GCIP LSA-NW EAOP 1999 WYDOT RWIS "Specials" Surface Data in QC Format 1.0 General Description The Wyoming Department of Transportation (WYDOT) Roadway Weather Information Systems (RWIS) "Specials" observational surface data in QC format is one of several surface datasets provided in the GEWEX Continental-Scale International Project (GCIP) Large Scale Area-North West (LSA-NW) Enhanced Annual Observing Period (EAOP) 1999. This dataset contains the "specials" data for the GCIP LSA-NW EAOP-99 domain and time period (01 April 1999 through 31 March 2000). The GCIP LSA-NW EAOP-99 domain is approximately 90W to 115W longitude and 36N to 51N latitude. These data were not quality controlled by the University Corporation for Atmospheric Research/Joint Office for Science Support (UCAR/JOSS). 2.0 Detailed Data Description WYDOT/RWIS Algorithms The Wyoming Department of Transportation maintains the Roadway Weather Information System (RWIS) which is comprised of two separate networks of automated climatological stations across the State of Wyoming. The purpose of the system is to provide near real-time atmospheric and road condition information to the Department of Transportation district and field offices as well as the Wyoming Highway Patrol. The system is also regularly used by the National Weather Service in the course of forecast activities. RWIS station deployment began in 1988 with 4 unique stations. The system has been upgraded and expanded through new station installation, and currently comprises a total of 27 stations statewide. RWIS stations operating in the State of Wyoming regularly monitor temperature, dew point, wind direction and speed, relative humidity, and precipitation determination. Accumulated precipitation values are also available for a few select sites. Significant changes in parameter values between pollings are identified with a special data flag. While only a minimal amount of QA/QC takes place with the climatological data that is collected, the information acquired in many cases represents the only known climatological monitoring ever done at these often remote locations. Individuals wishing to use RWIS climate data should be aware that only a very few agencies are archiving the information beyond the short term histories (last 3 months) resident on the Wyoming Department of Transportation servers. This includes the Department of Atmospheric Sciences at the University of Wyoming (UW), and the Water Resources Data System, which possess data back through the 1994 calendar year for a majority of the stations. For more information, contact source agency at Wyoming Department of Transportation 5300 Bishop Boulevard Cheyenne, WY 82009 307 777-4458 Or Wyoming Department of Transportation PO Box 1708 Cheyenne, WY 82009-1708 Additional information can be found at the following web sites; http://www.wrds.uwyo.edu/wydot/wydot.html , http://waterplan.state.wy.us/ and http://waterplan.state.wy.us/sdi/SP/SP06AP04.html , http://www.wyoroad.info/highway/sensors/sensors.html . The Wyoming Roadway Weather Information Systems database contains observerations of temperature, dewpoint, wind, relative humidity, wind speed and direction, and precipitation taken at 15-minute intervals. Data are available for 21 stations around the State of Wyoming. The following channels were converted to JOSS QCF format when they existed: Tmp - Temperature in Degrees F converted to Degrees C Dew - Dew point temperature in Degrees F converted to Degrees C Dir - Wind direction from true north (0-360) 999 is missing or calm Spd - Wind speed in mph converted to m/s Gst - Wind gust in mph converted to m/s No other channels were converted. 2.1 Detailed Format Description The GCIP LSA-NW EAOP-99 "Specials" observational Data contains ten metadata parameters and 38 data parameters and flags. The metadata parameters describe the station location and time at which the data were collected. The time of observation is reported both in Universal Time Coordinated (UTC) Nominal and UTC actual time. For the GCIP LSA-NW EAOP 1999 "Specials", the UTC Nominal and UTC actual times are identical. Days begin at UTC hour 0100 and end at UTC hour 0000 the following day. The data parameters are valid for the reported times. Missing values are reported as 9's in the data field. The table below details the data parameters in each record. Several data parameters have an associated Quality Control (QC) Flag Code. For a list of possible QC Flag values see the Quality Control Section 3.0. Parameters Units ---------- ----- Date of Observation UTC Nominal Time of Observation UTC Nominal Date of Observation UTC actual Time of Observation UTC actual 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, QC flag Hectopascals (mb) Reported Sea Level Pressure, QC flag Hectopascals (mb) Computed Sea Level Pressure, QC flag Hectopascals (mb) Dry Bulb Temperature, QC flag Celsius Dew Point, QC flag Celsius Wind Speed, QC flag m/s Wind Direction, QC flag Degrees Total Precipitation, QC flag mm Squall/Gust Indicator Code Value Squall/Gust Value, QC flag m/s Present Weather, QC flag Code Value Visibility, QC flag Meters Ceiling Height (first layer) Hundreds of feet Ceiling Flag (first layer), QC flag Code Value Cloud Amount (first layer), QC flag Code Value Ceiling Height (second layer) Hundreds of feet Ceiling Flag (second layer), QC flag Code Value Cloud Amount (second layer), QC flag Code Value Ceiling Height (third layer) Hundreds of feet Ceiling Flag (third layer), QC flag Code Value Cloud Amount (third layer), QC flag Code Value The list of code values for the Present Weather is too large to reproduce in this document. Refer to WMO, 1988 for a complete list of Present Weather codes. The code values for the Squall/Gust Indicator are: Code Definition ---- ---------- blank No Squall or Gust S Squall G Gust The code values for the Ceiling Flag Indicator are: Code Definition ---- ---------- 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 The code values for the Cloud Amount Indicator are: Code Definition ---- ---------- 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 no 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. 2.2 Data Remarks This dataset contains the GCIP LSA-NW EAOP 1999 Surface "Specials" observational data. The GCIP LSA-NW EAOP 1999 Wyoming RWIS Hourly Surface data contains only the "Nominal" hourly observations for the GCIP LSA-NW EAOP 1999 domain and time period. 3.0 Quality Control Processing These data were not quality controlled by UCAR/JOSS. See Table 3-1 for a list of the possible quality control flags and their meanings. Table 3-1 - Quality Control Flags QC Code Description ------- ----------- U Unchecked G Good M Normally recorded but missing. D Questionable B Unlikely N Not available or Not observed X Glitch E Estimated C Reported value exceeds output format field size or was negative precipitation. T Trace precipitation amount recorded I Derived parameter can not be computed due to insufficient data. 4.0 References Bolton, D., 1980: The computation of equivalent potential temperature., Mon. Wea. Rev., 108, pp 1046-1053. Wallace, J.M., P.V. Hobbs, 1977: Atmospheric Science, Academic Press, 467 pp. World Meteorological Organization (WMO), 1988: Manual on Codes Volume I, Part B - Binary Codes. WMO, Geneva, Switzerland.