Description of Indianapolis data.
(This is the file INDI_DOC.TXT from the package)
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Indianapolis Tracer Data and Meteorological Data Steven Hanna and Joseph Chang Earth Tech, 196 Baker Ave., Concord, MA 01742, USA tel: 508-371-4261 fax: 508-371-4280 e-mail: firstname.lastname@example.org Helge R. Olesen National Environmental Research Institute P.O. Box 358, DK-4000 Roskilde, Denmark Tel. +45 46 30 12 00, Fax. +45 46 30 11 14 E-mail: email@example.com May 1997 The original version of this document was written by Steve Hanna and Joe Chang. The present version has been slightly modified by H.R. Olesen, NERI. 1. Background This document briefly describes the Modeling Data Archive (MDA) for the Indianapo- lis field study. A full description of the field study is given by TRC (1986) and some results of analysis are given by Hanna and Chang (1991, 1993). The MDA represents a subset of the full data set, which includes many magnetic tapes full of lidar data and fast- response turbulence data. The MDA should be sufficient for modelers for evaluation exercises. The EPRI Indianapolis field study involved SF6 tracer releases from the 83.8 m stack (with diameter 4.72 m) at the Perry K power plant in Indianapolis, Indiana, USA. The geographic coordinates of this stack are UTM-N 4401.59 km (39.8ø latitude) and UTM-E 571.40 km (86.2ø longitude). The elevation of the plant is 214 m. 170 hours of tracer data are available from September and October, 1985, and represent all stability classes and most wind speed ranges. Data were taken in 8 or 9 hour blocks. There are a total of 19 such blocks in the Indianapolis dataset. Meteorological observations were taken from a 94 m height at the top of a building in the middle of the urban area, and from three 10 m towers in urban, suburban, and rural locations (at the urban site the measuring height for some variables was 11 m, however). Standard National Weather Source (NWS) observa- tions were available from the local airport. In addition, vertical profiles were taken by minisondes and acoustic sounders. Concentrations were observed on a network of about 160 ground-level monitors on arcs at distances ranging from 0.25 to 12.0 km from the stack. Vertical cross-sections of the plume were made by a lidar a few hundred meters downwind of the stack. The design of the field experiment was similar to earlier EPRI field experiments at the Kincaid and Bull Run power plants. The 83.8 m stack at the Perry K plant is located in a typical industrial/commer- cial/urban complex with many buildings within one or two kilometers of the stack. For example, the Hoosier Dome sports stadium is a few hundred meters to the east. Our analyses of the data and an independent wind tunnel study have suggested that the Hoosier Dome and the other buildings do not influence the plume, which tended to rise a hundred meters or more above the stack top most of the time. As a result, our modeling exercises have ignored the effects of nearby individual buildings. We specify a surface roughness length of 1 m in order to parameterize the overall effect of the buildings on the boundary layer. We also specify a "minimum Monin-Obukhov length, L" of 50 m during stable conditions for the urban area in order to account for the fact that the urban boundary layer does not stabilize significantly due to the mechanical mixing generated by the buildings and due to the anthropogenic heating in the urban area (Hanna and Chang, 1991). If other modelers would like to directly model the influence of the buildings or other aspects of the urban area, they can find the buildings' locations in the TRC (1986) report. The EPRI report "Urban Power Plant Plume Studies", EPRI EA-5468, contains the follo- wing description of the urban site: "The urban site was located at the northwest corner of Ohio and Senate Streets, adjacent to a State employees' parking lot. This area was surrounded by large buildings and received a heavy volume of traffic. The site was located approximately 1.5 km northeast of the Perry-K plant." 2. Observed Concentration Data Files for Each Monitoring Arc Hour Concentration data are summarized in the SF6_IND.DAT data file where a separate line of data is given for each monitoring arc for each hour. The hour notation refers to the one hour period ending at that time. Explanations of the data entries are given below: DIST (KM) The nominal downwind distance to the monitoring arc. Because it was not possible to site monitors exactly on the arc (buildings and traffic get in the way), the precise distance to a given monitor is likely to be somewhat different than the nominal distance. Twelve distance values are represented in SF6_IND.DAT: 0.25, 0.5, 0.75, 1.0, 1.5, 2, 3, 4, 6, 8, 10, 12 km. TOTAL SAMPLE The number of monitors represented at that arc distance for that hour. NONZERO SAMPLE The number of monitors that are recording nonzero concentrations at that arc