BOREAS HYD-09 Belfort Rain Gauge Data Summary This data set contains the measurements from the Belfort rain gauges at the BOREAS NSA andSSA. These measurements were submitted in 15-minute and 1-hour intervals. Only the 15-minute interval data set was loaded into the data base tables. Data were collected from the Belfort gauges from mid-April until mid- October in 1994, 1995, and 1996. The data are available as tabular ASCII files. Table of Contents * 1 Data Set Overview * 2 Investigator(s) * 3 Theory of Measurements * 4 Equipment * 5 Data Acquisition Methods * 6 Observations * 7 Data Description * 8 Data Organization * 9 Data Manipulations * 10 Errors * 11 Notes * 12 Application of the Data Set * 13 Future Modifications and Plans * 14 Software * 15 Data Access * 16 Output Products and Availability * 17 References * 18 Glossary of Terms * 19 List of Acronyms * 20 Document Information 1. Data Set Overview 1.1 Data Set Identification BOREAS HYD-09 Belfort Rain Gauge Data 1.2 Data Set Introduction This data set contains the measurements from the Belfort rain gauges at the BOReal Ecosystem-Atmosphere Study (BOREAS) Northern Study Area (NSA) and Southern Study Area (SSA). These measurements were submitted in 15-minute and 1-hour intervals. Only the 15-minute interval data set was loaded into the data base tables. 1.3 Objective/Purpose This investigation will seek to identify, through field measurements and computer modeling, the space-time distribution of meltwater supply to the soil during the spring melt period and the evolution of soil moisture, evaporation, and runoff from the end of the snowmelt period through freeze up. The snow modeling activity will consist of two components. The first phase will use existing "off- the-shelf" models to forecast the onset and spatial extent of snowmelt and meltwater supply to the soil column prior to the 1994 Intensive Field Campaigns (IFCs). The second phase will extend, implement, and verify a physically based energy balance snowmelt model of the two sites and will evaluate approaches to aggregating detailed snowmelt predictions and measurements based on the model to larger scales, up to the size of a rectangle of several hundred km containing the northern and southern sites. The soil moisture modeling is based on a grouped response unit method tat will allow characterization of soil moisture, evaporation, and runoff for the entire northern and southern sites. 1.4 Summary of Parameters The following phenomena and their parameters are being reported: Precipitation amount in a 15-minute period. 1.5 Discussion The locations for 12 tipping bucket measuring devices, 10 Belfort gauges, and 5 stream sites were selected within the two BOREAS study sites (NSA and SSA). These instruments were installed during the 1994 Focused Field Campaign-Thaw (FFC-T) in the last week of April. They were in operation until October 1994 when they were removed from service. The tipping buckets and Belfort gauges provided an approximate measure of the precipitation in the study areas and the discharge rates of the streams provided a measurement of water leaving the study area. When used together, these two sets of data provide a balance of the water cycle. Similar measurements were collected in 1995 and 1996 from approximately April to October of those years. 1.6 Related Data Sets BOREAS HYD-09 Tipping Bucket Rain Gauge Data BOREAS HYD-09 Stream Flow Data 2. Investigator(s) 2.1 Investigator(s) Name and Title Prof. Ric Soulis University of Waterloo Department of Civil Engineering 2.2 Title of Investigation From Micro-Scale to Meso-Scale Snowmelt, Soil Moisture and Evapotranspiration from Distributed Hydrologic Models 2.3 Contact Information Contact 1 ----------------------- Dr. Nicholas Kouwen Univ. of Waterloo Waterloo, ON (519) 885-1211 x3309 (519) 888-6197 kouwen@sunburn.uwaterloo.ca Contact 2 ----------------------- Dr. Ric Soulis Univ. of Waterloo Waterloo, ON (519) 885-1211 x2175 (519) 888-6197 ric@sunburn.uwaterloo.ca Contact 3 ------------------------ David Knapp NASA/GSFC Greenbelt, MD (301) 286-1424 David.Knapp@gsfc.nasa.gov 3. Theory of Measurements The Belfort gauges, used to measure precipitation, were 4 ft tall, had an orifice of 8 inches in diameter on top, and were supported in a stable, upright position on a wooden base at all of the sites. They are designed to find the vertical depth of water that would accumulate on a level surface if the precipitation remained where it fell. Precipitation falls through the 8-inch opening at the top of the apparatus and is funneled into a bucket near its center. This bucket is mounted on a gravimetric measuring device. Different weights are transmitted to the data logger as different voltages and recorded for later use. When the data are retrieved, the voltages must be converted to the corresponding volumes and precipitation using calibration coefficients. 