International Arctic Science Committee

Land improvement Under Conditions of Permafrost: Melioratsiia and Intended Forms of Environmental Change in Soviet Yakutia

Land improvement under con¬ditions of permafrost: melioratsiia and intended forms of environmental change in Soviet Yakutia
Habeck, J. Otto and A. Yakovlev

ABSTRACT:

Frozen-Ground Cartoons”: Permafrost Comics as an Innovative Tool for Polar Outreach, Education, and Engagement

Polar Record 54, 366-372

Frozen-Ground Cartoons”: Permafrost Comics as an Innovative Tool for Polar Outreach, Education, and Engagement
F. Bouchard, J. Sansoulet, M. Fritz, J. Malenfant-Lepage, A. Nieuwendam,M. Paquette, A.C.A. Rudy,M.B. Siewert,Y Sjöberg,G. Tanski,J.O. Habeck, and L. Harbor

ABSTRACT: Permafrost occupies 20 million square kilometres of Earth’s high-latitude and high-altitude landscapes. These regions are sensitive to climate change and human activities; hence, permafrost research is of considerable scientific and societal importance. However, the results of this research are generally not known by the general public. Communicating scientific concepts is an increasingly important task in the research world. Different ways to engage learners and incorporate narratives in teaching materials exist, yet they are generally underused. Here we report on an international scientific outreach project called “Frozen-Ground Cartoons”, which aims at making permafrost science accessible and fun for students, teachers, and parents through the creation of comic strips. We present the context in which the project was initiated, as well as recent education and outreach activities. The future phases of the project primarily involve a series of augmented reality materials, such as maps, photos, videos, and 3D drawings. With this project we aim to foster understanding of permafrost research among broader audiences, inspire future permafrost researchers, and raise public and science community awareness of polar science, education, outreach, and engagement

IASC Related Activity:
The Frozen-Ground Cartoons

The Greenland and Antarctic Ice Sheets under 1.5 °C Global Warming

The Greenland and Antarctic Ice Sheets Under 1.5 °C Global Warming
F. Pattyn, C. Ritz, E. Hanna, X. Asay-Davis, R. DeConto, G. Durand, L. Favier, X. Fettweis, H. Goelzer, N. R. Golledge, P. Kuipers Munneke, J.T. M. Lenaerts, S. Nowicki, A. J. Payne, A. Robinson, H. Seroussi, L.D. Trusel & M. van den Broeke

ABSTRACT: Even if anthropogenic warming were constrained to less than 2 °C above pre-industrial, the Greenland and Antarctic ice sheets will continue to lose mass this century, with rates similar to those observed over the past decade. However, nonlinear responses cannot be excluded, which may lead to larger rates of mass loss. Furthermore, large uncertainties in future projections still remain, pertaining to knowledge gaps in atmospheric (Greenland) and oceanic (Antarctica) forcing. On millennial timescales, both ice sheets have tipping points at or slightly above the 1.5–2.0 °C threshold; for Greenland, this may lead to irreversible mass loss due to the surface mass balance–elevation feedback, whereas for Antarctica, this could result in a collapse of major drainage basins due to ice-shelf weakening.
Article also available here.

IASC Related Activity:
SCAR/IASC/CliC Ice Sheet Mass Balance and Sea Level (ISMASS)

Local Arctic Air Pollution: A Neglected but Serious Problem

Local Arctic Air Pollution: A Neglected but Serious Problem
J. Schmale, S. R. Arnold, K. S. Law, T. Thorp, S. Anenberg, W. R. Simpson, J. Mao, K. A. Pratt

ABSTRACT: Air pollution in the Arctic caused by local emission sources is a challenge that is important but often overlooked. Local Arctic air pollution can be severe and significantly exceed air quality standards, impairing public health and affecting ecosystems. Specifically in the wintertime, pollution can accumulate under inversion layers. However, neither the contributing emission sources are well identified and quantified nor the relevant atmospheric mechanisms forming pollution are well understood. In the summer, boreal forest fires cause high levels of atmospheric pollution. Despite the often high exposure to air pollution, there are neither specific epidemiological nor toxicological health impact studies in the Arctic. Hence, effects on the local population are difficult to estimate at present. Socioeconomic development of the Arctic is already occurring and expected to be significant in the future. Arctic destination shipping is likely to increase with the development of natural resource extraction, and tourism might expand. Such development will not only lead to growth in the population living in the Arctic but will likely increase emission types and magnitudes. Present‐day inventories show a large spread in the amount and location of emissions representing a significant source of uncertainty in model predictions that often deviate significantly from observations. This is a challenge for modeling studies that aim to assess the impacts of within Arctic air pollution. Prognoses for the future are hence even more difficult, given the additional uncertainty of estimating emissions based on future Arctic economic development scenarios.

