STORM Surface Composite Datasets This document contains the following sections: I. General Information II. How to Access the Data III. Composite Format Description IV. Processing of Data Included in the Composite Datasets V. Quality Control VI. Instrumentation VII. Appendix A - Present Weather Codes VIII. References I. GENERAL INFORMATION ------------------- The second release (version 2) of the STORM-FEST composite datasets for surface observations are now available. The composites are available as hourly and 5-minute datasets separated into daily files. The files consist of several surface parameters, 1 station observation per record, and are sorted by time, station latitude and station longitude. Changes from release 1 to release 2 of the composites: ------------------------------------------------------ - PAM humidity data is included in release 2 - PAM boundary layer (1-minute) stations are included in release 2 - Data from 1-minute IOWA AWOS stations are included in release 2 in the 5-minute composite and replace information for these stations in the hourly composite. - Manual quality control was performed on selected hourly values The hourly surface composite dataset contains data from: -------------------------------------------------------- PAM Network ASOS Network AWOS Network Nebraska High Plains Climate Network Illinois State Water Survey Network PROFS Network Wind Profiler Demonstration Network National Climatic Data Center Surface Airways observations (SAO's) The 5-minute surface composite dataset contains data from: ---------------------------------------------------------- PAM Network ASOS Network Illinois State Water Survey Network PROFS Network Data were subject to the following quality control procedures: -------------------------------------------------------------- First level quality control (qc) was automatically done by computer. The type of qc check performed depends on the parameter. Depending on the outcome of each check observations were flagged as either "good", "questionable" or "unlikely". In addition, a manual quality check was performed on selected observations in the hourly composite. This check manually verified and/or adjusted unlikely and questionable quality flags. Limitations of the composites include: ------------------------------------------------- - No Canadian data is included - Quality control was mostly automatic and, therefore, observations with "unlikely" or "questionable" qc flags may require further inspection to determine their usefulness. II. HOW TO ACCESS THE DATA ---------------------- These datasets and appropriate documentation may be accessed online via the STORM Data Management System over the Internet at: http://www.joss.ucar.edu/codiac/ III. Composite Format Description ---------------------------- The composite dataset is archived in the standard WMO FM-94 BUFR code format enhanced with a fixed size headers preceeding each BUFR data record. This enhanced BUFR format is referred to as Enhanced-BUFR, or E-BUFR. The headers on BUFR records consist of date/time and location information to allow for easy sort and extraction of BUFR records without the need to decode the binary BUFR data. BUFR (and E-BUFR) has been designed to be machine independent. The dataset may be requested in a variety of formats through the STORM Data Management system. Supported formats include a tabular ASCII format designed for easy readability, NetCDF, CMF and E-BUFR. The following is a description of the precipitation composite with specifics for the E-BUFR and ASCII formats. A. Parameters in the Composite datasets. The Composite Format contains the parameters listed below. This format applies to both the hourly and 5-minute composites with one variation. The hourly composite dataset contains the nominal date and time of observation, whereas the 5-minute composite does not. The nominal date and time is the nearest top of the hour time for the observation as compared to the actual time of the observation. Most networks actually take the observation about 5-minutes before the hour, but this varies from network to network and station to station in a network. Parameter Units Nominal Date of Observation UTC (YY/MM/DD) Nominal Time of Observation UTC (HH:MM) Actual Date of Observation UTC (YY/MM/DD) Actual Time of Observation UTC (HH:MM) Network Identifier Abbreviation of platform name Station Identifier Network Dependent Latitude Decimal degrees, South is negative Longitude Decimal degrees, West is negative Station Occurrence Unitless Station Elevation Meters Station Pressure Hectopascals (mb) Reported Sea Level Pressure Hectopascals (mb) Computed Sea Level Pressure Hectopascals (mb) Dry Bulb Temperature Celsius Dew Point Celsius Wind Speed m/s Wind Direction Degrees Total Precipitation mm Squall/Gust Indicator Code Value Squall/Gust Value m/s Present Weather Code Value Visibility meters Ceiling Height (first layer) Hundreds of feet Ceiling Flag (first layer) Code Value Cloud Amount (first layer) Code Value Ceiling Height (second layer) Hundreds of feet Ceiling Flag (second layer) Code Value Cloud Amount (second layer) Code Value Ceiling Height (third layer) Hundreds of feet Ceiling Flag (third layer) Code Value Cloud Amount (third layer) Code Value In addition, there is a single character quality-control flag that follows each parameter as shown in the following file structure section. The code values for the quality-control flags are given later in this document. Parameter notes: 1. The nominal date and time differs from actual time. It is the actual time rounded to the nearest hour for the hourly dataset and rounded to the nearest quarter hour for the 5-Minute dataset. Actual times may vary a few minutes before or after nominal time. Actual times are not included in the dataset. 