Satellite-based analysis of CO and Fires in the Arctic

2021 ◽  
Author(s):  
Tomi Karppinen ◽  
Anu-Maija Sundström ◽  
Hannakaisa Lindqvist ◽  
Johanna Tamminen
Keyword(s):  
Greenhouse Gases ◽  
Forest Fire ◽  
Forest Fires ◽  
Arctic Region ◽  
Ground Level ◽  
Fire Effects ◽  
Satellite Observations ◽  
The Arctic ◽  
High Latitudes ◽  
Fire Emissions

<p><span>Climate change is proceeding fastest in the Arctic region. While human-induced emissions of long-lived greenhouse gases are the main driving factor of global warming, short-lived climate forcers or pollutants emitted from the forest fires are also playing an important role, especially in the Arctic. Forest fire emissions also affect local air quality and photochemical processes in the atmosphere. For example, CO contributes to the formation of tropospheric ozone and affects the abundance of greenhouse gases such as methane and CO2.</span></p><p><span>During past years Arctic summers have been warmer and drier elevating the risk for extensive forest fire episodes. Satellite observations show, that during the past three summers (2018-2020) fire detections in Arctic, especially in Arctic Siberia have increased considerably, affecting also local emissions of CO. This work focuses on studying CO concentration and its variation at high latitudes and in the Arctic using satellite and ground-based observations. Satellite observations of CO from TROPOMI are analyzed for the 2018-2020 (NH) summer months. To assess the satellite retrieved columns the satellite measurements are compared to ground-based remote sensing measurements at Sodankylä. Also, ground-based in-situ measurements are used to see how the total column changes mirror the ground level concentrations. The fire characteristics are analyzed using observations from MODIS instruments onboard Aqua and Terra. Fire effects on seasonal cycle and interannual variability of CO concentrations at Arctic high latitudes are analyzed.</span></p>

Satellite-Based Analysis of Fire Events and Transport of Emissions in the Arctic

2020 ◽  
Author(s):  
Anu-Maija Sundström ◽  
Tomi Karppinen ◽  
Antti Arola ◽  
Larisa Sogacheva ◽  
Hannakaisa Lindqvist ◽  
...  
Keyword(s):  
Greenhouse Gases ◽  
Forest Fire ◽  
Forest Fires ◽  
Arctic Region ◽  
Satellite Observations ◽  
The Arctic ◽  
Radiative Balance ◽  
Fire Emissions ◽  
Smoke Plumes ◽  
Absorbing Aerosols

<p>Climate change is proceeding fastest in the Arctic region. During past years Arctic summers have been warmer and drier elevating the risk for extensive forest fire episodes. In fact, satellite observations show, that during past two summers (2018, 2019) an increase is seen in the number of fires occurring above the Arctic Circle, especially in Siberia. While human-induced emissions of long-lived greenhouse gases are the main driving factor of global warming, short-lived climate forcers or pollutants emitted from the forest fires are also playing an important role especially in the Arctic. Absorbing aerosols can cause direct arctic warming locally. They can also alter radiative balance when depositing onto snow/ice and decreasing the surface albedo, resulting in subsequent warming. Aerosol-cloud interaction feedbacks can also enhance warming. Forest fire emissions also affect local air quality and photochemical processes in the atmosphere. For example, CO contributes to the formation of tropospheric ozone and affects the abundance of greenhouse gases such as methane and CO<sub>2</sub>.</p><p>This study focuses on analyzing fire episodes in the Arctic for the past 10 years, as well as investigating the transport of forest fire CO and smoke aerosols to the Arctic. Smoke plumes and their transport are analyzed using Absorbing Aerosol Index (AAI) from several satellite instruments: GOME-2 onboard Metop A and B, OMI onboard Aura, and TROPOMI onboard Copernicus Sentinel-5P satellite. Observations of CO are obtained from IASI (Metop A and B) as well as from TROPOMI, while the fire observations are obtained from MODIS instruments onboard Aqua and Terra, as well as from VIIRS onboard Suomi NPP.  In addition, observations e.g. from a space-borne lidar, CALIPSO, is used to obtain vertical distribution of smoke and to estimate plume heights.</p>

scholarly journals Comparison of approaches for reporting forest fire-related biomass loss and greenhouse gas emissions in southern Europe

