Data for "Spatiotemporal variability in precipitation-growth relations of Betula nana in the Siberian lowland tundra"

Data files and R code used to perform climate-growth analysis on tree rings of the Arctic dwarf shrub Betula nana sampled in topographically contrasting sites at the Kytalyk station in North-eastern Siberia. The purpose of the study was to assess whether associations between annual climate variables and shrub growth (evident from tree rings) varied over decadal timescales and spatial contrasts. We used moving-window orthogonalized partial least squares regression and supporting analyses. While associations of shrub growth and temperature were consistent across time and space, associations of shrub growth and precipitation were not

Rapid vegetation succession and coupled permafrost dynamics in arctic thaw ponds in the Siberian lowland tundra

Thermokarst features, such as thaw ponds, are hotspots for methane emissions in warming lowland tundra. Presently we lack quantitative knowledge on the formation rates of formation of thaw ponds and subsequent vegetation succession, necessary to determine their net contribution to greenhouse gas emissions. This study set out to identify development trajectories and formation rates approximate rates of of small-scale (< 1 km2) arctic thaw ponds in north-eastern Siberia. We selected 40 ponds of different age classes based on a time-series of satellite images and measured vegetation composition, microtopography, water table and active layer thicknessthaw depth in the field and measured age of recruiting colonizing shrubs in thaw ponds using dendrochronology. We found that young thaw ponds are characterised by dead shrubs, while older ponds show rapid paludification through colonization bycontain mostly sedges and Sphagnum moss. While dead shrubs and open water are associated with permafrost degradation (lower surface elevation, high active layer thicknesslarger thaw depth), sites with sedge and in particular Sphagnum display indications of permafrost recovery. Recruitment of Betula nana on Sphagnum carpets in ponds indicates a potential recovery towards shrub dominated vegetation, although it remains unclear if and on what timescale this occurs. Our results suggest that thaw ponds display potentially cyclic vegetation succession associated with permafrost degradation and recovery. Thaw pond formation and initial colonization by sedges can occur on subdecadal timescales, which is relatively fast compared to rates known for ice wedge degradation (subdecadal to century-scale). The rates of formation and recovery of small-scale thaw ponds have implications for the greening/browning dynamics and carbon balance of this ecosystem

Data for "Extremely wet summer events enhance permafrost thaw for multiple years in Siberian tundra"

Permafrost thaw can accelerate climate warming by releasing carbon from previously frozen soil in the form of greenhouse gases. Rainfall extremes have been proposed to increase permafrost thaw, but the magnitude and duration of this effect are poorly understood. Here we present empirical evidence showing that one extremely wet summer (+100mm; 120% increase relative to average June – August rainfall) enhanced thaw depth by up to 35% in a controlled irrigation experiment in an ice-rich Siberian tundra site. The effect persisted over two subsequent summers, demonstrating a carry-over effect of extremely wet summers. Using soil thermal hydrological modelling, we show that rainfall extremes delayed autumn freeze-up and rainfall-induced increases in thaw were most pronounced for warm summers with mid-summer precipitation rainfall extremes. Our results suggest that, with rainfall and temperature both increasing in the Arctic, permafrost will likely degrade and disappear faster than is currently anticipated based on rising air temperatures alone

Data 2022 - 2023 T-REX project Svalbard

All project info here: Metadata in .zi

Dataset for: "Shrub decline and expansion of wetland vegetation revealed by very high resolution land cover change detection in the Siberian lowland tundra"

Input materials, scripts and results for: - Trend analyses in MODIS Enhanced Vegetation Index for 2000-2019 in the Indigirka Lowlands, Sakha Republic, Russian federation. - Land Cover Change Detection of Vegetation Functional Groups in an Arcitc tundra site using very high resolution (0.5) satellite images in a focus area in the Kytalyk Reserve, Indigirka Lowlands over the period 2010-2019

Landschappen in 3D

At the GIS-studio of the Faculty of Science (FNWI) at the University of Amsterdam, a project has been completed in which two maps (models) are produced in 3D using ArcGIS, Blender and a 3D printer. 3D printing is an emerging technology in both science and in business, fine arts and for everyday objects. With the advent of LiDAR (Light Detection And Ranging), a relatively new remote sensing technology, more and more detailed digital elevation models are being produced, displaying the Earth's surface in 3D in very high detail. 3D printing offers an excellent supplement, because with the use of it, it is not necessary to visualize and analyze 3D data in 2D, but the data can be studied directly in 3D. A tutorial has been developed for making 3D-printed models from digital height models, which is included as an English appendix at the end of this document.Im GIS-Studio der Fakultät für Naturwissenschaften, Mathematik und Informatik (FNWI) der Universität Amsterdam wurde ein Projekt abgeschlossen, bei dem zwei Karten (Modelle) in 3D mit einem 3D-Drucker produziert wurden. 3D-Druck ist eine aufstrebende Technologie in Wissenschaft, Wirtschaft, bildender Kunst und für Alltagsgegenständen. Mit dem Aufkommen von LiDAR (Light Detection And Ranging), eine relativ neue Fernerkundungstechnologie, werden immer detailliertere digitale Höhenmodelle erstellt, die die Erdoberfläche sehr detailliert in 3D darstellen können. 3D-Druck bietet eine hervorragende Ergänzung dazu, da 3D-Daten in 2D nicht visualisiert und analysiert werden müssen, sondern Daten direkt in 3D untersucht werden können. Eine Anleitung (Tutorial) wurde entwickelt, um 3D-gedruckte Modelle aus digitalen Höhenmodelle zu erstellen, die als englischsprachiger Anhang (Appendix) am Ende dieses Dokuments enthalten ist.Samenvatting. Bij de GIS-studio van de Faculteit der Natuurwetenschappen, Wiskunde en Informatica (FNWI) aan de Universiteit van Amsterdam, is een project afgerond waarin twee kaarten (modellen) zijn geproduceerd in 3D met behulp van ArcGIS, Blender en een 3D-printer. 3D-printen is een techniek in opkomst in zowel de wetenschap als in het bedrijfsleven, beeldende kunst en voor alledaagse objecten. Met de opkomst van LiDAR (Light Detection And Ranging), een relatief nieuwe remote sensing-techniek, worden steeds gedetailleerdere digitale hoogtemodellen gemaakt, waardoor het aardoppervlak in zeer hoog detail in 3D kan worden weergegeven. 3D-printen biedt hierop een uitstekende aanvulling, doordat het hiermee niet nodig is 3D data in 2D te visualiseren en analyseren, maar data direct in 3D kunnen worden bestudeerd. Een tutorial is ontwikkeld voor het maken van 3D-geprinte modellen vanuit digitale hoogtemodellen, welke als Engelstalige appendix is toegevoegd aan het eind van dit document.Not Reviewe

