Tim Carlsen
YOU?
Author Swipe
Shortening of the Arctic cold air outbreak season detected by a phenomenological machine learning approach Open
Marine cold air outbreaks (CAOs) frequently occur in the Arctic when cold air moves over the relatively warm ocean, resulting in large turbulent fluxes, instability and cloud formation. Given the high frequency of CAOs during the Arctic wi…
View article: Achieving consistency between in-situ and remotely sensed optical and microphysical properties of Arctic cirrus: the impact of far-infrared radiances
Achieving consistency between in-situ and remotely sensed optical and microphysical properties of Arctic cirrus: the impact of far-infrared radiances Open
This paper describes the first retrieval of cirrus optical and microphysical properties from ground-based measurements simultaneously with co-located measurements from aircraft. In particular, the present effort exploits infrared radiances…
Strong pattern effect evident in Southern Ocean cloud feedback based on multiple lines of evidence Open
The Southern Ocean is known to be one of the cloudiest places on Earth, and the important contribution of Southern Ocean clouds to Earth’s energy budget is undisputed. By changing their composition in response to warming, clouds in this re…
How does the change from sea ice to open ocean alter Arctic mixed-phase clouds? Open
Mixed-phase clouds consist of both liquid water and ice crystals, which affect their radiative properties. The amount of ice in the clouds is also important for the formation of precipitation and the lifetime of the clouds. Mixed-phase clo…
Using a region-specific ice-nucleating particle parameterization improves the representation of Arctic clouds in a global climate model Open
Projections of global climate change and Arctic amplification are sensitive to the representation of low-level cloud phase in climate models. Ice-nucleating particles (INPs) are necessary for primary cloud ice formation at temperatures abo…
Evaluation of biases in mid-to-high-latitude surface snowfall and cloud phase in ERA5 and CMIP6 using satellite observations Open
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 a…
Using a region-specific ice-nucleating particle parameterization improves the representation of Arctic clouds in a global climate model Open
Projections of global climate change and Arctic amplification are sensitive to the representation of low-level cloud phase in climate models. Ice-nucleating particles (INPs) are necessary for primary cloud ice formation at temperatures abo…
Comment on egusphere-2024-754 Open
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 …
Comment on egusphere-2024-754 Open
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 …
Connection of Surface Snowfall Bias to Cloud Phase Bias – Satellite Observations, ERA5, and CMIP6 Open
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 a…
Coordinated observations of the water cycle of marine cold-air outbreaks in the European Arctic during the ISLAS 2022 field campaign Open
Marine cold-air outbreaks (mCAOs) are a characteristic type of high-impact weather in the European Arctic and are characterized by an intense water cycle where polar cloud processes play an important role. Model simulations and weather for…
View article: Realistic representation of mixed-phase clouds increases future climate warming
Realistic representation of mixed-phase clouds increases future climate warming Open
Clouds are the main source of uncertainties when projecting climate change. Mixed-phase clouds (MPCs) that contain ice and supercooled-liquid particles are especially hard to constrain, and climate models neither agree on their phase nor t…
Understanding the History of Two Complex Ice Crystal Habits Deduced From a Holographic Imager Open
The sizes and shapes of ice crystals influence the radiative properties of clouds, as well as precipitation initiation and aerosol scavenging. However, ice crystal growth mechanisms remain only partially characterized. We present the growt…
Conditions favorable for secondary ice production in Arctic mixed-phase clouds Open
The Arctic is very susceptible to climate change and thus is warming much faster than the rest of the world. Clouds influence terrestrial and solar radiative fluxes and thereby impact the amplified Arctic warming. The partitioning of therm…
Data from the NASCENT campaign used in the publications: "Conditions favorable for secondary ice production in Arctic mixed-phase clouds" and "Understanding the history of two complex ice crystal habits deduced from a holographic imager" Open
This repository contains the data from the Ny‐Ålesund AeroSol Cloud ExperimeNT campaign (NASCENT). This data were used to produce the figures in the two papers: (1) Pasquier, J. T., Henneberger, J., Ramelli, F., Korolev, A.,Wieder, J., Lau…
