When: January-February 2022 | Where: Fairbanks, Alaska
Contacts: Stefano Decesari
Polar Low Workshop
Arctic Climate and Weather Extremes
Please visit the Cross-Cutting Activities page for more information on upcoming activities co-sponsored by the Atmosphere Working Group.
Around fifty scientists with interests in Arctic air pollution gathered in Oslo, Norway, for the 3rd PACES Open Science Meeting in September 2019, where recent research highlights and ongoing and planned activities within “Air Pollution in the Arctic: Climate, Environment and Societies” (PACES) initiative and more broadly were discussed in-depth. Scientific session themes included long-range pollution transport to the Arctic and global-scale linkages, Arctic aerosol-cloud interactions, local Arctic air pollution sources and high latitude polluted boundary layers, and sustainable Arctic development. More than 25 scientific presentations were given and11 posters were presented across these topics, with additional group discussion around plans for new Arctic field activities and modeling exercises focused on addressing knowledge gaps in Arctic air pollution, sources and impacts. Funding from both IASC and IGAC allowed supported attendance of around 10 early career scientists.
• Strong engagement from the aerosol-cloud interactions community, with a highly active session on exploring links between our understanding of Arctic polluted and natural aerosol sources and implications for Arctic clouds and climate.
• Development of a plan for a new set of model experiments under PACES Working Group 1, focused on comparing model performance and addressing model uncertainties during specific long-range pollution transport events from Asia to the Arctic.
• Continued discussion and planning for a range of field activities centred on improving understanding of chemical processing and impacts of air pollution in high latitude towns and cities under PACES Working Group 2. These include the planned Alaskan Layered air Pollution and Chemical Analysis (ALPACA) project, and the “Twin Cities” concept for assessment of risks associated with weather and air pollution in Arctic urban environments, and comparison across different settlements (in collaboration with the WMO GURME initiative).
Winter Polar Vortex
Large and rapid changes in the Arctic represent a new driver of weather patterns in mid-latitudes, potentially affecting millions of people. Recent studies of this north/south linkage, however, are inconsistent. Studies based on observed data report robust conclusions in some areas, seasons, and background conditions, while model-simulated connections and averaging over large areas, long time periods, and many ensemble members are generally less clear. We suggest that one source of uncertainty arises from the inherent chaotic nature of the atmosphere. Thermodynamic forcing, by a rapidly warming Arctic and loss of sea ice, contributes to latitudinal weather linkages in the past decade. But internal atmospheric dynamics, i.e., large-scale wind patterns (jet stream location, strength, and orientation), may obscure the connections, making understanding of direct cause-and-effect challenging.
Three areas in the Arctic Ocean during early winter exhibit linkages through the increasingly delayed freeze-up of sea ice, which allows heat to escape into the atmosphere and helps anchor the geographic locations of large-scale wind patterns: Baffin Bay (BB), Chukchi/Beaufort (CB) Seas, and Barents/Kara (BK) Seas. Multiple factors contribute to these relationships, including BK sea-ice loss with atmospheric responses in the North Atlantic and east Asia and blocking near the Ural mountains, and CB with North Pacific Ocean temperature patterns. In late winter, the occasional disruption (movement, strength, and splitting) of the stratospheric polar vortex (SPV, i.e., the upper-atmospheric wind pattern) can influence weather patterns in Eurasia (e.g., the so-called ‘Beast from the East’ in winter 2018) and North America (e.g., wavy polar jet stream and associated persistent weather extremes during the winters of 2017/2018 and 2018/2019). The SPV plays a central role in vertically coupling the troposphere and stratosphere. Thus, evidence for Arctic/mid-latitude weather linkages have emerged from analyses of observed extreme events, while natural atmospheric and oceanic variability reduces seasonal correlations and provides weak signals in model studies.