2. The nominal date and time is included ONLY in the hourly composite. The 5-minute composite begins with actual date and time. 3. The station occurance is a uniqueness code to separate two different stations that may be co-located in the same latitude/longitude point. 4. Not all platforms report these parameters. If not available for a network the value was set to missing and the QC flag to "Not Observed". B. E-BUFR File Structure The following describes the BUFR descriptors used in the surface composite and summarizes the E-BUFR format of the surface data records. Every E-BUFR file contains header information at the beginning of the file and additional details not listed here. For a full description of BUFR and E-BUFR see the BUFR and E-BUFR description manuals. The BUFR Descriptors: --------------------- BUFR Code F XX YYY Description - -- --- ----------- 0 04 248 Nominal Year (Hourly Composite only) 0 04 249 Nominal Month (Hourly Composite only) 0 04 250 Nominal Day (Hourly Composite only) 0 04 251 Nominal Hour (Hourly Composite only) 0 04 252 Nominal Minute (Hourly Composite only) 0 04 001 Year 0 04 002 Month 0 04 003 Day 0 04 004 Hour 0 04 005 Minute 0 05 001 Latitude (high accuracy) 0 06 001 Longitude (high accuracy) 0 01 252 Station Occurance 0 01 254 Network Identifier 0 01 253 Station Identifier 0 07 001 Station Height 0 07 004 Station Pressure 0 10 051 Reported Sea Level Pressure 0 10 255 Calculated Sea Level Pressure (using GEMPAK algorithm) 0 11 001 Wind Direction 0 11 002 Wind Speed 0 11 041 Maximum Wind Speed (Gusts) 0 12 001 Dry Bulb Temperature 0 12 003 Dew Point Temperature 0 13 011 Precipitation 0 20 001 Visibility 0 20 003 Present Weather 0 20 011 Cloud Amount 0 20 254 Ceiling 0 20 255 Layer Height 0 33 255 Quality Control Flag E-BUFR encoded data record: --------------------------- Header portion: Nominal Date (GMT) Nominal Time (GMT) Latitude Longitude Station Occurance BUFR encoded portion: Actual Date (Hourly Composite Only) Actual Time (Hourly Composite Only) Network Identifier Station Identifier Station Height Station Pressure Reported Sea Level Pressure Calculated Sea Level Pressure (using GEMPAK algorithm) Wind Direction Wind Speed Maximum Wind Speed (Gusts) Dry Bulb Temperature Dew Point Temperature Precipitation Visibility Present Weather Cloud Amount Ceiling Layer Height Quality Control Flag The Quality Control Flag is repeated for each measured parameter. Cloud Amount, Ceiling and Layer Height is repeated as a group 3 times for 3 different heights. C. ASCII File Structure The ASCII composite file is a sequential tabular ASCII file containing fixed-length records. It consists of header records and data records. It is created upon request from the archived E-BUFR file. 1. 5 Minute Composite Header Records The following three header records are the first three records in each 5-minute file and identify the data: Date Time Network Station Latitude Longitude Occ Elev UTC ID ur ******** ***** ********** ********** ********** *********** *** ******* (Header Lines Continued) STN Q Sea Lvl Q Cmptd Q Drybulb Q Dewpnt Q Wind Q Wind Q Press F Press F Sea Lvl F Temp F Temp F Speed F Dir F ******* * ******* * ******* * ******* * ******* * ******* * ******* * (Header Lines Continued) Total Q S Squall/ Q Pres Q Visib Q Prcp F G Gust F Wx F F ******* * * ******* * **** * ******* * (Header Lines Continued) Ceiling CF Q CA Q Ceiling CF Q CA Q Ceiling CF Q CA Q Height1 F F Height2 F F Height3 F F ******* ** * ** * ******* ** * ** * ******* ** * ** * 2. Hourly Composite Header Records The following three header records are the first three records in each hourly composite file and identify the data: Nominal Time Date UTC ******** ***** (Header Lines Continued) Date Time Network Station Latitude Longitude Occ Elev UTC ID ur ******** ***** ********** ********** ********** *********** *** ******* (Header Lines Continued) STN Q Sea Lvl Q Cmptd Q Drybulb Q Dewpnt Q Wind Q Wind Q Press F Press F Sea Lvl F Temp F Temp F Speed F Dir F ******* * ******* * ******* * ******* * ******* * ******* * ******* * (Header Lines Continued) Total Q S Squall/ Q Pres Q Visib Q Prcp F G Gust F Wx F F ******* * * ******* * **** * ******* * (Header Lines Continued) Ceiling CF Q CA Q Ceiling CF Q CA Q Ceiling CF Q CA Q Height1 F F Height2 F F Height3 F F ******* ** * ** * ******* ** * ** * ******* ** * ** * 3. 5-minute Data Records Each 5-minute data record contains some value for all the parameters given above. The FORTRAN READ format of the data record is as follows: FORMAT(A2,1X,A2,1X,A2,1X,A2,1X,A2,1X,A10,1X,A10,1X,F10.5,1X, * F11.5,1X,I3,1X,F7.2,1X,8(F7.2,1X,A1,1X),A1,1X,F7.2,1X, * A1,1X,I4,1X,A1,1X,F7.2,1X,A1,1X, * 3(F7.2,1X,I2,1X,A1,1X,I2,1X,A1,1X)) 4. Hourly Data Records Each hourly data record contains some value for all the parameters given above. The FORTRAN READ format of the data record is as follows: FORMAT(A2,1X,A2,1X,A2,1X,A2,1X,A2,1X, * A2,1X,A2,1X,A2,1X,A2,1X,A2,1X,A10,1X,A10,1X,F10.5,1X, * F11.5,1X,I3,1X,F7.2,1X,8(F7.2,1X,A1,1X),A1,1X,F7.2,1X, * A1,1X,I4,1X,A1,1X,F7.2,1X,A1,1X, * 3(F7.2,1X,I2,1X,A1,1X,I2,1X,A1,1X)) D. Special Values 1. Missing Values A value that is missing, or is not observed by the given network is indicated by the value '-999.99', a Qualification code of 7 and a QC flag of 15 (E-BUFR) or 'M' (ASCII). 2. Quality-Control Flag Values The quality-control flag is a coded value. Codes and definitions are listed briefly here and are expanded in the section on quality control. BUFR ASCII Definition Code Code 0 U Unchecked 1 G Checked and Good 2 B Checked and Unlikely (Bad) 3 D Checked and Questionable (Dubious) 4 N Parameter not measured at this station or is not applicable 5 X Glitch 6 E Estimated Value 7 7-14 reserved (unused) 15 M Missing Value Upon initial conversion of the data all QC flags were initialized to 0 or 'U' to indicate that the data have not been checked, except for data that is missing (15 or 'M') or unobserved (4 or 'N'). 