A5079348237- Atmospheric chemistry and aerosols
- Atmospheric and Environmental Gas Dynamics
- Atmospheric Ozone and Climate
- Arctic and Antarctic ice dynamics
- Atmospheric aerosols and clouds
- Earthquake Detection and Analysis
- Methane Hydrates and Related Phenomena
- Mercury impact and mitigation studies
- Climate variability and models
- Climate change and permafrost
- Geophysics and Gravity Measurements
- Calibration and Measurement Techniques
- Air Quality Monitoring and Forecasting
- Advanced Chemical Sensor Technologies
- Marine animal studies overview
- Fire effects on ecosystems
- Chemical Analysis and Environmental Impact
- Geological Studies and Exploration
- Spacecraft and Cryogenic Technologies
- Solar and Space Plasma Dynamics
École Polytechnique Fédérale de Lausanne
2021-2025
Physikalisch-Meteorologisches Observatorium Davos
2014-2017
With the Arctic rapidly changing, needs to observe, understand, and model changes are essential. To support these needs, an annual cycle of observations atmospheric properties, processes, interactions were made while drifting with sea ice across central during Multidisciplinary Observatory for Study Climate (MOSAiC) expedition from October 2019 September 2020. An international team designed implemented comprehensive program document characterize all aspects system in unprecedented detail,...
The Arctic is warming faster than anywhere else on Earth, prompting glacial melt, permafrost thaw, and sea ice decline. These severe consequences induce feedbacks that contribute to amplified warming, affecting weather climate globally. Aerosols clouds play a critical role in regulating radiation reaching the surface. However, magnitude of their effects not adequately quantified, especially central where they impact energy balance over ice. Specifically, aerosols called nucleating particles...
Abstract Frequency and intensity of warm moist air-mass intrusions into the Arctic have increased over past decades been related to sea ice melt. During our year-long expedition in remote central Ocean, a record-breaking increase temperature, moisture downwelling-longwave radiation was observed mid-April 2020, during an intrusion carrying air pollutants from northern Eurasia. The two-day intrusion, caused drastic changes aerosol size distribution, chemical composition particle...
The rapid melt of snow and sea ice during the Arctic summer provides a significant source low-salinity meltwater to surface ocean on local scale. accumulation this on, under, around floes can result in relatively thin layers upper ocean. Due small-scale nature these upper-ocean features, typically order 1 m thick or less, they are rarely detected by standard methods, but nevertheless pervasive critically important summer. Observations Multidisciplinary drifting Observatory for Study Climate...
Abstract. The Arctic environment is rapidly changing due to accelerated warming in the region. trend driving a decline sea ice extent, which thereby enhances feedback loops surface energy budget Arctic. aerosols play an important role radiative balance and hence climate response region, yet direct observations of over Ocean are limited. In this study, we investigate annual cycle aerosol particle number size distribution (PNSD), concentration (PNC), black carbon (BC) mass central during...
Abstract. Aerosols play a critical role in the Arctic's radiative balance, influencing solar radiation and cloud formation. Limited observations central Arctic leave gaps understanding aerosol dynamics year-round, affecting model predictions of climate-relevant properties. Here, we present first annual high-time-resolution submicron chemical composition during Ocean 2018 (AO2018) 2019–2020 Multidisciplinary drifting Observatory for Study Climate (MOSAiC) expeditions. Seasonal variations mass...
Abstract Unlike bromine, the effect of iodine chemistry on Arctic surface ozone budget is poorly constrained. We present ship-based measurements halogen oxides in high boundary layer from sunlit period March to October 2020 and show that enhances springtime tropospheric depletion. find chemical reactions between are second highest contributor loss over study period, after photolysis-initiated ahead bromine.
Atmospheric gaseous elemental mercury (GEM) concentrations in the Arctic exhibit a clear summertime maximum, while origin of this peak is still matter debate community. Based on observations during Multidisciplinary drifting Observatory for Study Climate (MOSAiC) expedition and modeling approach, we further investigate sources atmospheric Hg central Arctic. Simulations with generalized additive model (GAM) show that long-range transport anthropogenic terrestrial from lower latitudes minor...
Abstract Despite the key role of Arctic in global Earth system, year-round in-situ atmospheric composition observations within are sparse and mostly rely on measurements at ground-based coastal stations. Measurements a suite trace gases were performed central during Multidisciplinary drifting Observatory for Study Climate (MOSAiC) expedition. These give comprehensive picture near-surface abundances greenhouse gases, i.e., carbon dioxide, methane, nitrous oxide, ozone, monoxide,...
Abstract. Atmospheric observations in remote locations offer a possibility of exploring trace gas and particle concentrations pristine environments. However, data from areas are often contaminated by pollution local sources. Detecting this contamination is thus central frequently encountered issue. Consequently, many different methods exist today to identify atmospheric composition measurement time series, but no single method has been widely accepted. In study, we present new primary...
Chlorine radicals are strong atmospheric oxidants known to play an important role in the depletion of surface ozone and degradation methane Arctic troposphere. Initial oxidation processes chlorine produce oxides, it has been speculated that final steps lead formation chloric (HClO3) perchloric (HClO4) acids, although these two species have not detected atmosphere. Here, we present observations gas-phase HClO3 HClO4. Significant levels were observed during springtime at Greenland (Villum...