With regard to research issues on the Arctic and East Asia weather linkage, the most important and controversial issue was the robustness of the relation between Arctic Warming and the East Asia cold anomaly. One study focused on the quantification of the relation suggested that at least 44% of recent winter Eurasian cooling is attributable to the sea ice loss over the Barents-Kara seas. Unfortunately, current state-of-the-art climate models underestimate the Eurasian cooling in response to the Arctic sea ice loss compared to the reanalysis suggested. Another study reported multi-decadal fluctuations of the relation between Arctic warming and the East Asia cold anomaly with a weaker relation from 1901 to 1929 and from 1955 to 1979, whereas a stronger relation occurred from 1930 to 1954 and from 1989 to 2013. Besides the cold air outbreak, Arctic cold air mass variability is proposed to be linked to extreme heat waves in summer over East Asia, which is a new perspective. The mechanism of the linkage in summer remains unclear as an incipient stage now and warrants further examination in the future. Knowledge on Arctic warming and sea ice loss and its influence on East Asia extreme weather via the troposphere or stratosphere needs to be utilized in improving skills for sub-seasonal to seasonal weather prediction in order to mitigate socio-economic impact.
• Arctic/mid-latitude weather linkages have emerged from analyses of observations
• One source of the linkage uncertainty is the inherent chaotic nature of the atmosphere
• Multiple factors contribute to these relationships .
Quantifying the Indirect Effect: from Sources to Climate Effects of Natural and Transported aerosol in the Arctic (QuIESCENT Arctic) Workshop
The QuIESCENT Arctic workshop was initiated by the PACES (air Pollution in the Arctic: Climate, Environment, and Societies) project, with support of the International Arctic Science Committee (IASC) Atmosphere Working Group, and was also endorsed by the International Association for Meteorology and Atmospheric Sciences (IAMAS, via both the International Commission on Polar Meteorology and the International Commission on Clouds and Precipitation) and International Global Atmospheric Chemistry (IGAC). Through discussions, the workshop identified the need to improve communication between the observing and modelling communities and to carry momentum forward to future workshops, activities, and projects targeting this topic.
• Arctic aerosol-cloud interactions are poorly understood, yet it is difficult to disentangle these processes and identify key drivers from others which influence clouds (e.g. boundary layer structure, moisture transport).
• We need more measurements of the vertical structure of the boundary layer, clouds, and aerosols, particularly during the winter, to improve our understanding of the Arctic indirect effect and quantify associated processes better in numerical models.
• Efforts are needed to improve communication and collaboration between the observing and modelling communities to facilitate better knowledge transfer to high-resolution atmospheric models and up-scaling to global circulation models.
For more information see the QuIESCENT Workshop website.
MOSAiC Final Implementation Workshop
When: 11 - 15 March 2019 | Where: Postdam (Germany)
Contact: Annette Rinke
230 scientists of the MOSAiC (Multidisciplinary Drifting Observatory of the Study of Arctic Climate) community participated in the final big workshop before the MOSAiC expedition starts in September 20th 2019. The workshop focused on the implementation of the expedition and to inform the participants of the cruise about logistical details. The schedule for the 6 legs and the exchanges of scientists and crew are finalized, including the announcement that Leg 6 will be extended and finishes on October 14th 2020 in Bremerhaven (Germany). With only 6 months until Polarstern leaves Tromsø, most of the cruise leader and, co-cruise leaders introduced themselves and the participants of each leg are defined. The deadlines for fright issues, training courses and medical exams were announced. Several new developments were announced, like the MOSAiC data policy, the media concept introducing the Progressive Web App (launched just before the start of the MOSAiC expedition) and education concept including the MOSAiC School onboard of Fedorov.
Scientifically, the MOSAiC workshop offers the last opportunity for the community to meet within their MOSAiC Teams (Atmosphere, Sea Ice, Ocean, Bio-Geochemistry and Remote Sensing) in addition to cover the MOSAiC cross-cutting topics (Aircraft Operation, Remote Sensing and Modeling). Besides, the workshop offers time slots for individual small meetings to come together in small groups and discuss about very detailed and special topics. Still open questions concerning the scientific set-up during the expedition and it’s organize and implementation could be answered. Responsible scientist for each leg has to be found to maintain unattended instruments onboard Polarstern, in the ice camp and the distributed network.