IASC Related Activity:
The Second PACES Science Workshop

Non-linear Response of Summertime Marine Productivity to Increased Meltwater Discharge Around Greenland

Non-linear Response of Summertime Marine Productivity to Increased Meltwater Discharge Around Greenland
M. J. Hopwood, D. Carroll, T. J. Browning, L. Meire, J. Mortensen, S. Krisch & E. P. Achterberg

ABSTRACT: Runoff from the Greenland Ice Sheet (GrIS) is thought to enhance marine productivity by adding bioessential iron and silicic acid to coastal waters. However, experimental data suggest nitrate is the main summertime growth-limiting resource in regions affected by meltwater around Greenland. While meltwater contains low nitrate concentrations, subglacial discharge plumes from marine-terminating glaciers entrain large quantities of nitrate from deep seawater. Here, we characterize the nitrate fluxes that arise from entrainment of seawater within these plumes using a subglacial discharge plume model. The upwelled flux from 12 marine-terminating glaciers is estimated to be >1000% of the total nitrate flux from GrIS discharge. This plume upwelling effect is highly sensitive to the glacier grounding line depth. For a majority of Greenland’s marine-terminating glaciers nitrate fluxes will diminish as they retreat. This decline occurs even if discharge volume increases, resulting in a negative impact on nitrate availability and thus summertime marine productivity.

IASC Related Activity:
The Importance of Arctic Glaciers for the Arctic Marine Ecosystem

Revisiting Perceptions and Evolving Culture: a Community Dialogue on Women in Polar Research

Revisiting Perceptions and Evolving Culture: a Community Dialogue on Women in Polar Research
S. Starkweather, M. Seag, O. Lee, A. Pope

ABSTRACT: Women have made outstanding contributions to polar research in recent decades, though full engagement may be hindered by persistent inequities, including notably the prevalence of workplace harassment. Remote field settings, such as those pervasive in polar research, have been identified as particularly susceptible to cultures of harassment. It was therefore timely at the Polar 2018 Open Science Conference in Davos, Switzerland, to convene a discussion focused on women’s perspectives and experiences. A panel discussion—“From Entering the Field to Taking the Helm: Perspectives of Women in Polar Research”—took place on 20 June 2018 and featured five women undertaking work from marine biotechnology to organizational leadership, across career levels. Over 300 conference attendees joined the lunchtime panel. The panellists’ perspectives on historical barriers, current challenges and future prospects revealed that while challenges persist, experiences vary greatly. Audience engagement underscored the need to sustain dialogue at polar meetings, to bring visibility to the statistics related to workplace harassment and to encourage polar science organizations to assume leadership on promoting equitable workplace culture.

IASC Related Activity:
From Entering the Field to Taking the Helm: Perspectives of Women in Polar Research

Where the Poles Come Together

Where the Poles Come Together, POLAR2018 Joint Open Science Conference
Juliana D’Andrilli

ABSTRACT: Polar research in the Arctic and Antarctic is imperative to understand our past, present, and future impact of such environments with global environmental change. Impacts from environmental change in polar regions will be felt worldwide, affecting all life on Earth on scales that previously seemed unimaginable.

IASC Related Activity:
POLAR2018

Arctic Science: From Knowledge to Action?

