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  1. Book ; Online: Implementation and evaluation of updated photolysis rates in the EMEP MSC-W chemistry-transport model using Cloud-J v7.3e

    Caspel, Willem E. / Simpson, David / Jonson, Jan Eiof / Benedictow, Anna M. K. / Ge, Yao / Sarra, Alcide / Pace, Giandomenico / Vieno, Massimo / Walker, Hannah L. / Heal, Mathew R.

    eISSN: 1991-9603

    2023  

    Abstract: The present work describes the implementation of the state of the art Cloud- J v7.3 photolysis rate calculation code in the EMEP MSC-W chemistry-transport model. Cloud- J calculates photolysis rates and accounts for cloud and aerosol optical properties ... ...

    Abstract The present work describes the implementation of the state of the art Cloud- J v7.3 photolysis rate calculation code in the EMEP MSC-W chemistry-transport model. Cloud- J calculates photolysis rates and accounts for cloud and aerosol optical properties at model run time, replacing the old system based on tabulated values. The performance of Cloud- J is evaluated against aerial photolysis rate observations made over the Pacific Ocean and against surface observations from three measurement sites in Europe. Numerical experiments are performed to investigate the sensitivity of the calculated photolysis rates to the spatial and temporal model resolution, input meteorology model, simulated ozone column, and cloud effect parameterization. These experiments indicate that the calculated photolysis rates are most sensitive to the choice of input meteorology model and cloud effect parameterization while also showing that surface ozone photolysis rates can vary by up to 20 % due to daily variations in total ozone column. Further analysis investigates the impact of Cloud- J on the oxidizing capacity of the troposphere, aerosol–photolysis interactions, and surface air quality predictions. Results find that the annual mean mass-weighted tropospheric hydroxyl concentration is increased by 26 %, while the photolytic impact of aerosols is mostly limited to large tropical biomass-burning regions. Overall, Cloud- J represents a major improvement over the tabulated system, leading to improved model performance for predicting carbon monoxide and daily maximum ozone surface concentrations.
    Subject code 551
    Language English
    Publishing date 2023-12-21
    Publishing country de
    Document type Book ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  2. Book ; Online: Multi-model evaluation of aerosol optical properties in the AeroCom phase III Control experiment, using ground and space based columnar observations from AERONET, MODIS, AATSR and a merged satellite product as well as surface in-situ observations from GAW sites

    Gliß, Jonas / Mortier, Augustin / Schulz, Michael / Andrews, Elisabeth / Balkanski, Yves / Bauer, Susanne E. / Benedictow, Anna M. K. / Bian, Huisheng / Checa-Garcia, Ramiro / Chin, Mian / Ginoux, Paul / Griesfeller, Jan J. / Heckel, Andreas / Kipling, Zak / Kirkevåg, Alf / Kokkola, Harri / Laj, Paolo / Sager, Philippe / Lund, Marianne Tronstad /
    Lund Myhre, Cathrine / Matsui, Hitoshi / Myhre, Gunnar / Neubauer, David / Noije, Twan / North, Peter / Olivié, Dirk J. L. / Sogacheva, Larisa / Takemura, Toshihiko / Tsigaridis, Kostas / Tsyro, Svetlana G.

    eISSN: 1680-7324

    2020  

    Abstract: Within the framework of the AeroCom (Aerosol Comparisons between Observations and Models) initiative, the present day modelling of aerosol optical properties has been assessed using simulated data representative for the year 2010, from 14 global aerosol ... ...

