenths. Missing = 999.9 (Meters/second to tenths for metric version.) GUST 90-94 Real Maximum wind gust reported for the day in knots to tenths. Missing = 999.9 (Meters/second to tenths for metric version.) MAX 97-102 Real Maximum temperature reported during the day in Fahrenheit to tenths--time of max temp report varies by country and region, so this will sometimes not be the max for the calendar day. Missing = 9999.9 (Celsius to tenths for metric version.) Flag 103-103 Char Blank indicates max temp was taken from the explicit max temp report and not from the 'hourly' data. * indicates max temp was derived from the hourly data (i.e., highest hourly or synoptic-reported temperature). MIN 105-110 Real Minimum temperature reported during the day in Fahrenheit to tenths--time of min temp report varies by country and region, so this will sometimes not be the min for the calendar day. Missing = 9999.9 (Celsius to tenths for metric version.) Flag 111-111 Char Blank indicates min temp was taken from the explicit min temp report and not from the 'hourly' data. * indicates min temp was derived from the hourly data (i.e., lowest hourly or synoptic-reported temperature). PRCP 113-117 Real Total precipitation (rain and/or melted snow) reported during the day in inches and hundredths; will usually not end with the midnight observation--i.e., may include latter part of previous day. .00 indicates no measurable precipitation (includes a trace). Missing = 99.99 (For metric version, units = millimeters to tenths & missing = 999.9.) Note: Many stations do not report '0' on days with no precipitation--therefore, '99.99' will often appear on these days. Also, for example, a station may only report a 6-hour amount for the period during which rain fell. See Flag field for source of data. Flag 118-118 Char A = 1 report of 6-hour precipitation amount. B = Summation of 2 reports of 6-hour precipitation amount. C = Summation of 3 reports of 6-hour precipitation amount. D = Summation of 4 reports of 6-hour precipitation amount. E = 1 report of 12-hour precipitation amount. F = Summation of 2 reports of 12-hour precipitation amount. G = 1 report of 24-hour precipitation amount. H = Station reported '0' as the amount for the day (eg, from 6-hour reports), but also reported at least one occurrence of precipitation in hourly observations--this could indicate a trace occurred, but should be considered as incomplete data for the day. I = Station did not report any precip data for the day and did not report any occurrences of precipitation in its hourly observations--it's still possible that precip occurred but was not reported. SNDP 120-124 Real Snow depth in inches to tenths--last report for the day if reported more than once. Missing = 999.9 (Centimeters to tenths for metric version.) Note: Most stations do not report '0' on days with no snow on the ground--therefore, '999.9' will often appear on these days. FRSHTT 127-132 Int. Indicators (1 = yes, 0 = no/not reported) for the occurrence during the day of: Fog ('F' - 1st digit). Rain or Drizzle ('R' - 2nd digit). Snow or Ice Pellets ('S' - 3rd digit). Hail ('H' - 4th digit). Thunder ('T' - 5th digit). Tornado or Funnel Cloud ('T' - 6th digit). ******************************************************************** REFERENCE The NCDC Climate Services Branch (CSB) is responsible for distribution of NCDC products to users. NCDC's CSB can be contacted via the following phone number, internet address, or fax number. Telephone Number: 828-271-4800 Fax Number: 828-271-4876 Internet Address: ncdc.orders@noaa.gov ******************************************************************** Neal Lott NCDC/DAB