An overview of the vertical structure of the atmospheric boundary layer in the central Arctic during MOSAiC

Atmospheric chemistry and physics, Год журнала: 2024, Номер 24(2), С. 1429 - 1450

Опубликована: Янв. 30, 2024

Abstract. Observations collected during the Multidisciplinary drifting Observatory for Study of Arctic Climate (MOSAiC) provide an annual cycle vertical thermodynamic and kinematic structure atmospheric boundary layer (ABL) in central Arctic. A self-organizing map (SOM) analysis conducted using radiosonde observations shows a range ABL from very shallow stable, with strong surface-based virtual potential temperature (θv) inversion, to deep near neutral, capped by weak elevated θv inversion. The patterns identified SOM allowed derivation criteria categorize stability within just above ABL, which revealed that MOSAiC was stable neutral similar frequencies, there always inversion lowest 1 km, usually had moderate stability. In conjunction additional measurement platforms, including 10 m meteorological tower, ceilometer, microwave radiometer, insight into relationships between stability, as well variety features. low-level jet observed 76 % radiosondes, stronger winds (LLJ) core located more closely corresponding weaker Wind shear found decrease, friction velocity increase, decreasing Clouds were 30 min preceding launch 64 time. These typically low clouds, where high clouds or no largely coincided ABL.

Язык: Английский

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Evaluation of the Planetary Boundary Layer Height From ERA5 Reanalysis With MOSAiC Observations Over the Arctic Ocean

Journal of Geophysical Research Atmospheres, Год журнала: 2024, Номер 129(12)

Опубликована: Июнь 22, 2024

Abstract The planetary boundary layer height ( PBLH ) is a crucial indicator reflecting the region of atmosphere characterized by continuous turbulence. Here, we use radiosonde and surface meteorological observations (4–7 times per day, year‐round measurements) during Multidisciplinary drifting Observatory for Study Arctic Climate (MOSAiC) expedition to derive MOSAiC ), further evaluate from ERA5 reanalysis ). Comparisons between different perspectives reveal that: (a) overestimation when sea ice concentration >90% significant with centered root mean squared error reaching up 201 m; (b) difference two products notably pronounced in cold seasons, while it comparatively diminished warm seasons; (c) In neutral layers, differences are larger compared stable convective layers. addition, analysis sources indicates that bias sensitive vertical thermal structure wind speed profiles data sets all conditions. Finally, find Random Forest model effectively reduces index agreement 0.71 test set, multiple linear regression demonstrates comparable performance model.

Язык: Английский

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An Overview of the Vertical Structure of the Atmospheric Boundary Layer in the Central Arctic during MOSAiC

Опубликована: Апрель 26, 2023

Abstract. Observations collected during the Multidisciplinary drifting Observatory for Study of Arctic Climate (MOSAiC) provide an annual cycle vertical thermodynamic and kinematic structure atmospheric boundary layer (ABL) in central Arctic. A self-organizing map (SOM) analysis conducted using radiosonde observations shows a range ABL from very shallow stable, with strong surface-based virtual potential temperature (θv) inversion, to deep near-neutral, weak elevated θv inversion. Profile DataHawk2 uncrewed aircraft system between 23 March 26 July 2020 largely sampled same profile structures, which can be further analyzed unique insight into turbulent characteristics ABL. The patterns identified by SOM allowed derivation criteria categorize stability within just above ABL, reveals that is stable near-neutral similar frequencies. In conjunction additional measurement platforms, including 10 m meteorological tower, ceilometer, microwave radiometer, relationships variety features. average height was found 150 m, increases decreasing stability. low-level jet observed 76 % radiosondes, 401 speed 11.5 s−1. At least one inversion below 5 km 99.7 base 260 intensity 4.8 °C. only cases without were those aloft. Clouds 30 minutes preceding launch 64 time. These typically low clouds, high clouds coincide amount moisture present

Язык: Английский

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A Case Study of a Wintertime Low-Level Jet Associated with a Downslope Wind Event at the Tiksi Observatory (Laptev Sea, Siberia)

