scholarly journals The magnitude of the snow-sourced reactive nitrogen flux to the boundary layer in the Uintah Basin, Utah, USA

2016 ◽  
Vol 16 (21) ◽  
pp. 13837-13851 ◽  
Author(s):  
Maria Zatko ◽  
Joseph Erbland ◽  
Joel Savarino ◽  
Lei Geng ◽  
Lauren Easley ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Optical Properties ◽  
Oil And Gas ◽  
Nitrogen Isotopes ◽  
Ground Level ◽  
Anthropogenic Sources ◽  
Reactive Nitrogen ◽  
Actinic Flux ◽  
Nitrogen Fluxes ◽  
Uintah Basin

Abstract. Reactive nitrogen (Nr  =  NO, NO2, HONO) and volatile organic carbon emissions from oil and gas extraction activities play a major role in wintertime ground-level ozone exceedance events of up to 140 ppb in the Uintah Basin in eastern Utah. Such events occur only when the ground is snow covered, due to the impacts of snow on the stability and depth of the boundary layer and ultraviolet actinic flux at the surface. Recycling of reactive nitrogen from the photolysis of snow nitrate has been observed in polar and mid-latitude snow, but snow-sourced reactive nitrogen fluxes in mid-latitude regions have not yet been quantified in the field. Here we present vertical profiles of snow nitrate concentration and nitrogen isotopes (δ15N) collected during the Uintah Basin Winter Ozone Study 2014 (UBWOS 2014), along with observations of insoluble light-absorbing impurities, radiation equivalent mean ice grain radii, and snow density that determine snow optical properties. We use the snow optical properties and nitrate concentrations to calculate ultraviolet actinic flux in snow and the production of Nr from the photolysis of snow nitrate. The observed δ15N(NO3−) is used to constrain modeled fractional loss of snow nitrate in a snow chemistry column model, and thus the source of Nr to the overlying boundary layer. Snow-surface δ15N(NO3−) measurements range from −5 to 10 ‰ and suggest that the local nitrate burden in the Uintah Basin is dominated by primary emissions from anthropogenic sources, except during fresh snowfall events, where remote NOx sources from beyond the basin are dominant. Modeled daily averaged snow-sourced Nr fluxes range from 5.6 to 71  ×  107 molec cm−2 s−1 over the course of the field campaign, with a maximum noontime value of 3.1  ×  109 molec cm−2 s−1. The top-down emission estimate of primary, anthropogenic NOx in Uintah and Duchesne counties is at least 300 times higher than the estimated snow NOx emissions presented in this study. Our results suggest that snow-sourced reactive nitrogen fluxes are minor contributors to the Nr boundary layer budget in the highly polluted Uintah Basin boundary layer during winter 2014.

scholarly journals The magnitude of the snow-sourced reactive nitrogen flux to the boundary layer in the Uintah Basin, Utah, USA

2016 ◽  
Author(s):  
Maria Zatko ◽  
Joseph Erbland ◽  
Joel Savarino ◽  
Lei Geng ◽  
Lauren Easley ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Optical Properties ◽  
Oil And Gas ◽  
Nitrogen Isotopes ◽  
Ground Level ◽  
Anthropogenic Sources ◽  
Reactive Nitrogen ◽  
Actinic Flux ◽  
Nitrogen Fluxes ◽  
Uintah Basin

