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1. The AeroCom evaluation and intercomparison of organic aerosol in global models

Author

Tsigaridis, K, Daskalakis, N, Kanakidou, M, Adams, PJ, Artaxo, P, Bahadur, R, Balkanski, Y, Bauer, SE, Bellouin, N, Benedetti, A, Bergman, T, Berntsen, TK, Beukes, JP, Bian, H, Carslaw, KS, Chin, M, Curci, G, Diehl, T, Easter, RC, Ghan, SJ, Gong, SL, Hodzic, A, Hoyle, CR, Iversen, T, Jathar, S, Jimenez, JL, Kaiser, JW, Kirkevåg, A, Koch, D, Kokkola, H, Lee, YH, Lin, G, Liu, X, Luo, G, Ma, X, Mann, GW, Mihalopoulos, N, Morcrette, J-J, Müller, J-F, Myhre, G, Myriokefalitakis, S, Ng, NL, O'Donnell, D, Penner, JE, Pozzoli, L, Pringle, KJ, Russell, LM, Schulz, M, Sciare, J, Seland, Ø, Shindell, DT, Sillman, S, Skeie, RB, Spracklen, D, Stavrakou, T, Steenrod, SD, Takemura, T, Tiitta, P, Tilmes, S, Tost, H, van Noije, T, van Zyl, PG, von Salzen, K, Yu, F, Wang, Z, Zaveri, RA, Zhang, H, Zhang, K, Zhang, Q, and Zhang, X

Subjects
Aging, Climate Action, Astronomical and Space Sciences, Atmospheric Sciences, Meteorology & Atmospheric Sciences
Abstract

This paper evaluates the current status of global modeling of the organic aerosol (OA) in the troposphere and analyzes the differences between models as well as between models and observations. Thirty-one global chemistry transport models (CTMs) and general circulation models (GCMs) have participated in this intercomparison, in the framework of AeroCom phase II. The simulation of OA varies greatly between models in terms of the magnitude of primary emissions, secondary OA (SOA) formation, the number of OA species used (2 to 62), the complexity of OA parameterizations (gas-particle partitioning, chemical aging, multiphase chemistry, aerosol microphysics), and the OA physical, chemical and optical properties. The diversity of the global OA simulation results has increased since earlier AeroCom experiments, mainly due to the increasing complexity of the SOA parameterization in models, and the implementation of new, highly uncertain, OA sources. Diversity of over one order of magnitude exists in the modeled vertical distribution of OA concentrations that deserves a dedicated future study. Furthermore, although the OA / OC ratio depends on OA sources and atmospheric processing, and is important for model evaluation against OA and OC observations, it is resolved only by a few global models. The median global primary OA (POA) source strength is 56 Tg a-1 (range 34-144 Tg a-1) and the median SOA source strength (natural and anthropogenic) is 19 Tg a-1 (range 13-121 Tg a-1). Among the models that take into account the semi-volatile SOA nature, the median source is calculated to be 51 Tg a-1 (range 16-121 Tg a-1), much larger than the median value of the models that calculate SOA in a more simplistic way (19 Tg a-1; range 13-20 Tg a-1, with one model at 37 Tg a-1). The median atmospheric burden of OA is 1.4 Tg (24 models in the range of 0.6-2.0 Tg and 4 between 2.0 and 3.8 Tg), with a median OA lifetime of 5.4 days (range 3.8-9.6 days). In models that reported both OA and sulfate burdens, the median value of the OA/sulfate burden ratio is calculated to be 0.77; 13 models calculate a ratio lower than 1, and 9 models higher than 1. For 26 models that reported OA deposition fluxes, the median wet removal is 70 Tg a-1 (range 28-209 Tg a-1), which is on average 85% of the total OA deposition. Fine aerosol organic carbon (OC) and OA observations from continuous monitoring networks and individual field campaigns have been used for model evaluation. At urban locations, the model-observation comparison indicates missing knowledge on anthropogenic OA sources, both strength and seasonality. The combined model-measurements analysis suggests the existence of increased OA levels during summer due to biogenic SOA formation over large areas of the USA that can be of the same order of magnitude as the POA, even at urban locations, and contribute to the measured urban seasonal pattern. Global models are able to simulate the high secondary character of OA observed in the atmosphere as a result of SOA formation and POA aging, although the amount of OA present in the atmosphere remains largely underestimated, with a mean normalized bias (MNB) equal to -0.62 (-0.51) based on the comparison against OC (OA) urban data of all models at the surface, -0.15 (+0.51) when compared with remote measurements, and -0.30 for marine locations with OC data. The mean temporal correlations across all stations are low when compared with OC (OA) measurements: 0.47 (0.52) for urban stations, 0.39 (0.37) for remote stations, and 0.25 for marine stations with OC data. The combination of high (negative) MNB and higher correlation at urban stations when compared with the low MNB and lower correlation at remote sites suggests that knowledge about the processes that govern aerosol processing, transport and removal, on top of their sources, is important at the remote stations. There is no clear change in model skill with increasing model complexity with regard to OC or OA mass concentration. However, the complexity is needed in models in order to distinguish between anthropogenic and natural OA as needed for climate mitigation, and to calculate the impact of OA on climate accurately.

Published
2014

2. Global dust model intercomparison in AeroCom phase I

Author

Huneeus, N., Schulz, M., Balkanski, Y., Griesfeller, J., Prospero, J., Kinne, S., Bauer, S., Boucher, O., Chin, M., Dentener, F., Diehl, T., Easter, R., Fillmore, D., Ghan, S., Ginoux, P., Grini, A., Horowitz, L., Koch, D., Krol, M. C, Landing, W., Liu, X., Mahowald, N., Miller, R., Morcrette, J.-J., Myhre, G., Penner, J., Perlwitz, J., Stier, P., Takemura, T., and Zender, C. S

Subjects
General-circulation model, atmospheric iron deposition, last glacial maximum, mineral dust, aerosol direct, tropospheric chemistry, optical-properties, Goddard-Institute, North-Atlantic, sulfur cycle
Abstract

This study presents the results of a broad intercomparison of a total of 15 global aerosol models within the AeroCom project. Each model is compared to observations related to desert dust aerosols, their direct radiative effect, and their impact on the biogeochemical cycle, i.e., aerosol optical depth (AOD) and dust deposition. Additional com parisons to Angstrom exponent (AE), coarse mode AOD and dust surface concentrations are included to extend the assessment of model performance and to identify common biases present in models. These data comprise a benchmark dataset that is proposed for model inspection and future dust model development. There are large differences among the global models that simulate the dust cycle and its impact on climate. In general, models simulate the climatology of vertically integrated parameters (AOD and AE) within a factor of two whereas the total deposition and surface concentration are reproduced within a factor of 10. In addition, smaller mean normalized bias and root mean square errors are obtained for the climatology of AOD and AE than for total deposition and surface concentration. Characteristics of the datasets used and their uncertainties may influence these differences. Large uncertainties still exist with respect to the deposition fluxes in the southern oceans. Further measurements and model studies are necessary to assess the general model performance to reproduce dust deposition in ocean regions sensible to iron contributions. Models overestimate the wet deposition in regions dominated by dry deposition. They generally simulate more realistic surface concentration at stations downwind of the main sources than at remote ones. Most models simulate the gradient in AOD and AE between the different dusty regions. However the seasonality and magnitude of both variables is better simulated at African stations than Middle East ones. The models simulate the offshore transport of West Africa throughout the year but they overestimate the AOD and they transport too fine particles. The models also reproduce the dust transport across the Atlantic in the summer in terms of both AOD and AE but not so well in winter-spring nor the southward displacement of the dust cloud that is responsible of the dust transport into South America. Based on the dependency of AOD on aerosol burden and size distribution we use model bias with respect to AOD and AE to infer the bias of the dust emissions in Africa and the Middle East. According to this analysis we suggest that a range of possible emissions for North Africa is 400 to 2200 Tg yr(-1) and in the Middle East 26 to 526 Tg yr(-1)

Published
2011

3. A review of coarse mineral dust in the Earth system

Author

Adebiyi, A., Kok, J.F., Murray, B.J., Ryder, C.L., Stuut, J.-B.W., Kahn, R.A., Knippertz, P., Formenti, P., Mahowald, N.M., Pérez García-Pando, C., Klose, M., Ansmann, A., Samset, B.H., Ito, A., Balkanski, Y., Di Biagio, C., Romanias, M.N., Huang, Y., Meng, J., Adebiyi, A., Kok, J.F., Murray, B.J., Ryder, C.L., Stuut, J.-B.W., Kahn, R.A., Knippertz, P., Formenti, P., Mahowald, N.M., Pérez García-Pando, C., Klose, M., Ansmann, A., Samset, B.H., Ito, A., Balkanski, Y., Di Biagio, C., Romanias, M.N., Huang, Y., and Meng, J.

Abstract

Mineral dust particles suspended in the atmosphere span more than three orders of magnitude in diameter, from <0.1 µm to more than 100 µm. This wide size range makes dust a unique aerosol species with the ability to interact with many aspects of the Earth system, including radiation, clouds, hydrology, atmospheric chemistry, and biogeochemistry. This review focuses on coarse and super-coarse dust aerosols, which we respectively define as dust particles with a diameter of 2.5–10 µm and 10–62.5 µm. We review several lines of observational evidence indicating that coarse and super-coarse dust particles are transported farther than previously expected and that the abundance of these particles is substantially underestimated in current global models. We synthesize previous studies that used observations, theories, and model simulations to highlight the impacts of coarse and super-coarse dust aerosols on the Earth system, including their effects on dust-radiation interactions, dust-cloud interactions, atmospheric chemistry, and biogeochemistry. Specifically, coarse and super-coarse dust aerosols produce a net positive direct radiative effect (warming) at the top of the atmosphere and can modify temperature and water vapor profiles, influencing the distribution of clouds and precipitation. In addition, coarse and super-coarse dust aerosols contribute a substantial fraction of ice-nucleating particles, especially at temperatures above –23 °C. They also contribute a substantial fraction to the available reactive surfaces for atmospheric processing and the dust deposition flux that impacts land and ocean biogeochemistry by supplying important nutrients such as iron and phosphorus. Furthermore, we examine several limitations in the representation of coarse and super-coarse dust aerosols in current model simulations and remote-sensing retrievals. Because these limitations substantially contribute to the uncertainties in simulating the abundance and impacts of coarse and super-c

Published
2023

4. A comparison of scavenging and deposition processes in global models: results from the WCRP Cambridge Workshop of 1995

Author

Rasch, P. J, Feichter, J., Law, K, Mahowald, N., Penner, J., Benkovitz, C., Genthon ENTH, C., Giannakopoulos, C., Kasibhatla, P., Koch, D., Levy, H., Maki, T., Prather, M., Roberts, D. L, Roelof, G.-J., Stevenson, D., Stockwell, Z., Taguchi, S., Kritz, M., Chipperfield, M., Baldocchi, D., McMurry, P., Barrie, L., Balkanski, Y., Chatfield, R., Kjellstrom, E., Lawrence, M., Lee, H. N, Lelieveld ELIEVELD, J., Noone, K. J, Seinfeld, J., Stenchikov, G., Schwartz, S., Walcek, C., and Williamson, D.