4. Equipment 4.1 Sensor/Instrument Description Belfort Gauge: A Belfort gauge is a device used to measure the amount of precipitation in a given area. When rain falls, it is collected in a bucket and weighed. When the weight of the water is calculated and compared to the calibration coefficient, the amount of rainfall can be calculated. The data logger stores this information at regular intervals until it can be retrieved. The Belfort gauges used were originally equipped with chart recorders. They were converted to electronic recorders before they were installed using the linear potentiometer so that data could be recorded at 15-minute intervals. Linear Potentiometer: The LP-XXFP linear potentiometer is a device designed to measure differences in resistance. The resistance is varied by a movable shaft. When the shaft is moved by the different weights of the collecting bucket, the resistance is changed, resulting in different voltages. The volume of water can then be calculated. Data Logger: The chart pac CP-X data logger was connected to the Belfort gauge so that it could record water levels every 15 minutes. The data logger stored the information in its memory until it was retrieved. 4.1.1 Collection Environment The equipment was operated in variable ambient atmospheric conditions at the field sites in Saskatchewan and Manitoba during 1994. 4.1.2 Source/Platform The Belfort gauge was mounted on a wide wooden base placed on the ground. The linear potentiometer was mounted inside the Belfort gauge housing. The data logger was mounted inside the Belfort gauge housing. 4.1.3 Source/Platform Mission Objectives In order to make a detailed estimate of the total amount of precipitation, sufficient precipitation data must be collected to account for all peak periods of precipitation and any variations that occur over time. To achieve this, the data were recorded at regular intervals of 15 minutes. The data logger stored the information until it was retrieved. Tipping bucket and Belfort gauges were used to provide independent measures of precipitation so that the error would be reduced. 4.1.4 Key Variables Belfort Gauge - Precipitation amount in a 15-minute period Linear Potentiometer - Voltage Data Logger - Voltage 4.1.5 Principles of Operation The Belfort gauge is a self-contained device designed to measure the amount of precipitation occurring in a given area over time. It is only an estimate of the total rainfall in an area. The amount of water is measured by weighing a bucket filled with rainwater and converting the weight to millimeters of rainfall using a calibration coefficient. 4.1.6 Sensor/Instrument Measurement Geometry The Belfort gauge is mounted at ground level. It must be in a clearing large enough so that a 45-degree inverted cone originating from its highest point can reach the atmosphere unimpeded. If trees or other obstructions are surrounding the Belfort gauge, they will affect the data. The device should be mounted on a stable base (example: a wooden platform) and leveled so that the opening is completely vertical (i.e., axis of gauge is perpendicular to a water level). 4.1.7 Manufacturer of Sensor/Instrument Belfort Gauge Belfort Instrument Company 727 S. Wolfe Street Baltimore, MD, 21231 U.S.A. Linear Potentiometer MIDORI America Corporation Corona CA, U.S.A. Data Logger - Lakewood Systems Edmonton, Alberta, Canada (403) 462-9211 4.2 Calibration A Belfort gauge is calibrated by pouring a known amount of water into the orifice at the top of the gauge or adding the calibration weights equivalent to known quantities of water and comparing this with the weight that the gauge registers. This will allow for the calculation of the millimeters of precipitation per milligram of weight. It is possible to find the volume of water associated with a certain mass by using the specific density of water at that temperature. The volume of water can then be compared to the specification sheet and a calibration coefficient calculated. 