scholarly journals Wet Scavenging in WRF‐Chem Simulations of Parameterized Convection for a Severe Storm During the DC3 Field Campaign

Author(s):  
Y. Li ◽  
K. E. Pickering ◽  
M. C. Barth ◽  
M. M. Bela ◽  
K. A. Cummings ◽  
...  

Abstract Clouds and precipitation play critical roles in wet removal of aerosols and soluble gases in the atmosphere, and hence their accurate prediction largely influences accurate prediction of air pollutants. In this study, the impacts of clouds and precipitation on wet scavenging and long-range transboundary transport of pollutants are examined during the 2016 Korea-United States Air Quality (KORUS-AQ) field campaign using the Weather Research and Forecasting model coupled with chemistry. Two simulations in which atmospheric moisture is constrained vs. it is not are performed and evaluated against surface and airborne observations. The simulation with moisture constraints is found to better reproduce precipitation as well as surface PM2.5, whereas the areal extent and amount of precipitation are overpredicted in the simulation without moisture constraints. As a results of overpredicted clouds and precipitation and consequently overpredicted wet scavenging, PM2.5 concentration is generally underpredicted across the model domain in the simulation without moisture constraints. The effects are significant not only in the precipitating region (upwind region, southern China in this study) but also in the downwind region (South Korea) where no precipitation is observed. The difference in upwind precipitation by 77% on average between the two simulations leads to the difference in PM2.5 by ∼39% both in the upwind and downwind regions. The transboundary transport of aerosol precursors, especially nitric acid, has a considerable impact on ammonium-nitrate aerosol formation in the ammonia-rich downwind region. This study highlights that skillful prediction of atmospheric moisture can have ultimate potential to skillful prediction of aerosols across regions.


Author(s):  
Justin Farrell

This chapter examines the bitter, long-lasting, and sometimes violent dispute over the Yellowstone bison herd—America's only remaining genetically pure and free-roaming herd, which once numbered more than 30 million but was exterminated down to a mere 23 single animals. This intractable issue hinges on current scientific disagreements about the biology and ecology of the disease brucellosis (Brucella abortus). But in recent years, a more radical, grassroots, and direct action activist group called the Buffalo Field Campaign (BFC) has found success by shifting the focus of the debate away from science, toward the deeper religious dimensions of the issue. The chapter shows how the infusion of the conflict with moral and spiritual feeling has brought to the fore deeper questions that ultimately needed to be answered, thus making this a public religious conflict as much as a scientific one, sidestepping rabbit holes of intractability. It observes the ways in which BFC activists engaged in a phenomenon called moral and religious “muting.” This has theoretical implications for understanding how certain elements of culture (e.g., individualism and moral relativism) can organize and pattern others—especially in post hoc explanations of religiously motivated activism.


1983 ◽  
Author(s):  
Toby N. Carlson ◽  
Thomas T. Warner ◽  
Michael J. Fritsch
Keyword(s):  

2016 ◽  
Author(s):  
Adam Bateman ◽  
◽  
Scott T. Martin
Keyword(s):  

2013 ◽  
Vol 13 (16) ◽  
pp. 8489-8503 ◽  
Author(s):  
D. Jarecka ◽  
H. Pawlowska ◽  
W. W. Grabowski ◽  
A. A. Wyszogrodzki

Abstract. This paper discusses aircraft observations and large-eddy simulation (LES) modeling of 15 May 2008, North Sea boundary-layer clouds from the EUCAARI-IMPACT field campaign. These clouds are advected from the northeast by the prevailing lower-tropospheric winds and featured stratocumulus-over-cumulus cloud formations. An almost-solid stratocumulus deck in the upper part of the relatively deep, weakly decoupled marine boundary layer overlays a field of small cumuli. The two cloud formations have distinct microphysical characteristics that are in general agreement with numerous past observations of strongly diluted shallow cumuli on one hand and solid marine stratocumulus on the other. Based on the available observations, a LES model setup is developed and applied in simulations using a novel LES model. The model features a double-moment warm-rain bulk microphysics scheme combined with a sophisticated subgrid-scale scheme allowing local prediction of the homogeneity of the subgrid-scale turbulent mixing. The homogeneity depends on the characteristic time scales for the droplet evaporation and for the turbulent homogenization. In the model, these scales are derived locally based on the subgrid-scale turbulent kinetic energy, spatial scale of cloudy filaments, mean cloud droplet radius, and humidity of the cloud-free air entrained into a cloud, all predicted by the LES model. The model reproduces contrasting macrophysical and microphysical characteristics of the cumulus and stratocumulus cloud layers. Simulated subgrid-scale turbulent mixing within the cumulus layer and near the stratocumulus top is on average quite inhomogeneous, but varies significantly depending on the local conditions.


2020 ◽  
Vol 20 (11) ◽  
pp. 6687-6706
Author(s):  
Mikhail Paramonov ◽  
Saskia Drossaart van Dusseldorp ◽  
Ellen Gute ◽  
Jonathan P. D. Abbatt ◽  
Paavo Heikkilä ◽  
...  

Abstract. Ice-nucleating particle (INP) measurements were performed in the boreal environment of southern Finland at the Station for Measuring Ecosystem–Atmosphere Relations (SMEAR II) in the winter–spring of 2018. Measurements with the Portable Ice Nucleation Chamber (PINC) were conducted at 242 K and 105 % relative humidity with respect to water. The median INP number concentration [INP] during a 6-week measurement period was 13 L−1. The [INP] spanned 3 orders of magnitude and showed a general increase from mid-February until early April. No single dominant local or regional sources of INPs in the boreal environment of southern Finland could be identified. Rather, it is hypothesised that the INPs detected at SMEAR II are a result of long-range transport and dilution of INPs sourced far from the measurement site. Despite high variability, the measured [INP] values fall within the range expected for the [INP] measured elsewhere under similar thermodynamic conditions. The [INP] did not correlate with any of the examined parameters during the entire field campaign, indicating that no one single parameter can be used to predict the [INP] at the measurement location during the examined time period. The absence of a correlation across the entire field campaign also suggests that a variety of particles act as INPs at different times, although it was indirectly determined that ambient INPs are most likely within the size range of 0.1–0.5 µm in diameter on average. On shorter timescales, several particle species correlated well with the [INP]. Depending on the meteorological conditions, black carbon (BC), supermicron biological particles and sub-0.1 µm particles, most likely nanoscale biological fragments such as ice-nucleating macromolecules (INMs), correlated with the INP signal. However, an increase in the concentration of any of these particle species may not necessarily lead to the increase in the [INP]; the reasons for this remain unknown. Limitations of the instrumental set-up and the necessity for future field INP studies are addressed.


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