Arctic Science: From Knowledge to Action?
K. Timm, A. Pope, M. Smieszek, G. Fugmann & Y. Zaika

ABSTRACT: The pace of Arctic change is outrunning the process of conducting scientific assessments. However, the demand and need for timely, accurate, relevant, and credible information is greater than ever. Scientific assessments synthesize, document and supply critical information to decision-makers on key issues. They continue to be the principal means for harnessing and communicating scientific knowledge, but the mechanisms of this process are unfamiliar to many early-career researchers. To address this need, the Association of Polar Early Career Researchers (APECS), the International Arctic Science Committee (IASC) and the Arctic Monitoring and Assessment Programme (AMAP) hosted a one-day workshop about scientific assessments on 24 April 2017 in conjunction with the International Conference on Arctic Science: Bringing Knowledge to Action. The workshop was attended by two dozen early-career and mid-career researchers and professionals from a range of countries and disciplines. Thirteen panellists, including assessment creators, contributors, communicators and end-users, discussed how assessments are produced, how scientific knowledge is translated and communicated, and how scientists can leverage assessments in their own outreach. Many valuable lessons and practical skills were discussed, as well as challenges and opportunities for the future of scientific assessments in the Arctic.

IASC Related Activity:
Workshop, Arctic Science: From Knowledge to Action?

Glacier Surface Velocity Retrieval Using D-InSAR and Offset Tracking Techniques Applied to Ascending and Descending Passes of Sentinel-1 Data for Southern Ellesmere Ice Caps, Canadian Arctic

Glacier Surface Velocity Retrieval Using D-InSAR and Offset Tracking Techniques Applied to Ascending and Descending Passes of Sentinel-1 Data for Southern Ellesmere Ice Caps, Canadian Arctic.
P. Sánchez-Gámez, and F.J. Navarro (Sens, 9(5), 442; doi: 10.3390/rs9050442)

ABSTRACT: The Terrain Observation by Progressive Scans (TOPS) acquisition mode of the Sentinel-1 mission provides a wide coverage per acquisition with resolutions of 5 m in range and 20 m in azimuth, which makes this acquisition mode attractive for glacier velocity monitoring. Here, we retrieve surface velocities from the southern Ellesmere Island ice caps (Canadian Arctic) using both offset tracking and Differential Interferometric Synthetic Aperture Radar (D-InSAR) techniques and combining ascending and descending passes. We optimise the offset tracking technique by omitting the azimuth offsets. By doing so, we are able to improve the final resolution of the velocity product, as Sentinel-1 shows a lower resolution in the azimuth direction. Simultaneously, we avoid the undesired ionospheric effect manifested in the data as azimuth streaks. The D-InSAR technique shows its merits when applied to slow-moving areas, while offset tracking is more suitable for fast-moving areas. This research shows that the methods used here are complementary and the use of both to determine glacier velocities is better than only using one or the other. We observe glacier surface velocities of up to 1200 m year −1 for the fastest tidewater glaciers. The land-terminating glaciers show typical velocities between 12 and 33 m year −1 , though with peaks up to 150 m year −1 in narrowing zones of the confining valleys.

IASC Related Activity:
Network on Arctic Glaciology

Modeling the Controls on the Front Position of a Tidewater Glacier in Svalbard

Modeling the Controls on the Front Position of a Tidewater Glacier in Svalbard
Otero J., Navarro F.J., Lapazaran J.J., Welty E., Puczko D. and R. Finkelnburg (Front. Earth Sci. 5:29. doi:10.3389/feart.2017.00029)

ABSTRACT: Calving is an important mass-loss process at ice sheet and marine-terminating glacier margins, but identifying and quantifying its principal driving mechanisms remains challenging. Hansbreen is a grounded tidewater glacier in southern Spitsbergen, Svalbard, with a rich history of field and remote sensing observations. The available data make this glacier suitable for evaluating mechanisms and controls on calving, some of which are considered in this paper. We use a full-Stokes thermomechanical 2D flow model (Elmer/Ice), paired with a crevasse-depth calving criterion, to estimate Hansbreen's front position at a weekly time resolution. The basal sliding coefficient is re-calibrated every 4 weeks by solving an inverse model. We investigate the possible role of backpressure at the front (a function of ice mélange concentration) and the depth of water filling crevasses by examining the model's ability to reproduce the observed seasonal cycles of terminus advance and retreat. Our results suggest that the ice-mélange pressure plays an important role in the seasonal advance and retreat of the ice front, and that the crevasse-depth calving criterion, when driven by modeled surface meltwater, closely replicates observed variations in terminus position. These results suggest that tidewater glacier behavior is influenced by both oceanic and atmospheric processes, and that neither of them should be ignored.

IASC Related Activity:
Network on Arctic Glaciology

Polar Low Workshop Summary

Polar Low Workshop Summary
Thomas Spengler (Corresponding author) et al. 