4.2.1 Specifications Belfort Gauge - orifice opening: 8 inches bucket size: 12 quarts orifice height above ground: 4 ft Linear Potentiometer - linearity: +/- 1% friction: 40-g maximum operating temperatures: -25°C to 80°C 4.2.1.1 Tolerance A Belfort gauge can measure volumes of water from 0 to 12 quarts (the volume of the bucket). The gauge can measure precipitation in 0.01-inch increments. 4.2.2 Frequency of Calibration The Belfort gauges were calibrated once at the beginning, the middle, and the end of the study period. 4.2.3 Other Calibration Information Not applicable. 5. Data Acquisition Methods A data logger recorded the precipitation data for the Belfort gauges. The data logger was connected to a notebook computer onsite, where the logger's stored information was transferred to the notebook. 6. Observations 6.1 Data Notes The following table describes the problems with the Belfort gauges. Year Date Event Belfort 1 1994 10-Apr Bel1 installed at Hwy 913 & 120 53° 51' 39"N 105° 56' 27"W approx. 05-May Bel1 moved to White Gull Drain 11-May Gauge reset at 11:00 21-Jul Gauge knocked over 24-Jul Lid knocked off 16-Oct Bel1 removed 1995 26-Apr Bel1 installed 17-Jun - 06-Jul Missing data - mechanical problems 07-Nov Bel1 removed 1996 05-Jun Bel1 installed 06-Nov Bel1 removed Belfort 2 1994 10-Apr Bel2 installed 01-Jun Gauge knocked over 13-Jun Lid knocked off, affecting all subsequent readings; readings adjusted by using the ratio of the diameter of the gauge opening to the diameter of the bucket 17-Oct Bel2 removed 1995 12-Apr Bel2 installed 12-Apr - 26-Apr Precip recordings by TB5 30-Aug Water level lowered - Belfort gauge hit maximum water level 08-Nov Bel2 removed 1996 15-Apr Bel2 installed 06-Nov Bel2 removed Belfort 3 1994 11-Apr Bel3 installed 28-Jun Lid knocked off gauge 21-Jul - 28-Jul Missing data 14-Oct Gauge damaged by bear 17-Oct Bel3 removed 1995 27-Apr Bel3 installed 07-Nov Bel3 removed 1996 05-Jun Bel3 installed 24-Jul - 11-Sep Missing data 05-Nov Bel3 removed Belfort 4 - Tipping Bucket 9 Note: Was replaced with TB9 for 1995 and 1996 1994 21-Apr Bel4 installed 13-Jun Lid knocked off 17-Oct Bel4 removed 1995 Installed as TB9 - see Tipping Bucket information 1996 Installed as TB9 - see Tipping Bucket information Belfort 5 1994 12-Apr Bel5 installed 04-May - 09-May Gauge knocked over during this period, data unreliable 16-May Gauge knocked over during windstorm 17-May Gauge reset 16-Oct Bel5 removed 1995 11-Apr Bel5 installed 07-Nov Bel5 removed 1996 23-Aug Bel5 installed 06-Nov Bel5 removed Belfort 21 - Tipping Bucket 26 Note: Was replaced with TB26 for 1995 and 1996 1994 11-May Bel21 installed 12-May Logger changed to double precision 11-Jul - 12-Jul Gauge knocked over, repaired and reset; missing data 04-Oct Bel21 removed 1995 Installed as TB26 - see Tipping Bucket information 1996 Installed as TB26 - see Tipping Bucket information Belfort 22 - Tipping Bucket 28 Note: Was replaced with TB28 for 1995 and 1996 1994 29-Apr Bel22 installed 09-Jul Changed logger number to 30 from 28 13-Oct Bel22 removed 1995 Installed as TB28 - see Tipping Bucket information 1996 Installed as TB28 - see Tipping Bucket information Belfort 23 - Tipping Bucket 27 Note: Was replaced with TB27 for 1995 and 1996 1994 28-Apr Bel23 installed 30-Jul Gauge knocked over 02-Aug Gauge repaired 13-Oct Bel23 removed 1995 Installed as TB27 - see Tipping Bucket information 1996 Installed as TB27 - see Tipping Bucket information Tipping Bucket 21 - Belfort 24 Note: Was TB21 in 1994 replaced with Bel24 in 1995 and 1996 1994 Installed as TB21 - see Tipping Bucket information 1995 23-Apr Bel24 installed 10-Nov Bel24 removed 1996 13-Apr Bel24 installed 04-Jul - 02-aug Missing data 06-Nov Bel24 removed Tipping Bucket 24 - Belfort 25 Note: Was TB24 in 1994 replaced with Bel25 in 1995 and 1996 1994 Installed as TB24 - see Tipping Bucket information 1995 23-Apr Bel25 installed 10-Nov Bel25 removed 1996 13-Apr Bel25 installed 06-Nov Bel25 removed Belfort at NW2 1994 25-Apr Bel NW2 installed 14-Oct Bel NW2 removed 1995 22-Apr Bel NW2 installed 03-Nov Missing data 09-Nov Bel NW2 removed 1996 13-Apr Bel NW2 installed 23-Oct Bel NW2 removed Belfort at NW3 1994 25-Apr Bel NW3 installed 14-Oct Bel NW3 removed 1995 23-Apr Bel NW3 installed 09-Nov Bel NW3 removed 1996 13-Apr Bel NW3 installed 09-Jun Bel NW3 moved downstream and renamed NW3A 24-Oct Bel NW3A removed 6.2 Field Notes None given. 