distance for that hour. ARC MAX (PPT or nG/M3) The hourly-averaged concentration at the monitor that has the maximum value at that arc distance. Note PPT = volume parts per trillion, and 1 nG = 10-9 G. ARCMAX / Q The normalized arc-wise maximum in units of 10-9 s/m3. AZIMUTH TO MAX The azimuth angle in degrees to the monitor registering the ARCMAX (where 0ø represents a monitor due east of the stack and angles increase counterclockwise). CY (æG/M2) The cross-wind integrated concentration at that arc distance. It is calculated only if there are at least four monitors registering nonzero concentrations. The trapezoidal rule is used to perform the integration. Note 1 æG = 10-6 G. (There are 39 hours with a quality index of 3 which have missing values of CY; for these 39 hours the maximum arcwise concentration is reasonably well-defined, but there are only three monitors with non-zero concentrations.) SIGY (M) åy, or the standard deviation of the cross-wind concentration distribution at that arc distance. Like CY, it is calculated only if there are at least four monitors registering nonzero concentrations. The moment method and the trapezoidal rule are used to calculate åy. QUALITY INDEX A subjective numerical ranking of the quality of the data on that monitoring arc. This ranking was also applied to the Kincaid data distributed previously (in the Model Validation Kit) It has been determined by studying the ground level SF6 observation patterns during each hour and assigning a quality index ranging from 0 to 3 to each monitoring arc. Monitoring arcs are recommended to be used in the model evaluation exercises only if their quality indicator is 2 or 3. The definitions for the quality indicators are given below: Quality Indicator Definition 0 This observed maximum concentration should clearly be disregarded (examples: the plume obviously missed the monitors, the arc has only one or two monitors). 1 This observed maximum concentration is most probably not the maximum value (examples: there are large gaps in the monitoring arc, the observed maximum is isolated in time and space, the maxi- mum is on the edge of the arc). 2 An observed maximum concentration is identified, but the true value may be slightly different (examples: the concentration pattern is irregular, there is no smooth variation from one arc to the next, the maximum is near the edge of the arc). This category also includes arcs where a "true-zero" concentration is indicated, as suggested by dense coverage of monitors and maxima occurring at that azimuth angle on arcs further downwind. 3 A relatively well-defined maximum concentration is observed, which is continuous in space, is away from the edge of the monitoring arc, and is not irregular or isolated. 3. Full Concentration Data Files for all Monitors For each hour and monitoring arc, observed concentrations at each receptors are listed in files labeled TEST??.TAB, where ?? corresponds to experiment number ranging from 1 to 19, in chronological order. A number was assigned to each experiment day, which includes 8 or 9 continuous hours of observations. These files contain the observed concentrations and the distance and azimuth to the receptors. 4. Observed Meteorology Data Files for Each Hour Meteorological data for each of the 170 hours are included in the INDI.DAT (in data file which also includes some derived meteorological parameters and stack parameters. The file is structured so that the columns on the left (through "Perry-K Buoy. Flux") contain data used as input to our HPDM modeling work (Hanna and Chang, 1993), and the columns on the right (beginning with "Rural Wind Dir.") contain data that were not used by us but may be of interest to other modelers. A file with the same contents as INDI.DAT, but in Excel spreadsheet format, is also included (INDI.XLS). The UTM coordinates for the primary monitoring sites were as follows: Location East (km) North (km) Elevation (m) Bank Tower 572.15E 4402.00N 316.2 Urban 571.65E 4402.69N 222.5 Suburban 572.11E 4406.30N 225.0 Rural 564.50E 4401.44N 221.9 Perry K plant, ground 571.40E 4401.59N 214 (approx.) Several boundary layer parameters in the data file were derived using a surface energy balance method assuming a surface roughness of 1.0 m, an albedo of 0.18, a moisture availability of 0.5, and a minimum Monin-Obukhov length of 50 m (see Hanna and Chang, 1991). Explanations of the data entries are given below: YR Year (e.g., 85) MO Month DY Day JULDAY Julian Day HR The hour notation in the file refers to the one-hour period ending at that time. Values range from 1 to 24. The value is Eastern Standard Time, i.e. GMT minus 5 hours. N_TEST Number of test (1-19) SAISTA SAI Onsite Stab. Class is the so-called Pasquill-Gifford-Turner stability class as determined soon after the experiment by an EPRI contractor (SAI) from the urban wind speeds and the airport cloud cover data. ZI Urban Mixing Height (m) is based on our analysis of the urban