Subjects
atmospheric chemistry, atmospheric circulation, atmospheric deposition, atmospheric modeling, scavenging, troposphere
Abstract

We report on results from a World Climate Research Program workshop on representations ofscavenging and deposition processes in global transport models of the atmosphere. 15 modelswere evaluated by comparing simulations of radon, lead, sulfur dioxide, and sulfate against eachother, and against observations of these constituents. This paper provides a survey on the simulationdifferences between models. It identifies circumstances where models are consistent withobservations or with each other, and where they differ from observations or with each other. Thecomparison shows that most models are able to simulate seasonal species concentrations nearthe surface over continental sites to within a factor of 2 over many regions of the globe. Modelstend to agree more closely over source (continental ) regions than for remote (polar and oceanic)regions. Model simulations differ most strongly in the upper troposphere for species undergoingwet scavenging processes. There are not a sufficient number of observations to characterize theclimatology ( long-term average) of species undergoing wet scavenging in the upper troposphere.This highlights the need for either a different strategy for model evaluation (e.g., comparisons onan event by event basis) or many more observations of a few carefully chosen constituents.

Published
2000

5. Three-dimensional climatological distribution of tropospheric OH: Update and evaluation

Author

Spivakovsky, C. M, Logan, J. A, Montzka, S. A, Balkanski, Y. J, Foreman-Fowler, M., Jones, D. B. A, Horowitz, L. W, Fusco, A. C, Brenninkmeijer, C. A. M, Prather, M. J, Wofsy, S. C, and McElroy, M. B

Subjects
: atmospheric chemistry, hydroxyl radical
Abstract

A global climatological distribution of tropospheric OH is computed using observed distributions of O3, H2O, NOt (NO2 +NO + 2N2O5 + NO3 + HNO2 +HNO4), CO, hydrocarbons, temperature, and cloud optical depth. Global annual mean OH is 1.16×106 molecules cm−3(integrated with respect to mass of air up to 100 hPa within ±32° latitude and up to 200 hPa outside that region). Mean hemispheric concentrations of OH are nearly equal. While global mean OH increased by 33% compared to that from Spivakovsky et al. [1990], mean loss frequencies of CH3CCl3 and CH4 increased by only 23% because a lower fraction of total OH resides in the lower troposphere in the present distribution. The value for temperature used for determining lifetimes of hydrochlorofluorocarbons (HCFCs) by scaling rate constants [Prather and Spivakovsky, 1990] is revised from 277 K to 272 K. The present distribution of OH is consistent within a few percent with the current budgets of CH3CCl3 and HCFC-22. For CH3CCl3, it results in a lifetime of 4.6 years, including stratospheric and ocean sinks with atmospheric lifetimes of 43 and 80 years, respectively. For HCFC-22, the lifetime is 11.4 years, allowing for the stratospheric sink with an atmospheric lifetime of 229 years. Corrections suggested by observed levels of CH2Cl2 (annual means) depend strongly on the rate of interhemispheric mixing in the model. An increase in OH in the Northern Hemisphere by 20% combined with a decrease in the southern tropics by 25% is suggested if this rate is at its upper limit consistent with observations of CFCs and 85Kr. For the lower limit, observations of CH2Cl2 imply an increase in OH in the Northern Hemisphere by 35% combined with a decrease in OH in the southern tropics by 60%. However, such large corrections are inconsistent with observations for 14CO in the tropics and for the interhemispheric gradient of CH3CCl3. Industrial sources of CH2Cl2 are sufficient for balancing its budget. The available tests do not establish significant errors in OH except for a possible underestimate in winter in the northern and southern tropics by 15–20% and 10–15%, respectively, and an overestimate in southern extratropics by ∼25%. Observations of seasonal variations of CH3CCl3, CH2Cl2,14CO, and C2H6 offer no evidence for higher levels of OH in the southern than in the northern extratropics. It is expected that in the next few years the latitudinal distribution and annual cycle of CH3CCl3 will be determined primarily by its loss frequency, allowing for additional constraints for OH on scales smaller than global.

Published
2000

7. Impact of dust in PMIP-CMIP6 mid-Holocene simulations with the IPSL model

Author

Braconnot, P, Albani, S, Balkanski, Y, Cozic, A, Kageyama, M, Sima, A, Marti, O, Peterschmitt, J, Braconnot P., Albani S., Balkanski Y., Cozic A., Kageyama M., Sima A., Marti O., Peterschmitt J. -Y., Braconnot, P, Albani, S, Balkanski, Y, Cozic, A, Kageyama, M, Sima, A, Marti, O, Peterschmitt, J, Braconnot P., Albani S., Balkanski Y., Cozic A., Kageyama M., Sima A., Marti O., and Peterschmitt J. -Y.

Abstract

We investigate the climate impact of reduced dust during the mid-Holocene using simulations with the IPSL model. We consider simulations where dust is either prescribed from an IPSL PI simulation or from CESM simulations (Albani et al., 2015). In addition, we also consider an extreme mid-Holocene case where dust is suppressed. We focus on the estimation of the dust radiative effects and the relative responses of the African and Indian monsoon, showing how local dust forcing or orography affect atmospheric temperature profiles, humidity and precipitation. The simulated mid-Holocene climate is statistically different in many regions compared to previous mid-Holocene simulations with the IPSL models. However, it translates to only minor improvements compared to palaeoclimate reconstructions, and the effect of dust has little impact on mid-Holocene model skill over large regions. Our analyses confirm the peculiar role of dust radiative effect over bright surfaces such as African deserts compared to other regions, brought about by the change of sign of the dust radiative effect at the top of atmosphere for high surface albedo. We also highlight a strong dependence of results on the dust pattern. In particular, the relative dust forcing between West Africa and the Middle East impacts the relative climate response between India and Africa and between Africa, the western tropical Atlantic and the Atlantic meridional circulation. It also affects the feedback on the Atlantic Ocean thermohaline circulation. Dust patterns should thus be better constrained to fully understand the changes in the dust cycle and forcing during the mid-Holocene, which also informs on the potential changes in key dust feedbacks in the future.

Published
2021

8. Contribution of the world's main dust source regions to the global cycle of desert dust

Author

Kok, J, Adebiyi, A, Albani, S, Balkanski, Y, Checa-Garcia, R, Chin, M, Colarco, P, Hamilton, D, Huang, Y, Ito, A, Klose, M, Li, L, Mahowald, N, Miller, R, Obiso, V, Perez Garcia-Pando, C, Rocha-Lima, A, Wan, J, Kok J. F., Adebiyi A. A., Albani S., Balkanski Y., Checa-Garcia R., Chin M., Colarco P. R., Hamilton D. S., Huang Y., Ito A., Klose M., Li L., Mahowald N. M., Miller R. L., Obiso V., Perez Garcia-Pando C., Rocha-Lima A., Wan J. S., Kok, J, Adebiyi, A, Albani, S, Balkanski, Y, Checa-Garcia, R, Chin, M, Colarco, P, Hamilton, D, Huang, Y, Ito, A, Klose, M, Li, L, Mahowald, N, Miller, R, Obiso, V, Perez Garcia-Pando, C, Rocha-Lima, A, Wan, J, Kok J. F., Adebiyi A. A., Albani S., Balkanski Y., Checa-Garcia R., Chin M., Colarco P. R., Hamilton D. S., Huang Y., Ito A., Klose M., Li L., Mahowald N. M., Miller R. L., Obiso V., Perez Garcia-Pando C., Rocha-Lima A., and Wan J. S.

