Strong changes in the relationship between storage and discharge during a period of thawing soils and climate warming in Northern Sweden

2020 ◽  
Author(s):  
Alexa Hinzman ◽  
Ylva Sjöberg ◽  
Steve Lyon ◽  
Stefan Ploum ◽  
Ype van der Velde
Keyword(s):  
Water Cycle ◽  
Landscape Configuration ◽  
The Arctic ◽  
Northern Sweden ◽  
Deep Soil ◽  
Frozen Soils ◽  
Soil Frost ◽  
Winter Conditions ◽  
Non Linear ◽  
Seasonally Frozen Soils

<p>The Arctic is warming at an unprecedented rate. This warming affects not just ecosystems, but also permafrost, landscape configuration, and water availability in watersheds. One relatively under researched process is how seasonally frozen soils and changes thereof affect the water cycle. As frozen soils thaw, flow pathways within a catchment open, allowing for enhanced hydrologic connectivity between groundwater and rivers. As the connectivity of flow paths increase, the storage-discharge relationship of a watershed changes, which can be perceived within a hydrograph. More specifically, previous studies hypothesized that storage-discharge relationships are relatively linear when soils are frozen and become increasingly non-linear as the landscape thaws.</p><p>The objective of our research is to expand on the assumption that soil thaw leads to increasingly non-linear storage-discharge relationships by quantifying trends and spatio-temporal differences of this relationship. We will present our analysis of sixteen watersheds within Northern Sweden throughout the years of 1951 and 2018. We focus on spring and summer storage-discharge relationships and show how they are affected by preceding winter conditions.</p><p>We found a clear increase in non-linearity of the storage-discharge relationship over time for all catchments with twelve out of sixteen watersheds (75%) having a statistically significant increase in non-linearity. For twelve watersheds, spring relationships were significantly more linear compared to summer, which supports the hypothesis that seasonally frozen soils have less hydrological connectivity leading to more linear storage-discharge relationships. Winter conditions that allow deep soil frost lead to more linear storage-discharge relationships for ten watersheds. Overall, we show that thawing soil leads to a more non-linear storage-discharge relationship which implies river runoff in the Arctic becomes more unpredictable.</p>

scholarly journals The Toba supervolcano eruption caused severe tropical stratospheric ozone depletion

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Sergey Osipov ◽  
Georgiy Stenchikov ◽  
Kostas Tsigaridis ◽  
Allegra N. LeGrande ◽  
Susanne E. Bauer ◽  
...  
Keyword(s):  
Ozone Depletion ◽  
Water Cycle ◽  
Stratospheric Ozone ◽  
System Model ◽  
Earth System ◽  
Sulfate Aerosols ◽  
Winter Conditions ◽  
Attenuation Mechanism ◽  
The Tropics ◽  
Sulfur Emissions

AbstractSupervolcano eruptions have occurred throughout Earth’s history and have major environmental impacts. These impacts are mostly associated with the attenuation of visible sunlight by stratospheric sulfate aerosols, which causes cooling and deceleration of the water cycle. Supereruptions have been assumed to cause so-called volcanic winters that act as primary evolutionary factors through ecosystem disruption and famine, however, winter conditions alone may not be sufficient to cause such disruption. Here we use Earth system model simulations to show that stratospheric sulfur emissions from the Toba supereruption 74,000 years ago caused severe stratospheric ozone loss through a radiation attenuation mechanism that only moderately depends on the emission magnitude. The Toba plume strongly inhibited oxygen photolysis, suppressing ozone formation in the tropics, where exceptionally depleted ozone conditions persisted for over a year. This effect, when combined with volcanic winter in the extra-tropics, can account for the impacts of supereruptions on ecosystems and humanity.

Nematode community resistant to deep soil frost in boreal forest soils

Pedobiologia ◽  
2016 ◽  
Vol 59 (5-6) ◽  
pp. 243-251 ◽  
Author(s):  
Jonathan R. De Long ◽  
Hjalmar Laudon ◽  
Gesche Blume-Werry ◽  
Paul Kardol
Keyword(s):  
Boreal Forest ◽  
Forest Soils ◽  
Nematode Community ◽  
Deep Soil ◽  
Soil Frost

scholarly journals From pole to pole: 33 years of physical oceanography onboard R/V <i>Polarstern</i>

2017 ◽  
Vol 9 (1) ◽  
pp. 211-220 ◽  
Author(s):  
Amelie Driemel ◽  
Eberhard Fahrbach ◽  
Gerd Rohardt ◽  
Agnieszka Beszczynska-Möller ◽  
Antje Boetius ◽  
...  
Keyword(s):  
Data Collection ◽  
Water Cycle ◽  
Heat Budget ◽  
Ocean Dynamics ◽  
The Arctic ◽  
Sensor Calibration ◽  
Data Sets ◽  
Calibration Data ◽  
Data Set ◽  
Different Characteristics

