Abstract. Severe regional haze pollution events occurred in eastern and central China in January 2013, which had adverse effects on the environment and public health. Extremely high levels of particulate matter with aerodynamic diameter of 2.5 µm or less (PM 2.5 ) with dominant components of sulfate and nitrate are responsible for the haze pollution. Although heterogeneous chemistry is thought to play an important role in the production of sulfate and nitrate during haze episodes, few studies have comprehensively evaluated the effect of heterogeneous chemistry on haze formation in China by using the 3-D models due to of a lack of treatments for heterogeneous reactions in most climate and chemical transport models. In this work, the WRF-CMAQ model with newly added heterogeneous reactions is applied to East Asia to evaluate the impacts of heterogeneous chemistry and the meteorological anomaly during January 2013 on regional haze formation. As the parameterization of heterogeneous reactions on different types of particles is not well established yet, we arbitrarily selected the uptake coefficients from reactions on dust particles and then conducted several sensitivity runs to find the value that can best match observations. The revised CMAQ with heterogeneous chemistry not only captures the magnitude and temporal variation of sulfate and nitrate, but also reproduces the enhancement of relative contribution of sulfate and nitrate to PM 2.5 mass from clean days to polluted haze days. These results indicate the significant role of heterogeneous chemistry in regional haze formation and improve the understanding of the haze formation mechanisms during the January 2013 episode.

An accurate speciation mapping of non-methane volatile organic compounds (NMVOC) emissions has an important impact on the performance of chemical transport models (CTMs) in simulating ozone mixing ratios and secondary organic aerosols. Taking the INTEX-B Asian NMVOC emission inventory as the case, we developed an improved speciation framework to generate model-ready anthropogenic NMVOC emissions for various gas-phase chemical mechanisms commonly used in CTMs in this work, by using an explicit assignment approach and updated NMVOC profiles. NMVOC profiles were selected and aggregated from a wide range of new measurements and the SPECIATE database v.4.2. To reduce potential uncertainty from individual measurements, composite profiles were developed by grouping and averaging source profiles from the same category. The fractions of oxygenated volatile organic compounds (OVOC) were corrected during the compositing process for those profiles which used improper sampling and analyzing methods. Emissions of individual species were then lumped into species in different chemical mechanisms used in CTMs by applying mechanism-dependent species mapping tables, which overcomes the weakness of inaccurate mapping in previous studies. Emission estimates for individual NMVOC species differ between one and three orders of magnitude for some species when different sets of profiles are used, indicating that source profile is the most important source of uncertainties of individual species emissions. However, those differences are diminished in lumped species as a result of the lumping in the chemical mechanisms. Gridded emissions for eight chemical mechanisms at 30 min x 30 min resolution as well as the auxiliary data are available at < a href='http://mic.greenresource.cn/intex-b2006'target='_blank'> http://mic.greenresource.cn/intex-b2006 . The framework proposed in this work can be also used to develop speciated NMVOC emissions for other regions

Published by Copernicus Publications on behalf of the European Geosciences Union. A. Baklanov et al.: Online coupled regional meteorology chemistry models in EuropeAbstract. Online coupled mesoscale meteorology atmospheric chemistry models have undergone a rapid evolution in recent years. Although mainly developed by the air quality modelling community, these models are also of interest for numerical weather prediction and regional climate modelling as they can consider not only the effects of meteorology on air quality, but also the potentially important effects of atmospheric composition on weather. Two ways of online coupling can be distinguished: online integrated and online access coupling. Online integrated models simulate meteorology and chemistry over the same grid in one model using one main time step for integration. Online access models use independent meteorology and chemistry modules that might even have different grids, but exchange meteorology and chemistry data on a regular and frequent basis. This article offers a comprehensive review of the current research status of online coupled meteorology and atmospheric chemistry modelling within Europe. Eighteen regional online coupled models developed or being used in Europe are described and compared. Topics discussed include a survey of processes relevant to the interactions between atmospheric physics, dynamics and composition; a brief overview of existing online mesoscale models and European model developments; an analysis on how feedback processes are treated in these models; numerical issues associated with coupled models; and several case studies and model performance evaluation methods. Finally, this article highlights selected scientific issues and emerging challenges that require proper consideration to improve the reliability and usability of these models for the three scientific communities: air quality, numerical meteorology modelling (including weather prediction) and climate modelling. This review will be of particular interest to model developers and users in all three fields as it presents a synthesis of scientific progress and provides recommendations for future research directions and priorities in the development, application and evaluation of online coupled models.

