Effect of Ice Number Concentration on the Evolution of Boundary Layer Clouds During Arctic Marine Cold‐Air Outbreaks

Journal of Geophysical Research Atmospheres, Journal Year: 2025, Volume and Issue: 130(3)

Published: Feb. 6, 2025

Abstract Marine cold‐air outbreaks (MCAOs) are crucial for Arctic Ocean heat loss, featuring convective cloud rolls that transition into convection cells downstream. Understanding factors controlling this transformation is the key improving MCAO representation in climate models. This study employs large‐eddy simulations to investigate how ice number concentrations () affect evolution using a case from Cold‐Air Outbreaks Boundary Layer Experiment (COMBLE) campaign. The simulations, performed Lagrangian framework following an air mass trajectory, driven by ERA5 reanalysis data. Initially, all produce similar patterns, but higher leads earlier breakup of rolls. Between 4 and 10 hr, surface precipitation rates across initiates earlier, cloud‐base when higher. stronger evaporation increased stability boundary layer reduced intensity vertical mixing between layer. An sink moisture via decreased source through diminished transport result conditions. Simulations with different sea temperatures (SST) indicate mechanism remains valid MCAOs strengths, although organization more sensitive SST changes low environments. work highlights importance accurate representations processes simulating clouds suggests need observational constraints nucleating particles over mixed‐phase regimes.

Language: Английский

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Overview: quasi-Lagrangian observations of Arctic air mass transformations – introduction and initial results of the HALO–(𝒜 𝒞)³ aircraft campaign

Atmospheric chemistry and physics, Journal Year: 2024, Volume and Issue: 24(15), P. 8865 - 8892

Published: Aug. 13, 2024

Abstract. Global warming is amplified in the Arctic. However, numerical models struggle to represent key processes that determine Arctic weather and climate. To collect data help constrain models, HALO–(𝒜𝒞)3 aircraft campaign was conducted over Norwegian Greenland seas, Fram Strait, central Ocean March April 2022. The focused on one specific challenge posed by namely reasonable representation of transformations air masses during their meridional transport into out via northward moist- warm-air intrusions (WAIs) southward marine cold-air outbreaks (CAOs). Observations were made areas open ocean, marginal sea ice zone, ice. Two low-flying long-range, high-altitude research flown colocated formation whenever possible. follow mass transformations, a quasi-Lagrangian flight strategy using trajectory calculations realized, enabling us sample same moving-air parcels twice along trajectories. Seven distinct WAI 12 CAO cases probed. From measurements, we have quantified diabatic heating/cooling moistening/drying transported masses. During CAOs, maximum values 3 K h−1 0.3 g kg−1 moistening obtained below 1 km altitude. observations WAIs, cooling rates up 0.4 moisture loss 0.1 from ground about 5.5 altitude derived. Furthermore, development cloud macrophysical (cloud-top height horizontal cover) microphysical (liquid water path, precipitation, index) properties pathways documented budget event estimated. In addition, discuss statistical frequency occurrence different thermodynamic phases low-level clouds, interaction cirrus clouds with vapor, characteristics chemical aerosol particles. Finally, provide proof concept measure mesoscale divergence subsidence dropsondes released flights.

Language: Английский

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Thermodynamic and cloud evolution in a cold-air outbreak during HALO-(AC)³: quasi-Lagrangian observations compared to the ERA5 and CARRA reanalyses

Atmospheric chemistry and physics, Journal Year: 2024, Volume and Issue: 24(6), P. 3883 - 3904

Published: April 2, 2024

Abstract. Arctic air masses undergo intense transformations when moving southward from closed sea ice to warmer open waters in marine cold-air outbreaks (CAOs). Due the lack of measurements diabatic heating and moisture uptake rates along CAO flows, studies often depend on atmospheric reanalysis output. However, uncertainties connected those datasets remain unclear. Here, we present height-resolved airborne observations heating, uptake, cloud evolution measured a quasi-Lagrangian manner. The investigated was observed 1 April 2022 during HALO-(AC)3 campaign. Shortly after passing sea-ice edge, maximum over 6 K h−1 0.3 gkg-1h-1 were near surface. Clouds started forming vertical mixing within deepening boundary layer intensified. are compared with fifth-generation global (ERA5) Copernicus Regional Reanalysis (CARRA). Compared these observations, mean absolute errors ERA5 versus CARRA data 14 % higher for temperature (1.14 1.00 K) 62 specific humidity ice-free ocean (0.112 g kg−1 0.069 kg−1). We relate differences issues representation marginal zone corresponding surface fluxes ERA5, as well scheme producing excess liquid-bearing, precipitating clouds, which causes too-dry layer. CARRA's high spatial resolution demonstrated fidelity towards make it promising candidate further mass transformations.

Language: Английский

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A comprehensive in situ and remote sensing data set collected during the HALO–(𝒜 𝒞)³ aircraft campaign

Earth system science data, Journal Year: 2025, Volume and Issue: 17(3), P. 1295 - 1328

Published: April 1, 2025

Abstract. The HALO–(𝒜𝒞)3 aircraft campaign was carried out in March and April 2022 over the Norwegian Greenland seas, Fram Strait, central Arctic Ocean. Three research – High Altitude Long Range Research Aircraft (HALO), Polar 5, 6 performed 54 partly coordinated flights on 23 flight days areas of open ocean, marginal sea ice zone (MIZ), ice. general objective to quantify evolution air mass properties during moist warm-air intrusions (WAIs) cold-air outbreaks (CAOs). To obtain a comprehensive data set, three operated following different strategies. HALO equipped with active passive remote sensing instruments dropsondes cover regional cloud thermodynamic processes. 5 similar payload HALO, instrumented situ cloud, aerosol, trace gas focusing initial transformation close MIZ. processed, calibrated, validated are published World Data Center PANGAEA as instrument-separated subsets listed aircraft-separated collections for (Ehrlich et al., 2024a, https://doi.org/10.1594/PANGAEA.968885), (Mech https://doi.org/10.1594/PANGAEA.968883), (Herber 2024, https://doi.org/10.1594/PANGAEA.968884). A detailed overview available sets is provided here. Furthermore, campaign-specific instrument setup, processing, quality summarized. Based measurements conducted specific CAO, it shown that scientific analysis benefits from operation aircraft.