7. Data Description 7.1 Spatial Characteristics Ten Belfort gauges were set up in and around the boundaries of the water basins that were being studied. They gave an estimation of the precipitation within these boundaries. Each Belfort gauge was a point measurement of the precipitation. From these point measurements, the average precipitation for the study basins could be estimated. 7.1.1 Spatial Coverage Each Belfort gauge is a point measurement of the precipitation, making their total area of coverage very small. Together they represent the total rainfall in the area. The size of both northern water basins being studied is 27 km2, while the size of the southern water basin is 574 km2. The following table lists the Belfort gauges used and their locations. These coordinates are in the North American Datum 1983 (NAD83). In some cases, gauges were moved during the measurement campaigns. If the change in location was significant, the new location was given a new site identifier. Information regarding changes in location and servicing of the sites is listed in Section 11.2. SITE_ID LONGITUDE LATITUDE -------------------- ---------- ---------- NSA-B21-HYD09-BLRG21 98.41114W 55.88857N NSA-B22-HYD09-BLRG22 98.49892W 55.77653N NSA-B23-HYD09-BLRG23 98.55822W 55.89147N NSA-B24-HYD09-BLRG24 98.34275W 55.91236N NSA-B25-HYD09-BLRG25 98.566W 55.92661N NSA-BN2-HYD09-BLRGN2 98.52806W 55.91528N NSA-BN3-HYD09-BLRGN3 98.37603W 55.91686N SSA-BL1-HYD09-BLRG01 105.01149W 53.89156N (moved slightly 05-May-1994) SSA-BL2-HYD09-BLRG02 105.03775W 54.08506N SSA-BL3-HYD09-BLRG03 104.76263W 54.08551N SSA-BL4-HYD09-BLRG04 104.89617W 54.0047N SSA-BL5-HYD09-BLRG05 104.82002W 53.92625N 7.1.2 Spatial Coverage Map Not available. 7.1.3 Spatial Resolution The resolution of the resultant data is low because the data were gathered as point measurements. They are meant only to give the average precipitation rates at 15-minute intervals for the study basins. 7.1.4 Projection Not applicable. 7.1.5 Grid Description Not applicable. 7.2 Temporal Characteristics 7.2.1 Temporal Coverage Data were collected from the Belfort gauges from mid-April until mid-October in 1994, 1995, and 1996. 7.2.2 Temporal Coverage Map Not available. 7.2.3 Temporal Resolution Measurements were recorded by the Belfort gauges at 15-minute intervals. 7.3 Data Characteristics Data characteristics are defined in the companion data definition file (h9rgbl94.def). 7.4 Sample Data Record Sample data format shown in the companion data definition file (h9rgbl94.def). 8. Data Organization 8.1 Data Granularity All of the Belfort Rain Gauge Data are available by the year. 8.2 Data Format(s) The data files contain numerical and character fields of varying length separated by commas. The character fields are enclosed with a single apostrophe marks. There are no spaces between the fields. Sample data records are shown in the companion data definition files (h9rgbl94.def). 9. Data Manipulations 9.1 Formulae After a Belfort gauge was calibrated, the amount of precipitation per measuring period was found by using: Total precipitation = weight of accumulated water * equivalent precipitation per milligram of weight i.e., 4.5 mm = 45 milligrams * 0.1 mm of rain per milligram 9.1.1 Derivation Techniques and Algorithms At regular intervals during the monitoring period, the accumulated weight of water in the bucket was recorded on a data logger. The weight was converted first to a volume of water and then to precipitation using the calibration coefficient. If the Belfort gauge was reset (bucket was emptied and data logger started to record from zero again), then the data were adjusted accordingly. Temperature fluctuations caused some variation in the collected data. An algorithm was run on the data to correct for this error. 