Thermodynamic and cloud evolution in a cold air outbreak during HALO-(AC)3: Quasi-Lagrangian observations compared to the ERA5 and CARRA reanalyses DOI Creative Commons
Benjamin Kirbus, Imke Schirmacher, Marcus Klingebiel

et al.

Published: Dec. 15, 2023

Abstract. Intense air mass transformations take place when cold, dry Arctic masses move southward from the closed sea ice onto much warmer ice-free ocean during marine cold outbreaks (MCAOs). In spite of intensive research on MCAOs recent years, temporal rates diabatic heating and moisture uptake relevant also for cloud formation/dissipation have not been measured along MCAO flows. Instead, reanalyses typically used climatological investigations or to supply higher-resolution models with lateral boundary conditions time-dependent forcings. Meanwhile, uncertainties connected those datasets remain unclear. Here, we present height-resolved observations rates, uptake, evolution in a quasi-Lagrangian manner. The investigated specific was observed 01 April 2022 HALO-(AC)3 airborne campaign that conducted spring 2022. Shortly after passing edge, maximum larger than 6 K h−1 more 0.3 g kg−1 were close above surface. As continued its drift southwards, clouds started form vertical mixing within steadily deepening layer intensified. quasi-Lagrange are compared reanalysis data European Centre Medium-Range Weather Forecasts (ECMWF) latest global ERA5 Copernicus Regional Reanalysis (CARRA). It found mean absolute errors (MAEs) versus CARRA 60 % higher temperature over (1.4 0.9 K), 70 humidity (0.12 0.07 ). We relate these differences only issues representations marginal zone corresponding surface fluxes ERA5, but scheme producing excess liquid-bearing precipitation, causing too-dry layer. Overall, combination CARRA’s high spatial resolution, an improved handling surfaces, demonstrated fidelity towards observations, make it well-suited candidate further transformations.

Language: Английский

Clouds and precipitation in the initial phase of marine cold-air outbreaks as observed by airborne remote sensing DOI Creative Commons
Imke Schirmacher, Sabrina Schnitt, Marcus Klingebiel

et al.

Atmospheric chemistry and physics, Journal Year: 2024, Volume and Issue: 24(22), P. 12823 - 12842

Published: Nov. 19, 2024

Abstract. Marine cold-air outbreaks (MCAOs) strongly affect the Arctic water cycle and, thus, climate through large-scale air mass transformations. The description of transformations is still challenging, partly because previous observations do not resolve fine scales, particularly for initial development an MCAO, and due to a lack information about thermodynamical evolution starting over sea ice continuing open ocean associated cloud microphysical properties. Therefore, we focus on crucial within first 200 km two case studies in April 2022 during HALO-(AC)3 campaign (named after High Altitude Long Range Research Aircraft Transregional Collaborative Centre ArctiC Amplification: Climate Relevant Atmospheric SurfaCe Processes Feedback Mechanisms (AC)3). events, just 3 d apart, belong long-lasting MCAO occurred under relatively similar thermodynamic conditions. Even though both events were stronger than climatological 75th percentile that period, event was characterized by colder masses from central which led index twice as high compared second event. structure assessed flight legs crossing Fram Strait multiple times at same location, sampling perpendicularly streets. Airborne remote sensing situ measurements used build statistical descriptions boundary layer, dynamics, clouds, precipitation. For this purpose, established novel approach based solely radar reflectivity detect roll circulation forms cases exhibit different properties riming, circulations, width similar. event, tops are higher; more liquid-topped clouds exist; liquid path, mean reflectivity, precipitation rate, occurrence have increased; riming active. variability rime has horizontal scale circulation, implying importance microphysics Boundary layer evolve with distance water, seen by, e.g., top height rising. In general, streets form traveling 15 water. After 20 km, formation enhances cover below 100 %. around 30 forms, weaker shifted larger distances. Within our analysis, developed various parameters (i) (ii) function These detailed metrics well suited evaluation cloud-resolving models close edge evaluate their representation dynamics microphysics.

Language: Английский

Citations

2
High ice-nucleating particle concentrations associated with Arctic haze in springtime cold-air outbreaks DOI Creative Commons
Erin N. Raif, Sarah Barr, Mark D. Tarn

et al.