Data from the NASCENT campaign used in the publications: "Conditions favorable for secondary ice production in Arctic mixed-phase clouds" and "Understanding the history of two complex ice crystal habits deduced from a holographic imager" Open
This repository contains the data from the Ny‐Ålesund AeroSol Cloud ExperimeNT campaign (NASCENT). This data were used to produce the figures in the two papers: (1) Pasquier, J. T., Henneberger, J., Ramelli, F., Korolev, A.,Wieder, J., Lau…
Observations of cold-cloud properties in the Norwegian Arctic using ground-based and spaceborne lidar Open
The role of clouds in the surface radiation budget is particularly complex in the rapidly changing Arctic. However, despite their importance, long-term observations of Arctic clouds are relatively sparse. Here, we present observations of c…
Understanding the history of complex ice crystal habits deduced from a holographic imager Open
Earth and Space Science Open Archive This preprint has been submitted to and is under consideration at Geophysical Research Letters. ESSOAr is a venue for early communication or feedback before peer review. Data may be preliminary.Learn mo…
View article: The Ny-Ålesund Aerosol Cloud Experiment (NASCENT): Overview and First Results
The Ny-Ålesund Aerosol Cloud Experiment (NASCENT): Overview and First Results Open
The Arctic is warming at more than twice the rate of the global average. This warming is influenced by clouds, which modulate the solar and terrestrial radiative fluxes and, thus, determine the surface energy budget. However, the interacti…
Spaceborne Evidence That Ice‐Nucleating Particles Influence High‐Latitude Cloud Phase Open
Mixed‐phase clouds (MPCs), which consist of both supercooled cloud droplets and ice crystals, play an important role in the Earth's radiative energy budget and hydrological cycle. In particular, the fraction of ice crystals in MPCs determi…
Airborne measurements of directional reflectivity over the Arctic marginal sea ice zone Open
The directional reflection of solar radiation by the Arctic Ocean is mainly shaped by two dominating surface types: sea ice (often snow-covered) and open ocean (ice-free). In the transitional zone between them, the marginal sea ice zone (M…
Conditions favorable for secondary ice production in Arctic mixed-phase clouds Open
The Arctic is very susceptible to climate change and thus warming much faster than the rest of the world. Clouds influence terrestrial and solar radiative fluxes, and thereby impact the amplified Arctic warming. The partitioning of thermod…
Comment on acp-2021-1072 Open
Abstract. The role of clouds in the surface radiation budget is particularly complex in the rapidly changing Arctic. However, despite their importance, long-term observations of Arctic clouds are relatively sparse. Here, we present observa…
Importance of secondary ice production over a large temperature range in Arctic mixed-phase clouds Open
The cloud radiative feedbacks are particularly complex and uncertain in the Arctic, which is a region of amplified warming. Within mixed-phase clouds (MPCs), the radiation fluxes are influenced by the thermodynamic phase and cloud particle…
Comment on acp-2021-1072 Open
The role of clouds for the surface radiation budget is particularly complex in the rapidly changing Arctic. However, despite their importance, long-term observations of Arctic clouds are relatively sparse. Here we present observations of c…
Comment on amt-2021-398 Open
Abstract. The directional reflection of solar radiation by the Arctic Ocean is mainly shaped by two dominating surface types: sea ice (often snow-covered) and open ocean (ice-free). In the transitional zone between them, the marginal sea i…
Comment on amt-2021-398 Open
Abstract. The directional reflection of solar radiation by the Arctic Ocean is mainly shaped by two dominating surface types: sea ice (often snow-covered) and open ocean (ice-free). In the transitional zone between them, the marginal sea i…
Observations of cold cloud properties in the Norwegian Arctic using ground-based and spaceborne lidar Open
The role of clouds for the surface radiation budget is particularly complex in the rapidly changing Arctic. However, despite their importance, long-term observations of Arctic clouds are relatively sparse. Here we present observations of c…
Spaceborne evidence that ice-nucleating particles influence cloud phase Open
Mixed-phase clouds (MPCs), which consist of both supercooled cloud droplets and ice crystals, play an important role in the Earth’s radiative energy budget and hydrological cycle. In particular, the fraction of ice crystals in MPCs determi…