Publications de Georgia Sotiropoulou

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

Cold air outbreaks (CAOs) are phenomena that occur across high latitudes during winter months and favor the development of extensive boundary layer clouds. As the boundary layer evolves, changes in cloud morphology often result in a stratocumulus to cumulu ...

2025

Unraveling ice multiplication in winter orographic clouds via in-situ observations, remote sensing and modeling

Alexis Berne, Satoshi Takahama, Athanasios Nenes, Georgia Sotiropoulou, Anne-Claire Marie Billault--Roux, Paraskevi Georgakaki, Romanos Foskinis, Kunfeng Gao

Recent years have shown that secondary ice production (SIP) is ubiquitous, affecting all clouds from polar to tropical regions. SIP is not described well in models and may explain biases in warm mixed-phase cloud ice content and structure. Through modeling ...

Nature Portfolio2024

Data and scripts for "Unraveling secondary ice production in winter orographic clouds through a synergy of in-situ observations, remote sensing and modeling"

Alexis Berne, Satoshi Takahama, Athanasios Nenes, Georgia Sotiropoulou, Anne-Claire Marie Billault--Roux, Paraskevi Georgakaki, Romanos Foskinis, Kunfeng Gao

This repository contains field observations and processed data from the Weather Research and Forecasting (WRF) model simulations and the Cloud Resolving Model Radar Simulator (CR-SIM), alongside scripts designed to reproduce the figures presented in the pa ...

Zenodo2024

Simulations of primary and secondary ice production during an Arctic mixed-phase cloud case from the Ny-Ålesund Aerosol Cloud Experiment (NASCENT) campaign

Georgia Sotiropoulou, Paraskevi Georgakaki

The representation of Arctic clouds and their phase distributions, i.e., the amount of ice and supercooled water, influences predictions of future Arctic warming. Therefore, it is essential that cloud phase is correctly captured by models in order to accur ...

Copernicus GmbH2024

Secondary ice production processes in wintertime alpine mixed-phase clouds

Alexis Berne, Athanasios Nenes, Georgia Sotiropoulou, Anne-Claire Marie Billault--Roux, Paraskevi Georgakaki

Observations of orographic mixed-phase clouds (MPCs) have long shown that measured ice crystal number concentrations (ICNCs) can exceed the concentration of ice nucleating particles by orders of magnitude. Additionally, model simulations of alpine clouds a ...

Copernicus GmbH2022

Furthering Understanding of Aerosol-Cloud-Precipitation Interactions in the Arctic

Georgia Sotiropoulou

AMER METEOROLOGICAL SOC2022

Ice multiplication from ice-ice collisions in the high Arctic: sensitivity to ice habit, rimed fraction, ice type and uncertainties in the numerical description of the process

Athanasios Nenes, Georgia Sotiropoulou

Atmospheric models often fail to correctly reproduce the microphysical structure of Arctic mixed-phase clouds and underpredict ice water content even when the simulations are constrained by observed levels of ice nucleating particles. In this study we inve ...

Copernicus GmbH2021

Challenging and Improving the Simulation of Mid-Level Mixed-Phase Clouds Over the High-Latitude Southern Ocean

Alexis Berne, Franziska Gerber, Etienne Gabriel Henri Vignon, Athanasios Nenes, Georgia Sotiropoulou

Climate models exhibit major radiative biases over the Southern Ocean owing to a poor representation of mixed-phase clouds. This study uses the remote-sensing dataset from the Measurements of Aerosols, Radiation and Clouds over the Southern Ocean (MARCUS) ...

2021

Modeling Extreme Warm-Air Advection in the Arctic During Summer: The Effect of Mid-Latitude Pollution Inflow on Cloud Properties

Georgia Sotiropoulou

Usually the Arctic is relatively free of anthropogenic influence in summer, which means that particles from natural sources can be the most significant nuclei for cloud droplets. However, this is not the case during anomalously warm-air intrusions when the ...

2021

Secondary ice production in summer clouds over the Antarctic coast: an underappreciated process in atmospheric models

Alexis Berne, Etienne Gabriel Henri Vignon, Athanasios Nenes, Georgia Sotiropoulou

The correct representation of Antarctic clouds in atmospheric models is crucial for accurate projections of the future Antarctic climate. This is particularly true for summer clouds which play a critical role in the surface melting of the ice shelves in th ...

European Geosciences Union2021

Properties of Arctic liquid and mixed-phase clouds from shipborne Cloudnet observations during ACSE 2014

Georgia Sotiropoulou

This study presents Cloudnet retrievals of Arctic clouds from measurements conducted during a 3-month research expedition along the Siberian shelf during summer and autumn 2014. During autumn, we find a strong reduction in the occurrence of liquid clouds a ...

Copernicus GmbH2020

Measured ice nucleating particle concentrations improve the simulation of mid-level mixed-phase clouds over the high-latitude Southern Ocean

Alexis Berne, Franziska Gerber, Etienne Gabriel Henri Vignon, Athanasios Nenes, Georgia Sotiropoulou

2020

The impact of secondary ice production on Arctic stratocumulus

Athanasios Nenes, Georgia Sotiropoulou

In situ measurements of Arctic clouds frequently show that ice crystal number concentrations (ICNCs) are much higher than the number of available ice-nucleating particles (INPs), suggesting that secondary ice production (SIP) may be active. Here we use a L ...

Copernicus GmbH2020