In addition, the MOSAiC workshop aims to bring together the modelling and observation community. Improving sea ice, weather, regional and global climate models and their parameterizations is the overarching goal of the MOSAiC project. Therefore, one day was dedicated to deal with modelling activity before and during the expedition to support the expedition with forecasts and to coordinate the modelling activity after the expedition to fulfil the overarching goal. To achieve this aim, the modeling day focus on bridging observations and large scale modeling.
Further information about the MOSAiC expedition and the whole project can be found on the Webpage (www.mosaic-expedition.org).
• Expedition extended and ends on October 14th 2020 in Bremerhaven
• Introduction of the cruise leader and co-cruise leader for almost all legs
• Both modelers and observers met for one day to discuss and implement the linkage of observations and modelling activity before, during, and after the expedition
Polar Prediction School 2018
When: 17 - 27 April 2018 | Where: Abisko (Sweden)
Contact: Fiona Tummon
The Polar Prediction School was held from 17-27 April 2018 at the beautiful Abisko Scientific Research Station in northern Sweden. It brought together 29 students from nine different countries and at various career stages, from early PhD students through to post-docs. The programme for the school was designed to provide a comprehensive overview of the main aspects related to polar weather and climate prediction. It included theoretical lectures, practical exercises, meteorological fieldwork, and a dedicated science communication programme.
Polar Lows and Mesoscale Weather Extremes
When: 5 - 6 April 2018 | Where: Trier (Germany) | Contact: Prof. Dr. Günther Heinemann
The workshop attracted 30 scientists from China, France, Germany, Japan, Norway, Russia, UK, and USA to present most recent findings on polar low research. The workshop summarized our present understanding of polar lows and mesocyclones as well as mesoscale weather extremes in the Arctic and Antarctic. This includes e.g. mesoscale weather phenomena such as katabatic winds, tip jets, boundary layer fronts, and cold air outbreaks in polar regions. The workshop had the following main themes: Polar low studies using satellite data and in-situ data; climatological aspects of polar lows; polar lows in reanalyses and model simulations; environments for polar low genesis and operational aspects; polar mesoscale weather phenomena and air-sea-ocean interactions. The workshop was concluded by a round table discussion resulting in recommendations for future research and actions.
MOSAiC Implementation Workshop
The 4-day MOSAiC workshop at Arctic and Antarctica Research Institute in St. Petersburg was the follow-up to the workshop in spring 2017 in Prague. Around 120 people participated in the workshop and made it a successful event with great progress of implementing MOSAiC.
During the first one and a half days, the workshop focused on overview presentations of the MOSAiC teams, cross-cutting teams and task groups, including several talks about the modelling hierarchy and modelling strategy. The coordinators of the teams presented the status of the implementation and organization of the measurements during the expedition, the scientific gaps, and the funding situation. The remaining time was spend on breakout sessions for each of the MOSAiC teams, the cross-cutting teams and the task groups. The results of the sessions were a clear understanding of the planned scientific work and how to implement and schedule the work. Additionally, the input for the modelling activity was discussed in each team to fulfill the requirements of the modelling community to achieve the overarching goal of improving sea ice forecasting, regional weather forecasting, and climate predictions.
For more information please see the MOSAiC website
Arctic/Midlatitude Weather and Climate Linkages
When: 12-13 September 2017 | Where: Helsinki (Finland) | Contact: James E. Overland
The workshop compared case studies of recent linkage events, focusing on large- and synoptic-scale circulation patterns. The two recent winters (2015-6 and 2016-7) had extreme warm Arctic temperatures, yet how they evolved on a month to month basis were different in both East Asia and eastern North America. An eastern shift in the longitudinal phasing of the long wave pattern was evident between years earlier in this decade. Activities include cases that represent strong and weak meridional flow (Eurasia), high amplitude flows (western N. America), the initiation and maintenance of high-latitude blocking episodes in key regions (Greenland, Siberia) and their teleconnections, planetary wave trains, and coupling with the stratosphere.
A key path forward is to improve mechanistic/dynamical understanding. Analyses are needed connecting extreme weather events with longer-term climate forcings. Multiple factors are involved that make it difficult to develop a whole picture; there are no single pathways.
