Observations of high-time-resolution and size-resolved aerosol chemical composition and microphysics in the central Arctic: implications for climate-relevant particle properties

Atmospheric chemistry and physics, Год журнала: 2025, Номер 25(4), С. 2207 - 2241

Опубликована: Фев. 19, 2025

Abstract. Aerosols play a critical role in the Arctic's radiative balance, influencing solar radiation and cloud formation. Limited observations central Arctic leave gaps understanding aerosol dynamics year-round, affecting model predictions of climate-relevant properties. Here, we present first annual high-time-resolution submicron chemical composition during Ocean 2018 (AO2018) 2019–2020 Multidisciplinary drifting Observatory for Study Climate (MOSAiC) expeditions. Seasonal variations mass concentrations were found to be driven by typical seasonal regimes resemble those pan-Arctic land-based stations. Organic aerosols dominated pristine summer, while anthropogenic sulfate prevailed autumn spring under haze conditions. Ammonium, which impacts acidity, was consistently less abundant, relative sulfate, compared lower latitudes Arctic. Cyclonic (storm) activity have significant influence on variability enhancing emissions from local sources transport remote aerosol. Local wind-generated particles contributed up 80 % (20 %) condensation nuclei population (spring). While analysis presented herein provides current baseline, will serve improve climate region, it also underscores importance integrating short-timescale processes, such as wind-driven blowing snow open leads/ocean simulations. This is particularly important, given decline mid-latitude increase ones.

Язык: Английский

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Low-level jets over the Arctic Ocean during MOSAiC

Elementa Science of the Anthropocene, Год журнала: 2022, Номер 10(1)

Опубликована: Янв. 1, 2022

We present an annual characterization of low-level jets (LLJs) over the Arctic Ocean using wind profiles from radiosondes launched during Multidisciplinary drifting Observatory for Study Climate expedition, October 2019 through September 2020. Our results show LLJs to be common throughout entire year, with a mean frequency occurrence more than 40%, typical height below 400 m, peaking at 120–180 and speed between 6 14 m s–1. Jet characteristics some seasonal variability: During winter freeze-up period, they are faster, average 55% speeds 8–16 s–1, while in summer transition have 46% 6–10 They similar all peak 120 180 m. The ERA5 reanalysis shows occurrence, but 75 high bias altitude, small, 0.28 slow speed. biases greater 130 is year. Examining full year whole Ocean, we find that depends strongly on both season distance sea-ice edge.

Язык: Английский

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Deciphering the Properties of Different Arctic Ice Types During the Growth Phase of MOSAiC: Implications for Future Studies on Gas Pathways

Frontiers in Earth Science, Год журнала: 2022, Номер 10

Опубликована: Авг. 9, 2022

The increased fraction of first year ice (FYI) at the expense old (second-year (SYI) and multi-year (MYI)) likely affects permeability Arctic cover. This in turn influences pathways gases circulating therein exchange interfaces with atmosphere ocean. We present sea temperature salinity time series from different types relevant to temporal development brine drainage efficiency freeze-up October onset spring warming May. Our study is based on a dataset collected during Multidisciplinary drifting Observatory for Study Climate (MOSAiC) Expedition 2019 2020. These physical properties were used derive Rayleigh numbers. main sites included FYI SYI. latter was composed an upper layer residual that had desalinated but survived previous summer melt became Below this new first-year formed. As has no direct contact atmosphere, we call it insulated (IFYI). residual/SYI-layer also contained refrozen ponds some areas. During freezing season, consistently impermeable, acting as barrier gas between While both SYI temperatures responded similarly atmospheric events, more resilient volume changes because its low ( < 2). Furthermore, later bottom growth observed comparison FYI. projected increase permeable autumn coming decades may favor atmosphere-ice interface when acts source relative atmosphere. areal extent decreasing, so thickness freeze-up. sets foundation studies dynamics within column interfaces, i.e.

