Sensitivity of Arctic sulfate aerosol and clouds to changes  in future surface seawater dimethylsulfide concentrations

Mahmood, Rashed; Salzen, Knut von; Norman, Ann‐Lise; Galí, Martí; Levasseur, Maurice

doi:10.5194/acp-19-6419-2019

Cited by 36 publications

(24 citation statements)

References 87 publications

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“…Nitrate and silicic acid concentrations in the SML were limiting, with values below 0.6 and 0.9 µmol L −1 , respectively, indicating that most of the nutrients, initially present in the surface, had already been consumed by the primary producers. The exhaustion of nitrate in surface waters, the deepening of the nitracline, and the development of a SCM are typical features of summer conditions in several regions of the Arctic as demonstrated by a host of comprehensive investigations (Tremblay et al, 2008;Mundy et al, 2009;Martin et al, 2010;Ardyna et al, 2013;Brown et al, 2015;Steiner et al, 2015).…”

Section: The Fyi Edge In Barrow Strait and The Adjacent Lancaster Soundmentioning

confidence: 99%

Phytoplankton and dimethylsulfide dynamics at two contrasting Arctic ice edges

et al. 2020

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Abstract. Arctic sea ice is retreating and thinning and its rate of decline has steepened in the last decades. While phytoplankton blooms are known to seasonally propagate along the ice edge as it recedes from spring to summer, the substitution of thick multiyear ice (MYI) with thinner, ponded first-year ice (FYI) represents an unequal exchange when considering the roles sea ice plays in the ecology and climate of the Arctic. Consequences of this shifting sea ice on the phenology of phytoplankton and the associated cycling of the climate-relevant gas dimethylsulfide (DMS) and its precursor dimethylsulfoniopropionate (DMSP) remain ill constrained. In July–August 2014, two contrasting ice edges in the Canadian High Arctic were explored: a FYI-dominated ice edge in Barrow Strait and a MYI-dominated ice edge in Nares Strait. Our results reveal two distinct planktonic systems and associated DMS dynamics in connection to these diverging ice types. The surface waters exiting the ponded FYI in Barrow Strait were characterized by moderate chlorophyll a (Chl a, <2.1 µg L−1) as well as high DMSP (115 nmol L−1) and DMS (12 nmol L−1), suggesting that a bloom had already started to develop under the markedly melt-pond-covered (ca. 40 %) FYI. Heightened DMS concentrations at the FYI edge were strongly related to ice-associated seeding of DMS in surface waters and haline-driven stratification linked to ice melt (Spearman's rank correlation between DMS and salinity, rs=-0.91, p<0.001, n=20). However, surface waters exiting the MYI edge at the head of Nares Strait were characterized by low concentrations of Chl a (<0.5 µg L−1), DMSP (<16 nmol L−1), and DMS (<0.4 nmol L−1), despite the nutrient-replete conditions characterizing the surface waters. The increase in autotrophic biomass and methylated sulfur compounds took place several kilometers (ca. 100 km) away from the MYI edge, suggesting the requisite for ice-free, light-sufficient conditions for a phytoplankton bloom to fully develop and for sulfur compound dynamics to follow and expand. In light of the ongoing and projected climate-driven changes to Arctic sea ice, results from this study suggest that the early onset of autotrophic blooms under thinner, melt-pond-covered ice may have vast implications for the timing and magnitude of DMS pulses in the Arctic.

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Section: The Fyi Edge In Barrow Strait and The Adjacent Lancaster Soundmentioning

confidence: 99%

Phytoplankton and dimethylsulfide dynamics at two contrasting Arctic ice edges

et al. 2020

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“…Recent modelling studies have examined the impact of DMS on Arctic aerosols. Marelle et al (2017) updated the WRF-Chem regional model by adding DMS(g) and reported an improvement in surface sulfate estimates in the Arctic. Mahmood et al (2019) evaluated the impact of DMS(g) emission on the formation of sulfate aerosol, CCN and cloud radiative forcing in a global climate model.…”

Section: Introductionmentioning

confidence: 99%

“…Marelle et al (2017) updated the WRF-Chem regional model by adding DMS(g) and reported an improvement in surface sulfate estimates in the Arctic. Mahmood et al (2019) evaluated the impact of DMS(g) emission on the formation of sulfate aerosol, CCN and cloud radiative forcing in a global climate model. Although they did not find a significant increase in sulfate aerosol, they predicted higher nucleation rates, increased sulfate deposition and an increase in the cloud droplet number concentration.…”

Section: Introductionmentioning

confidence: 99%

Dimethyl sulfide and its role in aerosol formation and growth in the Arctic summer – a modelling study

Ghahremaninezhad

Gong

Galí³

et al. 2019

Atmos. Chem. Phys.