Abstract. Reactive nitrogen (Nr = NO, NO2, HONO) and volatile organic carbon emissions from oil and gas extraction activities play a major role in wintertime ground-level ozone exceedance events of up to 140 ppb in the Uintah Basin in eastern Utah. Such events occur only when the ground is snow covered, due to the impacts of snow on the stability and depth of the boundary layer and ultraviolet actinic flux at the surface. Recycling of reactive nitrogen from the photolysis of snow nitrate has been observed in polar and mid-latitude snow, but snow-sourced reactive nitrogen fluxes in mid-latitude regions have not yet been quantified in the field. Here we present vertical profiles of snow nitrate concentration and nitrogen isotopes (δ15N) collected during the Uintah Basin Winter Ozone Study 2014 (UBWOS 2014), along with observations of insoluble light-absorbing impurities, radiation equivalent mean ice grain radii, and snow density that determine snow optical properties. We use the snow optical properties and nitrate concentrations to calculate ultraviolet actinic flux in snow and the production of Nr from the photolysis of snow nitrate. The observed δ15N(NO3−) is used to constrain modeled fractional loss of snow nitrate in a snow chemistry column model, and thus the source of snow-sourced Nr to the overlying boundary layer. Snow-surface δ15N(NO3−) measurements range from −5 ‰ to 10 ‰ and suggest that the local nitrate burden in the Uintah Basin is dominated by primary emissions from anthropogenic sources, except during fresh snowfall events, where remote NOx sources from beyond the basin are dominant. Modeled daily-averaged snow-sourced Nr fluxes range from 5.6−71 × 107 molec cm−2 s−1 over the course of the field campaign, with a maximum noon-time value of 3.1 × 109 molec cm−2 s−1. The top-down emission estimate of primary, anthropogenic NOx in the Uintah and Duchesne counties is at least 300 times higher than the estimated snow NOx emissions presented in this study. Our results suggest that snow-sourced reactive nitrogen fluxes are minor contributors to the Nr boundary layer budget in the highly-polluted Uintah Basin boundary layer during winter 2014.

Aerosol composition and related optical properties in the marine boundary layer over the Baltic Sea

2001 ◽  
Vol 32 (8) ◽  
pp. 933-955 ◽  
Author(s):  
J Kuśmierczyk-Michulec ◽  
M Schulz ◽  
S Ruellan ◽  
O Krüger ◽  
E Plate ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Optical Properties ◽  
Baltic Sea ◽  
Marine Boundary Layer ◽  
The Baltic Sea ◽  
Aerosol Composition ◽  
The Baltic

scholarly journals Entrainment and Mixing of Transported Ozone Layers: Implications for Surface Air Quality in the Western U.S.

2020 ◽  
Vol 237 ◽  
pp. 03012
Author(s):  
Christoph Senff ◽  
Andrew Langford ◽  
Raul Alvarez ◽  
Tim Bonin ◽  
Alan Brewer ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Air Quality ◽  
Mixed Layer ◽  
Las Vegas ◽  
Surface Ozone ◽  
Ground Level ◽  
San Joaquin Valley ◽  
Fire Emissions ◽  
Ozone Transport ◽  
The Impact

Recently, two air quality campaigns were conducted in the southwestern United States to study the impact of transported ozone, stratospheric intrusions, and fire emissions on ground-level ozone concentrations. The California Baseline Ozone Transport Study (CABOTS) took place in May – August 2016 covering the central California coast and San Joaquin Valley, and the Fires, Asian, and Stratospheric Transport Las Vegas Ozone Study (FAST-LVOS) was conducted in the greater Las Vegas, Nevada area in May – June 2017. During these studies, nearly 1000 hours of ozone and aerosol profile data were collected with the NOAA TOPAZ lidar. A Doppler wind lidar and a radar wind profiler provided continuous observations of atmospheric turbulence, horizontal winds, and mixed layer height. These measurements allowed us to directly observe the degree to which ozone transport layers aloft were entrained into the boundary layer and to quantify the resulting impact on surface ozone levels. Mixed layer heights in the San Joaquin Valley during CABOTS were generally below 1 km above ground level (AGL), while boundary layer heights in Las Vegas during FAST-LVOS routinely exceeded 3 km AGL and occasionally reached up to 4.5 km AGL. Consequently, boundary layer entrainment was more often observed during FAST-LVOS, while most elevated ozone layers passed untapped over the San Joaquin Valley during CABOTS.