The Second PACES Science Workshop
At the 2nd PACES Open Science Workshop, leading investigators in the Earth-Arctic system gathered to discuss the latest issues regarding sources, processing, and impacts of trace gas and aerosol pollution in the Arctic. The workshop was focused on improving predictive capabilities of Arctic air pollution processes and the interaction between Arctic air pollution and Arctic societies through discussions and presentations. PACES aims to review existing knowledge and foster new research on the sources and fate of Arctic air pollution, its impacts on climate, health, and ecosystems, on the feedbacks between pollution and natural sources, on climate responses, and on societal perspectives, including sustainability, adaptation and economic feedbacks.
Key recommendations for improved understanding of pollution processes and impacts emerged from discussions at the workshop, including motivation for new modelling and field observations.. These include efforts to develop international collaborative experiments aimed at improving knowledge of processes controlling export of pollution from mid-latitudes to the Arctic, as well as experiments targeted at sampling sources and processing of pollution in an Arctic urban environment.
For more information please see the PACES website
• Long-range transport of pollution to the Arctic is intimately linked to Arctic climate change and changes in large-scale circulation patterns but such linkages require improved quantification.
• Natural sources of trace constituents in the Arctic such as dust aerosols or biogenic hydrocarbons, and their potential evolution as a result of climate change, are poorly constrained.
• Large uncertainties surround the formation and processing of local air pollution under very cold, dry, stable conditions in the Arctic.
• Model treatments of wet deposition and chemical/aerosol processing are still significant and are motivating the planning of a new field experiment (IMPAACT) designed to sample air masses in a quasi-Lagrangian fashion during transport of pollution from Asia to the Arctic.
Towards an Interdisciplinary Research Agenda for Arctic Air Pollution (PACES)
The Arctic is increasingly considered an Anthropocene climate frontier, as the consequences of global warming look set to first and foremost impact the circumpolar hemisphere. The region is expected to become increasingly important as climatic changes look set to spark industrial-scale resource extraction and increased transport and commodity shipping, in turn, spelling severe impacts for the regions ecological and cultural landscapes due to industrialisation and consequent increases in pollution emissions from local sources related to mining and shipping. In studying the developments that are happening right now, research exchange and collaboration is timely not only between academic disciplines, but also increasingly, with relevant local partners and society at large.
This workshop provided a forum for focused discussions on how to combine research methodologies from humanities, social and natural sciences to understand current and future air pollution in the Arctic with the aim of proposing mitigation options. The conversations built on ideas from two previous PACES meetings held in 2015 and the “Air pollution and Arctic Societies” workshop in Fairbanks during ASSW 2016. Participants designed a multi-scale framework in which research methodologies of drivers, impacts and related decision making of air pollution were identified at the local, regional and global level.
For more information please see the PACES website
• The workshop engaged researchers from humanities, social and natural sciences into discussing Arctic air pollution from a multi-disciplinary perspective.
• Participants from three IASC working groups submitted a successful cross-cutting proposal to follow up with concrete on the ground research plans.
• A multi-scale framework of air pollution drivers, impacts and related decision making was created.
MOSAiC (2-day workshop during ASSW 2017)
When: 4-5 April 2017 | Where: Prague (Czech Republic)
The MOSAiC project is an international Arctic research initiative that aims to improve understanding of the climate system in the Arctic through a comprehensive, interdisciplinary, and sustained process. Primary goals of the initiative include enhanced process-level understanding of the coupled central Arctic climate system to improve numerical models for sea-ice forecasting, extended-range weather forecasting, climate projections, and climate change assessment. The fundamental design of MOSAiC is the year-round operation of an observatory onboard the RV Polarstern, drifting with the sea ice across the central Arctic. The MOSAiC workshop in April was the first strategic session concerning the expedition´s implementation.
As an IASC devised project, the MOSAiC workshop brought together 90 participants to explore the multidisciplinary research of the project through talks and breakout sessions. Strategically, the four breakout sessions focused on small scale processes, regional scale processes, green sea ice, and operational aspects of MOSAiC. The workshop highlighted the major scientific and logistic undertaking of MOSAiC and brought about productive discussions on the next steps for MOSAiC, including as the establishment of additional MOSAiC teams, capacity building, acquiring funding, how to involve stakeholders, and the next MOSAiC meetings.
For more information please see the following page.