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I URBAN 2000 Overview Summary of a presentation by Gerald Streit, DOE Los Alamos National Laboratory The URBAN 2000 tracer and meteorological experiments were conducted during October 2000, and they provide a unique set of nighttime atmospheric dispersion data covering transport scales from individual buildings on through the urban- to the regional-scale. The URBAN 2000 researchers collaborated closely with DOE's Environmental Meteorology Program by adding building-scale through urban-scale experiments (URBAN 2000) to their regional-scale Vertical Transport and Mixing Experiments (VTMX) in the greater Salt Lake City area. Meteorological measurement and tracer sampling instruments were installed throughout Salt Lake City and operated for most of the month of October 2000. Instruments were sited to resolve scales of motion ranging from flows around individual buildings in downtown Salt Lake City to flows throughout the urban area. The scale of the URBAN 2000 experiment was defined by an outermost 6 km arc of fixed sampler boxes and track for one of the plume-chasing vans. A five-block by five-block focus area was more heavily instrumented and the central experimental site was intensely instrumented during IOPs (Intensive Operations Period). The mobile van, gas chromatograph, IR, LLNL sonic anemometers, and all sampling instrumentation were deployed only during the IOPs. Further mention should be made of the six NOAA vans equipped with fast-response gas chromatographs for SF6 detection. Four of the vans did plume chasing during the IOPs roughly following 1, 2, 4, and 6 km arcs to the northwest of the release site. Two vans remained at fixed locations. During IOPs 2 and 4, Litton Industries deployed a van with a volume scanning Fourier transform infrared spectrometer. This was used relatively near the release site to map the vertical extent of the SF6 plume. For a little less than two weeks, from October 19 at 1800 MDT to October 27 at 1100 MDT, Coherent Technologies Incorporated deployed a wind-tracer doppler lidar at a site 4 km east of downtown and approximately 400 m higher than downtown. These dates covered IOPs 8-10. This unit mapped out the radial component of the wind in three dimensions over the city and up nearby canyons. Table I.1 gives detail about the shakedown IOP and six full-scale URBAN 2000 IOPs that were nested within the ten VTMX IOPs. Time-integrated tracer samples (nominally 5-minute to 2- hour integration times) were collected by 200 samplers located throughout the Salt Lake Basin. The sampling period extended from just before tracer release start (~2300 MDT) through the night until the next afternoon (~1300 MDT). The tracer samplers were distributed with the intent to resolve the various scales of motion being studied: 45 SF6 samplers were located around the 91
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APPENDIXI 93 downtown study buildings, 40 combined SF6/PFT (Perfluorocarbon Tracer) samplers and 24 SF6 samplers were located in a 5-block-square area (25 blocks) of downtown; 36 SF6 samplers were located on three sampling arcs (2, 4, and 6 ion) to the northwest of the downtown SF6 release location; and 55 PFT samplers were located throughout the Salt Lake Basin. A total of nearly 11,000 SF6 samples and 5,000 PET samples were collected during the tracer experiments. In addition to the 200 tracer samplers deployed during the combined VTMX/URBAN 2000 experi- ments, two SF6 analyzers were deployed by LLNL during the IOPs around the downtown study building. A summary of meteorological instrumentation deployed for URBAN 2000 follows: . Building scale (completely within the core block): 12 two-dimensional sonic anemometers (the five long-term locations included temperature measurements), 2 three- dimensional sonic anemometers, and 1 laser ceilometer; · Urban scale (a five-block by five-block square): 10 portable meterological stations, 3 two-dimensional sonic anemometers (1 station included temperature), 7 three-dimensional sonic anemometers, and 1 acoustic sodar; and · 1-6-lon scale: 6 wind stations, 2 acoustic sodars, 1 radar wind profiler, 54 temperature loggers, 1 Doppler lidar. The Pacific Northwest National Laboratory temperature loggers were sited on a north-to-south transect and on a west-to-east transect across Salt Lake City collecting 15-m~nute-average data for the month of October. They were located on 400 South from 1500 West to 1500 East, and on State from 1500 South to approximately 1500 North, so they crossed the urban- building-scale regimes. Some very early results for plume concentration measurements during IOP10 are shown in Plate 8. REFERENCE Allwine, K.J., J.H. Shinn, G.E. Streit, K.L. Clawson, and M.J. Brown. 2002. Overview of URBAN 2000: A multi-scale field study of dispersion through an urban environment. Bull. Amer. Meteor. Soc. 83:521- 536.