In this supplementary material, we discuss the calculation of the radio-frequency spectra arising from confinement-induced dimers and polarons in a quasi-two-dimensional Fermi gas. We determine the dimer binding energies, including both the tight axial confinement and the nonzero transverse confinement. We provide the probabilities for dimer-to-dimer transitions and the shape of the dimerto-scattering state spectrum. We also find the energy and quasi-particle weights for polarons in the two-dimensional gas and the corresponding spectra for polaron to polaron transitions.PACS numbers: 03.75.SsWe begin by reviewing briefly in § I the radio-frequency spectrum arising from confinement-induced pairs, including final state interactions, but ignoring manybody effects, using the method employed for the threedimensional case by Chin and Julienne [1]. We consider mixtures of the three lowest hyperfine states of 6 Li, denoted |1 , |2 , |3 . For the conditions of our experiments in a 12 mixture at 720 G, the observed 2 → 3 threshold spectrum is well described by a 12-dimer-to-13-scattering-state transition. In contrast, at 834 G, the predicted dimer spectrum is in marked disagreement with the data. In particular, we find that the difference between the ground and excited state dimer energies is too small. In § II we determine the energies for noninteracting confinement-induced polarons. We find that the locations of the observed resonances for a 12 mixture near 834 G are well modeled by the predicted energy difference between isolated state 2 polarons and state 3 polarons, in a bath of atoms in state 1. I. CONFINEMENT-INDUCED DIMERSA simple golden rule calculation gives the radiofrequency-induced transition rate out of the initial state to all possible final states R i (ω rf ) = F R f ←i , whereHere, Ω f i is the Rabi frequency for changing the hyperfine state of a single atom from the chosen populated state (i) to the initially unpopulated state (f ) and F |I is the overlap between the initial and final wave-functions for the relative motion of the atompair. Since the center of mass energy does not change in the rf transition, E f − E i is the total change in the atomic hyperfine energy (≡hω f i ) plus the change in the energy of the relative motion of the pair E F − E I . Since F | F |I | 2 = 1, dω rf R i (ω rf ) = (π/2)Ω 2 f i . We define a normalized spectrum I(ω) where R i (ω rf ) = (π/2)Ω 2 f i I(ω) and ω rf = ω f i + ω, with ω the frequency relative to the (unshifted) free-atom hyperfine transition frequency. Then,and dωI(ω) = 1.To determine the spatial wavefunctions and the pair binding energies, we note that the range of the two-body interaction is small compared to the interparticle spacing as well as to the harmonic oscillator confinement scale l z ≡ h/(mω z ). In this case, interactions between atoms in two different spin states are well described by the s-wave pseudopotential in three dimensions [2], V (r) = (4πh 2 a/m) δ(r)∂ r (r...), where r is the distance between the atoms, m is the mass of a single atom an...