9.2 Data Processing Sequence 9.2.1 Processing Steps The following steps were performed to collect the data: 1) Set up necessary equipment. 2) Measure the accumulated weight of water over time. 3) Calculate the cumulative precipitation amounts using the coefficient. 4) Convert cumulative amounts to incremental amounts and write ASCII files with the appropriate identifying information noted beside each row (location, year, day, month). 5) Add the necessary column headings. 6) Transfer the information to the data base. BOREAS Information System (BORIS) Staff processed the data by: 1) Reviewing the initial data files and loading them online for BOREAS team access. 2) Designing relational data base tables to inventory and store the data. 3) Loading the data into the relational data base tables. 4) Working with the Hydrology (HYD-09) team to document the data set. 5) Extracting the standardized data into logical files. 9.2.2 Processing Changes None. 9.3 Calculations 9.3.1 Special Corrections/Adjustments None. 9.3.2 Calculated Variables None. 9.4 Graphs and Plots See associated report file HYD9REP.DOC. 10. Errors 10.1 Sources of Error Most of the errors occur during the actual measuring of the precipitation. Some of the smaller sources of error occur from water splashing out of the funnel, evaporating water that cannot be measured, water used to initially wet the gauge's funnel and inside surfaces, and gauges that are not perfectly level. A larger source of error is the wind which can cause turbulent air flow around the gauge, creating updrafts and downdrafts that interfere with the normal path of precipitation. A high wind speed will create compressed lines of flow, reducing the amount of precipitation that enters the gauge. The higher the wind speed, the greater the effect on the measured precipitation. If the collecting rim (opening to the outside) is damaged in any way, the amount of precipitation being measured will be changed because less water can enter the gauge than it was calibrated for. 10.2 Quality Assessment 10.2.1 Data Validation by Source The effects of the wind were reduced considerably by placing the gauges in clearings surrounded by forest which shielded the gauge from oncoming winds. Evaporation was reduced through the use of a thin film of oil placed in the bucket. After the information was collected, it was run through an algorithm to detect any data that were abnormal when compared to the rest of the data. Computer programs were also used to adjust the gauges for periods when they had missing lids. There may be anomalies in the data that could not be resolved at the time this data was published. Please consult the data notes (Section 6.1) for information that might give some indication about the source of any anomalies. 10.2.2 Confidence Level/Accuracy Judgment The confidence level of the data varies with the particular Belfort gauge at the time of measurement. 10.2.3 Measurement Error for Parameters The collected data will eventually be compared to radar data and the calibration measurements, but at this time no steps have been taken to carry this out. 10.2.4 Additional Quality Assessments None. 10.2.5 Data Verification by Data Center Data that were loaded into the data tables were spot checked against the original ASCII data that were submitted to check for data loading errors. 11. Notes 11.1 Limitations of the Data None given. 11.2 Known Problems with the Data See Section 6.1 11.3 Usage Guidance Because of the problems that occurred, some periods of precipitation are not accurate. During the study period, the temperature was changing which affected the observations of the measuring equipment. Although this was corrected with an algorithm, the data were not as accurate those obtained from a float tube at a constant temperature. 11.4 Other Relevant Information HYD-09 wrote a report that is available through its Web page. See Section 9.4 for details. Kouwen, N., R. Soulis, W. Jenkinson, A. Graham and T. Neff. 1997. BOREAS: Boreal Forest Hydrological Research Study. Hydrology 9 Group: From Micro-scale to meso-scale snowmelt, soil moisture and evapotranspiration from distributed hydrological models, University of Waterloo, Dept. of Civil Engineering, August 1997. 