scholarly journals Augmented Reality for Pipe Thread Connection Type Training

2021 ◽  
Vol 5 (1) ◽  
pp. 17-28
Author(s):  
Ravi Wiyantoko ◽  
Ahmad Hamim Thohari ◽  
Muhammad Dzuhri Maarief
Keyword(s):  
Augmented Reality ◽  
Oil And Gas ◽  
3D Visualization ◽  
Ground Level ◽  
Application Development ◽  
Thread Connection ◽  
Steel Pipes ◽  
Multimedia Development ◽  
Pipe Joints ◽  
Connection Type

The process of extracting oil and gas is carried out by drilling with a depth of more than 200 meters below the surface of the ground, so one steel pipe is needed to run the process. The manufacture of steel pipes for the opening process has special standards, one of which is a long pipe. To reach a depth of 200 meters below the ground level, a pipe connection is needed to reach that height. The method of connecting the pipes is called the Thread Connection Type. This method has more than 20 types of threads to be applied in pipe joints. To facilitate the discussion of the types of threads and their specifications, we need a technology that can be used interactive and mobile learning media to deliver detailed information on the type of thread. The author uses the use of Augmented Reality (AR) technology to be applied as an Android-based training media that can facilitate the existing Connection Thread along with special specifications with 3D visualization. This study aims to measure the validity and practicality of using ISO 25010 (in terms of functional suitability, performance efficiency, portability and usability) of learning media so that it is easier to understand and practical. The study consisted of two parts: 1) Validity by experts (5 experts), 2) Practicality by trainees or employees (16 participants) using the USE Questionnaire instrument. Furthermore, in application development using the Multimedia Development Life Cycle (MDLC) method as its development method. As a result, the application was declared feasible with the results of the percentage of experts Validity of 96% and Practicality by employees of 79%.

scholarly journals Simulations of a cold-air pool associated with elevated wintertime ozone in the Uintah Basin, Utah

2014 ◽  
Vol 14 (11) ◽  
pp. 15953-16000 ◽  
Author(s):  
E. M. Neemann ◽  
E. T. Crosman ◽  
J. D. Horel ◽  
L. Avey
Keyword(s):  
Boundary Layer ◽  
Snow Cover ◽  
Layer Structure ◽  
Inversion Layer ◽  
Cloud Microphysics ◽  
Photochemical Reactions ◽  
Near Surface ◽  
Cold Air ◽  
Air Temperatures ◽  
Uintah Basin

Abstract. Numerical simulations are used to investigate the meteorological characteristics of the 1–6 February 2013 cold-air pool in the Uintah Basin, Utah, and the resulting high ozone concentrations. Flow features affecting cold-air pools and air quality in the Uintah Basin are studied, including: penetration of clean air into the basin from across the surrounding mountains, elevated easterlies within the inversion layer, and thermally-driven slope and valley flows. The sensitivity of the boundary layer structure to cloud microphysics and snow cover variations are also examined. Ice-dominant clouds enhance cold-air pool strength compared to liquid-dominant clouds by increasing nocturnal cooling and decreasing longwave cloud forcing. Snow cover increases boundary layer stability by enhancing the surface albedo, reducing the absorbed solar insolation at the surface, and lowering near-surface air temperatures. Snow cover also increases ozone levels by enhancing solar radiation available for photochemical reactions.

scholarly journals Observation of sensible and latent heat flux profiles with lidar

2020 ◽  
Vol 13 (6) ◽  
pp. 3221-3233 ◽  
Author(s):  
Andreas Behrendt ◽  
Volker Wulfmeyer ◽  
Christoph Senff ◽  
Shravan Kumar Muppa ◽  
Florian Späth ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Heat Flux ◽  
Latent Heat ◽  
Latent Heat Flux ◽  
Sensible Heat Flux ◽  
Ground Level ◽  
Sensible Heat ◽  
Flux Divergence ◽  
Convective Boundary ◽  
The Mean