Atmospheric chemistry and physics, Journal Year: 2024, Volume and Issue: 24(24), P. 14045 - 14072

Published: Dec. 17, 2024

Abstract. The global variation in ice-nucleating particle (INP) concentrations is an important modulator of the cloud-phase feedback, where albedo mixed-phase clouds increases a warming climate. Shallow clouds, such as those observed cold-air outbreaks (CAOs), are particularly for feedbacks and highly sensitive to INPs. To investigate sources INPs CAOs, we made airborne measurements over Norwegian Barents seas part March 2022 Arctic Cold-Air Outbreak (ACAO) field campaign. Aerosol samples were collected on filters at locations above, below upstream CAO cloud decks. Throughout campaign, INP comparable highest previously Arctic. Scanning electron microscopy analysis taken decks showed that supermicron aerosol was dominated by mineral dusts. Analysis size obtain active site density suggested sea spray unlikely be dominant type. These densities also too great components alone type above −20 °C. Accordingly, it likely dust mixed with other materials, possibly biogenic origin. Back-trajectory meteorological conditions lack local sources. We therefore hypothesise high concentration most associated aged haze has undergone long-range transport from lower-latitude regions.

Language: Английский

Citations

2
Analysis of an Arctic cold air outbreak during autumn and related air mass transformations forced by surface changes and advection in higher altitudes DOI Creative Commons
Benjamin Kirbus, Jan Chylik, André Ehrlich

et al.

Elementa Science of the Anthropocene, Journal Year: 2023, Volume and Issue: 11(1)

Published: Jan. 1, 2023

During marine cold air outbreaks (MCAOs), and dry Arctic masses are transported from the central southward across closed sea ice much warmer open oceans. They experience significant transformations including a rapid heating moistening, often leading to cloud formation. While intense wintertime MCAOs have been analyzed widely, mass during other seasons studied sparsely. We address this gap by investigating an MCAO case observed in September 2020. To study transformation processes, we combine fifth generation of atmospheric reanalyses global climate (ERA5), trajectory calculations, as well shipborne airborne measurements. In Arctic, observations acquired aboard research vessel (RV) Polarstern Multidisciplinary drifting Observatory for Study Climate (MOSAiC) expedition characterized initial state over ice. Trajectories indicated pathway took RV Fram Strait. For first 24 h southbound drift, remained quasi-stationary. Then, still 15 ahead marginal zone, differential advection boundary layer flow introduced humidity clouds at higher altitudes between 1.5 2.5 km. ERA5-derived temperature tendencies complex vertical interactions. Radiative cloud-top cooling, entrainment, turbulence were significantly reduced lower enhanced upper advected layer. Eventually, deck dissipated. After confluence 2 different masses, gathered Polar 5 Strait part MOSAiC Airborne Central campaign revealed cloudy, moist layers throughout lowest 3.5 km increasing height. Comparing with final 48 later, largest net +8 K was found close surface, yet moistening +2.5 g kg−1 altitude 1 km, profile exceptionally here. conclude that driven surface changes ocean but additionally strongly impacted moisture near-surface flow.

Language: Английский

Citations

3
Comment on egusphere-2023-2989 DOI Creative Commons
Benjamin Kirbus, Imke Schirmacher, Marcus Klingebiel

et al.

Published: Jan. 16, 2024

Abstract. Intense air mass transformations take place when cold, dry Arctic masses move southward from the closed sea ice onto much warmer ice-free ocean during marine cold outbreaks (MCAOs). In spite of intensive research on MCAOs recent years, temporal rates diabatic heating and moisture uptake relevant also for cloud formation/dissipation have not been measured along MCAO flows. Instead, reanalyses typically used climatological investigations or to supply higher-resolution models with lateral boundary conditions time-dependent forcings. Meanwhile, uncertainties connected those datasets remain unclear. Here, we present height-resolved observations rates, uptake, evolution in a quasi-Lagrangian manner. The investigated specific was observed 01 April 2022 HALO-(AC)3 airborne campaign that conducted spring 2022. Shortly after passing edge, maximum larger than 6 K h−1 more 0.3 g kg−1 were close above surface. As continued its drift southwards, clouds started form vertical mixing within steadily deepening layer intensified. quasi-Lagrange are compared reanalysis data European Centre Medium-Range Weather Forecasts (ECMWF) latest global ERA5 Copernicus Regional Reanalysis (CARRA). It found mean absolute errors (MAEs) versus CARRA 60 % higher temperature over (1.4 0.9 K), 70 humidity (0.12 0.07 ). We relate these differences only issues representations marginal zone corresponding surface fluxes ERA5, but scheme producing excess liquid-bearing precipitation, causing too-dry layer. Overall, combination CARRA’s high spatial resolution, an improved handling surfaces, demonstrated fidelity towards observations, make it well-suited candidate further transformations.