Abstract

Even though desert dust is the most abundant aerosol by mass in Earth s atmosphere, the relative contributions of the world s major source regions to the global dust cycle remain poorly constrained. This problem hinders accounting for the potentially large impact of regional differences in dust properties on clouds, the Earth s energy balance, and terrestrial and marine biogeochemical cycles. Here, we constrain the contribution of each of the world s main dust source regions to the global dust cycle. We use an analytical framework that integrates an ensemble of global aerosol model simulations with observationally informed constraints on the dust size distribution, extinction efficiency, and regional dust aerosol optical depth (DAOD). We obtain a dataset that constrains the relative contribution of nine major source regions to size-resolved dust emission, atmospheric loading, DAOD, concentration, and deposition flux. We find that the 22 29 Tg (1 standard error range) global loading of dust with a geometric diameter up to 20 um is partitioned as follows: North African source regions contribute 50% (11 15 Tg), Asian source regions contribute 40% (8 13 Tg), and North American and Southern Hemisphere regions contribute 10% (1.8 3.2 Tg). These results suggest that current models on average overestimate the contribution of North African sources to atmospheric dust loading at 65 %, while underestimating the contribution of Asian dust at 30 %. Our results further show that each source region s dust loading peaks in local spring and summer, which is partially driven by increased dust lifetime in those seasons. We also quantify the dust deposition flux to the Amazon rainforest to be 10 Tg yr1, which is a factor of 2 3 less than inferred from satellite data by previous work that likely overestimated dust deposition by underestimating the dust mass extinction efficiency. The data obtained in this paper can be used to obtain improved constraints on dust impacts on clouds, climat

Published
2021

9. Improved representation of the global dust cycle using observational constraints on dust properties and abundance

Author

Kok, J, Adebiyi, A, Albani, S, Balkanski, Y, Checa-Garcia, R, Chin, M, Colarco, P, Hamilton, D, Huang, Y, Ito, A, Klose, M, Leung, D, Li, L, Mahowald, N, Miller, R, Obiso, V, Perez Garcia-Pando, C, Rocha-Lima, A, Wan, J, Whicker, C, Kok J. F., Adebiyi A. A., Albani S., Balkanski Y., Checa-Garcia R., Chin M., Colarco P. R., Hamilton D. S., Huang Y., Ito A., Klose M., Leung D. M., Li L., Mahowald N. M., Miller R. L., Obiso V., Perez Garcia-Pando C., Rocha-Lima A., Wan J. S., Whicker C. A., Kok, J, Adebiyi, A, Albani, S, Balkanski, Y, Checa-Garcia, R, Chin, M, Colarco, P, Hamilton, D, Huang, Y, Ito, A, Klose, M, Leung, D, Li, L, Mahowald, N, Miller, R, Obiso, V, Perez Garcia-Pando, C, Rocha-Lima, A, Wan, J, Whicker, C, Kok J. F., Adebiyi A. A., Albani S., Balkanski Y., Checa-Garcia R., Chin M., Colarco P. R., Hamilton D. S., Huang Y., Ito A., Klose M., Leung D. M., Li L., Mahowald N. M., Miller R. L., Obiso V., Perez Garcia-Pando C., Rocha-Lima A., Wan J. S., and Whicker C. A.

Abstract

Even though desert dust is the most abundant aerosol by mass in Earth s atmosphere, atmospheric models struggle to accurately represent its spatial and temporal distribution. These model errors are partially caused by fundamental difficulties in simulating dust emission in coarseresolution models and in accurately representing dust microphysical properties. Here we mitigate these problems by developing a new methodology that yields an improved representation of the global dust cycle. We present an analytical framework that uses inverse modeling to integrate an ensemble of global model simulations with observational constraints on the dust size distribution, extinction efficiency, and regional dust aerosol optical depth.We then compare the inverse model results against independent measurements of dust surface concentration and deposition flux and find that errors are reduced by approximately a factor of 2 relative to current model simulations of the Northern Hemisphere dust cycle. The inverse model results show smaller improvements in the less dusty Southern Hemisphere, most likely because both the model simulations and the observational constraints used in the inverse model are less accurate. On a global basis, we find that the emission flux of dust with a geometric diameter up to 20 um (PM20) is approximately 5000 Tg yr1, which is greater than most models account for. This larger PM20 dust flux is needed to match observational constraints showing a large atmospheric loading of coarse dust. We obtain gridded datasets of dust emission, vertically integrated loading, dust aerosol optical depth, (surface) concentration, and wet and dry deposition fluxes that are resolved by season and particle size. As our results indicate that this dataset is more accurate than current model simulations and the MERRA-2 dust reanalysis product, it can be used to improve quantifications of dust impacts on the Earth system.

Published
2021

11. Delayed use of bioenergy crops might threaten climate and food security

Author

Xu, S., Wang, R., Gasser, T., Ciais, P., Peñuelas, J., Balkanski, Y., Boucher, O., Janssens, I.A., Sardans, J., Clark, J.H., Cao, J., Xing, X., Chen, J., Wang, L., Tang, X., Zhang, R., Xu, S., Wang, R., Gasser, T., Ciais, P., Peñuelas, J., Balkanski, Y., Boucher, O., Janssens, I.A., Sardans, J., Clark, J.H., Cao, J., Xing, X., Chen, J., Wang, L., Tang, X., and Zhang, R.

Abstract

The potential of mitigation actions to limit global warming within 2 °C (ref. 1) might rely on the abundant supply of biomass for large-scale bioenergy with carbon capture and storage (BECCS) that is assumed to scale up markedly in the future2,3,4,5. However, the detrimental effects of climate change on crop yields may reduce the capacity of BECCS and threaten food security6,7,8, thus creating an unrecognized positive feedback loop on global warming. We quantified the strength of this feedback by implementing the responses of crop yields to increases in growing-season temperature, atmospheric CO2 concentration and intensity of nitrogen (N) fertilization in a compact Earth system model9. Exceeding a threshold of climate change would cause transformative changes in social–ecological systems by jeopardizing climate stability and threatening food security. If global mitigation alongside large-scale BECCS is delayed to 2060 when global warming exceeds about 2.5 °C, then the yields of agricultural residues for BECCS would be too low to meet the Paris goal of 2 °C by 2200. This risk of failure is amplified by the sustained demand for food, leading to an expansion of cropland or intensification of N fertilization to compensate for climate-induced yield losses. Our findings thereby reinforce the urgency of early mitigation, preferably by 2040, to avoid irreversible climate change and serious food crises unless other negative-emission technologies become available in the near future to compensate for the reduced capacity of BECCS.

Published
2022
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14. Heterogeneous Interaction of Glyoxal with Gobi desert dust under simulated atmospheric conditions

Author

Zogka, Antonia, Romanias, Manolis, THEVENET, Frédéric, Formenti, P., BALKANSKI, Y., Ecole nationale supérieure Mines-Télécom Lille Douai (IMT Nord Europe), Institut Mines-Télécom [Paris] (IMT), Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12), Obeo [Gif-sur-Yvette], and none

Subjects
[SDE]Environmental Sciences, ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2021

17. Climate change projections using the IPSL-CM5 Earth System Model: from CMIP3 to CMIP5

Author

Dufresne, J.-L., Foujols, M.-A., Denvil, S., Caubel, A., Marti, O., Aumont, O., Balkanski, Y., Bekki, S., Bellenger, H., Benshila, R., Bony, S., Bopp, L., Braconnot, P., Brockmann, P., Cadule, P., Cheruy, F., Codron, F., Cozic, A., Cugnet, D., de Noblet, N., Duvel, J.-P., Ethé, C., Fairhead, L., Fichefet, T., Flavoni, S., Friedlingstein, P., Grandpeix, J.-Y., Guez, L., Guilyardi, E., Hauglustaine, D., Hourdin, F., Idelkadi, A., Ghattas, J., Joussaume, S., Kageyama, M., Krinner, G., Labetoulle, S., Lahellec, A., Lefebvre, M.-P., Lefevre, F., Levy, C., Li, Z. X., Lloyd, J., Lott, F., Madec, G., Mancip, M., Marchand, M., Masson, S., Meurdesoif, Y., Mignot, J., Musat, I., Parouty, S., Polcher, J., Rio, C., Schulz, M., Swingedouw, D., Szopa, S., Talandier, C., Terray, P., Viovy, N., and Vuichard, N.

Published
2013
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18. The contributions of individual countries and regions to the global radiative forcing

Author

Fu, B., Li, B., Gasser, T., Tao, S., Ciais, P., Piao, S., Balkanski, Y., Li, W., Yin, T., Han, L., Han, Y., Peng, S., Xu, J., Fu, B., Li, B., Gasser, T., Tao, S., Ciais, P., Piao, S., Balkanski, Y., Li, W., Yin, T., Han, L., Han, Y., Peng, S., and Xu, J.

Abstract

Knowing the historical relative contribution of greenhouse gases (GHGs) and short-lived climate forcers (SLCFs) to global radiative forcing (RF) at the regional level can help understand how future GHGs emission reductions and associated or independent reductions in SLCFs will affect the ultimate purpose of the Paris Agreement. In this study, we use a compact Earth system model to quantify the global RF and attribute global RF to individual countries and regions. As our evaluation, the United States, the first 15 European Union members, and China are the top three contributors, accounting for 21.9 ± 3.1%, 13.7 ± 1.6%, and 8.6 ± 7.0% of global RF in 2014, respectively. We also find a contrast between developed countries where GHGs dominate the RF and developing countries where SLCFs including aerosols and ozone are more dominant. In developing countries, negative RF caused by aerosols largely masks the positive RF from GHGs. As developing countries take measures to improve the air quality, their negative contributions from aerosols will likely be reduced in the future, which will in turn enhance global warming. This underlines the importance of reducing GHG emissions in parallel to avoid any detrimental consequences from air quality policies.

Published
2021

20. An AeroCom Assessment of Black Carbon in Arctic Snow and Sea Ice

Author

Jiao, C, Flanner, M. G, Balkanski, Y, Bauer, S. E, Bellouin, N, Bernsten, T. K, Bian, H, Carslaw, K. S, Chin, M, DeLuca, N, Diehl, T, Ghan, S. J, Iversen, T, Kirkevag, A, Koch, D, Liu, X, Mann, G. W, Penner, J. E, Pitari, G, Schulz, M, Seland, O, Skeie, R. B, Steenrod, S. D, Stier, P, and Tkemura, T

Subjects
Meteorology And Climatology
Abstract

Though many global aerosols models prognose surface deposition, only a few models have been used to directly simulate the radiative effect from black carbon (BC) deposition to snow and sea ice. Here, we apply aerosol deposition fields from 25 models contributing to two phases of the Aerosol Comparisons between Observations and Models (AeroCom) project to simulate and evaluate within-snow BC concentrations and radiative effect in the Arctic. We accomplish this by driving the offline land and sea ice components of the Community Earth System Model with different deposition fields and meteorological conditions from 2004 to 2009, during which an extensive field campaign of BC measurements in Arctic snow occurred. We find that models generally underestimate BC concentrations in snow in northern Russia and Norway, while overestimating BC amounts elsewhere in the Arctic. Although simulated BC distributions in snow are poorly correlated with measurements, mean values are reasonable. The multi-model mean (range) bias in BC concentrations, sampled over the same grid cells, snow depths, and months of measurements, are −4.4 (−13.2 to +10.7) ng/g for an earlier phase of AeroCom models (phase I), and +4.1 (−13.0 to +21.4) ng/g for a more recent phase of AeroCom models (phase II), compared to the observational mean of 19.2 ng/g. Factors determining model BC concentrations in Arctic snow include Arctic BC emissions, transport of extra-Arctic aerosols, precipitation, deposition efficiency of aerosols within the Arctic, and meltwater removal of particles in snow. Sensitivity studies show that the model-measurement evaluation is only weakly affected by meltwater scavenging efficiency because most measurements were conducted in non-melting snow. The Arctic (60-90degN) atmospheric residence time for BC in phase II models ranges from 3.7 to 23.2 days, implying large inter-model variation in local BC deposition efficiency. Combined with the fact that most Arctic BC deposition originates from extra-Arctic emissions, these results suggest that aerosol removal processes are a leading source of variation in model performance. The multi-model mean (full range) of Arctic radiative effect from BC in snow is 0.15 (0.07-0.25) W/sq m and 0.18 (0.06-0.28) W/sq m in phase I and phase II models, respectively. After correcting for model biases relative to observed BC concentrations in different regions of the Arctic, we obtain a multi-model mean Arctic radiative effect of 0.17 W/sq m for the combined AeroCom ensembles. Finally, there is a high correlation between modeled BC concentrations sampled over the observational sites and the Arctic as a whole, indicating that the field campaign provided a reasonable sample of the Arctic.

