Divergent consensuses on Arctic amplification influence on midlatitude severe winter weather

Nature Climate Change, Journal Year: 2019, Volume and Issue: 10(1), P. 20 - 29

Published: Dec. 23, 2019

Language: Английский

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Overview of the MOSAiC expedition: Atmosphere

Elementa Science of the Anthropocene, Journal Year: 2022, Volume and Issue: 10(1)

Published: Jan. 1, 2022

With the Arctic rapidly changing, needs to observe, understand, and model changes are essential. To support these needs, an annual cycle of observations atmospheric properties, processes, interactions were made while drifting with sea ice across central during Multidisciplinary Observatory for Study Climate (MOSAiC) expedition from October 2019 September 2020. An international team designed implemented comprehensive program document characterize all aspects system in unprecedented detail, using a variety approaches, multiple scales. These measurements coordinated other observational teams explore cross-cutting coupled Ocean, ice, ecosystem through physical biogeochemical processes. This overview outlines breadth complexity research program, which was organized into 4 subgroups: state, clouds precipitation, gases aerosols, energy budgets. Atmospheric variability over revealed important influences persistent large-scale winter circulation pattern, leading some storms pressure winds that outside interquartile range past conditions suggested by long-term reanalysis. Similarly, MOSAiC location warmer wetter summer than reanalysis climatology, part due its close proximity edge. The comprehensiveness characterizing analyzing phenomena is demonstrated via case study examining air mass transitions vertical evolution. Overall, successfully met objectives most measurement date conducted ice. obtained data will broad coupled-system scientific provide foundation advancing multiscale modeling capabilities Arctic.

Language: Английский

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Aerosols in current and future Arctic climate

Nature Climate Change, Journal Year: 2021, Volume and Issue: 11(2), P. 95 - 105

Published: Feb. 1, 2021

Language: Английский

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Radiative Effect of Clouds at Ny-Ålesund, Svalbard, as Inferred from Ground-Based Remote Sensing Observations

Journal of Applied Meteorology and Climatology, Journal Year: 2019, Volume and Issue: 59(1), P. 3 - 22

Published: Oct. 25, 2019

Abstract For the first time, cloud radiative effect (CRE) has been characterized for Arctic site Ny-Ålesund, Svalbard, Norway, including more than 2 years of data (June 2016–September 2018). The effect, that is, difference between all-sky and equivalent clear-sky net fluxes, derived based on a combination ground-based remote sensing observations properties application broadband transfer simulations. simulated fluxes have evaluated in terms closure study. Good agreement with observed surface shortwave (SW) longwave (LW) found, small biases (SW: 3.8 W m −2 ; LW: −4.9 ) −5.4 −0.2 situations. monthly averages, uncertainties CRE are estimated to be (~2 ). At is positive from September April/May negative summer. annual warming by clouds 11.1 . liquid-containing mainly driven liquid water path (LWP) an asymptote value 75 large LWP values. can largely explained LWP, solar zenith angle, albedo. Liquid-containing (LWP > 5 g clearly contribute most (70%–98%) and, late spring autumn, also (up 95%). Only winter ice (IWP 0 < equally important or even dominating signal CRE.

Language: Английский

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The unexpected smoke layer in the High Arctic winter stratosphere during MOSAiC 2019–2020

Atmospheric chemistry and physics, Journal Year: 2021, Volume and Issue: 21(20), P. 15783 - 15808

Published: Oct. 22, 2021

Abstract. During the 1-year MOSAiC (Multidisciplinary drifting Observatory for Study of Arctic Climate) expedition, German icebreaker Polarstern drifted through Ocean ice from October 2019 to May 2020, mainly at latitudes between 85 and 88.5∘ N. A multiwavelength polarization Raman lidar was operated on board research vessel continuously monitored aerosol cloud layers up a height 30 km. our mission, we expected observe thin residual volcanic layer in stratosphere, originating Raikoke eruption June 2019, with an optical thickness (AOT) 0.005–0.01 500 nm over North Pole area during winter season. However, highlight measurements detection persistent, 10 km deep upper troposphere lower stratosphere (UTLS), about 7–8 17–18 height, clear unambiguous wildfire smoke signatures 12 order magnitude higher AOT around 0.1 autumn 2019. Case studies are presented explain specific fingerprints aged detail. The pronounced present throughout half-year until strong polar vortex began collapse late April 2020. We hypothesize that detected originated extraordinarily intense long-lasting wildfires central eastern Siberia July August may have reached tropopause by self-lifting process. In this article, summarize main findings 7-month observations characterize terms geometrical, optical, microphysical properties. UTLS 532 ranged 0.05–0.12 October–November 0.03–0.06 fraction estimated always be than 15 %. assume above (above 13 height). As sign dominance 7–13 particle extinction-to-backscatter ratio (lidar ratio) 355 found much nm, mean values 55 sr, respectively. 355–532 Ångström exponent 0.65 also clearly indicated presence aerosol. For first time, show distinct view layering features High surface half-year. Finally, provide vertically resolved early spring conditions regarding ozone depletion, occurrence, stratospheric formation. latter will largely stimulate potential impact unexpected perturbation record-breaking depletion

Language: Английский

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Future warming exacerbated by aged-soot effect on cloud formation

Nature Geoscience, Journal Year: 2020, Volume and Issue: 13(10), P. 674 - 680

Published: Sept. 29, 2020

Language: Английский

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Wildfire smoke, Arctic haze, and aerosol effects on mixed-phase and cirrus clouds over the North Pole region during MOSAiC: an introduction

Atmospheric chemistry and physics, Journal Year: 2021, Volume and Issue: 21(17), P. 13397 - 13423