3. Network Identifiers ID Network PAM1 Pam Network for 1-minute stations PAM5 Pam Network for 5-minute stations ASOSH ASOS Network for hourly composite ASOS5 ASOS Network for 5-minute composite AWOSQ AWOS Qualimetrics Network (20-minute stations) AWOSH AWOS Handar Network (20-minute stations) AWOS1 AWOS for Iowa 1-minute stations HPLAINS Nebraska High Plains Climate Network ISWS Illinois State Water Survey Network PROFS5 PROFS Network WDPN Wind Profiler Demonstration Network NCDC National Climatic Data Center Surface Airways Observations 4. Station Identifiers The stations and their names and identifiers are listed in a separate file called fest_sites. 5. Squall/Gust Indicator The code values for the Squall/Gust Indicator are: Code Definition S Squall G Gust 6. Ceiling Flag The following codes define ceiling information that cannot be indicated by the numeric value. Code Description 0 None 1 Thin 2 Clear below 12,000 feet 3 Estimated 4 Measured 5 Indefinite 6 Balloon 7 Aircraft 8 Measured/Variable 9 Clear below 6,000 feet (AUTOB) 10 Estimated / Variable 11 Indefinite / Variable 12 12 - 14 reserved 15 Missing 7. Cloud Amount The following codes define the cloud amount indicator: Code Description 0 0 (or clear) 1 1 okta or less, but not zero or 1/10 or less, but not zero 2 2 oktas or 2/10-3/10 3 3 oktas or 4/10 4 4 oktas or 5/10 5 5 oktas or 6/10 6 6 oktas or 7/10-8/10 7 7 oktas or more, but not 8 oktas or 9/10 or more, but not 10/10 8 8 oktas or 10/10 (or overcast) 9 Sky obscured by fog and/or other meteorological phenomena 10 Sky partially obscured by fog and/or other meteorological phenomena 11 Scattered 12 Broken 13 13 - 14 Reserved 15 Cloud cover is indiscernible for reasons other than fog or other meteorological phenomena, or observation is not made 8. Present Weather Present weather codes are the same as the BUFR Code Table for Present Weather. See Appendix A for this table. IV. PROCESSING OF DATA INCLUDED IN THE COMPOSITE DATASETS ----------------------------------------------------- Most parameters are originally reported in integer units, such as temperature in degrees, wind speed in knots, cloud layer height in hundreds of feet, etc. Visibility is generally reported in whole miles and fractions, with the maximum visibility being 10+ miles and the minimum visibility being <1/4 mile. These two visibilities are converted into 18000. and 200. meters respectively. Only the ASOS stations use 10+ miles as the maximum visibility - the AWOS data uses a maximum of 10 miles. In the final data file, all of these parameters are shown with a precision that does not exist in the original data, since the real number parameters are shown with two digits to the right of the decimal. Additionally, any necessary units conversion may also slightly affect the results, depending upon the exact conversion factor used by the program. Computed sea level pressure uses the GEMPAK algorithms. 1. Handar AWOS data Handar data was for two stations only- FTG (Front Range Airport in Denver) and ASG (Springdale Municipal Airport in Arizona). Data is based upon original 20-minute data. There is no present weather or sea level pressure reported for Handar data. Springdale did not report sky conditions. The data is not complete for the entire STORMFEST period for either FTG or ASG. 2. Qualimetrics AWOS data Qualimetrics data is based upon original 20-minute data. Precipitation is the accumulated precipitation for the hour, but all other parameters are the numbers reported for the 20-minute observation that happens to fall on the hour. Station pressure is calculated from altimeter setting. Sea level pressure is not reported for the Qualimetrics AWOS data. Present weather is not reported for Qualimetrics AWOS data. There are occasional gaps in the data. 3. AWOS 1-minute data 1-minute data is from 3 stations in Iowa (Clinton, Creston and Denison). Data from these stations were summarized into 5-minute and hourly amounts and included in the 5-minute composite and hourly composite, respectively. Station pressure is calculated from altimeter setting. Sea level pressure and present weather are not reported. There are occasional gaps in the data. 4. ASOS data The ASOS data in the 5-minute composite is from the 5-minute reports from the ASOS stations. In the hourly composite the ASOS hourly reports were used. The processing to create the 5-minute and hourly reports was done at the ASOS stations. You should refer to the ASOS documentation to understand how the ASOS stations create the 5-minute and hourly reports from the raw data. Hourly ASOS data is taken nominally on the hour, but actual times are usually 2-4 minutes before the hour. Initial observations are in SAO format. No special processing notes for ASOS data. 5. NCDC Monthly Airways Extract (SAO's) The NCDC Monthly Airways Extract (MAE) dataset contains selected airways observations (both hourly and specials) from the Surface Records Retention System (SRRS), which is a recording of surface data from the NWS AFOS network. All standard hourly observations inside a window of +/- 15 minutes of the nominal hour were selected, converted to standard format and units, and included in the hourly composite. Other observations, such as specials and "hourly" observations that fell outside the time window, (about 27% of the original data) were also quality-controlled, and are available as a separate dataset from the STORM Project Office. 