GCIP LSA-NW EAOP 2000 NDARB Daily Precipitation Data in QC format 1.0 General Description The North Dakota Atmospheric Resource Board (NDARB) daily precipitation data in QC format is one of several precipitation datasets provided in the GEWEX Continental-Scale International Project (GCIP) Large Scale Area-North West (LSA-NW) Enhanced Annual Observing Period (EAOP) 2000. Data from this source was quality controlled. This dataset contains the available data for the GCIP LSA-NW EAOP-00 domain and time period (01 April 2000 through 31 March 2001). The GCIP LSA-NW EAOP-00 domain is approximately 90W to 115W longitude and 36N to 51N latitude. 2.0 Detailed Data Description NDARB Daily Precipitation Algorithms The NDARB rain gauges are all the same in each observer site. They are Tru-Chek "wedge type" rain gauges, which are issued from the NDARB office in Bismarck, ND. The only variable in siting is the individual siting of each gauge. NDARB relies on the volunteers to follow directions and site them properly. NDARB observers are asked take daily readings as near to 8AM as possible each day. The NDARB network only collects data from April through September each year. The algorithms used to compute the NDARB daily precipitation data are not currently available. 2.1 Detailed Format Description The NDARB GCIP LSA-NW EAOP-00 Daily Precipitation Data contains six metadata parameters and four data parameters. The metadata parameters describe the station location and time at which the data were collected. The four data parameters repeat once for each day in the monthly record. Every record has 31 days reported, regardless of the actual number of days in the month. For months with less than 31 days, the extra days are reported as missing (i.e., '-999.99 7 M'). Each 24 hour precipitation value has an associated observation hour. The observation hour is the ending UTC hour for the 24 hour period for which the precipitation value is valid. Data values are valid for the 24 hours preceding the observation hour given for the day. A Quality Flag and a Quality Control (QC) Code are assigned to each data value during quality control processing. For a list of possible Quality Flag and QC Code values see the Quality Control section 3.0. The table below details each parameter. Parameters Units ---------------------- ------------------------------------- Date of Observation UTC 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 Daily Precip Value millimeters Quality Flag See list of Definitions QC Code See list of Definitions Observation hour Beginning UTC hour for 24 hour period for which value is valid. 2.2 Data Remarks Negative precipitation and values too large to be represented in the output format were changed to missing ('-999.99') and were assigned the 'C' QC code. The NDARB network only records data from April through September. 3.0 Quality Control Processing Gross limit checks were used to determine the quality of the data in this dataset. Data values less than 101.6 millimeters (4 inches) were flagged as good. Any data value greater than or equal to 101.6 millimeters but less than 127 millimeters (5 inches) was flagged as questionable. Any data value greater than or equal to 127 millimeters was flagged as unlikely. UCAR/JOSS also checks the NDARB daily precipitation data for possible accumulated values and resets the UCAR/JOSS Quality Control flags for all "unchecked", "good", and "trace" accumulated precipitation values in the NDARB network to "questionable". For this purpose, UCAR/JOSS defines accumulated precipitation to be six identical, sequential daily precipitation values potentially followed by additional identical values or values that increase over time. Data were never modified, unless the precipitation value was negative or too large to be represented in the output format. In these cases the data value was flagged with a QC code of 'C' and changed to a missing value (i.e., '-999.99'). Table 1 and 2 list the quality control flags and codes plus their meanings. Table 1 Quality Control Flag Description --------------------------- --------------------------------------------- 0 No qualifier required 1 Accumulation period 2 End of Accumulation period 3 Deleted value. Original data was unreadable. 4 Trace of precipitation. 5 Probable amount as a result of melting frozen precipitation. 6 Suspect amount relative to time or period of occurrence. 7 Missing value Table 2 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 I Derived parameter can not be computed due to insufficient data. 4.0 References None.