Published
2014
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21. Missed atmospheric organic phosphorus emitted by terrestrial plants, part 2: Experiment of volatile phosphorus

Author

Li, W., Li, B., Tao, S., Ciais, P., Piao, S., Shen, G., Peng, S., Wang, R., Gasser, T., Balkanski, Y., Li, L., Fu, B., Yin, T., Li, X., An, J., Han, Y., Li, W., Li, B., Tao, S., Ciais, P., Piao, S., Shen, G., Peng, S., Wang, R., Gasser, T., Balkanski, Y., Li, L., Fu, B., Yin, T., Li, X., An, J., and Han, Y.

Abstract

The emission and deposition of global atmospheric phosphorus (P) have long been considered unbalanced, and primary biogenic aerosol particles (PBAP) and phosphine (PH3) are considered to be the only atmospheric P sources from the ecosystem. In this work, we found and quantified volatile organic phosphorus (VOP) emissions from plants unaccounted for in previous studies. In a greenhouse in which lemons were cultivated, the atmospheric total phosphorus (TP) concentration of particulate matter (PM) was 41.8% higher than that in a greenhouse containing only soil, and the proportion of organic phosphorus (OP) in TP was doubled. 31P nuclear magnetic resonance tests (31P-NMR) of PM showed that phosphate monoesters were the main components contributed by plants in both the greenhouse and at an outside observation site. Atmospheric gaseous P was directly measured to be 1–2 orders of magnitude lower than P in PM but appeared to double during plant growing seasons relative to other months. Bag-sampling and gas chromatography mass spectrometry (GCMS) tests showed that the gaseous P emitted by plants in the greenhouse was triethyl phosphate. VOP might be an important component of atmospheric P that has been underestimated in previous studies.

Published
2020

22. Short-lived climate forcers have long-term climate impacts via the carbon–climate feedback

Author

Fu, B., Gasser, T., Li, B., Tao, S., Ciais, P., Piao, S., Balkanski, Y., Li, W., Yin, T., Han, L., Li, X., Han, Y., An, J., Peng, S., Xu, J., Fu, B., Gasser, T., Li, B., Tao, S., Ciais, P., Piao, S., Balkanski, Y., Li, W., Yin, T., Han, L., Li, X., Han, Y., An, J., Peng, S., and Xu, J.

Abstract

Short-lived climate forcers (SLCFs) like methane, ozone and aerosols have a shorter atmospheric lifetime than CO2 and are often assumed to have a short-term effect on the climate system: should their emissions cease, so would their radiative forcing (RF). However, via their climate impact, SLCFs can affect carbon sinks and atmospheric CO2, causing additional climate change. Here, we use a compact Earth system model to attribute CO2 RF to direct CO2 emissions and to climate–carbon feedbacks since the pre-industrial era. We estimate the climate–carbon feedback contributed 93 ± 50 mW m−2 (~5%) to total RF of CO2 in 2010. Of this, SLCF impacts were −13 ± 50 mW m−2, made up of cooling (−115 ± 43 mW m−2) and warming (102 ± 26 mW m−2) terms that largely cancel. This study illustrates the long-term impact that short-lived species have on climate and indicates that past (and future) change in atmospheric CO2 cannot be attributed only to CO2 emissions.

Published
2020

24. Radiative Forcing in the ACCMIP Historical and Future Climate Simulations

Author

Shindell, Drew Todd, Lamarque, J.-F, Schulz, M, Flanner, M, Jiao, C, Chin, M, Young, P. J, Lee, Y. H, Rotstayn, L, Mahowald, N, Milly, G, Faluvegi, G, Balkanski, Y, Collins, W. J, Conley, A. J, Dalsoren, S, Easter, R, Ghan, S, Horowitz, L, Liu, X, Myhre, G, Nagashima, T, Naik, V, Rumbold, S. T, Skeie, R, and Voulgarakis, A

Subjects
Earth Resources And Remote Sensing
Abstract

A primary goal of the Atmospheric Chemistry and Climate Model IntercomparisonProject (ACCMIP) was to characterize the short-lived drivers of preindustrial to 2100climate change in the current generation of climate models. Here we evaluate historicaland 5 future radiative forcing in the 10 ACCMIP models that included aerosols, 8 of whichalso participated in the Coupled Model Intercomparison Project phase 5 (CMIP5).The models generally reproduce present-day climatological total aerosol opticaldepth (AOD) relatively well. components to this total, however, and most appear to underestimate AOD over East10 Asia. The models generally capture 1980-2000 AOD trends fairly well, though theyunderpredict AOD increases over the YellowEastern Sea. They appear to strongly underestimate absorbing AOD, especially in East Asia, South and Southeast Asia, SouthAmerica and Southern Hemisphere Africa.We examined both the conventional direct radiative forcing at the tropopause (RF) and the forcing including rapid adjustments (adjusted forcing AF, including direct andindirect effects). The models calculated all aerosol all-sky 1850 to 2000 global meanannual average RF ranges from 0.06 to 0.49 W m(sup -2), with a mean of 0.26 W m(sup -2) and a median of 0.27 W m(sup -2. Adjusting for missing aerosol components in some modelsbrings the range to 0.12 to 0.62W m(sup -2), with a mean of 0.39W m(sup -2). Screen20ing the models based on their ability to capture spatial patterns and magnitudes ofAOD and AOD trends yields a quality-controlled mean of 0.42W m(sup -2) and range of0.33 to 0.50 W m(sup -2) (accounting for missing components). The CMIP5 subset of ACCMIPmodels spans 0.06 to 0.49W m(sup -2), suggesting some CMIP5 simulations likelyhave too little aerosol RF. A substantial, but not well quantified, contribution to histori25cal aerosol RF may come from climate feedbacks (35 to 58). The mean aerosol AF during this period is 1.12W m(sup -2) (median value 1.16W m(sup -2), range 0.72 to1.44W m(sup -2), indicating that adjustments to aerosols, which include cloud, water vaporand temperature, lead to stronger forcing than the aerosol direct RF.

Published
2013
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25. Black Carbon Vertical Profiles Strongly Affect Its Radiative Forcing Uncertainty

Author

Samset, B. H, Myhre, G, Schulz, M, Balkanski, Y, Bauer, S, Berntsen, T. K, Bian, H, Bellouin, N, Diehl, T, Easter, R. C, Ghan, S. J, Iversen, T, Kinne, S, Kirkevag, A, Lamarque, J.-F, Lin, G, Liu, X, Penner, J. E, Seland, O, Skeie, R. B, Stier, P, Takemura, T, Tsigaridis, K, and Zhang, K

Subjects
Meteorology And Climatology
Abstract

The impact of black carbon (BC) aerosols on the global radiation balance is not well constrained. Here twelve global aerosol models are used to show that at least 20% of the present uncertainty in modeled BC direct radiative forcing (RF) is due to diversity in the simulated vertical profile of BC mass. Results are from phases 1 and 2 of the global aerosol model intercomparison project (AeroCom). Additionally, a significant fraction of the variability is shown to come from high altitudes, as, globally, more than 40% of the total BC RF is exerted above 5 km. BC emission regions and areas with transported BC are found to have differing characteristics. These insights into the importance of the vertical profile of BC lead us to suggest that observational studies are needed to better characterize the global distribution of BC, including in the upper troposphere.