6. Wind Profiler Demonstration Network Hourly Surface Observations The hourly surface observations from those wind profilers equipped with surface instrumentation were obtained, converted to standard format and units, and included in the hourly composite. 7. Nebraska Automated Weather Detection Network (AWDN) Data The data from this network of hourly agricultural stations were obtained from the University of Nebraska. Parameters appropriate for inclusion in the Hourly Composite were extracted and converted to standard format and units. One special processing note: The AWDN network reports only the moisture measurement of relative humidity, and does not report any pressure parameter. The hourly composite includes dewpoint as the moisture parameter. To convert relative humidity to dewpoint, the station elevation and the standard atmosphere were used to generate an estimate of the station pressure, which was then used in the relative humidity to dewpoint conversion. 8. ERL/FSL PROFS Mesonet The data from this network of mesonet stations were obtained from ERL/FSL. The five minute frequency data were converted to standard format and units, and included in the 5-Minute Composite. They were processed to obtain hourly observations and included in the Hourly Composite. The hourly observations were generated by selecting the data from the observation period ending at 55 minutes before the hour for all parameters except precipitation, which was totaled from minute 0 to minute 55. 9. NCAR PAM Mesonet The data from this network of mesonet stations were obtained from NCAR/RDP. The five minute frequency data were converted to standard format and units, and included in the 5-Minute Composite. The one minute frequency data were summarized to 5-minute amounts and also included in the 5-Minute Composite. They were then processed to obtain hourly observations and included in the Hourly Composite. The hourly observations were generated by selecting the data from the observation period ending at 55 minutes before the hour for all parameters except precipitation, which was totaled from minute 0 to minute 55. 10. Illinois State Water Survey The data from this network of mesonet stations were obtained from the ISWS. The five minute frequency data were converted to standard format and units, and included in the 5-Minute Composite. They were processed to obtain hourly observations and included in the Hourly Composite. The hourly observations were generated by selecting the data from the observation period ending at 55 minutes before the hour for all parameters except precipitation, which was totaled from minute 0 to minute 55. The PAM 1-minute stations and the AWOS 1-minute stations were summarized into 5-minute averages to be included in the 5-minute composite. The following describes how this summary was done: Parameter Summarization technique Station Pressure Convert altimeter setting to station pressure, average over 5 1-minute periods Sea Level Pressure Average over the 5 1-minute periods Temperature Average over the 5 1-minute periods Dew Point Average over the 5 1-minute periods Wind Speed/Dir Break into components, average components over last two 1-minute periods, compute new vector Precipitation Total over the 5 1-minute periods Wind Gust Greatest value in last two 1-minute periods Visibility Use amount reported at each 5-minute interval Cloud Height Use amount reported at each 5-minute interval A 5-minute average is calculated from the 1-minute averages provided that at least 4 valid 1-minute averages are available. The 5-minute observation is set to missing if more than one 1-minute observation is missing in the 5-minute interval. The 5 1-minute times include the time of the 5-minute observation and the 4 previous 1-minute observations. For wind speed, direction and wind gusts a 5-minute average is calculated from the last two 1-minute averages for the 5-minute time period. If either of these two 1-minute averages are missing, then wind direction, speed, and wind gusts are set to missing. V. QUALITY CONTROL --------------- A. Description of QC method ------------------------ Observations contained within the STORM-FEST surface composite datasets (hourly and 5-minute composites) were automatically checked by computer. The type of test performed depends on the parameter. Not all parameters were checked. The most significant check was performed by comparing the MAPS (Mesoscale Analysis and Prediction System) hourly gridded surface analyses with the observed values. Station pressure, sea level pressure, temperature, dew point, wind speed and wind direction were checked using MAPS. Other checks included flagging impossible values (i.e. negative wind speeds), checking values against gross limits (i.e. maximum precipitation levels per hour) and checking for consistency within parameters (i.e. dew point must be less than temperature). In addition, a manual quality check was performed on selected observations (this is new in release 2). The effect of the manual check was to verify and/or adjust unlikely and questionable quality flags. This check was performed only on the hourly composites and only on selected observations and there is no way to tell which flags were adjusted manually. All manual checks were performed by a meteorologist by visually inspecting a time series of observations for a station and comparing them to both MAPS and nearby stations (buddies) on the same time series plot. The main effect of this inspection was to change flags that were erroneously flagged either unlikely or questionable to good. B. Quality control flags --------------------- Quality control flags are stored with each parameter in the composite datasets. The codes have the following meanings: U - Unchecked. No qc has been done for this observation. (E-BUFR