    Abstract Within the framework of the AeroCom (Aerosol Comparisons between Observations and Models) initiative, the present day modelling of aerosol optical properties has been assessed using simulated data representative for the year 2010, from 14 global aerosol models participating in the Phase III Control experiment. The model versions are close or equal to those used for CMIP6 and AerChemMIP and inform also on bias in state of the art ESMs. Modelled column optical depths (total, fine and coarse mode AOD) and Angstrom Exponents (AE) were compared both with ground based observations from the Aerosol Robotic Network (AERONET, version 3) as well as space based observations from AATSR-SU instruments. In addition, the modelled AODs were compared with MODIS (Aqua and Terra) data and a satellite AOD data-set (MERGED-FMI) merged from 12 different individual AOD products. Furthermore, for the first time, the modelled near surface scattering (under dry conditions) and absorption coefficients were evaluated against measurements made at low relative humidity at surface in-situ GAW sites. Statistics are based mainly on normalised mean biases and Pearson correlation coefficients from colocated model and observation data in monthly resolution. Hence, the results are mostly representative for the regions covered by each of the observation networks. Model biases established against satellite data yield insights into remote continental areas and oceans, where ground-based networks lack site coverage. The satellite data themselves are evaluated against AERONET observations, to test our aggregation and re-gridding routines, suggesting relative AOD biases of −5 %, −6 %, +9 % and +18 % for AATSR-SU, MERGED-FMI, MODIS-aqua and MODIS-terra, respectively, with high correlations exceeding 0.8. Biases of fine and coarse AOD and AE in AATSR are found to be +2 %, −16 % and +14.7 % respectively, at AERONET sites, with correlations of the order of 0.8. The AeroCom MEDIAN and most of the participating models underestimate the optical properties investigated, relative to remote sensing observations. AERONET AOD is underestimated by 21 % ± 17 %. Against satellite data, the model AOD biases range from −38 % (MODIS-terra) to −17 % (MERGED-FMI). Correlation coefficients of model AODs with AERONET, MERGED-FMI and AATSR-SU are high (0.8–0.9) and slightly lower against the two MODIS data-sets (0.6–0.8). Investigation of fine and coarse AODs from the MEDIAN model reveals biases of −10% ± 20 % and −41 % ± 29 % against AERONET and −13 % and −24 % against AATSR-SU, respectively. The differences in bias against AERONET and AATSR-SU are in agreement with the established satellite bias against AERONET. These results indicate that most of the AOD bias is due to missing coarse AOD in the regions covered by these observations. Underestimates are also found when comparing the models against the surface GAW observations, showing AeroCom MEDIAN mean bias and inter-model variation of −44 % ± 22 % and −32 % ± 34 % for scattering and absorption coefficients, respectively. Dry scattering shows higher underestimation than AOD at ambient relative humidity and is in agreement with recent findings that suggest that models tend to overestimate scattering enhancement due to hygroscopic growth. Broadly consistent negative bias in AOD and scattering suggest a general underestimate in aerosol effects in current global aerosol models. The large diversity in the surface absorption results suggests differences in the model treatment of light absorption by black carbon (BC), dust (DU) and to a minor degree, organic aerosol (OA). Considerable diversity is found among the models in the simulated near surface absorption coefficients, particularly in regions associated with dust (e.g. Sahara, Tibet), biomass burning (e.g. Amazonia, Central Australia) and biogenic emissions (e.g. Amazonia). Regions associated with high anthropogenic BC emissions such as China and India exhibit comparatively good agreement for all models. Evaluation of modelled column AEs shows an underestimation of 9 % ± 24 % against AERONET and −21 % against AATSR-SU. This suggests that overall, models tend to overestimate particle size, with implications for lifetime and radiative transfer calculations. An investigation of modelled emissions, burdens and lifetimes, mass-specific-extinction coefficients (MECs) and optical depths (ODs) for each species and model reveals considerable diversity in most of these parameters. These are discussed in detail for each model individually. Inter-model spread of aerosol species lifetime appears to be similar to that of mass extinction coefficients, suggesting that AOD uncertainties are still associated to a broad spectrum of parameterised aerosol processes.
    Subject code 551
    Language English
    Publishing date 2020-03-18
    Publishing country de
    Document type Book ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  3. Article: Two-scale multi-model ensemble: is a hybrid ensemble of opportunity telling us more?

    Galmarini, Stefano / Kioutsioukis, Ioannis / Solazzo, Efisio / Alyuz, Ummugulsum / Balzarini, Alessandra / Bellasio, Roberto / Benedictow, Anna M K / Bianconi, Roberto / Bieser, Johannes / Brandt, Joergen / Christensen, Jesper H / Colette, Augustin / Curci, Gabriele / Davila, Yanko / Dong, Xinyi / Flemming, Johannes / Francis, Xavier / Fraser, Andrea / Fu, Joshua /
    Henze, Daven K / Hogrefe, Christian / Im, Ulas / Vivanco, Marta Garcia / Jiménez-Guerrero, Pedro / Jonson, Jan Eiof / Kitwiroon, Nutthida / Manders, Astrid / Mathur, Rohit / Palacios-Peña, Laura / Pirovano, Guido / Pozzoli, Luca / Prank, Marie / Schultz, Martin / Sokhi, Rajeet S / Sudo, Kengo / Tuccella, Paolo / Takemura, Toshihiko / Sekiya, Takashi / Unal, Alper

    Atmospheric chemistry and physics

    2019  Volume 18, Page(s) 2727–2744

    Abstract: In this study we introduce ... ...

    Abstract In this study we introduce a
    Language English
    Publishing date 2019-03-26
    Publishing country Germany
    Document type Journal Article
    ISSN 1680-7316
    ISSN 1680-7316
    DOI 10.5194/acp-18-8727-2018
    Database MEDical Literature Analysis and Retrieval System OnLINE

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