Assessing the cloud radiative bias at Macquarie Island in the ACCESS-AM2 model DOI Creative Commons
Zhangcheng Pei, Sonya L. Fiddes,

W. R. French

et al.

Atmospheric chemistry and physics, Journal Year: 2023, Volume and Issue: 23(23), P. 14691 - 14714

Published: Nov. 29, 2023

Abstract. As a long-standing problem in climate models, large positive shortwave radiation biases exist at the surface over Southern Ocean, impacting accurate simulation of sea temperature, atmospheric circulation, and precipitation. Underestimations low-level cloud fraction liquid water content are suggested to predominantly contribute these biases. Most model evaluations for focus on summer rely satellite products, which have their own limitations. In this work, we use surface-based observations Macquarie Island provide first long-term, seasonal evaluation both downwelling longwave Australian Community Climate Earth System Simulator Atmosphere-only Model version 2 (ACCESS-AM2) Ocean. The capacity Clouds Earth’s Radiant Energy (CERES) product simulate is also investigated. We utilize novel lidar simulator, Automatic Lidar Ceilometer Framework (ALCF), all-sky camera investigate how influenced by properties. Overall, find an overestimation +9.5±33.5 W m−2 fluxes underestimation -2.3±13.5 ACCESS-AM2 conditions, with more pronounced +25.0±48.0 occurring summer. CERES presents +8.0±18.0 -12.1±12.2 conditions. For radiative effect (CRE) biases, there +4.8±28.0 -7.9±20.9 CERES. An associated underestimated occurrence. suggest that modeled phase having impact Our results show require further development reduce not just but clear-sky

Language: Английский

ARMTRAJ: a set of multipurpose trajectory datasets augmenting the Atmospheric Radiation Measurement (ARM) user facility measurements DOI Creative Commons
Israel Silber, J. M. Comstock,

Michael R. Kieburtz

et al.

Earth system science data, Journal Year: 2025, Volume and Issue: 17(1), P. 29 - 42

Published: Jan. 8, 2025

Abstract. Ground-based instruments offer unique capabilities such as detailed atmospheric, thermodynamic, cloud, and aerosol profiling at a high temporal sampling rate. The U.S. Department of Energy Atmospheric Radiation Measurement (ARM) user facility provides comprehensive datasets from key locations around the globe, facilitating long-term characterization process-level understanding clouds, aerosol, aerosol–cloud interactions. However, with other ground-based datasets, fixed (Eulerian) nature these measurements often introduces knowledge gap in relating those observations air-mass hysteresis. Here, we describe ARMTRAJ (https://doi.org/10.5439/2309851, Silber, 2024a; https://doi.org/10.5439/2309849, 2024b; https://doi.org/10.5439/2309850, 2024c; https://doi.org/10.5439/2309848, 2024d), set multipurpose trajectory that helps close this ARM deployments. Each dataset targets different aspect atmospheric research, including analysis surface, planetary boundary layer, distinct liquid-bearing cloud layers, (primary) decks. Trajectories are calculated using Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model informed by European Centre for Medium-Range Weather Forecasts ERA5 reanalysis its highest spatial resolution (0.25°) initialized datasets. include information about coordinates state variables extracted before after site overpass. Ensemble runs generated each initialization enhance consistency, while ensemble variability serves valuable uncertainty metric reported variables. Following description processing structure, demonstrate applications to case study few bulk analyses collected during ARM's Eastern Pacific Cloud Aerosol Precipitation Experiment (EPCAPE) field deployment. will soon become near real-time product accompanying new deployments an augmenting ongoing previous deployments, promoting reaching science goals research relying on observations.

Language: Английский

Citations

4
Moderate climate sensitivity due to opposing mixed-phase cloud feedbacks DOI Creative Commons
Ivy Tan, Chen Zhou,

Aubert Lamy

et al.

npj Climate and Atmospheric Science, Journal Year: 2025, Volume and Issue: 8(1)

Published: March 4, 2025

Earth's climate sensitivity quantifies the ultimate change in global mean surface air temperature response to a doubling of atmospheric CO2 concentrations. Recent assessments estimate that very likely lies between 2.3 °C and 4.7 °C, with representation clouds models accounting for large portion its uncertainty. Here, we adjust individual contemporary after using satellite observations alleviate biases their mixed-phase clouds. A resulting moderate average 3.63 ± 0.98(1σ) arises due opposing responses While increasing proportion liquid within cold prior increases via transitions from solid hydrometeors, strongly increase reflective cloud cover decreases sensitivity. This emphasizes need reconsider role changes assessments.

Language: Английский

Citations

1
ARM Trajectories Data Set Value-Added Product Report DOI
Israel Silber, J. M. Comstock,

Michael R. Kieburtz

et al.

