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

Stratocumulus Precipitation Properties Over the Southern Ocean Observed From Aircraft During the SOCRATES Campaign DOI Creative Commons
Litai Kang, Roger Marchand, Robert Wood

et al.

Journal of Geophysical Research Atmospheres, Journal Year: 2024, Volume and Issue: 129(6)

Published: March 11, 2024

Abstract Precipitation plays an important role in cloud and aerosol processes over the Southern Ocean (SO). The main objective of this study is to characterize SO precipitation properties associated with stratocumulus clouds. We use data from Clouds Radiation Aerosol Transport Experimental Study (SOCRATES), leverage observations airborne radar, lidar, situ probes. find that for cold‐topped clouds (cloud‐top‐temperature <0°C), phase reflectivity >0 dBZ predominantly ice, while < −10 liquid. Liquid‐phase are retrieved where radar lidar zenith‐pointing. Power‐law relationships between (Z) rain rate (R) developed, derived Z–R show vertical dependence sensitivity presence droplets diameters 10 40 μm. Using relationships, a reflectivity‐velocity (ZV) retrieval method, radar‐lidar we derive other properties. all three methods shows good agreement in‐situ aircraft estimates, rates typically being quite light (<0.1 mm hr −1 ). examine distribution properties, rate, number concentration, liquid water decrease as one gets closer surface, size width increases. also how base ( R CB ) depends on depth (H) concentration N particles diameter greater than 70 nm, proportional .

Language: Английский

Citations

5
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
Quantifying the Differences in Southern Ocean Clouds Observed by Radar and Lidar From Three Platforms DOI Creative Commons
Xiquan Dong, Anik Das, Baike Xi

et al.

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

Published: May 4, 2025

Abstract A synergistic analysis of the radar‐only and combined radar‐lidar observations across three platforms was conducted. To align with well‐calibrated CloudSat cloud profiling radar (CPR) (and HCR) reflectivity measurements, a constant 4.5 dB offset applied to all M‐WACR reflectivitives during MARCUS. This brings data into better agreement both HCR CPR measurements facilitates more reliable fraction (CF) comparison. The total CFs (CF T s) derived from radars show excellent agreement. All detect large drizzle drops, but excel at detecting smaller droplets that are often missed by CPR. underestimated due increased attenuation below 3 km, effects surface clutter 1 km. Combining lidar enhanced detection 20%–60%. results this study provide new insights for designing future systems.

Language: Английский

Citations

0
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