Published: Sept. 9, 2021

Abstract. An advanced multiwavelength polarization Raman lidar was operated aboard the icebreaker Polarstern during MOSAiC (Multidisciplinary drifting Observatory for Study of Arctic Climate) expedition to continuously monitor aerosol and cloud layers in central up 30 km height. The lasted from September 2019 October 2020 measurements were mostly taken between 85 88.5∘ N. integrated into a complex remote-sensing infrastructure Polarstern. In this article, novel techniques, innovative concepts study aerosol–cloud interaction Arctic, unique findings will be presented. highlight detection 10 deep wildfire smoke layer over North Pole region 7–8 17–18 height with an optical thickness (AOT) at 532 nm around 0.1 (in October–November 2019) 0.05 December March. dual-wavelength technique allowed us unambiguously identify as dominating type upper troposphere lower stratosphere (UTLS). additional contribution AOT by volcanic sulfate (Raikoke eruption) estimated always than 15 %. microphysical properties UTLS are presented accompanying paper (Ohneiser et al., 2021). This event offered opportunity influence organic particles (serving ice-nucleating particles, INPs) on cirrus formation troposphere. example closure is explain our concept investigating field. obviously able control evolution system caused low ice crystal number concentration. After discussion two typical haze events, we present case long-lasting mixed-phase embedded free recently introduced dual-field-of-view applied, first time, observations order determine water droplets. experiment (based combined radar observations) indicated that observed levels controlled concentrations nucleated droplets crystals.

Language: Английский

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Ship-based measurements of ice nuclei concentrations over the Arctic, Atlantic, Pacific and Southern oceans

Atmospheric chemistry and physics, Journal Year: 2020, Volume and Issue: 20(23), P. 15191 - 15206

Published: Dec. 8, 2020

Abstract. Ambient concentrations of ice-forming particles measured during ship expeditions are collected and summarised with the aim determining spatial distribution variability in ice nuclei oceanic regions. The presented data from literature previously unpublished over 23 months ship-based measurements stretch Arctic to Southern Ocean include a circumnavigation Antarctica. In comparison continental observations, ambient show 1 2 orders magnitude lower mean concentrations. To quantify geographical areas, concentration range potential different climate zones is analysed by meridionally dividing expedition tracks into tropical, temperate polar zones. We find that these meridional follow temperature spectra similar slopes but vary absolute concentration. Typically, frequency which specific observed at certain follows log-normal distribution. A consequence higher than most frequently Finally, contribution exhaust on board research vessels as function temperature. sharp onset influence approximately −36 ∘C none warmer temperatures could bias measurements.

Language: Английский

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PAMTRA 1.0: the Passive and Active Microwave radiative TRAnsfer tool for simulating radiometer and radar measurements of the cloudy atmosphere

Geoscientific model development, Journal Year: 2020, Volume and Issue: 13(9), P. 4229 - 4251

Published: Sept. 13, 2020

Abstract. Forward models are a key tool to generate synthetic observations given knowledge of the atmospheric state. In this way, they an integral part inversion algorithms that aim retrieve geophysical variables from or in data assimilation. Their application for exploitation full information content remote sensing becomes increasingly important when these used evaluate performance cloud-resolving (CRMs). Herein, CRM profiles fields provide input forward model whose simulation results subsequently compared observations. This paper introduces freely available comprehensive microwave PAMTRA (Passive and Active Microwave TRAnsfer), demonstrates its capabilities simulate passive active measurements across spectral region upward- downward-looking geometries, illustrates how simulations can be CRMs interpret improve our understanding cloud processes. is unique as it treats radiative transfer (RT) consistent way with providing upwelling downwelling polarized brightness temperatures radiances arbitrary observation angles. The capable simulating radar Doppler spectrum moments. designed flexible respect instrument specifications interfaces many different formats output, especially CRMs, spanning range bin-resolved microphysical output one- two-moment schemes, situ measured hydrometeor properties. A specific highlight incorporation self-similar Rayleigh–Gans approximation (SSRGA) both applications, which investigation frozen hydrometeors.

Language: Английский

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Reassessment of shortwave surface cloud radiative forcing in the Arctic: consideration of surface-albedo–cloud interactions

Atmospheric chemistry and physics, Journal Year: 2020, Volume and Issue: 20(16), P. 9895 - 9914

Published: Aug. 26, 2020

Abstract. The concept of cloud radiative forcing (CRF) is commonly applied to quantify the impact clouds on surface energy budget (REB). In Arctic, specific interactions between microphysical and macrophysical properties strongly modify warming or cooling effect clouds, complicating estimate CRF obtained from observations models. Clouds tend increase broadband albedo over snow sea ice surfaces compared cloud-free conditions. However, this not adequately considered in derivation Arctic so far. Therefore, we have quantified effects caused by surface-albedo–cloud highly reflective using transfer simulations below-cloud airborne above heterogeneous springtime marginal zone (MIZ) during CLoud Observations Using measurements polar Day (ACLOUD) campaign. a modified presence as conditions, its dependence optical thickness found be relevant for estimation shortwave CRF. A method proposed consider estimates continuously retrieving under cloudy an available parameterization. ACLOUD data reveals that estimated average almost doubles snow- ice-covered (−62 W m−2 instead −32 m−2), if are considered. As result, observed total (shortwave plus longwave) shifted neutral one. Concerning seasonal cycle albedo, it demonstrated enhances periods when dominates potentially weakens optically thin summertime melting season. These findings suggest interaction should global climate models long-term studies obtain realistic role amplification.

Language: Английский

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