A New Vertical Diffusion Package with an Explicit Treatment of Entrainment Processes

Hong, Song; Noh, Yign; Dudhia, Jimy

doi:10.1175/mwr3199.1

Cited by 5,745 publications

(2,796 citation statements)

References 27 publications

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“…Meteorological fields are assimilated by using the Weather Research and Forecasting model constrained by the CFSR data. Transport schemes (advection, convection, and turbulent mixing) are implemented by following previous work (50)(51)(52). SI Appendix, The chemical mechanism is adopted from GEOS-Chem v9.1 with updates on chemistry of aromatics (47), isoprene (54,55), and isoprene nitrates (56)(57)(58).…”

Section: Methodsmentioning

confidence: 99%

Climate-driven ground-level ozone extreme in the fall over the Southeast United States

Zhang

Wang

2016

Proc. Natl. Acad. Sci. U.S.A.

110

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Ground-level ozone is adverse to human and vegetation health. High ground-level ozone concentrations usually occur over the United States in the summer, often referred to as the ozone season. However, observed monthly mean ozone concentrations in the southeastern United States were higher in October than July in 2010. The October ozone average in 2010 reached that of July in the past three decades . Our analysis shows that this extreme October ozone in 2010 over the Southeast is due in part to a dry and warm weather condition, which enhances photochemical production, air stagnation, and fire emissions. Observational evidence and modeling analysis also indicate that another significant contributor is enhanced emissions of biogenic isoprene, a major ozone precursor, from water-stressed plants under a dry and warm condition. The latter finding is corroborated by recent laboratory and field studies. This climate-induced biogenic control also explains the puzzling fact that the two extremes of high October ozone both occurred in the 2000s when anthropogenic emissions were lower than the 1980s and 1990s, in contrast to the observed decreasing trend of July ozone in the region. The occurrences of a drying and warming fall, projected by climate models, will likely lead to more active photochemistry, enhanced biogenic isoprene and fire emissions, an extension of the ozone season from summer to fall, and an increase of secondary organic aerosols in the Southeast, posing challenges to regional air quality management.ground-level ozone | ozone season | regional climate change | isoprene | air quality G round-level ozone is a pollutant harmful to human and vegetation health (1, 2). High ground-level ozone events are typically found in the summer when the formation of ozone is active through photochemical reactions involving nitrogen oxides (NO x = NO + NO 2 ) and volatile organic compounds (VOCs). However, ozone concentrations are sensitive to weather and climate (3-8), and the high-ozone season could extend beyond summer in the future (9-13). Previous climate-chemistry model studies have estimated the change of ground-level ozone (ΔO 3 ) in the United States resulting only from meteorological changes. Their results show large variation in the sign and magnitude of ΔO 3 in the fall, especially over forested regions such as the southeastern United States (SE) (10, 13). The lack of consensus reflects the uncertainties in modeling regional climate change and the consequent response of ground-level ozone.In this study, we focus on analyzing the historical ozone records. Fig. 1A Fig. S1). The number increases to 324 exceedances at 112 stations if the new US ambient ozone standard threshold value, 70 ppbv, is used (SI Appendix, Fig. S1). The regional average reached 65 ppbv during October 8-10, 2010 ( Fig. 2A). ppbv, considerably lower than that in the summer ozone season (∼50 ppbv in July). However, in the two extreme years, 2000 and 2010, regional monthly mean [O 3 ] MDA8 are 52 and 49 ppbv, respectively, two interannual standa...

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Section: Methodsmentioning

confidence: 99%

Climate-driven ground-level ozone extreme in the fall over the Southeast United States

Zhang

Wang

2016

Proc. Natl. Acad. Sci. U.S.A.