Published
2013
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26. Radiative Forcing of the Direct Aerosol Effect from AeroCom Phase II Simulations

Author

Myhre, G, Samset, B. H, Schulz, M, Balkanski, Y, Bauer, S, Berntsen, T. K, Bian, H, Bellouin, N, Chin, M, Diehl, T, Easter, R. C, Feichter, J, Ghan, S. J, Hauglustaine, D, Iversen, T, Kinne, S, Kirkevag, A, Lamarque, J.-F, Lin, G, Liu, X, Lund, M. T, Luo, G, Ma, X, vanNoije, T, Penner, J. E, Rasch, P. J, Ruiz, A, Seland, O, Skeie, R. B, Stier, P, Takemura, T, Tsigaridis, K, Wang, P, Wang, Z, Xu, L, Yu, H, Yu, F, Yoon, J. -H, Zhang, K, Zhang, H, and Zhou, C

Subjects
Meteorology And Climatology
Abstract

We report on the AeroCom Phase II direct aerosol effect (DAE) experiment where 16 detailed global aerosol models have been used to simulate the changes in the aerosol distribution over the industrial era. All 16 models have estimated the radiative forcing (RF) of the anthropogenic DAE, and have taken into account anthropogenic sulphate, black carbon (BC) and organic aerosols (OA) from fossil fuel, biofuel, and biomass burning emissions. In addition several models have simulated the DAE of anthropogenic nitrate and anthropogenic influenced secondary organic aerosols (SOA). The model simulated all-sky RF of the DAE from total anthropogenic aerosols has a range from −0.58 to −0.02 W m(sup−2), with a mean of −0.27 W m(sup−2 for the 16 models. Several models did not include nitrate or SOA and modifying the estimate by accounting for this with information slightly strengthens the mean. Modifying the model estimates for missing aerosol components and for the time period 1750 to 2010 results in a mean RF for the DAE of −0.35 W m(sup−2). Compared to AeroCom Phase I (Schulz et al., 2006) we find very similar spreads in both total DAE and aerosol component RF. However, the RF of the total DAE is stronger negative and RF from BC from fossil fuel and biofuel emissions are stronger positive in the present study than in the previous AeroCom study.We find a tendency for models having a strong (positive) BC RF to also have strong (negative) sulphate or OA RF. This relationship leads to smaller uncertainty in the total RF of the DAE compared to the RF of the sum of the individual aerosol components. The spread in results for the individual aerosol components is substantial, and can be divided into diversities in burden, mass extinction coefficient (MEC), and normalized RF with respect to AOD. We find that these three factors give similar contributions to the spread in results

Published
2013
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28. Increased Global Land Carbon Sink Due to Aerosol‐Induced Cooling

Author

Zhang, Y., Goll, D., Bastos, A., Balkanski, Y., Boucher, O., Cescatti, A., Collier, M., Gasser, T., Ghattas, J., Li, L., Piao, S., Viovy, N., Zhu, D., Ciais, P., Zhang, Y., Goll, D., Bastos, A., Balkanski, Y., Boucher, O., Cescatti, A., Collier, M., Gasser, T., Ghattas, J., Li, L., Piao, S., Viovy, N., Zhu, D., and Ciais, P.

Abstract

Anthropogenic aerosols have contributed to historical climate change through their interactions with radiation and clouds. In turn, climate change due to aerosols has impacted the C cycle. Here we use a set of offline simulations made with the Organising Carbon and Hydrology In Dynamic Ecosystems (ORCHIDEE) land surface model driven by bias-corrected climate fields from simulations of three Coupled Model Intercomparison Project Phase 5 (CMIP5) Earth system models (ESMs; IPSL-CM5A-LR, CSIRO-Mk3.6.0, and GISS-E2-R) to quantify the climate-related impacts of aerosols on land carbon fluxes during 1860–2005. We found that climate change from anthropogenic aerosols (CCAA) globally cooled the climate, and increased land carbon storage, or cumulative net biome production (NBP), by 11.6–41.8 PgC between 1860 and 2005. The increase in NBP from CCAA mainly occurs in the tropics and northern midlatitudes, primarily due to aerosol-induced cooling. At high latitudes, cooling caused stronger decrease in gross primary production (GPP) than in total ecosystem respiration (TER), leading to lower NBP. At midlatitudes, cooling-induced decrease in TER is stronger than that of GPP, resulting in NBP increase. At low latitudes, NBP was also enhanced due to the cooling-induced GPP increase, but precipitation decline from CCAA may negate the effect of temperature. The three ESMs show large divergence in low-latitude CCAA precipitation response to aerosols, which results in considerable uncertainties in regional estimations of CCAA effects on carbon fluxes. Our results suggest that better understanding and simulation of how anthropogenic aerosols affect precipitation in ESMs is required for a more accurate attribution of aerosol effects on the terrestrial carbon cycle.

Published
2019

30. Aerosol-Climate Interactions During the Last Glacial Maximum

Author

Albani, S, Balkanski, Y, Mahowald, N, Winckler, G, Maggi, V, Delmonte, B, Albani, Samuel, Balkanski, Yves, Mahowald, Natalie, Winckler, Gisela, Maggi, Valter, Delmonte, Barbara, Albani, S, Balkanski, Y, Mahowald, N, Winckler, G, Maggi, V, Delmonte, B, Albani, Samuel, Balkanski, Yves, Mahowald, Natalie, Winckler, Gisela, Maggi, Valter, and Delmonte, Barbara

Abstract

Purpose of Review: Natural archives are imprinted with signs of the past variability of some aerosol species in connection to major climate changes. In certain cases, it is possible to use these paleo-observations as a quantitative tool for benchmarking climate model simulations. Where are we on the path to use observations and models in connection to define an envelope on aerosol feedback onto climate? Recent Findings: On glacial-interglacial time scales, the major advances in our understanding refer to mineral dust, in terms of quantifying its global mass budget, as well as in estimating its direct impacts on the atmospheric radiation budget and indirect impacts on the oceanic carbon cycle. Summary: Even in the case of dust, major uncertainties persist. More detailed observational studies and model intercomparison experiments such as in the Paleoclimate Modelling Intercomparison Project phase 4 will be critical in advancing the field. The inclusion of new processes such as cloud feedbacks and studies focusing on other aerosol species are also envisaged.

Published
2018

31. Aerosols at the poles: an AeroCom Phase II multi-model evaluation

Author

Sand, M., Samset, B. H., Balkanski, Y., Bauer, S., Bellouin, N., Berntsen, T. K., Bian, H., Chin, M., Diehl, T., Easter, R., Ghan, S. J., Iversen, T., Kirkevåg, A., Lamarque, J.-F., Lin, G., Liu, X., Luo, G., Myhre, G., Noije, T. V., Penner, J. E., Schulz, M., Seland, Ø., Skeie, R. B., Stier, P., Takemura, T., Tsigaridis, K., Yu, F., Zhang, K., Zhang, H., Center for International Climate and Environmental Research [Oslo] (CICERO), University of Oslo (UiO), Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Modelling the Earth Response to Multiple Anthropogenic Interactions and Dynamics (MERMAID), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Department of Meteorology [Reading], University of Reading (UOR), Joint Center for Earth Systems Technology [Baltimore] (JCET), NASA Goddard Space Flight Center (GSFC)-University of Maryland [Baltimore County] (UMBC), University of Maryland System-University of Maryland System, NASA Goddard Space Flight Center (GSFC), JRC Institute for Environment and Sustainability (IES), European Commission - Joint Research Centre [Ispra] (JRC), Pacific Northwest National Laboratory (PNNL), Atmospheric Chemistry Observations and Modeling Laboratory (ACOML), National Center for Atmospheric Research [Boulder] (NCAR), Norwegian Meteorological Institute [Oslo] (MET), Department of Physics [Oxford], University of Oxford [Oxford], Kyushu University [Fukuoka], Center for Climate Systems Research [New York] (CCSR), Columbia University [New York], Atmospheric Sciences Research Center (ASRC), University at Albany [SUNY], State University of New York (SUNY)-State University of New York (SUNY), University of Maryland [Baltimore County] (UMBC), University of Maryland System-University of Maryland System-NASA Goddard Space Flight Center (GSFC), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), University of Oxford, and Kyushu University

Subjects
Earth's energy budget, Atmospheric Science, 010504 meteorology & atmospheric sciences, 010502 geochemistry & geophysics, Atmospheric sciences, 7. Clean energy, 01 natural sciences, Latitude, lcsh:Chemistry, chemistry.chemical_compound, Sea ice, Sulfate, Optical depth, 0105 earth and related environmental sciences, [PHYS.PHYS.PHYS-AO-PH]Physics [physics]/Physics [physics]/Atmospheric and Oceanic Physics [physics.ao-ph], [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, geography, geography.geographical_feature_category, Radiative forcing, lcsh:QC1-999, Aerosol, lcsh:QD1-999, Arctic, chemistry, 13. Climate action, Climatology, Environmental science, lcsh:Physics
Abstract

International audience; Atmospheric aerosols from anthropogenic and natural sources reach the polar regions through long-range transport and affect the local radiation balance. Such transport is, however, poorly constrained in present-day global climate models, and few multi-model evaluations of polar an-thropogenic aerosol radiative forcing exist. Here we compare the aerosol optical depth (AOD) at 550 nm from simulations with 16 global aerosol models from the AeroCom Phase II model intercomparison project with available observations at both poles. We show that the annual mean multi-model median is representative of the observations in Arctic, but that the intermodel spread is large. We also document the geographical distribution and seasonal cycle of the AOD for the individual aerosol species: black carbon (BC) from fossil fuel and biomass burning, sulfate, organic aerosols (OAs), dust, and sea-salt. For a subset of models that represent nitrate and secondary organic aerosols (SOAs), we document the role of these aerosols at high latitudes. The seasonal dependence of natural and anthropogenic aerosols differs with natural aerosols peaking in winter (sea-salt) and spring (dust), whereas AOD from anthropogenic aerosols peaks in late spring and summer. The models produce a median annual mean AOD of 0.07 in the Arctic (de-fined here as north of 60 • N). The models also predict a noteworthy aerosol transport to the Antarctic (south of 70 • S) with a resulting AOD varying between 0.01 and 0.02. The Published by Copernicus Publications on behalf of the European Geosciences Union. 12198 M. Sand et al.: Aerosols at the poles: an AeroCom Phase II multi-model evaluation models have estimated the shortwave anthropogenic radia-tive forcing contributions to the direct aerosol effect (DAE) associated with BC and OA from fossil fuel and biofuel (FF), sulfate, SOAs, nitrate, and biomass burning from BC and OA emissions combined. The Arctic modelled annual mean DAE is slightly negative (−0.12 W m −2), dominated by a positive BC FF DAE in spring and a negative sulfate DAE in summer. The Antarctic DAE is governed by BC FF. We perform sensitivity experiments with one of the AeroCom models (GISS modelE) to investigate how regional emissions of BC and sulfate and the lifetime of BC influence the Arctic and Antarctic AOD. A doubling of emissions in eastern Asia results in a 33 % increase in Arctic AOD of BC. A doubling of the BC lifetime results in a 39 % increase in Arctic AOD of BC. However, these radical changes still fall within the AeroCom model range.