2013 ◽  
Vol 22 (6) ◽  
pp. 730 ◽  
Author(s):  
Maria Vincenza Chiriacò ◽  
Lucia Perugini ◽  
Dora Cimini ◽  
Enrico D'Amato ◽  
Riccardo Valentini ◽  
...  
Keyword(s):  
Land Use ◽  
Greenhouse Gas ◽  
Forest Fire ◽  
Forest Fires ◽  
Fire Effects ◽  
Southern Europe ◽  
Gas Emissions ◽  
Fire Emissions ◽  
Biomass Loss ◽  
Mediterranean Forest Ecosystems

Wildfires are the most common disturbances in Mediterranean forest ecosystems that cause significant emissions of greenhouse gases as a result of biomass burning. Despite this, there is reasonably high uncertainty regarding the actual fraction of burnt biomass and the related CO2 and non-CO2 gas emissions released during forest fires. The aim of this paper is to compare existing methodologies adopted in the National Greenhouse Gas Inventory reports of five of the most fire-affected countries of southern Europe (Italy, Spain, Greece, Portugal, France) with those proposed in the literature, to operationally estimate forest fire emissions, and to discuss current perspectives on reducing uncertainties in reporting activities for the Land Use, Land Use Change and Forestry sector under the United Nations Framework Convention on Climate Change and the Kyoto Protocol. Five selected approaches have been experimentally applied for the estimation of burnt biomass in forest fire events that occurred in Italy in the period 2008–2010. Approaches based on nominal rates of biomass loss can lead to an overly conservative value or, conversely, to underestimation of the fraction of burnt biomass. Uncertainties can be greatly reduced by an operational method able to assess inter-annual and local variability of fire effects on fire-affected forest types.

scholarly journals Black Carbon Emissions from the Siberian Fires 2019: Modelling of the Atmospheric Transport and Possible Impact on the Radiation Balance in the Arctic Region

Atmosphere ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 814
Author(s):  
Sergey Kostrykin ◽  
Anastasia Revokatova ◽  
Alexey Chernenkov ◽  
Veronika Ginzburg ◽  
Polina Polumieva ◽  
...  
Keyword(s):  
Black Carbon ◽  
Forest Fires ◽  
Radiative Forcing ◽  
Climate Model ◽  
Arctic Region ◽  
The Arctic ◽  
Radiation Balance ◽  
Climatic Effects ◽  
Fire Emissions ◽  
Trajectory Model

The work is devoted to the study of the climatic effects of black carbon (BC) transferred from forest fires to the Arctic zone. The HYSPLIT (The Hybrid Single-Particle Lagrangian Integrated Trajectory model) trajectory model was used to initially assess the potential for particle transport from fires. The results of the trajectory analysis of the 2019 fires showed that the probability of the transfer of particles to the Arctic ranges from 1% to 10%, and in some cases increases to 20%. Detailed studies of the possible influence of BC ejected as a result of fires became possible by using the climate model of the INMCM5 (Institute of Numerical Mathematics Climate Model). The results of the numerical experiments have shown that the maximum concentration of BC in the Arctic atmosphere is observed in July and August and is associated with emissions from fires. The deposition of BC in the Arctic increases by about 1.5–2 times in the same months, in comparison with simulation without forest fire emissions. This caused an average decrease in solar radiation forcing of 0.3–0.4 Wt/m2 and an increase in atmospheric radiation heating of up to 5–6 Wt/m2. To assess the radiation forcing from BC contaminated snow, we used the dependences of the change in the snow albedo on the snow depth, and the albedo of the underlying surface for a given amount of BC fallen on the snow. These dependences were constructed on the basis of the SNICAR (Snow, Ice, and Aerosol Radiative) model. According to our calculations, the direct radiative forcing from BC in the atmosphere with a clear sky is a maximum of 4–5 W/m2 in July and August.

Forest fires in Russia: carbon dioxide emissions to the atmosphere

1993 ◽  
Vol 23 (4) ◽  
pp. 700-705 ◽  
Author(s):  
Robert K. Dixon ◽  
Olga N. Krankina
Keyword(s):  
Greenhouse Gases ◽  
General Circulation Model ◽  
Forest Fire ◽  
Forest Fires ◽  
General Circulation ◽  
Vegetation Change ◽  
Circulation Model ◽  
Fire Control ◽  
Fire Emissions ◽  
Biogenic Carbon