Language: 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, Journal Year: 2025, Volume and Issue: 25(7), P. 3929 - 3960

Published: April 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.

Language: Английский

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Unveiling Cloud Microphysics of Marine Cold Air Outbreaks Through A-Train’s Active Instrumentation

Atmosphere, Journal Year: 2025, Volume and Issue: 16(5), P. 518 - 518

Published: April 28, 2025

Marine Cold Air Outbreaks (MCAOs) are critical drivers of high-latitude climates because they regulate the exchange heat, moisture, and momentum between cold continental or polar air masses relatively warmer ocean surfaces. In this study, we combined CloudSat–CALIPSO observations (2007–2017) with ERA5 reanalysis data to investigate microphysical properties vertical structure snowfall during MCAOs. By classifying events using a low-level instability parameter, provide detailed comparison spatial characteristics different regimes, focusing on key cloud such as effective radius, particle concentration, ice water content. Our analysis identified two distinct regimes: shallow stratocumulus-dominated snowfall, prevalent typical MCAOs characterized by top heights below 3 km comparatively lower content (IWC), deeper occurring non-CAO conditions. We demonstrate that, despite their instantaneous rates, CAO-related cumulatively contribute significantly total mass production in subpolar North Atlantic. Additionally, CAO greater number particles near surface, which also smaller (reff 59 μm versus 62 μm) than those associated events. These differences impact optical properties, influencing surface radiative balance.

Language: Английский

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Developing a Lagrangian Frame Transformation on Satellite Data to Study Cloud Microphysical Transitions in Arctic Marine Cold Air Outbreaks

Geophysical Research Letters, Journal Year: 2025, Volume and Issue: 52(9)

Published: May 8, 2025

Abstract Arctic marine cold air outbreaks (CAOs) generate distinct and dynamic cloud regimes due to intense air‐sea interactions. To understand the temporal evolution of CAO properties compare different events, a Lagrangian perspective is particularly useful. We developed novel technique that enables conversion inherently Eulerian satellite data into framework, combining broad spatiotemporal coverage observations with advantages tracking. This was applied eight cases associated recent field campaign. Our results reveal striking contrast among in terms cloud‐top phase transitions, providing new insights properties.

Language: Английский

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A stratocumulus to cumulus transition during a cold-air outbreak: The role of aerosols

Atmospheric Research, Journal Year: 2025, Volume and Issue: unknown, P. 108211 - 108211

Published: May 1, 2025

Language: Английский

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Cloud Characteristics during Intense Cold Air Outbreaks over the Barents Sea Based on Satellite Data

Atmosphere, Journal Year: 2024, Volume and Issue: 15(3), P. 317 - 317

Published: March 2, 2024

The Arctic experiences remarkable changes in environmental parameters that affect fluctuations the surface energy budget, including radiation and sensible latent heat fluxes. Cold air masses cloud transformations during marine cold outbreaks (MCAOs) substantially influence radiative fluxes, thereby shaping link between large-scale dynamics, sea ice conditions, budget. In this study, we investigate various characteristics intense MCAOs over Barents Sea from 2000 to 2018 using satellite data. We identify 72 MCAO events propagated southward reanalysis data of temperature potential at 800 hPa level. macro- microphysical properties clouds within selected MCAOs, their dependence on concentration, initial mass A significant increase low-level near edge (up +25% anomalies) a smooth transition upper-level is revealed. total top height generally 500–700 m lower than under neutral conditions. induce positive net effect, which peaks +20 W m−2 (100 km edge) gradually decreases towards continent (−2.3 per 100 km). Our study provides evidence for importance effect should be accurately simulated regional global climate models.

Language: Английский

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Air mass history linked to the development of Arctic mixed-phase clouds

Atmospheric chemistry and physics, Journal Year: 2024, Volume and Issue: 24(19), P. 11115 - 11132

Published: Oct. 7, 2024

Abstract. Clouds formed during marine cold-air outbreaks (MCAOs) exhibit a distinct transition from stratocumulus decks near the ice edge to broken cumuliform fields further downwind. The mechanisms associated with formation are believed be crucial in driving this transition, yet factors influencing such remain unclear. Through Lagrangian trajectories collocated satellite data, study investigates development of mixed-phase clouds using these outbreaks. Cloud MCAOs characterized by swift shift liquid ice-containing states, contrasting non-MCAO also moving off edge. These predominantly observed at temperatures below −20 °C However, into outbreak, they become dominant as high −13 °C. This is consistent influence biological ice-nucleating particles (INPs), which more prevalent air mass ages over ocean. evolution closely linked history mass, especially length time it spends snow- and ice-covered surfaces – terrains may that deficient INPs. connection accounts for seasonal variations Arctic clouds, both within outside MCAO events. findings highlight importance understanding local aerosol sources overarching INP distribution modelling cloud phase region.

Language: Английский

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