ABSTRACT: The 13th European Polar Low Workshop was organized by the European Polar Low Working Group (www.uni-trier.de/index.php?id=20308)and gathered scientists from nine countries focusing on polar mesocyclones in both hemispheres and other mesoscale weather phenomena such as katabatic winds, tip jets, boundary layer fronts, cold air outbreaks, and weather extremes in polar regions. Topics included experimental, climatological, theoretical, modeling, and remote sensing studies. The aim was to bring together scientists and forecasters to present their latest work and recent findings on these topics and to encourage discussions on improving forecasting and understanding of these phenomena.

IASC Related Activity:

The Arctic Science Agreement Propels Science Diplomacy

The Arctic Science Agreement propels science diplomacy

Global geopolitics are fueling the renewal of East-West tensions, with deteriorating U.S.-Russia relations in the wake of conflicts in Ukraine and Syria, issues involving cyber-security, and broader concerns about expanding militarization. Against this backdrop, the Agreement on Enhancing International Arctic Scientific Cooperation, signed on 11 May 2017 by foreign ministers of the eight Arctic States, including the U.S. and Russia, as well as Greenland and the Faroe Islands, is a milestone. This “Arctic Science Agreement” is a strong signal reaffirming the global relevance of science as a tool of diplomacy, reflecting a common interest to promote scientific cooperation even when diplomatic channels among nations are unstable (1–3). It provides a framework for enhancing the efforts of scientists working on cutting-edge issues, but translating the general language of the agreement into enhanced action requires further attention, collaboration, and effort among diplomats and scientists to ensure its successful implementation. With the International Arctic Science Committee (IASC) convening the International Science Initiative in the Russian Arctic (ISIRA) at the Russian Academy of Sciences in Moscow next week, we highlight steps to advance science, its contributions to informed decision-making, and its role in maintaining the Arctic as a zone of peace and cooperation. Authors: Paul Arthur Berkman, Lars Kullerud (UArctic), Allen Pope (IASC), Alexander N. Vylegzhanin, Oran R. Young

Arctic terrestrial hydrology: A synthesis of processes, regional effects, and research challenges

Arctic terrestrial hydrology: A synthesis of processes, regional effects, and research challenges
A. Bring, I. Fedorova, Y. Dibike, L. Hinzman, J. Mård, S. H. Mernild, T. Prowse, O. Semenova, S. L. Stuefer, M.‐K. Woo

ABSTRACT: Terrestrial hydrology is central to the Arctic system and its freshwater circulation. Water transport and water constituents vary, however, across a very diverse geography. In this paper, which is a component of the Arctic Freshwater Synthesis, we review the central freshwater processes in the terrestrial Arctic drainage and how they function and change across seven hydrophysiographical regions (Arctic tundra, boreal plains, shield, mountains, grasslands, glaciers/ice caps, and wetlands). We also highlight links between terrestrial hydrology and other components of the Arctic freshwater system. In terms of key processes, snow cover extent and duration is generally decreasing on a pan‐Arctic scale, but snow depth is likely to increase in the Arctic tundra. Evapotranspiration will likely increase overall, but as it is coupled to shifts in landscape characteristics, regional changes are uncertain and may vary over time. Streamflow will generally increase with increasing precipitation, but high and low flows may decrease in some regions. Continued permafrost thaw will trigger hydrological change in multiple ways, particularly through increasing connectivity between groundwater and surface water and changing water storage in lakes and soils, which will influence exchange of moisture with the atmosphere. Other effects of hydrological change include increased risks to infrastructure and water resource planning, ecosystem shifts, and growing flows of water, nutrients, sediment, and carbon to the ocean. Coordinated efforts in monitoring, modeling, and processing studies at various scales are required to improve the understanding of change, in particular at the interfaces between hydrology, atmosphere, ecology, resources, and oceans

IASC Related Activity:
Arctic Freshwater Synthesis (AFS)

High-Latitude Dynamics of Atmosphere–Ice–Ocean Interactions

High-Latitude Dynamics of Atmosphere–Ice–Ocean Interactions
Thomas Spengler (Corresponding author) et al. 