Abstract. We present the first measurement of the sensible heat flux (H) profile in the convective boundary layer (CBL) derived from the covariance of collocated vertical-pointing temperature rotational Raman lidar and Doppler wind lidar measurements. The uncertainties of the H measurements due to instrumental noise and limited sampling are also derived and discussed. Simultaneous measurements of the latent heat flux profile (L) and other turbulent variables were obtained with the combination of water-vapor differential absorption lidar (WVDIAL) and Doppler lidar. The case study uses a measurement example from the HOPE (HD(CP)2 Observational Prototype Experiment) campaign, which took place in western Germany in 2013 and presents a cloud-free well-developed quasi-stationary CBL. The mean boundary layer height zi was at 1230 m above ground level. The results show – as expected – positive values of H in the middle of the CBL. A maximum of (182±32) W m−2, with the second number for the noise uncertainty, is found at 0.5 zi. At about 0.7 zi, H changes sign to negative values above. The entrainment flux was (-62±27) W m−2. The mean sensible heat flux divergence in the observed part of the CBL above 0.3 zi was −0.28 W m−3, which corresponds to a warming of 0.83 K h−1. The L profile shows a slight positive mean flux divergence of 0.12 W m−3 and an entrainment flux of (214±36) W m−2. The combination of H and L profiles in combination with variance and other turbulent parameters is very valuable for the evaluation of large-eddy simulation (LES) results and the further improvement and validation of turbulence parameterization schemes.

scholarly journals Boundary layer evolution over the central Himalayas from radio wind profiler and model simulations

2016 ◽  
Vol 16 (16) ◽  
pp. 10559-10572 ◽  
Author(s):  
Narendra Singh ◽  
Raman Solanki ◽  
Narendra Ojha ◽  
Ruud H. H. Janssen ◽  
Andrea Pozzer ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Mixed Layer ◽  
Surface Ozone ◽  
Wrf Model ◽  
Ground Level ◽  
Wind Profiler ◽  
Pollution Transport ◽  
Local Boundary ◽  
The Mean

Abstract. We investigate the time evolution of the Local Boundary Layer (LBL) for the first time over a mountain ridge at Nainital (79.5° E, 29.4° N, 1958 m a.m.s.l.) in the central Himalayan region, using a radar wind profiler (RWP) during November 2011 to March 2012, as a part of the Ganges Valley Aerosol Experiment (GVAX). We restrict our analysis to clear–sunny days, resulting in a total of 78 days of observations. The standard criterion of the peak in the signal-to-noise ratio (S ∕ N) profile was found to be inadequate in the characterization of mixed layer (ML) top at this site. Therefore, we implemented a criterion of S ∕ N > 6 dB for the characterization of the ML and the resulting estimations are shown to be in agreement with radiosonde measurements over this site. The daytime average (05:00–10:00 UTC) observed boundary layer height ranges from 440 ± 197 m in November (late autumn) to 766 ± 317 m above ground level (a.g.l.) in March (early spring). The observations revealed a pronounced impact of mountain topography on the LBL dynamics during March, when strong winds (> 5.6 m s−1) lead to LBL heights of 650 m during nighttime. The measurements are further utilized to evaluate simulations from the Weather Research and Forecasting (WRF) model. WRF simulations captured the day-to-day variations up to an extent (r2 = 0.5), as well as the mean diurnal variations (within 1σ variability). The mean biases in the daytime average LBL height vary from −7 % (January) to +30 % (February) between model and observations, except during March (+76 %). Sensitivity simulations using a mixed layer model (MXL/MESSy) indicated that the springtime overestimation of LBL would lead to a minor uncertainty in simulated surface ozone concentrations. However, it would lead to a significant overestimation of the dilution of black carbon aerosols at this site. Our work fills a gap in observations of local boundary layer over this complex terrain in the Himalayas, and highlights the need for year-long simultaneous measurements of boundary layer dynamics and air quality to better understand the role of lower tropospheric dynamics in pollution transport.

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