Continentality determines warming or cooling impact of heavy rainfall events on permafrost

Permafrost thaw can cause an intensification of climate change through the release of carbon as greenhouse gases. While the effect of air temperature on permafrost thaw is well quantified, the effect of rainfall is highly variable and not well understood. Here, we provide a literature review of studies reporting on effects of rainfall on ground temperatures in permafrost environments and use a numerical model to explore the underlying physical mechanisms under different climatic conditions. Both the evaluated body of literature and the model simulations indicate that continental climates are likely to show a warming of the subsoil and hence increased end of season active layer thickness, while maritime climates tend to respond with a slight cooling effect. This suggests that dry regions with warm summers are prone to more rapid permafrost degradation under increased occurrences of heavy rainfall events in the future, which can potentially accelerate the permafrost carbon feedback

Data for "Spatiotemporal variability in precipitation-growth relations of Betula nana in the Siberian lowland tundra"

Data files and R code used to perform climate-growth analysis on tree rings of the Arctic dwarf shrub Betula nana sampled in topographically contrasting sites at the Kytalyk station in North-eastern Siberia. The purpose of the study was to assess whether associations between annual climate variables and shrub growth (evident from tree rings) varied over decadal timescales and spatial contrasts. We used moving-window orthogonalized partial least squares regression and supporting analyses. While associations of shrub growth and temperature were consistent across time and space, associations of shrub growth and precipitation were not

Tundra Browning in the Indigirka Lowlands (North-Eastern Siberia) Explained by Drought, Floods and Small-Scale Vegetation Shifts

Contrary to the general “greening of the Arctic”, the Siberian Indigirka Lowlands show strong “browning” (a decrease in the Normalized Difference Vegetation Index or “NDVI”) in various recent satellite records. Since greening and browning are generally indicative of increases and losses in photosynthetically active biomass, this browning trend may have implications for the carbon balance and vegetation of this Arctic tundra region. To explore potential mechanisms responsible for this trend break from general Arctic greening, we studied timeseries of Landsat summer maximum NDVI, weather data, and high-resolution maps of vegetation compositional change, topography, geomorphology and hydrology. We find that a significant proportion of browning (lower summer NDVI) is explained by moisture dynamics, with high snow depths and resulting floods as well as summer drought coinciding with low NDVI. Relations between seasonal weather variables and NDVI are spatially heterogeneous, with floodplains, drained thaw lake basins and Yedoma ridges showing different patterns of association with weather variables. Low summer NDVI after high snowfall was particularly evident in floodplains, likely explained by early summer floods. Local small-scale vegetation changes explained only small amounts of variance in browning rates in Landsat NDVI. Local expansion of Sphagnum vegetation in particular may have contributed to recent browning of our study site, but higher resolution NDVI timeseries are necessary to accurately constrain the role of small-scale vegetation shifts. Overall, associations identified in this study suggest that future increases in Arctic precipitation variability and extremes may limit tundra greening, but to different extents even across comparatively small topographical contrasts.</p

Influence of glacial sediments on the chemical quality of surface water in the Ulta valley, Cordillera Blanca, Peru

The Río Santa (Ancash, Peru) and its tributaries are an essential source of drinking and irrigation water. Its discharge relies on glacial meltwater, which is diminishing due to the rapid decrease in glacial extent. As a secondary effect, water quality can be compromised (e.g. pH < 3 and high concentrations of SO42− and trace metals). Although this has previously been attributed to pyrite rich Chicama bedrock exposed by glacial retreat, little is known about the occurrence of Chicama fragments in Quaternary glacial sediments and its influence on water quality. This research aims at elucidating this effect by relating observed changes in water quality in streams to presence and chemical composition of morainic ridges in the Quebrada Ulta in the Río Santa basin. Changes in water quality before and after contact with a morainic ridge were assessed using carbonate alkalinity titration, ion analysis and elemental analysis. Moreover, relative contributions of glacial meltwater and precipitation were assessed qualitatively using stable water isotope analysis. We used a novel method to explain the provenance of contaminated glacial sediments using a reconstruction of their source area. The mineralogical composition of a morainic ridge was strongly related to the geology of the source area indicating that mineralogical composition of tills may be predicted using this technique. Effects of glacial sediments in morainic ridges on water quality were minimal but depended on their mineralogical composition. Morainic ridges with a high content of Chicama shales tended to increase solute loads of Mg and SO42−. Additionally, isotope signatures suggest that during the dry season, moraines may act as reservoirs for precipitation-derived shallow groundwater. Clear trends in water quality were observed along the whole flow path of the Río Buín, which could potentially be explained by increased groundwater contribution downstream and shifts in dominant weathering mechanisms. Future research should focus on disentangling these various drivers of water quality in glacial catchments