12. Application of the Data Set None given. 13. Future Modifications and Plans None. 14. Software Several computer programs are required to convert the data logger information into precipitation and to check it for quality. 14.1 Software Description None given. 14.2 Software Access None given. 15. Data Access 15.1 Contact Information Ms. Beth Nelson BOREASData Manager NASA/GSFC Greenbelt, Maryland (301) 286-4005 (301) 286-0239 (fax) beth@ltpmail.gsfc.nasa.gov 15.2 Data Center Identification See Section 15.1. 15.3 Procedures for Obtaining Data Users may place requests by telephone, electronic mail, or fax. 15.4 Data Center Status/Plans The HYD-09 Belfort rain gauge data are available from the Earth Observing System Data and Information System (EODIS) Oak Ridge National Laboratory (ORNL) Distributed Active Archive Center (DAAC). The BOREAS contact at ORNL is: ORNL DAAC User Services Oak Ridge National Laboratory Oak Ridge, TN (423) 241-3952 ornldaac@ornl.gov ornl@eos.nasa.gov 16. Output Products and Availability 16.1 Tape Products None. 16.2 Film Products None. 16.3 Other Products The data and documentation are available as ASCII files. 17. References 17.1 Platform/Sensor/Instrument/Data Processing Documentation Belfort Instrument Company. Instruction Manual Catalog Number 5-780 Series Universal Recording Rain Gauge. 1986. Hoskin Scientific Limited. 1992. Chart Pac Cp-X (price and specification sheet). Kouwen, N., R. Soulis, W. Jenkinson, A. Graham and T. Neff. 1997. BOREAS: Boreal Forest Hydrological Research Study. Hydrology 9 Group: From Micro-scale to meso-scale snowmelt, soil moisture and evapotranspiration from distributed hydrological models, University of Waterloo, Dept. of Civil Engineering, August 1997. MIDORI America Corporation, Corona, CA. Specification Diagram for Model LP-XXFP Linear Potentiometer. 17.2 Journal Articles and Study Reports Sellers, P. and F. Hall. 1994. Boreal Ecosystem-Atmosphere Study: Experiment Plan. Version 1994-3.0, NASA BOREAS Report (EXPLAN 94). Sellers, P. and F. Hall. 1996. Boreal Ecosystem-Atmosphere Study: Experiment Plan. Version 1996-2.0, NASA BOREAS Report (EXPLAN 96). Sellers, P. and F. Hall. 1997. BOREAS Overview Paper. JGR Special Issue (in press). Sellers, P., F. Hall, and K.F. Huemmrich. 1996. Boreal Ecosystem-Atmosphere Study: 1994 Operations. NASA BOREAS Report (OPS DOC 94). Sellers, P., F. Hall, and K.F. Huemmrich. 1997. Boreal Ecosystem-Atmosphere Study: 1996 Operations. NASA BOREAS Report (OPS DOC 96). Sellers, P., F. Hall, H. Margolis, B. Kelly, D. Baldocchi, G. den Hartog, J. Cihlar, M.G. Ryan, B. Goodison, P. Crill, K.J. Ranson, D. Lettenmaier, and D.E. Wickland. 1995. The boreal ecosystem-atmosphere study (BOREAS): an overview and early results from the 1994 field year. Bulletin of the American Meteorological Society. 76(9):1549-1577. 17.3 Archive/DBMS Usage Documentation None. 18. Glossary of Terms None. 19. List of Acronyms AES - Atmospheric Environment Service of Canada ASCII - American Standard Code for Information Interchange BEL - Belfort Gauge BOREAS - BOReal Ecosystem-Atmosphere Study BORIS - BOREAS Information System CD-ROM - Compact Disk (optical), Read-Only Memory DAAC - Distributed Active Archive Center EOS - Earth Observing System EOSDIS - EOS Data and Information System FFC-T - Focused Field Campaign - Thaw GMT - Greenwich Mean Time GSFC - Goddard Space Flight Center HYD - Hydrology IFC - Intense Field Campaign ml - milliliters mm - millimeters NAD83 - North American Datum 1983 NASA - National Aeronautics and Space Administration NSA - Northern Study Area ORNL - Oak Ridge National Laboratory PANP - Prince Albert National Park SSA - Southern Study Area TB - Tipping Bucket URL - Uniform Resource Locator 20. Document Information 20.1 Document Revision Dates Written: 02-Dec-1996 Last Updated: 26-Feb-1998 20.2 Document Review Dates BORIS Review: 12-Sep-1997 Science Review: 01-Oct-1997 20.3 Document ID 20.4 Citation The efforts of Ric Soulis and Nick Kouwen from the University of Waterloo in collecting these data and making them available as well as the efforts of BORIS staff in processing the data are greatly appreciated. 20.5 Document Curator 20.6 Document URL Keywords ------------- RAINFALL HYD09_BELF_RG.doc Page 16 of 16 04/17/98