Abstract. Extremely severe and persistent haze occurred in January 2013 over eastern and northern China. The record-breaking high concentrations of fine particulate matter (PM 2.5 ) of more than 700 µg m −3 on hourly average and the persistence of the episodes have raised widespread, considerable public concerns. During that period, 7 of the top 10 polluted cities in China were within the Hebei Province. The three cities in southern Hebei (Shijiazhuang, Xingtai, and Handan) have been listed as the top three polluted cities according to the statistics for the first half of the year 2013. In this study, the Mesoscale Modeling System Generation 5 (MM5) and the Models-3/Community Multiscale Air Quality (CMAQ) modeling system are applied to simulate the 2013 severe winter regional hazes in East Asia and northern China at horizontal grid resolutions of 36 and 12 km, respectively, using the Multi-resolution Emission Inventory for China (MEIC). The source contributions of major source regions and sectors to PM 2.5 concentrations in the three most polluted cities in southern Hebei are quantified by aiming at the understanding of the sources of the severe haze pollution in this region, and the results are compared with December 2007, the haziest month in the period 2001-2010. Model evaluation against meteorological and air quality observations indicates an overall acceptable performance and the model tends to underpredict PM 2.5 and coarse particulate matter (PM 10 ) concentrations during the extremely polluted episodes. The MEIC inventory is proven to be a good estimation in terms of total emissions of cities but uncertainties exist in the spatial allocations of emissions into fine grid resolutions within cities. The source apportionment shows that emissions from northern Hebei and the Beijing-Tianjin city cluster are two major regional contributors to the pollution in January 2013 in Shijiazhuang, compared with those from Shanxi and northern Hebei for December 2007. For Xingtai and Handan, the emissions from northern Hebei and Henan are important. The industrial and domestic sources are the most significant local contributors, and the domestic and agricultural emissions from Shandong and Henan are non-negligible regional sources, especially for Xingtai and Handan. Even in the top two haziest months (i.e., January 2013 and December 2007), a large fraction of PM 2.5 in the three cities may originate from quite different regional sources. These results indicate the importance of establishing a regional joint framework of policymaking and action system to effectively mitigate air pollution in this area, not only over the Beijing-Tianjin-Hebei area, but also surrounding provinces such as Henan, Shandong, and Shanxi.

Abstract. The climate-chemistry-aerosol-cloud-radiation feedbacks are important processes occurring in the atmosphere. Accurately simulating those feedbacks requires fully-coupled meteorology, climate, and chemistry models and presents significant challenges in terms of both scientific understanding and computational demand. This paper reviews the history and current status of the development and application of online-coupled meteorology and chemistry models, with a focus on five representative models developed in the US including GATOR-GCMOM, WRF/Chem, CAM3, MIRAGE, and Caltech unified GCM. These models represent the current status and/or the state-of-the science treatments of online-coupled models worldwide. Their major model features, typical applications, and physical/chemical treatments are compared with a focus on model treatments of aerosol and cloud microphysics and aerosol-cloud interactions. Aerosol feedbacks to planetary boundary layer meteorology and aerosol indirect effects are illustrated with case studies for some of these models. Future research needs for model development, improvement, application, as well as major challenges for online-coupled models are discussed.

[1] The mixing state of black carbon (BC) aerosols, namely, the degree to which BC particles are coated with other aerosol components, has been recognized as important for evaluating aerosol radiative forcing. In order to resolve the BC mixing state explicitly in model simulations, a two-dimensional aerosol representation, in which aerosols are given for individual particle diameters and BC mass fractions, is introduced. This representation was incorporated into an aerosol module, the Model of Aerosol Dynamics, Reaction, Ionization, and Dissolution (MADRID), and a new box model, MADRID-BC, was developed. MADRID-BC can accurately simulate changes in the entire BC mixing state resulting from condensation/evaporation processes. Aircraft observations conducted in March 2004 show that the mass fraction of thickly coated BC particles increased in air horizontally transported out from an urban area in Japan over the ocean. MADRID-BC generally reproduces this feature well when observed bulk aerosol concentrations are used as constraints. The model simulations in this particular case show that for particles with BC core diameters of 100-200 nm, the particle diameters, including both core and coating materials, had already increased by a factor of 1.6 on average when they left the source region and by as large as a factor of 1.9 of the BC core diameters after their transport over the ocean for a half day. The model simulations also show that 58% of the total condensed mass was partitioned onto BC-free particles during transport, indicating their importance for the BC mixing state. Although the model simulations are applied to a limited number of the observations in this study, they clearly show the time evolution of the coating thicknesses of BC-containing particles, which is necessary for calculating aerosol optical properties and cloud condensation nuclei activities.

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