Language: Английский

Citations

0
Reply on RC1 DOI Creative Commons
Benjamin Kirbus

Published: Feb. 16, 2024

Abstract. Intense air mass transformations take place when cold, dry Arctic masses move southward from the closed sea ice onto much warmer ice-free ocean during marine cold outbreaks (MCAOs). In spite of intensive research on MCAOs recent years, temporal rates diabatic heating and moisture uptake relevant also for cloud formation/dissipation have not been measured along MCAO flows. Instead, reanalyses typically used climatological investigations or to supply higher-resolution models with lateral boundary conditions time-dependent forcings. Meanwhile, uncertainties connected those datasets remain unclear. Here, we present height-resolved observations rates, uptake, evolution in a quasi-Lagrangian manner. The investigated specific was observed 01 April 2022 HALO-(AC)3 airborne campaign that conducted spring 2022. Shortly after passing edge, maximum larger than 6 K h−1 more 0.3 g kg−1 were close above surface. As continued its drift southwards, clouds started form vertical mixing within steadily deepening layer intensified. quasi-Lagrange are compared reanalysis data European Centre Medium-Range Weather Forecasts (ECMWF) latest global ERA5 Copernicus Regional Reanalysis (CARRA). It found mean absolute errors (MAEs) versus CARRA 60 % higher temperature over (1.4 0.9 K), 70 humidity (0.12 0.07 ). We relate these differences only issues representations marginal zone corresponding surface fluxes ERA5, but scheme producing excess liquid-bearing precipitation, causing too-dry layer. Overall, combination CARRA’s high spatial resolution, an improved handling surfaces, demonstrated fidelity towards observations, make it well-suited candidate further transformations.

Language: Английский

Citations

0
Thermodynamic and cloud evolution in a cold air outbreak during HALO-(AC)3: Quasi-Lagrangian observations compared to the ERA5 and CARRA reanalyses DOI Creative Commons
Benjamin Kirbus, Imke Schirmacher, Marcus Klingebiel

et al.

Published: Dec. 15, 2023

Abstract. Intense air mass transformations take place when cold, dry Arctic masses move southward from the closed sea ice onto much warmer ice-free ocean during marine cold outbreaks (MCAOs). In spite of intensive research on MCAOs recent years, temporal rates diabatic heating and moisture uptake relevant also for cloud formation/dissipation have not been measured along MCAO flows. Instead, reanalyses typically used climatological investigations or to supply higher-resolution models with lateral boundary conditions time-dependent forcings. Meanwhile, uncertainties connected those datasets remain unclear. Here, we present height-resolved observations rates, uptake, evolution in a quasi-Lagrangian manner. The investigated specific was observed 01 April 2022 HALO-(AC)3 airborne campaign that conducted spring 2022. Shortly after passing edge, maximum larger than 6 K h−1 more 0.3 g kg−1 were close above surface. As continued its drift southwards, clouds started form vertical mixing within steadily deepening layer intensified. quasi-Lagrange are compared reanalysis data European Centre Medium-Range Weather Forecasts (ECMWF) latest global ERA5 Copernicus Regional Reanalysis (CARRA). It found mean absolute errors (MAEs) versus CARRA 60 % higher temperature over (1.4 0.9 K), 70 humidity (0.12 0.07 ). We relate these differences only issues representations marginal zone corresponding surface fluxes ERA5, but scheme producing excess liquid-bearing precipitation, causing too-dry layer. Overall, combination CARRA’s high spatial resolution, an improved handling surfaces, demonstrated fidelity towards observations, make it well-suited candidate further transformations.

Language: Английский

Citations

0