Published
2017
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33. Aerosol indirect effects - General circulation model intercomparison and evaluation with satellite data

Author

Quaas, J, Ming, Y, Menon, S, Takemura, T, Wang, M, Penner, J, Gettelman, A, Lohmann, U, Bellouin, N, Boucher, O, Sayer, A, Thomas, G, McComiskey, A, Feingold, G, Hoose, C, Kristjansson, J, Liu, X, Balkanski, Y, Donner, L, Ginoux, P, Stier, P, Grandey, B, Feichter, J, Sednev, I, and Bauer, SE

Abstract

Aerosol indirect effects continue to constitute one of the most important uncertainties for anthropogenic climate perturbations. Within the international AEROCOM initiative, the representation of aerosol-cloud-radiation interactions in ten different general circulation models (GCMs) is evaluated using three satellite datasets. The focus is on stratiform liquid water clouds since most GCMs do not include ice nucleation effects, and none of the model explicitly parameterises aerosol effects on convective clouds. We compute statistical relationships between aerosol optical depth (andtau; a) and various cloud and radiation quantities in a manner that is consistent between the models and the satellite data. It is found that the model-simulated influence of aerosols on cloud droplet number concentration (Nd) compares relatively well to the satellite data at least over the ocean. The relationship between andtau;a and liquid water path is simulated much too strongly by the models. This suggests that the implementation of the second aerosol indirect effect mainly in terms of an autoconversion parameterisation has to be revisited in the GCMs. A positive relationship between total cloud fraction (fcld) and andtau; a as found in the satellite data is simulated by the majority of the models, albeit less strongly than that in the satellite data in most of them. In a discussion of the hypotheses proposed in the literature to explain the satellite-derived strong f cldĝ€"andtau;a relationship, our results indicate that none can be identified as a unique explanation. Relationships similar to the ones found in satellite data between andtau;a and cloud top temperature or outgoing long-wave radiation (OLR) are simulated by only a few GCMs. The GCMs that simulate a negative OLRĝ€"andtau; a relationship show a strong positive correlation between andtau;a and fcld. The short-wave total aerosol radiative forcing as simulated by the GCMs is strongly influenced by the simulated anthropogenic fraction of andtau;a, and parameterisation assumptions such as a lower bound on Nd. Nevertheless, the strengths of the statistical relationships are good predictors for the aerosol forcings in the models. An estimate of the total short-wave aerosol forcing inferred from the combination of these predictors for the modelled forcings with the satellite-derived statistical relationships yields a global annual mean value of andminus;1.5andplusmn;0.5 Wmandminus;2. In an alternative approach, the radiative flux perturbation due to anthropogenic aerosols can be broken down into a component over the cloud-free portion of the globe (approximately the aerosol direct effect) and a component over the cloudy portion of the globe (approximately the aerosol indirect effect). An estimate obtained by scaling these simulated clear- and cloudy-sky forcings with estimates of anthropogenic andtau;a and satellite-retrieved Ndĝ€"andtau;a regression slopes, respectively, yields a global, annual-mean aerosol direct effect estimate of andminus;0.4andplusmn;0.2 Wmandminus;2 and a cloudy-sky (aerosol indirect effect) estimate of andminus;0.7andplusmn;0.5 Wmandminus;2, with a total estimate of andminus;1.2andplusmn;0. 4 Wmandminus;2.

Published
2016

34. Evaluation of black carbon estimations in global aerosol models

Author

Koch, D, Schulz, M, Kinne, S, McNaughton, C, Spackman, JR, Balkanski, Y, Bauer, S, Berntsen, T, Bond, T, Boucher, O, Chin, M, Clarke, A, De Luca, N, Dentener, F, Diehl, T, Dubovik, O, Easter, R, Fahey, D, Feichter, J, Fillmore, D, Freitag, S, Ghan, S, Ginoux, P, Gong, S, and Horowitz, L

Abstract

We evaluate black carbon (BC) model predictions from the AeroCom model intercomparison project by considering the diversity among year 2000 model simulations and comparing model predictions with available measurements. These model-measurement intercomparisons include BC surface and aircraft concentrations, aerosol absorption optical depth (AAOD) retrievals from AERONET and Ozone Monitoring Instrument (OMI) and BC column estimations based on AERONET. In regions other than Asia, most models are biased high compared to surface concentration measurements. However compared with (column) AAOD or BC burden retreivals, the models are generally biased low. The average ratio of model to retrieved AAOD is less than 0.7 in South American and 0.6 in African biomass burning regions; both of these regions lack surface concentration measurements. In Asia the average model to observed ratio is 0.7 for AAOD and 0.5 for BC surface concentrations. Compared with aircraft measurements over the Americas at latitudes between 0 and 50N, the average model is a factor of 8 larger than observed, and most models exceed the measured BC standard deviation in the mid to upper troposphere. At higher latitudes the average model to aircraft BC ratio is 0.4 and models underestimate the observed BC loading in the lower and middle troposphere associated with springtime Arctic haze. Low model bias for AAOD but overestimation of surface and upper atmospheric BC concentrations at lower latitudes suggests that most models are underestimating BC absorption and should improve estimates for refractive index, particle size, and optical effects of BC coating. Retrieval uncertainties and/or differences with model diagnostic treatment may also contribute to the model-measurement disparity. Largest AeroCom model diversity occurred in northern Eurasia and the remote Arctic, regions influenced by anthropogenic sources. Changing emissions, aging, removal, or optical properties within a single model generated a smaller change in model predictions than the range represented by the full set of AeroCom models. Upper tropospheric concentrations of BC mass from the aircraft measurements are suggested to provide a unique new benchmark to test scavenging and vertical dispersion of BC in global models.

Published
2016

35. An AeroCom initial assessment - optical properties in aerosol component modules of global models

Author

Kinne, S, Schulz, M, Textor, C, Guibert, S, Balkanski, Y, Bauer, SE, Berntsen, T, Berglen, T, Boucher, O, Chin, M, Collins, W, Dentener, F, Diehl, T, Easter, R, Feichter, J, Fillmore, D, Ghan, S, Ginoux, P, Gong, S, Grini, A, Hendricks, J, Herzog, M, Horowitz, L, Isaksen, I, and Iversen, T

Abstract

The AeroCom exercise diagnoses multicomponent aerosol modules in global modeling. In an initial assessment simulated global distributions for mass and mid-visible aerosol optical thickness (aot) were compared among 20 different modules. Model diversity was also explored in the context of previous comparisons. For the component combined aot general agreement has improved for the annual global mean. At 0.11 to 0.14, simulated aot values are at the lower end of global averages suggested by remote sensing from ground (AERONET ca. 0.135) and space (satellite composite ca. 0.15). More detailed comparisons, however, reveal that larger differences in regional distribution and significant differences in compositional mixture remain. Of particular concern are large model diversities for contributions by dust and carbonaceous aerosol, because they lead to significant uncertainty in aerosol absorption (aab). Since aot and aab, both, influence the aerosol impact on the radiative energy-balance, the aerosol (direct) forcing uncertainty in modeling is larger than differences in aot might suggest. New diagnostic approaches are proposed to trace model differences in terms of aerosol processing and transport: These include the prescription of common input (e.g. amount, size and injection of aerosol component emissions) and the use of observational capabilities from ground (e.g. measurements networks) or space (e.g. correlations between aerosol and clouds).

Published
2016

36. The effect of harmonized emissions on aerosol properties in global models - an AeroCom experiment

Author

Textor, C, Schulz, M, Guibert, S, Kinne, S, Balkanski, Y, Bauer, S, Berntsen, T, Berglen, T, Boucher, O, Chin, M, Dentener, F, Diehl, T, Feichter, J, Fillmore, D, Ginoux, P, Gong, S, Grini, A, Hendricks, J, Horowitz, L, Huang, P, Isaksen, I, Iversen, T, Kloster, S, Koch, D, and Kirkevåg, A

Abstract

The effects of unified aerosol sources on global aerosol fields simulated by different models are examined in this paper. We compare results from two AeroCom experiments, one with different (ExpA) and one with unified emissions, injection heights, and particle sizes at the source (ExpB). Surprisingly, harmonization of aerosol sources has only a small impact on the simulated inter-model diversity of the global aerosol burden, and consequently global optical properties, as the results are largely controlled by modelspecific transport, removal, chemistry (leading to the formation of secondary aerosols) and parameterizations of aerosol microphysics (e.g., the split between deposition pathways) and to a lesser extent by the spatial and temporal distributions of the (precursor) emissions. The burdens of black carbon and especially sea salt become more coherent in ExpB only, because the large ExpA diversities for these two species were caused by a few outliers. The experiment also showed that despite prescribing emission fluxes and size distributions, ambiguities in the implementation in individual models can lead to substantial differences. These results indicate the need for a better understanding of aerosol life cycles at process level (including spatial dispersal and interaction with meteorological parameters) in order to obtain more reliable results from global aerosol simulations. This is particularly important as such model results are used to assess the consequences of specific air pollution abatement strategies.