ABSTRACT: Scientists from 13 countries involved with modeling and observing the coupled high-latitude weather and climate system discussed our current understanding and challenges in polar prediction, extreme events, and coupled processes on scales ranging from cloud and turbulent processes, from micrometers and a few hundred meters to processes on synoptic-scale weather phenomena and pan-Arctic energy budgets of hundreds to thousands of kilometers. Workshop participants also evaluated research needs to improve numerical models with usages spanning from uncoupled to fully coupled models used for weather and climate prediction (http://highlatdynamics.b.uib.no/).

IASC Related Activity:
Workshop on Dynamics of Atmosphere-Ice-Ocean Interactions in High Latitudes

ICARP III Final Report

ICARP III Final Report (PDF - 4,5 MB)

Integrating Arctic Research - a Roadmap for the Future:

The official outcomes of the Third International Conference on Arctic Research Planning (ICARP III) were published online today. The report, entitled "Integrating Arctic Research – A Roadmap for the Future“ presents the key messages that emerged from the 2-year ICARP III process.

IASC Related Activity:
ICARP III

MOSAiC Science Plan 2016

MOSAiC Science Plan 2016 (PDF - 3MB)

The plan was developed by the MOSAiC Science Plan writing team during 2013-2016 and lays out the scientific vision and design of the MOSAiC initiative. The Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) is a key international flagship initiative under the auspices of the International Arctic Science Committee (IASC).

The Arctic Freshwater System in a Changing Climate

“The Arctic Freshwater System in a Changing Climate” Report (PDF - 17MB)

The report is an assessment produced jointly by the World Climate Research Programme’s Climate and Cryosphere Project (CliC), IASC and AMAP. The AFS Summary report is based on the scientific articles that have been peer-reviewed and accepted for publication in a Special Issue of the Journal of Geophysical Research: Biogeosciences.

Arctic Freshwater Synthesis: Introduction

Arctic Freshwater Synthesis: Introduction
T. Prowse, A. Bring, J. Mård, E. Carmack

Abstract:In response to a joint request from the World Climate Research Program's Climate and Cryosphere Project, the International Arctic Science Committee, and the Arctic Council's Arctic Monitoring and Assessment Program, an updated scientific assessment has been conducted of the Arctic Freshwater System, entitled the Arctic Freshwater Synthesis (AFS). The major reason for joint request was an increasing concern that changes to the Arctic Freshwater System have produced, and could produce even greater, changes to biogeophysical and socioeconomic systems of special importance to northern residents and also produce extra‐Arctic climatic effects that will have global consequences. Hence, the key objective of the AFS was to produce an updated, comprehensive, and integrated review of the structure and function of the entire Arctic Freshwater System. The AFS was organized around six key thematic areas: atmosphere, oceans, terrestrial hydrology, terrestrial ecology, resources and modeling, and the review of each coauthored by an international group of scientists and published as separate articles in this special section of Journal of Geophysical Research: Biogeosciences. This Introduction reviews the motivations for, and foci of, previous studies of the Arctic Freshwater System, discusses criteria used to define the domain of the Arctic Freshwater System, and details key characteristics of the definition adopted for the AFS.

IASC Related Activity:
Arctic Freshwater Synthesis (AFS)

Arctic Freshwater Synthesis: Summary of Key Emerging Issues

Arctic Freshwater Synthesis: Summary of Key Emerging Issues
T. Prowse, A. Bring, J. Mård, E. Carmack, M. Holland, A. Instanes, T. Vihma, F. J. Wrona

Abstract:In response to a joint request from the World Climate Research Program's Climate and Cryosphere Project, the International Arctic Science Committee, and the Arctic Council's Arctic Monitoring and Assessment Program an updated scientific assessment has been conducted of the Arctic Freshwater System, entitled the Arctic Freshwater Synthesis (AFS). The major reason behind the joint request was an increasing concern that changes to the Arctic Freshwater System have produced, and could produce even greater, changes to biogeophysical and socioeconomic systems of special importance to northern residents and also produce extra‐Arctic climatic effects that will have global consequences. The AFS was structured around six key thematic areas: atmosphere, oceans, terrestrial hydrology, terrestrial ecology, resources, and modeling, the review of each coauthored by an international group of scientists and published as separate articles in this special section of Journal of Geophysical Research: Biogeosciences. This AFS summary article reviews key issues that emerged during the conduct of the synthesis, especially those that are cross‐thematic in nature, and identifies future research required to address such issues.