code 0). G - Checked and found "Good". In the case of pressure, temperature and wind parameters, this qc flag means the value compared favorable with the MAPS surface analyses. (E-BUFR code 1). B - Checked and found "Unlikely". In the case of pressure, temperature and wind parameters, this qc flag means the value compared poorly with the MAPS surface analyses. Observations with this qc flag should only be used after careful analysis as to the validity of its value. (E-BUFR code 2). D - Checked and found "Questionable". In the case of pressure, temperature and wind parameters, this qc flag means the value compared questionably with the MAPS surface analyses. Observations with this qc flag should be used with caution. (E-BUFR code 3). N - Not observed or not applicable. This parameter is not observed at this station, or, this parameter is optionally reported and is not applicable for this station and time. (E-BUFR code 4). X - "Glitch" flag. Either the instrumentation was faulty, or, some other known problem was known to exist which invalidates the value of this observation. Observations with this qc flag should not be used. (E-BUFR code 5). E - Estimated value. This parameter's value was estimated and is not a directly observed value. This flag overrides the qc flags "G" ("good") and "D" (questionable), but the qc flag "B" ("unlikely") overrides this flag. Use values with this qc flag with caution. (E-BUFR code 6). M - Missing. This value is normally reported but for some unknown reason is missing for this station and time. (E-BUFR code 15). C. MAPS comparison --------------- Hourly MAPS 60km gridded surface analyses for North America were obtained for the STORM-FEST time period. For each stations time report the adjacent MAPS gridded values were interpolated to the station latitude, longitude, elevation and observation time and were then compared to the observed values. Observations were flagged as "good", "questionable" or "unlikely" based on this comparison with MAPS. Predetermined maximum variance levels for each parameter (given below) were used to determine the appropriate quality control flags. We used 7 parameters provided with the MAPS surface analyses. Some of these required conversion before comparison. The conversions we did were as follows: Parameter Conversion performed Altimeter Pressure (mb) Converted to station pressure (uses station elevation in the conversion) NWS Sea Level Pressure (mb) No conversion necessary MAPS Sea Level Pressure (mb) No conversion necessary Potential Temperature (deg K) Converted to station temperature (deg C) (uses station pressure in the conversion Dew Point Temperature (deg K) Converted to deg C U,V wind components (m/s) Converted to wind speed and direction D. Checks performed ---------------- MAPS comparison checks: - Station Pressure was compared with MAPS altimeter (converted to station pressure). - Sea Level Pressure was compared with MAPS NWS Sea Level Pressure. - Calculated Sea Level Pressure adopted the same qc flag as station pressure. This was done because this parameter was calculated by the STORM Project Office directly from the station pressure using the GEMPAK method. If for some reason the station pressure qc flag could not be used, then this parameter was compared with MAPS sea level pressure. The MAPS sea level pressure was calculated by a completely different method so the comparison has questionable meaning. However, if this comparison happened at all it was very rare. - Dry Bulb Temperature was compared with MAPS potential temperature converted to station temperature. - Dew Point Temperature was compared with MAPS dew point temperature. - Wind Speed was compared with MAPS wind speed. - Wind Direction was compared with MAPS wind direction. Gross limit checks: - Precipitation was compared with maximum allowable rates. - Squall/gust wind speed was compared with maximum allowable speeds. Consistency checks: - Dry bulb temperature must be greater than dew point temperature. If not both values were flagged "questionable". - Wind direction for observed "calm" winds were given the same qc flag as the wind speed. - There can't be precipitation with a "clear" sky. If there was a cloud amount of "1" ("none" or clear sky) and a positive precipitation was reported, both the cloud amount and the precipitation values were flagged "questionable". Impossible values checks: - Negative wind speeds were flagged "unlikely". - Negative squall/gust wind speeds were flagged "unlikey". - Wind direction < 0 or > 360 degrees were flagged "unlikely". - Negative precipitation was flagged "unlikely". E. Variance and gross limits ------------------------- For the following parameters any observation that varied from the MAPS value (plus or minus) more than the variances given were flagged either "unlikely" or "questionable". MAPS variance parameter unlikely questionable Station Pressure 10.00 mb 3.00 mb Sea Level Pressure 10.00 mb 3.00 mb Calculated Sea Level Pressure 20.00 mb 6.00 mb Dry Bulb Temperature 8.00 C 5.00 C Dew Point Temperature 8.00 C 5.00 C Wind Speed 20.00 m/s 5.00 m/s Wind Direction ---- 90.00 deg For the following parameters any observation that exceeded the gross limit in an hourly or 5-minute time period was flagged either "unlikely" or "questionable". Gross limit unlikely questionable Precipitation 75.00 mm/hr 25.00 mm/hr 25.00 mm/5-min 10.00 mm/5-min Squall/gust winds 35.00 m/s 25.00 m/s F. Quality Control Results ----------------------- The following table summarizes some of the qc test results: parameter qc'd good unlikely questionable Station Pressure 99.5 % 99.2 % 0.1 % 0.7 % Sea Level Pressure 99.5 % 98.9 % 0.4 % 0.7 % Calculated Sea Level Pressure 99.5 % 99.2 % 0.1 % 0.7 % Dry Bulb Temperature 99.5 % 96.3 % 2.1 % 1.6 % Dew Point Temperature 99.5 % 96.8 % 0.9 % 2.3 % Wind Speed 99.5 % 98.0 % <.1 % 1.9 % Wind Direction 99.5 % 95.1 % 0.0 % 4.9 % Precipitation 99.6 % 99.9 % <.1 % 0.1 % Squall/gust winds 99.7 % >99.9 % <.1 % <.1 % G. Miscellaneous QC Notes ---------------------- 1. It is important to understand that the qc flags simply represent a comparison to MAPS. Because of inaccuracies in the MAPS analyses values in the composite can have misleading qc flags. It is our experience that many of the observations that were flagged as "unlikely" or "questionable" should really have been flagged "good". Individual attention should be given to the non-good flags before deciding whether to use the value or not. 2. Observations with the "X" flag (glitch) may have values that look realistic. This is only coincidental. Do not trust these values. 