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Abstract. Atmospheric dimethyl sulfide, DMS(g), is a climatically important sulfur compound and is the main source of biogenic sulfate aerosol in the Arctic atmosphere. DMS(g) production and emission to the atmosphere increase during the summer due to the greater ice-free sea surface and higher biological activity. We implemented DMS(g) in the Environment and Climate Change Canada’s (ECCC) online air quality forecast model, GEM-MACH (Global Environmental Multiscale–Modelling Air quality and CHemistry), and compared model simulations with DMS(g) measurements made in Baffin Bay and the Canadian Arctic Archipelago in July and August 2014. Two seawater DMS(aq) datasets were used as input for the simulations: (1) a DMS(aq) climatology dataset based on seawater concentration measurements (Lana et al., 2011) and (2) a DMS(aq) dataset based on satellite detection (Galí et al., 2018). In general, GEM-MACH simulations under-predict DMS(g) measurements, which is likely due to the negative biases in both DMS(aq) datasets. However, a higher correlation and smaller bias were obtained with the satellite dataset. Agreement with the observations improved when climatological values were replaced by DMS(aq) in situ values that were measured concurrently with atmospheric observations over Baffin Bay and the Lancaster Sound area in July 2014. The addition of DMS(g) to the GEM-MACH model resulted in a significant increase in atmospheric SO2 for some regions of the Canadian Arctic (up to 100 %). Analysis of the size-segregated sulfate aerosol in the model shows that a significant increase in sulfate mass occurs for particles with a diameter smaller than 200 nm due to the formation and growth of biogenic aerosol at high latitudes (>70∘ N). The enhancement in sulfate particles is most significant in the size range from 50 to 100 nm; however, this enhancement is stronger in the 200–1000 nm size range at lower latitudes (<70∘ N). These results emphasize the important role of DMS(g) in the formation and growth of fine and ultrafine sulfate-containing particles in the Arctic during the summertime.

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“…Marelle et al (2017) updated the WRF-Chem regional model by adding DMS(g) and reported an improvement of surface sulfate estimates in the Arctic. Mahmood et al (2019) evaluated the impact of DMS(g) emission on the formation of sulfate aerosol, CCN and cloud radiative forcing in global climate model. Although they did not find a significant increase of sulfate aerosol, they predicted higher nucleation rates, increased sulfate deposition, and an increase of cloud droplet number concentration.…”

Section: Introductionmentioning

confidence: 99%

Dimethyl sulfide and its role in aerosol formation and growth in the Arctic summer – a modelling study

Ghahremaninezhad¹,

Gong²,

Galí³

et al. 2019

Preprint

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Abstract. Atmospheric dimethyl sulfide, DMS(g), is a climatically important sulfur compound and is the main source of biogenic sulfate aerosol in the Arctic atmosphere. DMS(g) production and emission to the atmosphere increase during the summer due to greater ice-free sea surface and higher biological activity. We implemented DMS(g) in the GEM-MACH model (GEM: Global Environmental Multiscale &#8211; Environment and Climate Change Canada's (ECCC) numerical weather forecast model, MACH: ECCC's Modelling Air quality and CHemistry &#8211; chemistry and aerosol microphysics) for the Arctic region, and compared model simulations with DMS(g) measurements made in Baffin Bay and the Canadian Arctic Archipelago in July and August 2014. Two sea water DMS(aq) datasets were used as input to the simulations: (1) DMS(aq) climatology dataset based on seawater concentration measurements (Lana et al., 2011) and (2) DMS(aq) dataset based on satellite detection (Gali&#769; et al., 2018). In general, GEM-MACH simulations underpredict DMS(g) measurements, likely due to negative biases in both DMS(aq) datasets. Yet, higher correlation and smaller bias were obtained with the satellite dataset. Agreement with the observations improved by replacing climatological values with in situ measured DMS(aq) concurrently with atmospheric observations over Baffin Bay and Lancaster Sound area in July 2014. The addition of DMS(g) to the GEM-MACH model resulted in a significant increase in atmospheric SO2 for some regions in the Canadian Arctic (up to 100&#8201;%). Analysis of the size-segregated sulfate aerosol in the model shows that a significant increase in sulfate mass occurs for particles with a diameter smaller than 200&#8201;nm due to formation and growth of biogenic aerosol at high latitudes (>&#8201;70&#176;&#8201;N). The enhancement in sulfate particles is most significant in the size range of 50 to 100&#8201;nm, however, this enhancement is stronger in the 200&#8211;1000&#8201;nm size range at lower latitudes (<&#8201;70&#176;&#8201;N). These results emphasise the important role of DMS(g) in the formation and growth of fine and ultrafine sulfate-containing particles in the Arctic during the month of July.

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Sensitivity of Arctic sulfate aerosol and clouds to changes in future surface seawater dimethylsulfide concentrations

Cited by 36 publications

References 87 publications

Phytoplankton and dimethylsulfide dynamics at two contrasting Arctic ice edges

Phytoplankton and dimethylsulfide dynamics at two contrasting Arctic ice edges

Dimethyl sulfide and its role in aerosol formation and growth in the Arctic summer – a modelling study

Dimethyl sulfide and its role in aerosol formation and growth in the Arctic summer – a modelling study

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