IASC Related Activity:
Arctic Freshwater Synthesis (AFS)

Changes to Freshwater Systems Affecting Arctic Infrastructure and Natural Resources

Changes to Freshwater Systems Affecting Arctic Infrastructure and Natural Resources
A. Instanes, V. Kokorev, R. Janowicz, O. Bruland, K. Sand, T. Prowse

Abstract:The resources component of the Arctic Freshwater Synthesis focuses on the potential impact of future climate and change on water resources in the Arctic and how Arctic infrastructure and exploration and production of natural resources are affected. Freshwater availability may increase in the Arctic in the future in response to an increase in middle‐ and high‐latitude annual precipitation. Changes in type of precipitation, its seasonal distribution, timing, and rate of snowmelt represent a challenge to municipalities and transportation networks subjected to flooding and droughts and to current industries and future industrial development. A reliable well‐distributed water source is essential for all infrastructures, industrial development, and other sectorial uses in the Arctic. Fluctuations in water supply and seasonal precipitation and temperature may represent not only opportunities but also threats to water quantity and quality for Arctic communities and industrial use. The impact of future climate change is varying depending on the geographical area and the current state of infrastructure and industrial development. This paper provides a summary of our current knowledge related to the system function and key physical processes affecting northern water resources, industry, and other sectorial infrastructure.

IASC Related Activity:
Arctic Freshwater Synthesis (AFS)

Freshwater and its Role in the Arctic Marine System: Sources, Disposition, Storage, Export, and Physical and Biogeochemical Consequences in the Arctic and Global Oceans

Freshwater and its Role in the Arctic Marine System: Sources, Disposition, Storage, Export, and Physical and Biogeochemical Consequences in the Arctic and Global Ocean
E.C. Carmack, M. Yamamoto-Kawai, T. Haine, S. Bacon, B. Bluhm, C. Lique, H. Melling, I. Polyakov, F. Straneo, M.-L. Timmermans, W.J. Williams;

Abstract: The Arctic Ocean is a fundamental node in the global hydrological cycle and the ocean's thermohaline circulation. We here assess the system's key functions and processes: (1) the delivery of fresh and low‐salinity waters to the Arctic Ocean by river inflow, net precipitation, distillation during the freeze/thaw cycle, and Pacific Ocean inflows; (2) the disposition (e.g., sources, pathways, and storage) of freshwater components within the Arctic Ocean; and (3) the release and export of freshwater components into the bordering convective domains of the North Atlantic. We then examine physical, chemical, or biological processes which are influenced or constrained by the local quantities and geochemical qualities of freshwater; these include stratification and vertical mixing, ocean heat flux, nutrient supply, primary production, ocean acidification, and biogeochemical cycling. Internal to the Arctic the joint effects of sea ice decline and hydrological cycle intensification have strengthened coupling between the ocean and the atmosphere (e.g., wind and ice drift stresses, solar radiation, and heat and moisture exchange), the bordering drainage basins (e.g., river discharge, sediment transport, and erosion), and terrestrial ecosystems (e.g., Arctic greening, dissolved and particulate carbon loading, and altered phenology of biotic components). External to the Arctic freshwater export acts as both a constraint to and a necessary ingredient for deep convection in the bordering subarctic gyres and thus affects the global thermohaline circulation. Geochemical fingerprints attained within the Arctic Ocean are likewise exported into the neighboring subarctic systems and beyond. Finally, we discuss observed and modeled functions and changes in this system on seasonal, annual, and decadal time scales and discuss mechanisms that link the marine system to atmospheric, terrestrial, and cryospheric systems.

IASC Related Activity:
Arctic Freshwater Synthesis (AFS)

Modeling the Arctic freshwater system and its integration in the global system: Lessons learned and future challenges

Modeling the Arctic freshwater system and its integration in the global system: Lessons learned and future challenges/span>
C. Lique, M. M. Holland, Y. B. Dibike, D. M. Lawrence, J. A. Screen

Abstract:Numerous components of the Arctic freshwater system (atmosphere, ocean, cryosphere, and terrestrial hydrology) have experienced large changes over the past few decades, and these changes are projected to amplify further in the future. Observations are particularly sparse, in both time and space, in the polar regions. Hence, modeling systems have been widely used and are a powerful tool to gain understanding on the functioning of the Arctic freshwater system and its integration within the global Earth system and climate. Here we present a review of modeling studies addressing some aspect of the Arctic freshwater system. Through illustrative examples, we point out the value of using a hierarchy of models with increasing complexity and component interactions, in order to dismantle the important processes at play for the variability and changes of the different components of the Arctic freshwater system and the interplay between them. We discuss past and projected changes for the Arctic freshwater system and explore the sources of uncertainty associated with these model results. We further elaborate on some missing processes that should be included in future generations of Earth system models and highlight the importance of better quantification and understanding of natural variability, among other factors, for improved predictions of Arctic freshwater system change.