110

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“…For all simulations, the vertical grid consisted of 48 levels and was stretched such that its finest grid spacing (about 100 m) was in the boundary layer and gradually became coarser with height to a maximum grid spacing of about 1.5 km near the model top at about 20 km. The simulations also used the following schemes: Morrison et al's (2005) two-moment microphysics parameterization, the Yonsei University boundary layer parameterization (Hong et al 2006), the Noah land surface model (Chen and Dudhia 2001), and the Rapid Radiative Transfer Model for GCMs (RRTMG; Iacono et al 2008).…”

Section: Methodsmentioning

confidence: 99%

Influence of Terrain Resolution on Banded Convection in the Lee of the Rocky Mountains

Schumacher

Schultz

Knox

2015

Monthly Weather Review

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On 16-17 February 2007, snowbands formed in the lee of the Rocky Mountains in Wyoming, Colorado, and Nebraska on the anticyclonic-shear side of a midlevel jet streak. Two types of bands were prevalent: a longer, wider band associated with frontogenesis along an equatorward-moving cold front (major band) and multiple shorter, narrower bands farther poleward (minor bands). To understand how the upstream terrain affected the occurrence and intensity of the bands, multiple mesoscale model simulations were performed in which the terrain was incrementally smoothed. The evolutions of the synoptic patterns were similar in all simulations that included topography, but the synoptic pattern differed and no bands developed in a simulation with a flat land surface. These results allowed a focus on the changes to the banded precipitation due to the terrain resolution. Remarkably, although the exact location of the bands differed from run to run, the bands in all simulations with topography were in roughly the same region where they occurred on 16-17 February 2007. The major band was associated with frontogenesis along an equatorward-moving cold front that became stalled against the terrain. The minor bands formed from the release of conditional, symmetric, and inertial instabilities by ascent up the large-scale topography, rather than by ascent up specific small-scale topographic features. Because the bands were not tied to specific terrain features, these results suggest that the precise location of the minor bands is unpredictable.

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“…Iacono et al, 2008) were used to couple with aerosol scheme in order to reproduce aerosol-radiation interactions. The YSU non-local K boundary layer scheme (Hong et al, 2006) and the Noah land surface scheme (Tewari et al, 2016) were applied for boundary layer evolution and land-atmosphere interactions, respectively. For representation of cloud and precipitation processes the Lin 15 microphysics scheme (Lin, 1983) together with the Grell-Deveny cumulus parameterization (Grell and Devenyi, 2002) were employed.…”

Section: Model Configurationmentioning

confidence: 99%

Dome effect of black carbon and its key influencing factors: A one-dimensional modelling study

Wang¹,

Huang²,

Ding³

2017

Preprint

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Black carbon (BC) has been identified to play a critical role in aerosol-planet boundary layer (PBL) interaction and further deterioration of near-surface air pollution in megacities, which has been named as its "dome effect". However, the impacts of key factors that influence this effect, such as the vertical distribution and aging processes of BC, and also the underlying land surface, have not been quantitatively explored yet. Here, based on available in-situ measurements of meteorology and 15 atmospheric aerosols together with the meteorology-chemistry online coupled model, WRF-Chem, we conduct a set of parallel simulations to quantify the roles of these factors in influencing the BC's dome effect and surface haze pollution, and discuss the main implications of the results to air pollution mitigation in China. We found that the impact of BC on PBL is very sensitive to the altitude of aerosol layer. The upper level BC, especially those near the capping inversion, is more essential in suppressing the PBL height and weakening the turbulence mixing. The dome effect of BC tends to be significantly intensified 20 as BC aerosol mixed with scattering aerosols during winter haze events, resulting in a decrease of PBL height by more than 25%. In addition, the dome effect is more substantial (up to 15%) in rural areas than that in the urban areas with the same BC loading, indicating an unexpected regional impact of such kind of effect to air quality in countryside. This study suggests that China's regional air pollution would greatly benefit from BC emission reductions, especially those from the elevated sources from the chimneys and also the domestic combustions in rural areas, through weakening the aerosol-boundary layer 25 interactions that triggered by BC.

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A New Vertical Diffusion Package with an Explicit Treatment of Entrainment Processes

Cited by 5,745 publications

References 27 publications

Climate-driven ground-level ozone extreme in the fall over the Southeast United States

Climate-driven ground-level ozone extreme in the fall over the Southeast United States

Influence of Terrain Resolution on Banded Convection in the Lee of the Rocky Mountains

Dome effect of black carbon and its key influencing factors: A one-dimensional modelling study

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