Abstract. Measuring temperature and salinity profiles in the world's oceans is crucial to understanding ocean dynamics and its influence on the heat budget, the water cycle, the marine environment and on our climate. Since 1983 the German research vessel and icebreaker Polarstern has been the platform of numerous CTD (conductivity, temperature, depth instrument) deployments in the Arctic and the Antarctic. We report on a unique data collection spanning 33 years of polar CTD data. In total 131 data sets (1 data set per cruise leg) containing data from 10 063 CTD casts are now freely available at doi:10.1594/PANGAEA.860066. During this long period five CTD types with different characteristics and accuracies have been used. Therefore the instruments and processing procedures (sensor calibration, data validation, etc.) are described in detail. This compilation is special not only with regard to the quantity but also the quality of the data – the latter indicated for each data set using defined quality codes. The complete data collection includes a number of repeated sections for which the quality code can be used to investigate and evaluate long-term changes. Beginning with 2010, the salinity measurements presented here are of the highest quality possible in this field owing to the introduction of the OPTIMARE Precision Salinometer.

scholarly journals Wintertime Arctic Air Pollution over central Alaska: pre-ALPACA campaign

2021 ◽  
Author(s):  
Eleftherios Ioannidis ◽  
Kathy S. Law ◽  
Jean-Christophe Raut ◽  
Tatsuo Onishi ◽  
Louis Marelle ◽  
...  
Keyword(s):  
Air Pollution ◽  
The United States ◽  
Point Sources ◽  
The Arctic ◽  
Formation Mechanisms ◽  
Winter Conditions ◽  
Local Point ◽  
Temperature Inversions ◽  
Local Emissions ◽  
Pollution Episodes

&lt;p&gt;The wintertime Arctic is influenced by air pollution transported from mid-latitudes, leading to formation of Arctic Haze, as well as local emissions such as combustion for heating and power production in very cold winter conditions. This contributes to severe air pollution episodes, with enhanced aerosol concentrations, inter-dispersed with cleaner periods. However, the formation of secondary aerosol particles (sulphate, organics, nitrate) in cold/dark wintertime Arctic conditions, which could contribute to these pollution episodes, is poorly understood.&lt;/p&gt;&lt;p&gt;In this study, which contributes to the Air Pollution in the Arctic: Climate, Environment and Societies - Alaskan Layered Pollution and Arctic Chemical Analysis (PACES-ALPACA) initiative, the Weather Research Forecasting Model with chemistry (WRF-Chem) is used to investigate wintertime pollution over central Alaska focusing on the Fairbanks region, during the pre-ALPACA campaign in winter 2019-2020. Fairbanks is the most polluted city in the United States during wintertime, due to high local emissions and the occurrence of strong surface temperature inversions trapping pollutants near the surface.&lt;/p&gt;&lt;p&gt;Firstly, different WRF meteorological and surface schemes were tested over Alaska with a particular focus on improving simulations of the wintertime boundary layer structure including temperature inversions. An optimal WRF set-up, with increased vertical resolution below 2km, was selected based on evaluation against available data.&lt;/p&gt;&lt;p&gt;Secondly, a quasi-hemispheric WRF-Chem simulation, using the improved WRF setup, was used to assess large-scale synoptic conditions and to evaluate background aerosols originating from remote anthropogenic and natural sources affecting central Alaska during the campaign. The model was run with Evaluating the Climate and Air Quality Impacts of Short-Lived Pollutants (ECLIPSE) v6b anthropogenic emissions and improved sea-spray aerosol emissions. Discrepancies in modelled aerosols compared available data are being investigated (e.g. missing dark formation mechanisms, treatment of removal processes).&lt;/p&gt;&lt;p&gt;Thirdly, fine resolution simulations, using high resolution emissions (e.g. 2019 CAMS inventory), including local point sources, over the Fairbanks region, were used to investigate chemical and dynamical processes influencing aerosols under different meteorological conditions observed during the field campaign including a cold stable episode and a period with possible mixing of air masses from aloft. The model was evaluated against available aerosol, oxidant (ozone) and aerosol precursor data from surface monitoring sites and collected during the pre-campaign, including vertical profile data collected in the lowest 20m. The sensitivity of modelled aerosols to meteorological factors, such as relative humidity, temperature gradients and vertical mixing under winter conditions are investigated.&lt;/p&gt;

scholarly journals Hydroclimatic Controls on the Isotopic (δ18 O, δ2 H, d-excess) Traits of Pan-Arctic Summer Rainfall Events