Published: Jan. 1, 2025

Per detected liquid-bearing cloud layer (see section 2.2) ** Ensemble size of 9 in free-tropospheric runs 2.3) *** Includes an equivalent surface run (same initial coordinates as the AAF system) 2.5) **** flight altitude ARMTRAJ-SFC -Surface Trajectory Data SetThe data set is designed to support research using ARM's measurements, with emphasis on aerosol observations.For a given day at ARM site, initialized three-hour intervals, each including 240-hour (10-day) back trajectory.The ensemble two starting heights (surface and 50 m AGL), rendering 18 members.ARMTRAJ-SFC files are supplemented 1-hour mean standard deviation values (starting trajectory initialization time) observations from corresponding site Surface Meteorology System (MET; Kyrouac Tuftedal 2024). ARMTRAJ-CLD -Liquid-Bearing Cloud Layer SetARMTRAJ-CLD aims augment studies warm mixed-phase clouds.The 120-hour (five-day) forward trajectories reported this set, among other uses,

Language: Английский

Citations

0
Evaluation of biases in mid-to-high-latitude surface snowfall and cloud phase in ERA5 and CMIP6 using satellite observations DOI Creative Commons
Franziska Hellmuth, Tim Carlsen, Anne Sophie Daloz

et al.

Atmospheric chemistry and physics, Journal Year: 2025, Volume and Issue: 25(2), P. 1353 - 1383

Published: Jan. 31, 2025

Abstract. Supercooled liquid-containing clouds (sLCCs) play a significant role in Earth's radiative budget and the hydrological cycle, especially through surface snowfall production. Evaluating state-of-the-art climate models with respect to their ability simulate frequency of occurrence sLCCs which they produce snow is, therefore, critically important. Here, we compare these quantities as derived from satellite observations, reanalysis datasets, Earth system Phase 6 Coupled Model Intercomparison Project (CMIP6) find discrepancies between datasets for mid- high latitudes both hemispheres. Specifically, that ERA5 10 CMIP6 consistently overestimate frequencies compared CloudSat–CALIPSO observations. The biases are very similar models, indicates cloud phase stem differences representation microphysics rather than meteorological conditions. This, turn, highlights need refinements models’ parameterizations order them represent accurately. thermodynamic precipitation has strong influence on simulated feedbacks and, thus, projections future climate. Understanding origin(s) identified here crucial improving overall reliability models.

Language: Английский

Citations

0
Simulation of Cloud Processes Over Offshore Coastal Antarctica Using the High‐Resolution Regional UK Met Office Unified Model With Interactive Aerosols DOI Creative Commons
Ruth Price, Andrew Orr, Paul R. Field

et al.

Journal of Geophysical Research Atmospheres, Journal Year: 2025, Volume and Issue: 130(4)

Published: Feb. 14, 2025

Abstract The Southern Ocean and offshore coastal Antarctica are key regions for global climate. Low level mixed‐phase clouds strongly control the surface radiation budget of this region but remain challenging climate models because complex processes controlling sources sinks cloud liquid water, including both water ice crystals. Here, we examine these interactions using Unified Model (UM) regional model, with Cloud AeroSol Interacting Microphysics (CASIM) UK Chemistry Aerosol (UKCA) included interactive aerosol microphysics. We simulate two case studies from second field campaign Clouds Aerosols Precipitation Radiation atmospheric Composition over Phase 2 (CAPRICORN‐2), which represent open ocean Antarctica. Compared observations, find that UM underestimates concentration by up to an order magnitude investigate effect bias on simulated microphysical radiative properties. path (LWP) fluxes also biased in Antarctic study, a 32% mean underestimation LWP 76% overestimation downwelling shortwave flux. Sensitivity tests show is largely caused deficiencies representation meteorology, less or Our results provide insights modeling high southern latitudes.

Language: Английский

Citations

0
MODIS Aerosol and Low‐Cloud Retrievals: Orographic Effects in the Wake of Macquarie Island DOI Creative Commons
Emily Tansey, Roger Marchand, D. Chand

et al.