3. Any parameter not mentioned in the checks performed section above had no qc test performed on them and contain the "U" qc flag ("unchecked"). 4. This ascii data set sometimes contains false precision. Real numbers were calculated to two decimals. This does not necessarily represent the precision of the intrumentation. For example, precipitation may have been reported in hundreths of an inch. We converted this to hundreths of a millimeter. VI. INSTRUMENTATION --------------- To be added at a later date. VII. APPENDIX A ---------- This is the present weather code table: Code Description 00-19 => No precipitation, fog, ice fog (except for 11 and 12), duststorm, sandstorm, drifting or blowing snow at the station* at the time of observation or, except for 09 and 17, during the preceding hour. 00-49 => No precipitation at the station at the time of observation. 00 Cloud Development not observed or not observable. 01 Clouds generally dissolving or becoming less developed 02 State of sky on the whole unchanged 03 Clouds generally forming or developing 04 Visibility reduced by smoke, e.g. veldt or forest fires, industrial smoke or volcanic ashes 05 Haze 06 Widespread dust in suspension in the air, not raised by wind at or near the station at the time of observation 07 Dust or sand raised by wind at or near the station at the time of observation, but no well-developed dust whirl(s) or sand whirl(s) and no duststorm or sandstorm seen; or, in the case of sea stations and coastal stations, blowing spray at the station 08 Well-developed dust whirl(s) or sand whirl(s) seen at or near the station during the preceding hour or at the same time of whirl(s) and no duststorm or sandstorm seen; or, in the case of sea stations and coastal stations, blowing spray at the station 09 Duststorm or sandstorm within sight at the time of observation, or at the station during the preceding hour 10 Mist-shallow fog or ice fog at the station, whether on land or sea, not deeper than about 2 metres on land or 10 metres at sea 11 Patches-shallow fog or ice fog at the station, whether on land or sea, not deeper than about s metres on land or 10 metres at sea 12 More or less continuous-shallow fog or ice fog at the station, whether on land or sea, not deeper than about 2 metres on and or 10 metres at sea 13 Lightning visible, no thunder 14 Preciptation within sight, not reaching the ground or the surface of the sea 15 Precipitation within sight, reaching the ground or the surface of the sea, but distant, i.e. estimated to be more than 5 km from the station 16 Precipitation within sight, reaching the ground or the surface of the sea, near to, but not at the station 17 Thunderstorm, but no precipitation at the time of observation 18 Squalls-at or within sight of the station during the preceding hour or at the time of observation 19 Funnel cloud(s) (Tormado cloud or waterspout) at or within sight of the station during the preceding hour or at the time of observation 20-29 => Precipitation, fog, ice fog or thunderstorm at the station during the preceding hour but not at the time of observation 20 Drizzle (not freezing) or snow grains. 21 Rain (not freezing) 22 Snow 23 Rain and snow or ice pellets 24 Freezing drizzle or freezing rain 25 Shower(s) of rain 26 Shower(s) of snow, or of rain and snow 27 Shower(s) Hail, small hail, snow pellets, or of rain and hail, small hail, snow pellets 28 Fog or ice fog 29 Thunderstorm (with or without precipitation) 30-39 => Duststorm, sandstorm, drifting or blowing snow. 30 Slight or moderate duststorm or sandstorm - has decreased during the preceding hour. 31 Slight or moderate duststorm or sandstorm - no appreciable change during the preceding hour. 32 Slight or moderate duststorm or sandstorm - has begun or has increased during the preceding hour. 33 Severe duststorm or sandstorm - has decreased during the preceding hour. 32 Severe duststorm or sandstorm - no appreciable change during the preceding hour. 33 Severe duststorm or sandstorm - has begun or has increased during the preceding hour. 36 Slight or moderate drifting snow-generally low (below eye level) 37 Heavy drifting snow-generally low (below eye level) 38 Slight or moderate blowing snow-generally high (above eye level) 39 Heavy blowing snow-generally high (above eye level) 40-49 => Fog or Ice Fog at time of observation 40 Fog or ice fog at at distance at the time of observation, but not at the station during the preceding hour, the fog or ice fog extending to a level above that of the observer. 41 Fog or ice fog in patches 42 Fog or ice fog, sky visible-has become thinner during the preceding hour 43 Fog or ice fog, sky invisible-has become thinner during the preceding hour 44 Fog or ice fog, sky visible-no appreciable change during the preceding hour 45 Fog or ice fog, sky invisible-no appreciable change during the preceding hour 46 Fog or ice fog, sky visible-has begun or has become thicker during the preceding hour 47 Fog or ice fog, sky invisible - has begun or has become thicker during the preceding hour 48 Fog, depositing rime, sky visible 49 Fog, depositing rime, sky invisible 50-99 => Precipitation at the time of observation. 