Boreal forests of Russia play a prominent role in the global carbon cycle and the flux of greenhouse gases to the atmosphere. Large areas of Russian forest burn annually, and contributions to the net flux of carbon to the atmosphere may be significant. Forest fire emissions were calculated for the years 1971–1991 using fire frequency and distribution data and fuel and carbon density for different forest ecoregions of Russia. Both direct carbon release and indirect post-fire biogenic carbon flux were estimated. From 1971 to 1991 the annual total forest area burned by wildfire ranged from 1.41 × 106 to 10.0 × 106 ha. Approximately 15 000–25 000 forest fires occurred annually during this period. Mean annual direct CO2-C emissions from wildfire was approximately 0.05 Pg over this 21-year period. Total post-fire biogenic CO2-C emissions for 1971–1991 ranged from 2.5 to 5.9 Pg (0.12–0.28 Pg annually). Forest fires and other disturbances are expected to be a primary mechanism driving vegetation change associated with projected global climate change. Future forest fire scenarios in Russia based on general circulation model projections suggest that up to 30–50% of the land surface area, or 334 × 106 to 631 × 106 ha of forest, will be affected. An additional 6.7 × 106 to 12.6 × 106 ha of Russian boreal forest are projected to burn annually if general circulation model based vegetation-change scenarios are achieved within the next 50 years. The direct flux of CO2-C from future forest fires is estimated to total 6.1–10.7 Pg over a 50-year period. Indirect post-fire biogenic release of greenhouse gases in the future is expected to be two to six times greater than direct emissions. Forest management and fire-control activities may help reduce wildfire severity and mitigate the associated pulse of greenhouse gases into the atmosphere.

scholarly journals Climate change and forest management affect forest fire risk in Fennoscandia

2021 ◽  
Author(s):  
Keyword(s):  
Climate Change ◽  
Forest Management ◽  
Black Carbon ◽  
Forest Fire ◽  
Forest Fires ◽  
Fire Risk ◽  
The Arctic ◽  
Large Fires ◽  
Forest Fire Risk ◽  
Fire Ignition

Forest and wildland fires are a natural part of ecosystems worldwide, but large fires in particular can cause societal, economic and ecological disruption. Fires are an important source of greenhouse gases and black carbon that can further amplify and accelerate climate change. In recent years, large forest fires in Sweden demonstrate that the issue should also be considered in other parts of Fennoscandia. This final report of the project “Forest fires in Fennoscandia under changing climate and forest cover (IBA ForestFires)” funded by the Ministry for Foreign Affairs of Finland, synthesises current knowledge of the occurrence, monitoring, modelling and suppression of forest fires in Fennoscandia. The report also focuses on elaborating the role of forest fires as a source of black carbon (BC) emissions over the Arctic and discussing the importance of international collaboration in tackling forest fires. The report explains the factors regulating fire ignition, spread and intensity in Fennoscandian conditions. It highlights that the climate in Fennoscandia is characterised by large inter-annual variability, which is reflected in forest fire risk. Here, the majority of forest fires are caused by human activities such as careless handling of fire and ignitions related to forest harvesting. In addition to weather and climate, fuel characteristics in forests influence fire ignition, intensity and spread. In the report, long-term fire statistics are presented for Finland, Sweden and the Republic of Karelia. The statistics indicate that the amount of annually burnt forest has decreased in Fennoscandia. However, with the exception of recent large fires in Sweden, during the past 25 years the annually burnt area and number of fires have been fairly stable, which is mainly due to effective fire mitigation. Land surface models were used to investigate how climate change and forest management can influence forest fires in the future. The simulations were conducted using different regional climate models and greenhouse gas emission scenarios. Simulations, extending to 2100, indicate that forest fire risk is likely to increase over the coming decades. The report also highlights that globally, forest fires are a significant source of BC in the Arctic, having adverse health effects and further amplifying climate warming. However, simulations made using an atmospheric dispersion model indicate that the impact of forest fires in Fennoscandia on the environment and air quality is relatively minor and highly seasonal. Efficient forest fire mitigation requires the development of forest fire detection tools including satellites and drones, high spatial resolution modelling of fire risk and fire spreading that account for detailed terrain and weather information. Moreover, increasing the general preparedness and operational efficiency of firefighting is highly important. Forest fires are a large challenge requiring multidisciplinary research and close cooperation between the various administrative operators, e.g. rescue services, weather services, forest organisations and forest owners is required at both the national and international level.

scholarly journals Production of peroxy nitrates in boreal biomass burning plumes over Canada during the BORTAS campaign