minisonde profiles. It was found that urban and rural mixing depths showed little differences. WD94 WS94 Bank Wind Dir. (degrees) and Speed (m/s) are observed at the 94 m level at the top of the bank building. These data are used in HPDM to calculate plume rise, plume dilution, and plume trajectory. SWD94 Bank SIGWD (degrees) is åþ, the standard deviation of the wind direction fluctuation on the bank tower. When HPDM is run in "observed åþ" mode, this observation is used. WD11 WS11 T11 Urban Wind Dir. (degrees), Wind Speed (m/s), and Temp (K) are observed at a 11 m height and are used to calculate surface boundary layer parameters u*, H*, L, and w*. NNWS_ CEILNWS_ PNWS_ National Weather Service Cloud Cover (%), Cloud Height (m), and Pressure (mb) are observed at the NWS airport site and are used in our surface energy balance cal- culations. UST Param. Friction Velocity is u* (m/s), as calculated from observations at the 10 m urban tower and at the airport using surface energy balance considerations. L Param. M-L Length is the Monin-Obukhov length, L (m), as calculated from u* and H*. H_FLUX Param. Heat Flux is H* (w2/m2) as calculated from observations on the 10 m urban tower and at the airport using surface energy balance considerations. WST Param. Conv. Scaling Velocity is the convective scaling velocity, w* (m/s), as cal- culated from H* and the urban mixing height. Q Perry-K Emission Rate (g/s) is the SF6 mass emission rate from the 83.8 m stack. TQ Perry-K Exit Temp. (K) is the initial temperature, To, of the plume as it exits the stack. VSQ Perry-K Exit Vel. (m/s) is the initial velocity, wo, of the plume as it exits the stack. BUOY_Q Perry-K Buoy. Flux (m4/s3) is the initial buoyancy flux, Fo, of the plume. WDRUR WSRUR TRUR Rural Wind Dir. (degrees), Wind Speed (m/s), and Temp (K) are observed at the 10 m level on the rural tower. WDSUB WSSUB TSUB Suburban Wind Dir. (degrees), Wind Speed (m/s), and Temp (K) are observed at the 10 m level on the suburban tower. DIFURB NETURB DIRURB DIFRUR NETRUR DIRRUR Urban and Rural Diffusive Sky Rad., Net Rad., and Direct Solar Rad. (all in w/m2) are components of the radiation budget observed at the urban and rural sites. There are three "Turbulence groups" with 6 entries for each of three sites: an Urban (index 1), a Rural (index 2) and a Suburban (index 3). The six entries are: SIGFSTMP SIGFSTMP is åT the standard deviation (K) of temperature fluctuations. SIGFSTMP(1) is from the urban site, SIGFSTMP(2) from the rural site, and SIGFSTMP(3) from the suburban. SIGWD SIGWD is åþ (degrees) at a 10 m height observed by the cup anemometers. SIGWDSON SIGWDSON is åþ (degrees) observed by the sonic anemometers. UWSON UWSON is (in m2/s2, equal to -u*2) observed by the sonic anemometer. WTSON WTSON is (in K m/s, equal to H*/cþP) observed by the sonic anemometer. SIGWSON SIGWSON is åw (m/s) observed by the sonic anemometer. (end of "Turbulence groups") The NWS (National Weather Service) group of 4 entries represents observations from the In- dianapolis Airport: STANWS Stab. Class is the airport Pasquill-Gifford-Turner stability class. WSNWS_ TNWS_ WDNWS Wind Speed WSNWS_ (m/s) and Direction WDNWS_ (degrees) are observed at a 6.1 m height at the airport. TNWS_ (K) is NWS temperature. 5. Other Available Data The data files provided in this brief report should satisfy most modelers' needs. If anyone is interested in obtaining the very extensive raw data files from which the above tables were derived, or if they would like to analyze the many magnetic tapes full of lidar data, they should request these data from the authors. We operate the EPRI Atmospheric Sciences Data Center, which is responsible for archiving and distributing data from all EPRI atmospheric field experiments. In a case involving satisfying a request for the PERRY-K magnetic tapes or any other effort that would require more than a day of work, the requesting agency may have to negotiate a fee for the time and materials involved. 6. Points to be noted There are missing values for a number of variables. Details are listed in the file PAR_INDI.DAT. To most modellers, the missing values will not be any problem, except possibly for the case of September 29, where winds from the 94 m level are missing. Further, note that there is a mixing height of 0 m for several nighttime hours (Septem- ber 21, 28 and 29). Rawinsonde showed a ground-based inversion on the hours in question. References Hanna, S.R. and J.C. Chang, 1993: Hybrid Plume Dispersion Model (HPDM) improve- ments and testing at three field sites. Atmos. Environ., 27A, 1491-1508. Hanna, S.R. and J.C. Chang, 1991: Modification of HPDM for Urban Conditions and Its Evaluation using the Indianapolis Data Set. Final Report Prepared for EPRI by EARTH TECH, 196 Baker Ave., Concord, MA 10742. TRC, 1986: Urban power plant plume studies, EPRI Report EA-5468, EPRI, 3412 Hillview Ave, Palo Alto, Ca 94304.
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