The central Arctic ocean (CAO) is transforming rapidly due to climate change with wide spread consequences. Therefore, understanding the mechanisms of change, in particular related surface energy budget, indispensable. Aerosols affect radiation budget both directly and indirectly through interactions clouds.In CAO, cloud formation radiative processes are particularly susceptible aerosols, because their number concentration can be very low. To date, climatic effects aerosols CAO have mostly...
Sea salt aerosol (SSaer) significantly impacts aerosol-radiation and aerosol-cloud interactions, sublimated blowing snow is hypothesized to be an important SSaer source in polar regions. Understanding other wind-sourced aerosols’ climate relevant properties needed, especially during winter when Arctic amplification greatest. However, most of our understanding comes from modeling studies, direct observations are sparse. Additionally, can originate multiple sources, making it difficult...
Ice nucleating particles (INPs) initiate ice formation, affecting the liquid versus distribution and radiative properties of clouds. INPs have been measured around Arctic, but few INP concentration measurements reported for air during movement south out central Arctic pack regions cold outbreaks (CAOs). We analyzed cases transports connecting Central location Multidisciplinary Drifting Observatory Study Climate (MOSAiC) expedition to near sea edge in Svalbard across ice-free ocean Cold-air...
In this study, we present and analyze the first continuous time series of relevant aerosol precursorvapors from central Arctic (north 80° N) during Multidisciplinary drifting Observatory for Study ofArctic Climate (MOSAiC) expedition. These precursor vapors include sulfuric acid (SA), methanesulfonic acid(MSA), iodic (IA). We use FLEXPART simulations, inverse modeling, sulfur dioxide (SO2) mixingratios, chlorophyll a (chl a) observations to interpret seasonal variability in vapor...
The Arctic environment is transforming rapidly due to climate change. Aerosols' abundance and physicochemical characteristics play a crucial, yet uncertain, role in these changes their influence on the surface energy budget through direct interaction with solar radiation indirectly via cloud formation. Importantly, aerosol properties are also changing response Despite importance, year-round measurements of sparse often confined lower latitudes at land-based stations and/or short...
The compact lightweight absolute radiometer (CLARA) experiment aims at measuring the total solar irradiance (TSI) in space and is scheduled to fly on Norwegian NORSAT-1 micro satellite. CLARA will contribute long term monitoring of TSI variability support analysis potential trends Sun's variability. traceable National Institute Standards Technology radiometric scale provide further evidence for value an scale. In this paper we present design, characterization, calibration details instrument....
Dry deposition to the surface is one of main removal pathways tropospheric ozone (O3). We quantified for first time impact O3 Arctic sea ice on planetary boundary layer (PBL) concentration and budget using year-round flux observations from Multidisciplinary drifting Observatory Study Climate (MOSAiC) campaign simulations with a single-column atmospheric chemistry meteorological model (SCM). Based eddy-covariance observations, we find median resistance order 20,000 s m−1, resulting in dry...
Near-surface mercury and ozone depletion events occur in the lowest part of atmosphere during Arctic spring. Mercury is first step a process that transforms long-lived elemental to more reactive forms within are deposited cryosphere, ocean, other surfaces, which can ultimately get integrated into food web. Depletion both due presence halogen radicals released from snow, ice, aerosols. In this work, we added detailed description atmospheric cycle our recently published version Weather...
The Arctic is sensitive to cloud radiative forcing. Due the limited number of aerosols present throughout much year, formation susceptible presence condensation nuclei and ice nucleating particles (INPs). Primary biological aerosol (PBAP) contribute INPs can impact phase, lifetime, properties. We yearlong observations hyperfluorescent (HFA), tracers for PBAP, conducted with a Wideband Integrated Bioaerosol Sensor, New Electronics Option during Multidisciplinary drifting Observatory Study...
<title>Abstract</title> In the central Arctic, warm and moist air intrusions (WAMIs) are increasingly prevalent during winter spring, significantly impacting near-surface energy budget. This study investigates WAMI-induced transport wet deposition of black carbon (BC) its subsequent influence on snow properties melting. Using a modeling approach combined with extensive observational data from 2019–2020 Multidisciplinary drifting Observatory for Study Arctic Climate (MOSAiC) expedition, we...
Abstract. In this study, we present and analyze the first continuous time series of relevant aerosol precursor vapors from central Arctic (north 80° N) during Multidisciplinary drifting Observatory for Study Climate (MOSAiC) expedition. These include sulfuric acid (SA), methanesulfonic (MSA), iodic (IA). We use FLEXPART simulations, inverse modeling, sulfur dioxide (SO2) mixing ratios, chlorophyll a (chl a) observations to interpret seasonal variability in vapor concentrations identify...
PMOD/WRC is building the Compact and Light-weight Absolute RAdiometer (CLARA) to fly on Norwegian Space Centre's (NSC) NORSAT-1 mission. The CLARA based a new design by which minimizes size weight while improving radiometric performance. mission planned be launched polar LEO in Q4 2015. nominal duration three years but NSC intends operate for long as platform payload remain functional.