Published
2016

37. Analysis and quantification of the diversities of aerosol life cycles within AeroCom

Author

Textor, C, Schulz, M, Guibert, S, Kinne, S, Balkanski, Y, Bauer, S, Berntsen, T, Berglen, T, Boucher, O, Chin, M, Dentener, F, Diehl, T, Easter, R, Feichter, H, Fillmore, D, Ghan, S, Ginoux, P, Gong, S, Grini, A, Hendricks, J, Horowitz, L, Huang, P, Isaksen, I, Iversen, T, and Kloster, S

Abstract

Simulation results of global aerosol models have been assembled in the framework of the AeroCom intercomparison exercise. In this paper, we analyze the life cycles of dust, sea salt, sulfate, black carbon and particulate organic matter as simulated by sixteen global aerosol models. The differences among the results (model diversities) for sources and sinks, burdens, particle sizes, water uptakes, and spatial dispersals have been established. These diversities have large consequences for the calculated radiative forcing and the aerosol concentrations at the surface. Processes and parameters are identified which deserve further research. The AeroCom all-models-average emissions are dominated by the mass of sea salt (SS), followed by dust (DU), sulfate (SO4), particulate organic matter (POM), and finally black carbon (BC). Interactive parameterizations of the emissions and contrasting particles sizes of SS and DU lead generally to higher diversities of these species, and for total aerosol. The lower diversity of the emissions of the fine aerosols, BC, POM, and SO 4, is due to the use of similar emission inventories, and does therefore not necessarily indicate a better understanding of their sources. The diversity of S04-sources is mainly caused by the disagreement on depositional loss of precursor gases and on chemical production. The diversities of the emissions are passed on to the burdens, but the latter are also strongly affected by the model-specific treatments of transport and aerosol processes. The burdens of dry masses decrease from largest to smallest: DU, SS, SO 4, POM, and BC. The all-models-average residence time is shortest for SS with about half a day, followed by SO4 and DU with four days, and POM and BC with six and seven days, respectively. The wet deposition rate is controlled by the solubility and increases from DU, BC, POM to SO4 and SS. It is the dominant sink for SO4, BC, and POM, and contributes about one third to the total removal of SS and DU species. For SS and DU we find high diversities for the removal rate coefficients and deposition pathways. Models do neither agree on the split between wet and dry deposition, nor on that between sedimentation and other dry deposition processes. We diagnose an extremely high diversity for the uptake of ambient water vapor that influences the particle size and thus the sink rate coefficients. Furthermore, we find little agreement among the model results for the partitioning of wet removal into scavenging by convective and stratiform rain. Large differences exist for aerosol dispersal both in the vertical and in the horizontal direction. In some models, a minimum of total aerosol concentration is simulated at the surface. Aerosol dispersal is most pronounced for SO4 and BC and lowest for SS. Diversities are higher for meridional than for vertical dispersal, they are similar for the individual species and highest for SS and DU. For these two components we do not find a correlation between vertical and meridional aerosol dispersal. In addition the degree of dispersals of SS and DU is not related to their residence times. SO4, BC, and POM, however, show increased meridional dispersal in models with larger vertical dispersal, and dispersal is larger for longer simulated residence times.

Published
2016

38. Wildfires in northern Eurasia affect the budget of black carbon in the Arctic - a 12-year retrospective synopsis (2002-2013)

Author

Evangeliou, N., Balkanski, Y., Hao, W. M., Petkov, A., Silverstein, R. P., Corley, R., Nordgren, B. L., Urbanski, S. P., Eckhardt, S., Stohl, A., Tunved, Peter, Crepinsek, S., Jefferson, A., Sharma, S., Nojgaard, J. K., Skov, H., Evangeliou, N., Balkanski, Y., Hao, W. M., Petkov, A., Silverstein, R. P., Corley, R., Nordgren, B. L., Urbanski, S. P., Eckhardt, S., Stohl, A., Tunved, Peter, Crepinsek, S., Jefferson, A., Sharma, S., Nojgaard, J. K., and Skov, H.

Abstract

In recent decades much attention has been given to the Arctic environment, where climate change is happening rapidly. Black carbon (BC) has been shown to be a major component of Arctic pollution that also affects the radiative balance. In the present study, we focused on how vegetation fires that occurred in northern Eurasia during the period of 2002-2013 influenced the budget of BC in the Arctic. For simulating the transport of fire emissions from northern Eurasia to the Arctic, we adopted BC fire emission estimates developed independently by GFED3 (Global Fire Emissions Database) and FEI-NE (Fire Emission Inventory - northern Eurasia). Both datasets were based on fire locations and burned areas detected by MODIS (Moderate resolution Imaging Spectroradiometer) instruments on NASA's (National Aeronautics and Space Administration) Terra and Aqua satellites. Anthropogenic sources of BC were adopted from the MACCity (Monitoring Atmospheric Composition and Climate and megacity Zoom for the Environment) emission inventory. During the 12-year period, an average area of 250aEuro-000aEuro-km(2)aEuro-yr(-1) was burned in northern Eurasia (FEI-NE) and the global emissions of BC ranged between 8.0 and 9.5aEuro-TgaEuro-yr(-1) (FEI-NE+MACCity). For the BC emitted in the Northern Hemisphere (based on FEI-NE+MACCity), about 70aEuro-% originated from anthropogenic sources and the rest from biomass burning (BB). Using the FEI-NE+MACCity inventory, we found that 102aEuro-+/- aEuro-29aEuro-ktaEuro-yr(-1) BC was deposited in the Arctic (defined here as the area north of 67A degrees aEuro-N) during the 12 years simulated, which was twice as much as when using the MACCity inventory (56aEuro-+/- aEuro-8aEuro-ktaEuro-yr(-1)). The annual mass of BC deposited in the Arctic from all sources (FEI-NE in northern Eurasia, MACCity elsewhere) is significantly higher by about 37aEuro-% in 2009 (78 vs. 57aEuro-ktaEuro-yr(-1)) to 181aEuro-% in 2012 (153 vs. 54aEuro-ktaEuro-yr(-1)), compared to the BC

Published
2016
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39. Wildfires in northern Eurasia affect the budget of black carbon in the Arctic – a 12-year retrospective synopsis (2002–2013)

Author

Evangeliou, N., primary, Balkanski, Y., additional, Hao, W. M., additional, Petkov, A., additional, Silverstein, R. P., additional, Corley, R., additional, Nordgren, B. L., additional, Urbanski, S. P., additional, Eckhardt, S., additional, Stohl, A., additional, Tunved, P., additional, Crepinsek, S., additional, Jefferson, A., additional, Sharma, S., additional, Nøjgaard, J. K., additional, and Skov, H., additional

Published
2016
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41. Evaluation of observed and modelled aerosol lifetimes using radioactive tracers of opportunity and an ensemble of 19 global models

Author

Kristiansen, N. I., primary, Stohl, A., additional, Olivié, D. J. L., additional, Croft, B., additional, Søvde, O. A., additional, Klein, H., additional, Christoudias, T., additional, Kunkel, D., additional, Leadbetter, S. J., additional, Lee, Y. H., additional, Zhang, K., additional, Tsigaridis, K., additional, Bergman, T., additional, Evangeliou, N., additional, Wang, H., additional, Ma, P.-L., additional, Easter, R. C., additional, Rasch, P. J., additional, Liu, X., additional, Pitari, G., additional, Di Genova, G., additional, Zhao, S. Y., additional, Balkanski, Y., additional, Bauer, S. E., additional, Faluvegi, G. S., additional, Kokkola, H., additional, Martin, R. V., additional, Pierce, J. R., additional, Schulz, M., additional, Shindell, D., additional, Tost, H., additional, and Zhang, H., additional

Published
2016
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42. Supplementary material to "Wildfires in Northern Eurasia affect the budget of black carbon in the Arctic. A 12-year retrospective synopsis (2002–2013)."

Author

Evangeliou, N., primary, Balkanski, Y., additional, Hao, W. M., additional, Petkov, A., additional, Silverstein, R. P., additional, Corley, R., additional, Nordgren, B. L., additional, Urbanski, S. P., additional, Eckhardt, S., additional, Stohl, A., additional, Tunved, P., additional, Crepinsek, S., additional, Jefferson, A., additional, Sharma, S., additional, Nøjgaard, J. K., additional, and Skov, H., additional

Published
2016
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43. Application of the CALIOP layer product to evaluate the vertical distribution of aerosols estimated by global models: AeroCom phase I results

Author

Koffi, B., Schulz, M., Breon, F.M., Griesfeller, J., Winker, D., Balkanski, Y., Bauer, S., Berntsen, T., Chin, M.A., Collins, W.D., Dentener, F., Diehl, T., Easter, R., Ghan, S., Ginoux, P., Gong, S.L., Horowitz, L.W., Iversen, T., Kirkevag, A., Koch, D., Krol, M.C., Myhre, G., Stier, P., Takemura, T., JRC Institute for Environment and Sustainability (IES), European Commission - Joint Research Centre [Ispra] (JRC), Norwegian Meteorological Institute [Oslo] (MET), Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Modélisation INVerse pour les mesures atmosphériques et SATellitaires (SATINV), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), NASA Langley Research Center [Hampton] (LaRC), Modelling the Earth Response to Multiple Anthropogenic Interactions and Dynamics (MERMAID), Department of Geosciences [Tucson], University of Arizona, NASA Goddard Space Flight Center (GSFC), Department of Meteorology [Monterey], Naval Postgraduate School (NPS), Pacific Northwest National Laboratory (PNNL), NOAA Geophysical Fluid Dynamics Laboratory (GFDL), National Oceanic and Atmospheric Administration (NOAA), Air Quality Research Branch, Meteorological Service of Canada, Environment and Climate Change Canada, Wageningen University and Research [Wageningen] (WUR), Center for International Climate and Environmental Research [Oslo] (CICERO), University of Oslo (UiO), Department of Physics [Oxford], University of Oxford [Oxford], Kyushu University [Fukuoka], Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Department of Geosciences [University of Arizona], University of Oxford, and Kyushu University

Subjects
Meteorologie en Luchtkwaliteit, mineral dust, [PHYS.PHYS.PHYS-AO-PH]Physics [physics]/Physics [physics]/Atmospheric and Oceanic Physics [physics.ao-ph], WIMEK, Meteorology and Air Quality, goddard-institute, gocart model, general-circulation model, [SDU.STU.ME]Sciences of the Universe [physics]/Earth Sciences/Meteorology, emission inventories, optical-properties, north-atlantic, satellite-observations, sun photometer measurements, calipso lidar
Abstract

The CALIOP (Cloud-Aerosol Lidar with Orthogonal Polarization) layer product is used for a multimodel evaluation of the vertical distribution of aerosols. Annual and seasonal aerosol extinction profiles are analyzed over 13 sub-continental regions representative of industrial, dust, and biomass burning pollution, from CALIOP 2007-2009 observations and from AeroCom (Aerosol Comparisons between Observations and Models) 2000 simulations. An extinction mean height diagnostic (Z) is defined to quantitatively assess the models' performance. It is calculated over the 0-6 km and 0-10 km altitude ranges by weighting the altitude of each 100 m altitude layer by its aerosol extinction coefficient. The mean extinction profiles derived from CALIOP layer products provide consistent regional and seasonal specificities and a low inter-annual variability. While the outputs from most models are significantly correlated with the observed Z climatologies, some do better than others, and 2 of the 12 models perform particularly well in all seasons. Over industrial and maritime regions, most models show higher Z than observed by CALIOP, whereas over the African and Chinese dust source regions, Z is underestimated during Northern Hemisphere Spring and Summer. The positive model bias in Z is mainly due to an overestimate of the extinction above 6 km. Potential CALIOP and model limitations, and methodological factors that might contribute to the differences are discussed. Copyright 2012 by the American Geophysical Union.