Earth and Space Science, Journal Year: 2025, Volume and Issue: 12(5)

Published: April 30, 2025

Abstract Visible/infrared imagery from passive satellites is commonly relied upon to study low cloud microphysics over oceanic regions, including for the Southern Ocean (SO), but relatively little validation has been undertaken SO. In this article, we compare low‐cloud effective radius ( r e ), droplet number concentration N d ) and liquid water path (LWP) retrievals NASA Moderate Imaging Spectroradiometer (MODIS) with surface measurements collected during Macquarie Island Cloud Radiation Experiment (MICRE). MODIS 3.7‐μm band show bias moderately good correlation relative MICRE liquid‐phase clouds when restricted Solar Zenith Angles <65° on spatial scales of 50–100 km. However, overall in 3.7 partly results cancellation errors: overestimated non‐to‐lightly precipitating clouds, underestimated heavier drizzling by ∼1–1.5 μm. 1.6‐μm 2.1‐μm are biased high. may likewise be slightly under‐ or depending concentration, there insufficient data provide confidence result. Interestingly, a composite 2002 2020 distinct region enhanced cover (and lower wake associated orographic formation. aerosol optical depth (AOD) Angstrom Exponent (AE) upwind downwind island do not differ significantly. Comparison suggests that Collection 6 AOD reasonable, while AE problematically large.

Language: Английский

Citations

0
Observational constraint on a feedback from supercooled clouds reduces projected warming uncertainty DOI Creative Commons
G Cesana, Andrew S. Ackerman, Ann M. Fridlind

et al.

Communications Earth & Environment, Journal Year: 2024, Volume and Issue: 5(1)

Published: April 6, 2024

Abstract The increase of carbon-dioxide-doubling-induced warming (climate sensitivity) in the latest climate models is primarily attributed to a larger extratropical cloud feedback. This thought be partly driven by greater ratio supercooled liquid-phase clouds all clouds, termed liquid phase ratio. We use an instrument simulator approach show that this has increased and overestimated rather than underestimated as previously thought. In our analysis multiple models, corresponds stronger negative feedback, contradiction with single-model-based studies. trace unexpected result feedback involving shift from warm warms, which amount optical depth weakens Better constraining – thus impacts their sensitivities up 1 ˚C reduces inter-model spread.

Language: Английский

Citations

3
Impacts of Synoptic‐Scale Dynamics on Clouds and Radiation in High Southern Latitudes DOI Creative Commons

Tyler Barone,

Minghui Diao, Yang Shi

et al.

Journal of Geophysical Research Atmospheres, Journal Year: 2024, Volume and Issue: 129(16)

Published: Aug. 14, 2024

Abstract High‐latitudinal mixed‐phase clouds significantly affect Earth's radiative balance. Observations of cloud and properties from two field campaigns in the Southern Ocean Antarctica were compared with global climate model simulations. A cyclone compositing method was used to quantify “dynamics‐cloud‐radiation” relationships relative extratropical centers. show larger asymmetry between western eastern sectors at McMurdo Macquarie Island. Most observed quantities are higher (i.e., post‐frontal) than (frontal) sector, including fraction, liquid water path (LWP), net surface shortwave longwave radiation (SW LW), except for ice (IWP) being sector. The models found overestimate fraction LWP Island but underestimate them Station. IWP is consistently underestimated both locations, sectors, all seasons. Biases LWP, negatively correlated SW biases positively LW biases. persistent negative may have become one leading causes over high southern latitudes, after correcting underestimation supercooled older versions. By examining multi‐scale factors microphysics synoptic dynamics, this work will help increase fidelity simulations remote region.

Language: Английский

Citations

2
Assessing the cloud radiative bias at Macquarie Island in the ACCESS-AM2 model DOI Creative Commons
Zhangcheng Pei, Sonya L. Fiddes,

W. R. French

et al.

Atmospheric chemistry and physics, Journal Year: 2023, Volume and Issue: 23(23), P. 14691 - 14714

Published: Nov. 29, 2023

Abstract. As a long-standing problem in climate models, large positive shortwave radiation biases exist at the surface over Southern Ocean, impacting accurate simulation of sea temperature, atmospheric circulation, and precipitation. Underestimations low-level cloud fraction liquid water content are suggested to predominantly contribute these biases. Most model evaluations for focus on summer rely satellite products, which have their own limitations. In this work, we use surface-based observations Macquarie Island provide first long-term, seasonal evaluation both downwelling longwave Australian Community Climate Earth System Simulator Atmosphere-only Model version 2 (ACCESS-AM2) Ocean. The capacity Clouds Earth’s Radiant Energy (CERES) product simulate is also investigated. We utilize novel lidar simulator, Automatic Lidar Ceilometer Framework (ALCF), all-sky camera investigate how influenced by properties. Overall, find an overestimation +9.5±33.5 W m−2 fluxes underestimation -2.3±13.5 ACCESS-AM2 conditions, with more pronounced +25.0±48.0 occurring summer. CERES presents +8.0±18.0 -12.1±12.2 conditions. For radiative effect (CRE) biases, there +4.8±28.0 -7.9±20.9 CERES. An associated underestimated occurrence. suggest that modeled phase having impact Our results show require further development reduce not just but clear-sky

Language: Английский

Citations

4