2016 ◽  
Vol 16 (5) ◽  
pp. 3485-3497 ◽  
Author(s):  
Marcella Busilacchio ◽  
Piero Di Carlo ◽  
Eleonora Aruffo ◽  
Fabio Biancofiore ◽  
Cesare Dari Salisburgo ◽  
...  
Keyword(s):  
Boreal Forest ◽  
Forest Fire ◽  
Biomass Burning ◽  
Forest Fires ◽  
Chemical Mechanism ◽  
Fire Emissions ◽  
Fire Plumes ◽  
Peroxy Nitrates ◽  
In Fire ◽  
The Impact

Abstract. The observations collected during the BOReal forest fires on Tropospheric oxidants over the Atlantic using Aircraft and Satellites (BORTAS) campaign in summer 2011 over Canada are analysed to study the impact of forest fire emissions on the formation of ozone (O3) and total peroxy nitrates ∑PNs, ∑ROONO2). The suite of measurements on board the BAe-146 aircraft, deployed in this campaign, allows us to calculate the production of O3 and of  ∑PNs, a long-lived NOx reservoir whose concentration is supposed to be impacted by biomass burning emissions. In fire plumes, profiles of carbon monoxide (CO), which is a well-established tracer of pyrogenic emission, show concentration enhancements that are in strong correspondence with a significant increase of concentrations of ∑PNs, whereas minimal increase of the concentrations of O3 and NO2 is observed. The ∑PN and O3 productions have been calculated using the rate constants of the first- and second-order reactions of volatile organic compound (VOC) oxidation. The ∑PN and O3 productions have also been quantified by 0-D model simulation based on the Master Chemical Mechanism. Both methods show that in fire plumes the average production of ∑PNs and O3 are greater than in the background plumes, but the increase of ∑PN production is more pronounced than the O3 production. The average ∑PN production in fire plumes is from 7 to 12 times greater than in the background, whereas the average O3 production in fire plumes is from 2 to 5 times greater than in the background. These results suggest that, at least for boreal forest fires and for the measurements recorded during the BORTAS campaign, fire emissions impact both the oxidized NOy and O3,  but (1 ∑PN production is amplified significantly more than O3 production and (2) in the forest fire plumes the ratio between the O3 production and the ∑PN production is lower than the ratio evaluated in the background air masses, thus confirming that the role played by the ∑PNs produced during biomass burning is significant in the O3 budget. The implication of these observations is that fire emissions in some cases, for example boreal forest fires and in the conditions reported here, may influence more long-lived precursors of O3 than short-lived pollutants, which in turn can be transported and eventually diluted in a wide area.

scholarly journals Climate change between the mid and late Holocene in northern high latitudes – Part 2: Model-data comparisons

2010 ◽  
Vol 6 (5) ◽  
pp. 609-626 ◽  
Author(s):  
Q. Zhang ◽  
H. S. Sundqvist ◽  
A. Moberg ◽  
H. Körnich ◽  
J. Nilsson ◽  
...  
Keyword(s):  
Sea Ice ◽  
Climate Models ◽  
Barents Sea ◽  
Arctic Region ◽  
Summer Temperature ◽  
The Arctic ◽  
High Latitudes ◽  
Climate Response ◽  
Model Data ◽  
Model Simulations

Abstract. The climate response over northern high latitudes to the mid-Holocene orbital forcing has been investigated in three types of PMIP (Paleoclimate Modelling Intercomparison Project) simulations with different complexity of the modelled climate system. By first undertaking model-data comparison, an objective selection method has been applied to evaluate the capability of the climate models to reproduce the spatial response pattern seen in proxy data. The possible feedback mechanisms behind the climate response have been explored based on the selected model simulations. Subsequent model-model comparisons indicate the importance of including the different physical feedbacks in the climate models. The comparisons between the proxy-based reconstructions and the best fit selected simulations show that over the northern high latitudes, summer temperature change follows closely the insolation change and shows a common feature with strong warming over land and relatively weak warming over ocean at 6 ka compared to 0 ka. Furthermore, the sea-ice-albedo positive feedback enhances this response. The reconstructions of temperature show a stronger response to enhanced insolation in the annual mean temperature than winter and summer temperature. This is verified in the model simulations and the behaviour is attributed to the larger contribution from the large response in autumn. Despite a smaller insolation during winter at 6 ka, a pronounced warming centre is found over Barents Sea in winter in the simulations, which is also supported by the nearby northern Eurasian continental and Fennoscandian reconstructions. This indicates that in the Arctic region, the response of the ocean and the sea ice to the enhanced summer insolation is more important for the winter temperature than the synchronous decrease of the insolation.