Published
2012
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44. Changes in tropospheric aerosol and reactive gases burdens and concentrations under IPCC-AR5 emission scenarios for 1850-2100

Author

Szopa, S., Balkanski, Y., Cozic, A., Cugnet, David, Déandreis, C., Dufresne, J., Hauglustaine, D., Foujols, M., Lathière, J., de Noblet-Ducoudré, N., Schulz, M., Yan, N., Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), TROPO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut Pierre-Simon-Laplace (IPSL), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Météorologie Dynamique (UMR 8539) (LMD), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-École des Ponts ParisTech (ENPC)-Centre National de la Recherche Scientifique (CNRS)-Département des Géosciences - ENS Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS-PSL), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)

Subjects
Troposphere: composition and chemistry, [SDU]Sciences of the Universe [physics], Evolution of the atmosphere, Geochemical cycles
Abstract

International audience; Tropospheric ozone and aerosols are major climate forcing agents but the quantification of their forcings are still highly uncertain. In the framework of the ACC-MIP, a global decadal dataset describing the emissions of aerosols and ozone precursors and consistent with those provided for long-lived GHG, was made available. It allowed chemistry-climate models to simulate the evolution of short-lived GHG over the historical period (1850-2005) and for 4 future projections (Representative Concentration Pathways). This work describes the results obtained with the LMDz-INCA model using these state-of-the-art emissions and considering past and future climate change trajectories in a General Circulation Model. These concentrations are currently used as forcing by the two French Earth system models (IPSL-CM5 and CNRM-CM5) to simulate the climate evolution in the CMIP5 framework. The variability and trends of the concentrations along with their relevance will be discussed. In parallel to these projections considering the anthropogenic emissions changes, a short insight on the potential impact of natural isoprene emission changes on ozone will be shown.

Published
2010

45. Evaluation of observed and modelled aerosol lifetimes using radioactive tracers of opportunity and an ensemble of 19 global models

Author

Kristiansen, N. I., primary, Stohl, A., additional, Olivié, D. J. L., additional, Croft, B., additional, Søvde, O. A., additional, Klein, H., additional, Christoudias, T., additional, Kunkel, D., additional, Leadbetter, S. J., additional, Lee, Y. H., additional, Zhang, K., additional, Tsigaridis, K., additional, Bergman, T., additional, Evangeliou, N., additional, Wang, H., additional, Ma, P.-L., additional, Easter, R. C., additional, Rasch, P. J., additional, Liu, X., additional, Pitari, G., additional, Di Genova, G., additional, Zhao, S. Y., additional, Balkanski, Y., additional, Bauer, S. E., additional, Faluvegi, G. S., additional, Kokkola, H., additional, Martin, R. V., additional, Pierce, J. R., additional, Schulz, M., additional, Shindell, D., additional, Tost, H., additional, and Zhang, H., additional

Published
2015
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48. Corrigendum to 'Evaluation of black carbon estimations in global aerosol models'

Author

Koch, D, Schulz, M, Kinne, S, Mcnaughton, C, Spackman, Jr, Balkanski, Y, Bauer, S, Berntsen, T, Bond, Tc, Boucher, O, Chin, M, Clarke, A, DE LUCA, N, Dentener, F, Diehl, T, Dubovik, O, Easter, R, Fahey, Dw, Feichter, J, Fillmore, D, Freitag, S, Ghan, S, Ginoux, P, Gong, S, Horowitz, L, Iversen, T, Kirkevag, A, Klimont, Z, Kondo, Y, Krol, M, Liu, X, Miller, R, Montanaro, V, Moteki, N, Myhre, G, Penner, Je, Perlwitz, J, Pitari, Giovanni, Reddy, S, Sahu, L, Sakamoto, H, Schuster, G, Schwarz, Jp, Seland, O, Stier, P, Takegawa, N, Takemura, T, Textor, C, VAN AARDENNE JA, and Zhao, Y.

Published
2010

49. Modeled black carbon radiative forcing and atmospheric lifetime in AeroCom Phase II constrained by aircraft observations

Author

Samset, B.H., Myhre, G., Herber, Andreas, Kondo, Y., Li, S.-M., Moteki, N., Koike, M., Oshima, N., Schwarz, J.P., Balkanski, Y., Bauers, S.E., Bellouin, N., Berntsen, T.K., Bian, H., Chin, M., Diehl, T., Easter, R.C., Ghan, S.J., Iversen, T., Kirkevåg, Alf, Lamarque, J. F., Lin, G., Liu, X., Penners, J.E., Schulz, M., Seland, Øyvind, Skeie, R.B., Stier, P., Tamemura, T., Tsigaridis, K., Zhang, K., Samset, B.H., Myhre, G., Herber, Andreas, Kondo, Y., Li, S.-M., Moteki, N., Koike, M., Oshima, N., Schwarz, J.P., Balkanski, Y., Bauers, S.E., Bellouin, N., Berntsen, T.K., Bian, H., Chin, M., Diehl, T., Easter, R.C., Ghan, S.J., Iversen, T., Kirkevåg, Alf, Lamarque, J. F., Lin, G., Liu, X., Penners, J.E., Schulz, M., Seland, Øyvind, Skeie, R.B., Stier, P., Tamemura, T., Tsigaridis, K., and Zhang, K.

Abstract

Atmospheric black carbon (BC) absorbs solar radiation, and exacerbates global warming through exerting positive radiative forcing (RF). However, the contribution of BC to ongoing changes in global climate is under debate. Anthropogenic BC emissions, and 5 the resulting distribution of BC concentration, are highly uncertain. In particular, long range transport and processes affecting BC atmospheric lifetime are poorly understood. Here we discuss whether recent assessments may have overestimated present day BC radiative forcing in remote regions. We compare vertical profiles of BC concentration from four recent aircraft measurement campaigns to simulations by 13 aerosol 10 models participating in the AeroCom Phase II intercomparision. An atmospheric lifetime of BC of less than 5 days is shown to be essential for reproducing observations in remote ocean regions, in line with other recent studies. Adjusting model results to measurements in remote regions, and at high altitudes, leads to a 25% reduction in AeroCom Phase II median direct BC forcing, from fossil fuel and biofuel burning, over 15 the industrial era. The sensitivity of modeled forcing to BC vertical profile and lifetime highlights an urgent need for further flight campaigns, close to sources and in remote regions, to provide improved quantification of BC effects for use in climate policy.

Published
2014

50. Aerosol indirect effects - general circulation model intercomparison and evaluation with satellite data

Author

Quaas, J, Ming, Y, Menon, S, Takemura, T, Wang, M, Penner, JE, Gettelman, A, Lohmann, U, Bellouin, N, Boucher, O, Sayer, AM, Thomas, GE, McComiskey, A, Feingold, G, Hoose, C, Kristjánsson, JE, Liu, X, Balkanski, Y, Donner, LJ, Ginoux, PA, Stier, P, Feichter, J, Sednev, I, Bauer, SE, Koch, D, Grainger, RG, Kirkevåg, A, Iversen, T, Seland, Ø, Easter, R, Ghan, SJ, Rasch, PJ, Morrison, H, Lamarque, J-F, Iacono, MJ, Kinne, S, and Schulz, M

Abstract

Aerosol indirect effects continue to constitute one of the most important uncertainties for anthropogenic climate perturbations. Within the international AEROCOM initiative, the representation of aerosol-cloud-radiation interactions in ten different general circulation models (GCMs) is evaluated using three satellite datasets. The focus is on stratiform liquid water clouds since most GCMs do not include ice nucleation effects, and none of the models explicitly parameterizes aerosol effects on convective clouds. We compute statistical relationships between aerosol optical depth (τa) and various cloud and radiation quantities in a manner that is consistent between the models and the satellite data. It is found that the model-simulated influence of aerosols on cloud droplet number concentration (Nd) compares relatively well to the satellite data at least over the ocean. The relationship between τa and liquid water path is simulated much too strongly by the models. It is shown that this is partly related to the representation of the second aerosol indirect effect in terms of autoconversion. A positive relationship between total cloud fraction (fcld) and τa as found in the satellite data is simulated by the majority of the models, albeit less strongly than that in the satellite data in most of them. In a discussion of the hypotheses proposed in the literature to explain the satellite-derived strong fcld – τa relationship, our results indicate that none can be identified as unique explanation. Relationships similar to the ones found in satellite data between τa and cloud top temperature or outgoing long-wave radiation (OLR) are simulated by only a few GCMs. The GCMs that simulate a negative OLR – τa relationship show a strong positive correlation between τa and fcld. The short-wave total aerosol radiative forcing as simulated by the GCMs is strongly influenced by the simulated anthropogenic fraction of τa, and parameterisation assumptions such as a lower bound on Nd. Nevertheless, the strengths of the statistical relationships are good predictors for the aerosol forcings in the models. An estimate of the total short-wave aerosol forcing inferred from the combination of these predictors for the modelled forcings with the satellite-derived statistical relationships yields a global annual mean value of −1.5±0.5 Wm−2. An alternative estimate obtained by scaling the simulated clear- and cloudy-sky forcings with estimates of anthropogenic τa and satellite-retrieved Nd – τa regression slopes, respectively, yields a global annual mean clear-sky (aerosol direct effect) estimate of −0.4±0.2 Wm−2 and a cloudy-sky (aerosol indirect effect) estimate of −0.7±0.5 Wm−2, with a total estimate of −1.2±0.4 Wm−2.

Published
2009

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