Meteorology, Год журнала: 2025, Номер 4(1), С. 7 - 7

Опубликована: Март 18, 2025

Low-level jets (LLJs) are important features in the Arctic atmospheric boundary layer (ABL). In present paper, a LLJ event during winter 2014/15 is investigated, which was observed at Tiksi observatory (71.586° N, 128.918° E, 7 m asl) Laptev Sea region. Besides routine synoptic observations, data from meteorological tower and SODAR/RASS (sound detection ranging/radio acoustic sounding system) were available. The latter yielded vertical profiles of wind temperature ABL with resolution 10 temporal 20 min. addition to measurements, simulations performed using regional climate model CCLM 5 km resolution. run nesting ERA5 forecast mode, measurements used for comparison occurring 31 December 2014 1 January 2015. agreed well near-surface SODAR observations represented development very well. showed that part downslope structures over large flow preconditioned by barrier channeling Lena Valley initial phase, but forcing low dominated mature dissipation phases LLJ. High turbulence intensity occurred phase LLJ, seemed be associated wave breaking. Downslope events likely reason most LLJs Tiksi.

Язык: Английский

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Estimation of the radiation budget during MOSAiC based on ground-based and satellite remote sensing observations

Atmospheric chemistry and physics, Год журнала: 2025, Номер 25(7), С. 3929 - 3960

Опубликована: Апрель 8, 2025

Abstract. An accurate representation of the radiation budget is essential for investigating impact clouds on climate system, especially in Arctic, an environment highly sensitive to complex and rapid environmental changes. In this study, we analyse a unique dataset observations from central Arctic made during MOSAiC (Multidisciplinary drifting Observatory Study Climate) expedition conjunction with state-of-the-art satellite products CERES (Clouds Earth's Radiant Energy System) investigate radiative effect closure at surface top atmosphere (TOA). We perform series transfer simulations using derived cloud macro- microphysical properties as inputs entire period, comparing our results collocated ice-floe observations. The biases were generally within instrumental uncertainty, indicating that are sufficiently reproduce MOSAiC. Comparisons simulated relative show similar values terrestrial flux but relatively large differences solar flux, which attributed lower albedo possible underestimation atmospheric opacity by CERES. While simulation consistent observations, more detailed analyses reveal overestimation cases involving geometrically thick ice clouds. annual mean, found that, expedition, presence leads loss 5.2 W m−2 atmosphere–surface system space, while gains 25.0 cooled 30.2 m−2.

Язык: Английский

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Climatology of Low‐Level Jets Over Scandinavia and the Nordic Seas Using Model Datasets and Radiosondes

International Journal of Climatology, Год журнала: 2025, Номер unknown

Опубликована: Апрель 25, 2025

ABSTRACT Vertical wind speed profiles occasionally exhibit a maximum within the first 1–2 km above surface, called low‐level jet (LLJ). This phenomenon can occur anywhere in world. Here, we detect such jets rawinsonde data as well two reanalyses (ERA5 and CERRA) one hindcast (NORA3) over large Scandinavian domain during period 2000–2015 order to find datasets best reproducing observed LLJs, although keeping mind that some are assimilated reanalyses. We both same climatology pattern frequency, height, annual cycle of though their values differ. However, all three reanalysis/hindcast present differences compared rawinsondes, especially terms which tends be underestimated by models. When considering seven stations, CERRA seems simulate LLJs frequencies features, probably because observations reanalysis. The analysis cases shows direction is driven large‐scale atmospheric circulation, while intensity enhanced local topography. In most investigated, atmosphere stable state with temperature inversion when occur. These conditions known common formation LLJs. location (Novaya Zemlya), LLJ associated downslope winds Foehn effect. Finally, show that, for region North Sea where offshore farms may built, there spatial variability height speed. could taken into consideration energy production estimates instead prescribing fixed profile wind.

Язык: Английский

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Atmospheric Turbulent Intermittency Over the Arctic Sea‐Ice Surface During the MOSAiC Expedition

Journal of Geophysical Research Atmospheres, Год журнала: 2023, Номер 128(15)

Опубликована: Июль 19, 2023

Abstract Turbulent motions in the Arctic stable boundary layer are characterized by intermittency, but they rarely investigated due to limited observations, particular over sea‐ice surface. In present study, we explore characteristics of turbulent intermittency surface using data collected during Multidisciplinary drifting Observation for Study Climate expedition from October 2019 September 2020. We first develop a new algorithm, which performs well identifying spectral gap Then investigated. It is found that strength increases under conditions light wind speed, small speed gradient, and strong air temperature gradient. The momentum flux, sensible heat latent flux calculated raw eddy‐covariance fluctuations overestimated 3%, 10%, 24%, respectively, because submesoscale included. Furthermore, atmospheric structure various reveal low‐level jets favorable result weak while inversions above suppress lead intermittency.