Язык: Английский

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Different mechanisms of Arctic first-year sea-ice ridge consolidation observed during the MOSAiC expedition

Elementa Science of the Anthropocene, Год журнала: 2023, Номер 11(1)

Опубликована: Янв. 1, 2023

Sea-ice ridges constitute a large fraction of the ice volume in Arctic Ocean, yet we know little about evolution these masses. Here examine thermal and morphological an first-year sea-ice ridge, from its formation to advanced melt. Initially mean keel depth was 5.6 m sail height 0.7 m. The initial rubble macroporosity (fraction seawater filled voids) estimated at 29% drilling 43%–46% buoy temperature. From January until mid-April, ridge consolidated slowly by heat loss atmosphere total layer growth during this phase mid-April mid-June, there sudden increase consolidation rate despite no conductive flux. We surmise change related decreased due transport snow-slush via adjacent open leads. In period, thickness increased 2.1 At peak melt June–July suggest that refreezing surface snow meltwater (the latter only 15% consolidation). used morphology parameters calculate hydrostatic equilibrium obtained more accurate estimate actual keel, correcting 2.2 2.8 for average consolidation. This approach also allowed us 0.3 m, June–July, accompanied decrease draft 0.9 An mass balance indicated which rapid mode April June. By resulted drastic interior while flanks had or macroporosity. These results are important understanding role keels as sources sinks sanctuary ice-associated organisms pack ice.

Язык: Английский

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Arctic Sea Ice Loss Enhances the Oceanic Contribution to Climate Change

Atmosphere, Год журнала: 2023, Номер 14(2), С. 409 - 409

Опубликована: Фев. 20, 2023

Since the mid-1990s, there has been a marked decrease in sea ice extent (SIE) Arctic Ocean. After reaching an absolute minimum September 2012, seasonal variations SIE have settled at new level, which is almost one-quarter lower than average climatic norm of 1979–2022. Increased melting and accelerated export from marginal seas ensure increase open water area, affects atmosphere surface layer ocean. Scientists are cautiously predicting transition to seasonally ice-free Ocean as early middle this century, about 50 years earlier was predicted just few ago. Such predictions based on fact that thinning occurred beginning initially caused by air temperature, triggered thermal dynamic contribution ocean further reduction cover. This paper reviews published evidence such changes discusses possible mechanisms behind observed regional anomalies Sea cover parameters last decade.

Язык: Английский

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Preconditioning of Summer Melt Ponds From Winter Sea Ice Surface Temperature

Geophysical Research Letters, Год журнала: 2023, Номер 50(4)

Опубликована: Фев. 22, 2023

Abstract Comparing helicopter‐borne surface temperature maps in winter and optical orthomosaics summer from the year‐long Multidisciplinary drifting Observatory for Study of Arctic Climate expedition, we find a strong geometric correlation between warm anomalies melt pond location following summer. Warm are associated with thinner snow ice, that is, depression refrozen leads, allow water accumulation during melt. January were 0.3–2.5 K warmer on sea ice later formed ponds. A one‐dimensional steady‐state thermodynamic model shows observed differences line thickness depth. We demonstrate potential seasonal prediction coverage observations. threshold‐based classification achieves correct 41%

Язык: Английский

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Lead fractions from SAR-derived sea ice divergence during MOSAiC

˜The œcryosphere, Год журнала: 2024, Номер 18(3), С. 1259 - 1285

Опубликована: Март 19, 2024

Abstract. Leads and fractures in sea ice play a crucial role the heat gas exchange between ocean atmosphere, impacting atmospheric, ecological, oceanic processes. We estimated lead fractions from high-resolution divergence obtained satellite synthetic aperture radar (SAR) data evaluated them against existing products. derived two new fraction products with spatial resolution of 700 m calculated daily Sentinel-1 images. For first product, we advected accumulated individual time instances. With those divergence-derived fractions, comprehensively described presence up to 10 d old leads analyzed their deformation history. second used only pixels that were identified as part linear kinematic features (LKFs). Both accurately captured formation widths few hundred meters. presented Lagrangian series divergence-based along drift Multidisciplinary drifting Observatory for Study Arctic Climate (MOSAiC) expedition central Ocean during winter 2019–2020. Lead activity was high fall spring, consistent wind forcing pack consolidation. At larger scales 50–150 km around MOSAiC expedition, on all similar, but differences emerged at smaller (10 km). compared our six others airborne sources, including classified SAR, thermal infrared, microwave radiometer, altimeter data. found mean varied by 1 order magnitude across different due physical properties observed sensors methodological factors such resolution. Thus, choice product should align specific application.