Satellite-derived spatiotemporal patterns of environmental changes caused by 2018-2019 wildfires in Arctic-Boreal Russia

2020 ◽  
Author(s):  
Elena Cherepanova ◽  
Valery Bondur ◽  
Viktor Zamshin ◽  
Natalia Feoktistova
Keyword(s):  
Time Series ◽  
Greenhouse Gases ◽  
Forest Fires ◽  
Environmental Changes ◽  
Negative Impact ◽  
Spatiotemporal Patterns ◽  
Atmospheric Composition ◽  
The Arctic ◽  
Satellite Monitoring ◽  
Local Conditions

<p>Forest fires affect environmental changes both directly, changing the type of land cover, causing local and regional air pollution through emissions of greenhouse gases and aerosols, and indirectly through a secondary effect on atmospheric, soil and hydrological processes. The increase in the number and area of uncontrolled wildfires, the degradation of permafrost in high latitude areas leads to a change in the balance of greenhouse gases in the atmosphere, and it results in the negative impact on the Earth’s climatic system.</p><p>This study examined the Arctic-Boreal territories of the Russian Federation, where huge forest fires were observed in 2018-2019. In most of these areas, forest fire detection is carried out only by means of the satellite monitoring without aviation support. The sparsely populated and inaccessible territories are a major factor of the rapid spread of fires over large areas. Most of the forest areas in the region are so-called control zones, where the authorities may decide not to extinguish the fires if they do not threaten settlements and economic facilities, and consider the salvation of forests economically unprofitable. However, there is no reliable data on the environmental consequences of large forest fires in the Arctic-Boreal territories.</p><p>Satellite monitoring of wildfires provides the detection of fire locations, an assessment of their area and burning time. In our study, we used various indices calculated from remote sensing data for the pre-fire and post-fire periods to identify the spatiotemporal patterns of environmental change caused by large wildfires. The Sentinel 5 TROPOMI time series have been analyzed for the short-term and long-term atmospheric composition anomalies detection caused by forest fires in the region. In the process of comparing the methane concentrations time series for the 2018- 2019 fire seasons the constantly high values anomaly zones were found. We believe that these anomalies are resulting from Sentinel-5 CH4 algorithm constrains, which requires additional work on data validation with relation to the local conditions.</p><p>The reported study was funded by RFBR, MOST (China) and DST (India) according to the research project № 19-55-80021</p>

scholarly journals Estimation of black carbon emissions from Siberian fires using satellite observations of absorption and extinction optical depths

2018 ◽  
Author(s):  
Igor B. Konovalov ◽  
Daria A. Lvova ◽  
Matthias Beekmann ◽  
Hiren Jethva ◽  
Eugene F. Mikhailov ◽  
...  
Keyword(s):  
Black Carbon ◽  
Optical Depth ◽  
Transport Model ◽  
Measurement Data ◽  
Satellite Observations ◽  
The Arctic ◽  
Fire Season ◽  
Northern Eurasia ◽  
Top Down ◽  
Fire Emissions