50 Drizzle, not freezing, intermittent-slight at time of observation. 51 Drizzled, not freezing, continuous-slight at time of observation 52 Drizzle, not freezing, intermittent-moderate at time of observation 53 Drizzle, not freezing, continuous-moderate at time of observation 54 Drizzle, not freezing, intermittent-heavy (dense) at time of observation 55 Drizzle, not freezing, continuous-heavy (dense) at time of observation 57 Drizzle, freezing, moderate or heavy (dense) 58 Drizzle and rain, slight 59 Drizzle and rain, moderate or heavy 60 Rain, not freezing, intermittent-slight at time of observation 61 Rain, not freezing, continuous-slight at time of observation 62 Rain, not freezing, intermittent-moderate at time of observation 63 Rain, not freezing, continuous-moderate at time of observation 64 Rain, not freezing, intermittent-heavy at time of observation 65 Rain, not freezing, continuous-heavy at time of observation 66 Rain, freezing, slight 67 Rain, freezing, moderate or heavy 69 Rain or drizzle and snow, moderate or heavy 70-79 => Solid precipitation not in showers. 70 Intermittent fall of snowflakes -slight at time of observation. 71 Continuous fall of snowflakes-slight at time of observation 72 Intermittent fall of snowflakes-moderate at time of observation 73 Continuous fall of snowflakes-moderate at time of observation 74 Intermittent fall of snowflakes-heavy at time of observation 75 Continuous fall of snowflakes-heavy at time of observation 76 Diamond dust (with or without fog) 77 Snow grains (with or without fog) 78 Isolated star-like snow crystals (with or without fog) 79 Ice pellets 80-99 => Showery precipitation, or precipitation with current or recent thunderstorm. 80 Rain shower(s), slight. 81 Rain shower(s), moderate or heavy 82 Rain shower(s), violent 83 Shower(s) of rain and snow mixed, slight 84 Shower(s) of rain and snow mixed, moderate or heavy 85 Snow shower(s), slight 86 Snow shower(s), moderate or heavy 87 Shower(s) of snow pellets or small hail, with or without rain or rain and snow mixed-slight 88 Shower(s) of snow pellets or small hail, with or without rain or rain and snow mixed-moderate or heavy 89 Shower (s) of hail, with or without rain or rain and snow mixed, not associated with thunder-slight 90 Shower (s) of hail, with or without rain or rain and snow mixed, not associated with thunder-moderate or heavy 91 Slight rain at time or observation-Thunderstorm during the preceding hour but not at time of observation 92 Moderate or heavy rain at time of observation-Thunderstorm during the preceding hour but not at time of observation 93 Slight snow, or rain and snow mixed or hail, small hail or snow pellets at time of observation - Thunderstorm during the preceding hour but not at time of observation 94 Moderate or heavy snow, or rain and snow mixed or hail, small hail or snow pellets, at time of observation 95 Thunderstorm, slight or moderate, without hail, small hail or snow pellets, but with rain and/or snow at time of observation-Thunderstorm at time of ovservation 96 Thunderstorm, slight or moderate, with hail, small hail or snow pellets at time of observation-Thunderstorm at time of observation 97 Thunderstorm, heavy, without hail, small hail or snow pellets, but with rain and/or snow at time of observation-Thunderstorm at time of observation 98 Thunderstorm combined with duststorm or sandstorm at time of observation - Thunderstorm at time of observation 99 Thunderstorm, heavy, with hail, small hail or snow pellets at time of observation Present weather reported from an automatic weather station. ----------------------------------------------------------- 100 No significant weather observed 101 Clouds generally dissolving or becoming less developed during the past hour 102 State of sky on the whole unchanged during the past hour 103 Clouds generally forming or developing during the past hour 104 Haze or smoke, or dust in suspension in the air, visibility equal to, or greater than 1km 105 Haze or smoke, or dust in suspension in the air, visibility less than 1 km 106 Reserved 107 Reserved 230 Duststorm or sandstorm with temperature below 0 degrees C 109 Reserved 110 Mist 111 Diamond dust 112 Distant lightning 113 Reserved 114 Reserved 115 Reserved 116 Reserved 117 Reserved 118 Squalls 119 Reserved 120 Fog 121 PRECIPITATION 122 Drizzle (not freezing) or snow grains 123 Rain (not freezing) 124 Snow 125 Freezing drizzle or freezing rain 126 Thunderstorm (with or without precipitation) 127 BLOWING OR DRIFTING SNOW OR SAND 128 Blowing or drifting snow or sand, visibility equal to, or greater than, 1 km 129 Blosing or drifting snow or sand, visibility less than l km 130 FOG 131 Fog or ice fog in patches 132 Fog or ice fog, has become thinner during the past hour 133 Fog or ice fog, no appreciable change during the past hour 134 Fog or ice fog, has begun or decome thicker during the past hour 135 Fog, depositing rime 136 Reserved 137 Reserved 138 Reserved 139 Reserved 140 PRECIPITATION 141 Prercipitation, slight or moderate 142 Precipitation, heavy 143 Liquid precipitation, slight or moderate 144 Liquid precipitation, heavy 145 Solid precipitation, slight or moderate 146 Solid precipitation, heavy 147 Freezing precipitation, slight or moderate 148 Freezing precipitation, heavy 149 Reserved 150 DRIZZLE 151 Drizzle, not freezing, slight 152 Drizzle, not freezing, moderate 153 Drizzle, not freezing, heavy 154 Drizzle, freezing, slight 155 Drizzle, freezing, moderate 