Язык: Английский

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HESS Opinions: Towards a common vision for the future of hydrological observatories

Hydrology and earth system sciences, Год журнала: 2025, Номер 29(2), С. 465 - 483

Опубликована: Янв. 23, 2025

Abstract. The Unsolved Problems in Hydrology (UPH) initiative has emphasized the need to establish networks of multi-decadal hydrological observatories gain a deep understanding complex hydrologic processes occurring within diverse environmental conditions. already existing monitoring infrastructures have provided an enormous amount hydrometeorological data, facilitating detailed insights into causal mechanisms processes, testing scientific theories and hypotheses, revelation physical laws governing catchment behavior. Yet, programs often produced limited outcomes due intermittent availability financial resources substantial efforts required operate conduct comparative studies advance previous findings. Recently, some initiatives emerged that aim coordinate data acquisition hypothesis facilitate efficient cross-site synthesis To this end, common vision practical management solutions be developed. This opinion paper provocatively discusses two potential endmembers future observatory (HO) network based on given hypothesized community budget: comprehensive set moderately instrumented or, alternatively, small number highly supersites. A sites would provide broad spatial coverage across major pedoclimatic regions by supporting lumped response (e.g., rainfall–runoff relationship, Budyko analysis) continental landscapes. However, moderate instrumentation at each site may hamper in-depth processes. In contrast, extensively research enable community-based experiments unprecedented manner, thereby deeper complex, non-linear modulated scale-dependent feedback multiscale spatiotemporal heterogeneity. Lumping proven effective strategy other geosciences, e.g., vessels oceanography drilling geology. On downside, limitation approach is few catchments will not representative all regions, necessitating consideration generalization issues. discussion relative merits limitations these visions regarding HOs presented build consensus optimal path for address UPH coming decades. final proposes integrating flexible strategy. Keywords: network, experimental catchments, synthesis, vs. exploratory science, unsolved problems hydrology, societal needs, technology advancements.

Язык: Английский

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Observations of surface energy fluxes and meteorology in the seasonally snow-covered high-elevation East River watershed during SPLASH, 2021–2023

Earth system science data, Год журнала: 2025, Номер 17(4), С. 1481 - 1499

Опубликована: Апрель 11, 2025

Abstract. From autumn 2021 through summer 2023, scientists from the National Oceanic and Atmospheric Administration (NOAA) partners conducted Study of Precipitation, Lower Atmosphere, Surface for Hydrometeorology (SPLASH) campaign in East River watershed Colorado. One objective SPLASH was to observe transfer energy between atmosphere surface, which done at several locations. Two remote sites were chosen that did not have access power utilities. These along valley floor near vicinity unincorporated town Gothic, Energy balance measurements made these locations using autonomous, single-level flux towers referred as atmospheric surface stations (ASFSs). The ASFSs deployed on 28 September Kettle Ponds Annex site 12 October Avery Picnic operated until 19 July 21 June respectively. Measurements included basic meteorology; upward downward longwave shortwave radiative fluxes subsurface conductive flux, each 1 min resolution; 3-D winds a sonic anemometer H2O/CO2 an open-path gas analyzer, both 20 Hz sensible, latent heat, CO2 derived; profiles soil properties upper 0.5 m (both sites) temperature snow (at Picnic), reported 10 6 h. system uptime 97 % (Kettle Ponds) 90 (Avery collectively 1184 d data obtained stations. purpose this article is document ASFS deployment SPLASH, acquisition post-processing measurements, serve guide interested users sets, are archived Zenodo (https://doi.org/10.5281/zenodo.10313363, Cox et al., 2023b; https://doi.org/10.5281/zenodo.10327409, 2023c; https://doi.org/10.5281/zenodo.10313894, 2023d; https://doi.org/10.5281/zenodo.10307825, 2023e; https://doi.org/10.5281/zenodo.10310520, 2023f) with Creative Commons Attribution 4.0 International license.

Язык: Английский

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Meltwater layer dynamics in a central Arctic lead: Effects of lead width, re-freezing, and mixing during late summer

Elementa Science of the Anthropocene, Год журнала: 2023, Номер 11(1)

Опубликована: Янв. 1, 2023

Leads play an important role in the exchange of heat, gases, vapour, and particles between seawater atmosphere ice-covered polar oceans. In summer, these processes can be modified significantly by formation a meltwater layer at surface, yet we know little about dynamics persistence. During drift campaign Multidisciplinary drifting Observatory for Study Arctic Climate (MOSAiC), examined how variation lead width, re-freezing, mixing events affected vertical structure waters during late summer central Arctic. At beginning 4-week survey period, occupied surface 0.8 m lead, temperature salinity showed strong gradients. Stable oxygen isotopes indicate that consisted mainly sea ice rather than snow meltwater. first half period (before freezing), thickness decreased rapidly as width increased stretched horizontally. latter (after freezing surface), stratification weakened became thinner before disappearing completely due to processes. Removal explained 43% reduction layer. The remaining approximate 57% could within water column initiated disturbance lower boundary through wind-induced floe drift. These results rapid, dynamic changes have potentially significant effects on physical biogeochemical components throughout atmosphere–lead–underlying system.

Язык: Английский

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