Язык: Английский

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Derivation and compilation of lower-atmospheric properties relating to temperature, wind, stability, moisture, and surface radiation budget over the central Arctic sea ice during MOSAiC

Earth system science data, Год журнала: 2023, Номер 15(11), С. 4983 - 4995

Опубликована: Ноя. 10, 2023

Abstract. Atmospheric measurements taken over the span of an entire year between October 2019 and September 2020 during icebreaker-based Multidisciplinary drifting Observatory for Study Arctic Climate (MOSAiC) expedition provide insight into processes acting in atmosphere. Through merging disparate yet complementary situ observations, we can derive information about these thermodynamic kinematic with great detail. This paper describes methods used to create a lower-atmospheric properties dataset containing on several key features relating central atmospheric boundary layer, including temperature inversions, low-level jets, near-surface meteorological conditions, cloud cover, surface radiation budget. The was developed using observations from radiosondes launched at least four times per day, 10 m tower station deployed sea ice near research vessel Polarstern, ceilometer located deck Polarstern. dataset, which be found https://doi.org/10.1594/PANGAEA.957760 (Jozef et al., 2023), contains metrics fall overarching categories temperature, wind, stability, clouds, time each radiosonde launch. purpose is consistent description general layer conditions throughout MOSAiC year, aid applications overall goal gaining greater understanding governing how they may contribute future climate change.

Язык: Английский

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A model-based study of the dynamics of Arctic low-level jet events for the MOSAiC drift

Elementa Science of the Anthropocene, Год журнала: 2024, Номер 12(1)

Опубликована: Янв. 1, 2024

Low-level jets (LLJs) are studied for the period of ship-based experiment MOSAiC 2019/2020 using regional climate model Consortium Small-scale Model—Climate Limited area Mode (CCLM). The domain covers whole Arctic with 14 km resolution. CCLM is run in a forecast mode (nested ERA5) and different configurations sea ice data winter. focus on study LLJs site. detected output every 1 h. We define LLJ events as that last at least 6 Case studies shown wind lidar radiosonde well simulations. not local but embedded large jet structures extending hundreds kilometers advected toward simulations used to statistics all profiles dynamics. found about 40% hourly profiles, only 26% associated events. Strong (≥15 m/s) 13% which same fraction strong mean duration 12 characterized dynamical criteria speed profile evolution core. A 35% baroclinic, more than show contribution advection initial generation Only very few fulfill inertial oscillations. occur months, have higher frequency during turbulent kinetic energy lower atmospheric boundary layer (ABL) twice (4 times) (strong LLJs) situations without LLJs, underlines impact processes ABL.

Язык: Английский

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Air‐Ice‐Ocean Coupling During a Strong Mid‐Winter Cyclone: Observing Coupled Dynamic Interactions Across Scales

Journal of Geophysical Research Atmospheres, Год журнала: 2024, Номер 129(17)

Опубликована: Сен. 2, 2024

Abstract Arctic cyclones are key drivers of sea ice and ocean variability. During the 2019–2020 Multidisciplinary drifting Observatory for Study Climate (MOSAiC) expedition, joint observations coupled air‐ice‐ocean system were collected at multiple spatial scales. Here, we present a strong mid‐winter cyclone that impacted MOSAiC site as it drifted in central pack ice. The dynamical response showed structure scale evolving translating cyclonic wind field. Internal stress play significant roles, resulting timing offsets between atmospheric forcing post‐cyclone inertial ringing ocean. Ice motion to field then forces upper currents through frictional drag. strongest impacts from passing occur result surface low‐level jet (LLJ) behind trailing cold front changing directions warm‐sector LLJ post cold‐frontal LLJ. Impacts prolonged ice‐ocean response. Local approximately 120 km wide over 12 hr period or less scales kilometer few tens kilometers, meaning these combined smaller faster time than most satellite Earth models can resolve.

Язык: Английский

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