156 Drizzle, freezing, heavy 157 Drizzle and rain, slight 158 Drizzle and rain, moderate or heavy 159 Reserved 160 Rain, not freezing, slight 161 Rain, not freezing, slight 162 Rain, not freezing, moderate 163 Rain, not freezing, heavy 164 Rain, freezing, slight 165 Rain, freezing, moderate 166 Rain, freezing, heavy 167 Rain (or drizzle) and snow, slight 168 Rain (or drizzle) and snow, moderate or heavy 169 Reserved 170 SNOW 171 Snow, slight 172 Snow, moderate 173 Snow, heavy 174 Ice pellets, slight 175 Ice pellets, moderate 176 Ice pellets, heavy 177 Reserved 178 Reserved 179 Reserved 180 SHOWERS(S) or INTERMITTENT PRECIPITATION 181 Rain shower(s) or intermittent rain, slight 182 Rain shower(s) or intermittent rain, moderate 183 Rain shower(s) or intermittent rain, heavy 184 Rain shower(s) or intermittent rain, violent 185 Snow shower(s) or intermittent snow, slight 186 Snow shower(s) or intermittent snow, moderate 187 Snow shower(s) or intermittent snow, heavy 188 Reserved 189 Reserved 190 TUNDERSTORM 191 Thunderstorm, slight or moderate, with no precipitation 192 Thunderstorm, slight or moderate, with rain showers and/or snow showers 193 Thunderstorm, slight or moderate, with hail 194 Thunderstorm, heavy, with no precipitation 195 Thunderstorm, heavy, with rain showers and/or snow showers 196 Thunderstorm, heavy, with hail 197 Reserved 198 Reserved 199 Tornado Present weather (in addition to present weather report from either a manned or an automatic station). ----------------------------------------------------------------- 200 - 203 Not used 204 Volcanic ash suspended in the air aloft 205 Not used 206 Thick dust haze, visibility less than 1 km 207 Blowing spray at the station 208 Drifting dust (sand) 209 Wall of dust or sand in distance (like haboob) 210 Snow haze 211 Whiteout 212 Not used 213 Lightning, cloud to surface 214 - 216 Not used 217 Dry thunderstorm 218 Not used 219 Tornado cloud (destructive) at or within sight of the station during preceding hour or at the time of observation 220 Deposition of volcanic ash 221 Deposition of dust or sand 222 Deposition of dew 223 Deposition of wet snow 224 Deposition of soft rime 225 Deposition of hard rime 226 Deposition of hoar frost 227 Deposition of glaze 228 Deposition of ice crust (ice slick) 229 Not used 231 - 238 Not used 239 Blowing snow, impossible to determine whether snow is falling or not 240 Not used 241 Fog on sea 242 Fog in valleys 243 Arctic or Antarctic sea smoke 244 Steam fog (sea, lake or river) 245 Steam fog (land) 246 Fog over ice or snow cover 247 Dense fog, visibility 60-90 m 248 Dense fog, visibility 30-60 m 249 Dense fog, visibility less than 30 m 250 Drizzle, rate of all less than 0.10 mm h -1 251 Drizzle, rate of fall 0.10-0/19 mm h -1 252 Drizzle, rate of fall 0.20-0.39 mm h -1 253 Drizzle, rate of fall 0.40-0.79 mm h -1 254 Drizzle, rate of fall 0.80-1.59 mm h -1 255 Drizzle, rate of fall 1.60-3.19 mm h -1 256 Drizzle, rate of fall 3.20-6.39 mm h -1 257 Drizzle, rate of fall 6.4 mm h -1 or more 258 Not used 259 Drizzle and snow 260 Rain, rate of fall less than 1.0 mm h -1 261 Rain, rate of fall 1.0 - 1.9 mm h -1 262 Rain, rate of fall 2.0 - 3.9 mm h -1 263 Rain, rate of fall 4.0 - 7.9 mm h -1 264 Rain, rate of fall 8.0 - 15.9 mm h -1 265 Rain, rate of fall 16.0 - 31.9 mm h -1 266 Rain, rate of fall 32.0 - 63.9 mm h -1 267 Rain, rate of fall 64.0 mm h -1 or more 268 Not used 269 Not used 270 Snow, rate of fall less than 1.0 cm h -1 271 Snow, rate of fall 1.0 - 1.9 cm h -1 272 Snow, rate of fall 2.0 - 3.9 cm h -1 273 Snow, rate of fall 4.0 - 7.9 cm h -1 274 Snow, rate of fall 8.0 - 15.9 cm h -1 275 Snow, rate of fall l6.0 - 31.9 cm h -1 276 Snow, rate of fall 32.0 - 63.9 cm h -1 277 Snow, rate of fall 64.0 cm h -1 or more 278 Snow or ice crystal precipitation from a clear sky 279 Wet snow, freezing on contact 280 Precipitation of rain (code figures=87-99) 281 Precipitation of rain, freezing (code figures=80-82) 282 Precipitation of rain and snow mixed 283 Precipitation of snow 284 Precipitation of snow pellets or small hail 285 Precipitation of snow pellets or small hail, with rain 286 Precipitation of snow pellets or small hail, with rain and snow mixed 287 Precipitation of snow pellets or small hail, with snow 288 Precipitation of hail 289 Precipitation of hail, with rain 290 Precipitation of hail, with rain and snow mixed 291 Precipitation of hail, with snow 292 Shower(s) or thunderstorm over sea 293 Shower(s) or thunderstorm over mountains 294 - 299 Not used 300 - 507 Reserved 508 No significant phenomenon to report, present and past weather omitted 509 No observation, data not available, present and past weather omitted 510 Present and past weather missing, but expected 511 Missing value VIII. REFERENCES ---------- "E-BUFR Version 0 Technical Reference Manual", December 1991, UCAR/OFPS, Boulder, CO. This document explains the details of the E-BUFR format. A digital version of this document may be retrieved via anonymous FTP. Telnet to 128.117.90.53. The document is named "ebufr.doc" and is in directory "documentation". Manual on Codes, 1988, World Meteorological Organization, Geneva, Switzerland. WMO Publication 306, Supplement No. 3 (VIII.1991) Section FM 94-IX Ext., pages I-Bi--43 to I-Bi--174. Format description, code definitions, network conversion details, quality controls details, etc. are documented in this "readme.sfc" file. IX. ADDENDUM -------- The wind speed parameter for the PROFS Mesonet network (denoted as "PROFS" in the data) was incorrectly converted. The units are indicated as meters/second, but the data are in knots. To correct this problem, multiple the wind speed by 1.943844 (CRC Handbook of Chemistry and Physics, 70th ed.) to obtain meters/second.