2021 ◽  
Vol 9 ◽  
Author(s):  
Moein Mellat ◽  
Hannah Bailey ◽  
Kaisa-Riikka Mustonen ◽  
Hannu Marttila ◽  
Eric S. Klein ◽  
...  
Keyword(s):  
Sea Ice ◽  
Water Cycle ◽  
Global Climate ◽  
Meteorological Data ◽  
Summer Rainfall ◽  
Arctic Sea Ice ◽  
The Arctic ◽  
Arctic Water ◽  
Ongoing Research ◽  
Air Masses

Arctic sea-ice loss is emblematic of an amplified Arctic water cycle and has critical feedback implications for global climate. Stable isotopes (δ18O, δ2H, d-excess) are valuable tracers for constraining water cycle and climate processes through space and time. Yet, the paucity of well-resolved Arctic isotope data preclude an empirically derived understanding of the hydrologic changes occurring today, in the deep (geologic) past, and in the future. To address this knowledge gap, the Pan-Arctic Precipitation Isotope Network (PAPIN) was established in 2018 to coordinate precipitation sampling at 19 stations across key tundra, subarctic, maritime, and continental climate zones. Here, we present a first assessment of rainfall samples collected in summer 2018 (n = 281) and combine new isotope and meteorological data with sea ice observations, reanalysis data, and model simulations. Data collectively establish a summer Arctic Meteoric Water Line where δ2H = 7.6⋅δ18O–1.8 (r2 = 0.96, p &lt; 0.01). Mean amount-weighted δ18O, δ2H, and d-excess values were −12.3, −93.5, and 4.9‰, respectively, with the lowest summer mean δ18O value observed in northwest Greenland (−19.9‰) and the highest in Iceland (−7.3‰). Southern Alaska recorded the lowest mean d-excess (−8.2%) and northern Russia the highest (9.9‰). We identify a range of δ18O-temperature coefficients from 0.31‰/°C (Alaska) to 0.93‰/°C (Russia). The steepest regression slopes (&gt;0.75‰/°C) were observed at continental sites, while statistically significant temperature relations were generally absent at coastal stations. Model outputs indicate that 68% of the summer precipitating air masses were transported into the Arctic from mid-latitudes and were characterized by relatively high δ18O values. Yet 32% of precipitation events, characterized by lower δ18O and high d-excess values, derived from northerly air masses transported from the Arctic Ocean and/or its marginal seas, highlighting key emergent oceanic moisture sources as sea ice cover declines. Resolving these processes across broader spatial-temporal scales is an ongoing research priority, and will be key to quantifying the past, present, and future feedbacks of an amplified Arctic water cycle on the global climate system.

Forest fires in the Muddus National Park (northern Sweden) during the past 600 years

1984 ◽  
Vol 62 (5) ◽  
pp. 893-898 ◽  
Author(s):  
Ola Engelmark
Keyword(s):  
Forest Fires ◽  
National Park ◽  
Pine Forests ◽  
The Arctic ◽  
Northern Sweden ◽  
Fire Scars ◽  
Dead Trees ◽  
Humus Layer ◽  
The Mean ◽  
Park Area

The occurrence of forest fires in the Muddus National Park (area, 50 000 ha), just north of the Arctic Circle in northern Sweden, was investigated on 75 separate sample plots. Between 1413 and the present, evidence of 47 fire years was obtained by dating the fire scars on living Scots pines (Pinus sylvestris), the oldest of which had germinated in 1274. The fire traces found on the sample plots were fire scars on living or dead trees or charcoal fragments in the humus layer. Plots lacking all traces of former forest fires were mainly those situated on sites surrounded by extensive mires. Forest fires were shown to have occurred in the five different types of forest investigated. The commonest frequencies of fires in the pine forests occurred with the interval 81–90 years, while the mean frequency was 110 years. The mean interval of time elapsed since the last forest fire occurred in the pine forests was 144 years. Some of the major fire years in the Muddus area coincide with forest fires in other parts of northern Sweden, in the taiga of western Russia, and in central Siberia.

Soil frost and runoff at Svartberget, northern Sweden-measurements and model analysis

2002 ◽  
Vol 16 (17) ◽  
pp. 3379-3392 ◽  
Author(s):  
Göran Lindström ◽  
Kevin Bishop ◽  
Mikaell Ottosson Löfvenius
Keyword(s):  
Model Analysis ◽  
Northern Sweden ◽  
Soil Frost
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