IASC Related Activity:
Arctic Freshwater Synthesis (AFS)

The Atmospheric Role In The Arctic Water Cycle: A Review On Processes, Past And Future Changes, And Their Impacts

The Atmospheric Role In The Arctic Water Cycle: A Review On Processes, Past And Future Changes, And Their Impacts
T. Vihma, J. Screen, M. Tjernström, B. Newton, X. Zhang, V. Popova, C. Deser, M. Holland, T. Prowse

Abstract:Atmospheric humidity, clouds, precipitation, and evapotranspiration are essential components of the Arctic climate system. During recent decades, specific humidity and precipitation have generally increased in the Arctic, but changes in evapotranspiration are poorly known. Trends in clouds vary depending on the region and season. Climate model experiments suggest that increases in precipitation are related to global warming. In turn, feedbacks associated with the increase in atmospheric moisture and decrease in sea ice and snow cover have contributed to the Arctic amplification of global warming. Climate models have captured the overall wetting trend but have limited success in reproducing regional details. For the rest of the 21st century, climate models project strong warming and increasing precipitation, but different models yield different results for changes in cloud cover. The model differences are largest in months of minimum sea ice cover. Evapotranspiration is projected to increase in winter but in summer to decrease over the oceans and increase over land. Increasing net precipitation increases river discharge to the Arctic Ocean. Over sea ice in summer, projected increase in rain and decrease in snowfall decrease the surface albedo and, hence, further amplify snow/ice surface melt. With reducing sea ice, wind forcing on the Arctic Ocean increases with impacts on ocean currents and freshwater transport out of the Arctic. Improvements in observations, process understanding, and modeling capabilities are needed to better quantify the atmospheric role in the Arctic water cycle and its changes.

IASC Related Activity:
Arctic Freshwater Synthesis (AFS)

Transitions in Arctic Ecosystems: Ecological Implications of a Changing Hydrological Regime

Transitions in Arctic Ecosystems: Ecological Implications of a Changing Hydrological Regime
F.J. Wrona, M. Johansson, J. M. Culp, A. Jenkins, J. Mård, I. H. Myers‐Smith, T. D. Prowse, W. F. Vincent, P. A. Wookey

Abstract:Numerous international scientific assessments and related articles have, during the last decade, described the observed and potential impacts of climate change as well as other related environmental stressors on Arctic ecosystems. There is increasing recognition that observed and projected changes in freshwater sources, fluxes, and storage will have profound implications for the physical, biogeochemical, biological, and ecological processes and properties of Arctic terrestrial and freshwater ecosystems. However, a significant level of uncertainty remains in relation to forecasting the impacts of an intensified hydrological regime and related cryospheric change on ecosystem structure and function. As the terrestrial and freshwater ecology component of the Arctic Freshwater Synthesis, we review these uncertainties and recommend enhanced coordinated circumpolar research and monitoring efforts to improve quantification and prediction of how an altered hydrological regime influences local, regional, and circumpolar‐level responses in terrestrial and freshwater systems. Specifically, we evaluate (i) changes in ecosystem productivity; (ii) alterations in ecosystem‐level biogeochemical cycling and chemical transport; (iii) altered landscapes, successional trajectories, and creation of new habitats; (iv) altered seasonality and phenological mismatches; and (v) gains or losses of species and associated trophic interactions. We emphasize the need for developing a process‐based understanding of interecosystem interactions, along with improved predictive models. We recommend enhanced use of the catchment scale as an integrated unit of study, thereby more explicitly considering the physical, chemical, and ecological processes and fluxes across a full freshwater continuum in a geographic region and spatial range of hydroecological units (e.g., stream‐pond‐lake‐river‐near shore marine environments).

IASC Related Activity:
Arctic Freshwater Synthesis (AFS)