Abstract. Black carbon (BC) emissions from open biomass burning (BB) are known to have a considerable impact on the radiative budget of the atmosphere on global and regional scales but are poorly constrained in models by atmospheric observations, especially in remote regions. Here, we investigate the feasibility of constraining BC emissions from BB with satellite observations of the aerosol absorption optical depth (AAOD) and the aerosol extinction optical depth (AOD) retrieved from OMI (Ozone monitoring instrument) and MODIS (Moderate Resolution Imaging Spectroradiometer) measurements, respectively. We consider the case of Siberian BB BC emissions, which have a strong potential to impact the Arctic climate system. Using aerosol remote sensing data collected at Siberian sites of the Aerosol Robotic Network (AERONET) along with the results of the Fourth Fire Lab at Missoula Experiment (FLAME-4), we establish an empirical parameterization relating the ratio of the elemental carbon (EC) and organic carbon (OC) contents in BB aerosol to the ratio of AAOD and AOD at the wavelengths of the satellite observations. Applying this parameterization to the BC and OC column amounts simulated with the CHIMERE chemistry transport model, we optimize the parameters of the BB emission model based on MODIS measurements of the fire radiative power (FRP) and obtain top-down optimized estimates of the total monthly BB BC amounts emitted from intense Siberian fires that occurred in May–September 2012. The top-down estimates are compared to the corresponding values obtained using the Global Fire Emissions Database (GFED4) and the Fire Emission Inventory–northern Eurasia (FEI-NE). Our simulations using the optimized BB aerosol emissions are verified against AAOD and AOD data that were withheld from the estimation procedure. The simulations are further evaluated against in situ EC and OC measurements at the Zotino Tall Tower Observatory (ZOTTO) and also against aerosol measurement data collected on board of an aircraft in the framework of the Airborne Extensive Regional Observations (YAK-AEROSIB) experiments. We conclude that our BC and OC emission estimates, considered with their confidence intervals, are consistent with the ensemble of the measurement data analyzed in this study. Siberian fires are found to emit 0.41 ± 0.14 Tg of BC over the whole period of the five months considered; this estimate is a factor of 2 larger and a factor of 1.5 smaller compared to that the corresponding estimates based on the GFED4 (0.20 Tg) and FEI-NE (0.61 Tg) data, respectively. Our estimates of monthly BC emissions are also found to be larger than the BC amounts calculated with the GFED4 data and smaller than those calculated with the FEI-NE data for any of the five months. Especially large positive differences of our estimates of monthly BC emissions with respect to the GFED4 data are found in May and September. This finding indicates that the GFED4 database is likely to strongly underestimate BC emissions from agricultural burns and grass fires in Siberia. All these differences have important implications for climate change in the Arctic, as it is found that about a quarter of the huge BB BC mass emitted in Siberia during the fire season of 2012 was transported across the polar circle into the Arctic. Overall, the results of our analysis indicate that a combination of the available satellite observations of AAOD and AOD can provide the necessary constraints on BB BC emissions.

scholarly journals Condensation and immersion freezing Ice Nucleating Particle measurements at Ny-Ålesund (Svalbard) during 2018: evidence of multiple source contribution

2020 ◽  
Author(s):  
Matteo Rinaldi ◽  
Naruki Hiranuma ◽  
Gianni Santachiara ◽  
Mauro Mazzola ◽  
Karam Mansour ◽  
...  
Keyword(s):  
Regional Climate ◽  
Arctic Region ◽  
Ground Level ◽  
Test System ◽  
Ice Nucleation ◽  
The Arctic ◽  
Activation Temperature ◽  
Back Trajectories ◽  
Local Sources ◽  
Immersion Freezing

Abstract. The current inadequate understanding of ice nucleating particle (INP) sources in the Arctic region affects the uncertainty in global radiative budgets and in regional climate predictions. In this study, we present atmospheric INP concentrations by offline analyses on samples collected at ground level in Ny-Ålesund (Svalbard), in spring and summer 2018. The ice nucleation properties of the samples were characterized by means of two offline instruments: the Dynamic Filter Processing Chamber (DFPC), detecting condensation freezing INPs, and the West Texas Cryogenic Refrigerator Applied to Freezing Test system (WT-CRAFT), measuring INPs by immersion freezing. Both measurements agreed within an order of magnitude although with some notable offset. INP concentration measured by DFPC ranged 33–185 (median 88), 5–107 (50) and 3–66 (20) m−3, for T = −22, −18 and −15 °C, respectively, while at the same activation temperatures WT-CRAFT measured 3–199 (26), 1–34 (6) and 1–4 (2) m−3, with an offset apparently dependent on the INP activation temperature. This observation may indicate a different sensitivity of Arctic INPs to different ice nucleation modes, even though a contribution from measurement and/or sampling uncertainties cannot be ruled out. An increase in the coarse INP fraction was observed from spring to summer, particularly at the warmest temperature (up to ~ 70 % at −15 °C). This suggests a non-negligible contribution from local sources of biogenic aerosol particles. This conclusion is also supported by the INP temperature spectra, showing ice-forming activity at temperatures higher than −15 °C. Contrary to recent works (e.g., INP measurements from Ny-Ålesund in 2012), our results do not show a sharp spring-to-summer increase of the INP concentration, with distinct behaviors for particles active in different temperature ranges. This likely indicates that the inter-annual variability of conditions affecting the INP emission by local sources may be wider than previously considered and suggests a complex interplay between INP sources. This demonstrate the necessity of further data coverage. Analysis of INP concentrations, active site density, low-travelling back-trajectories (

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