scholarly journals Heterogeneous response of Siberian tree-ring and stable isotope proxies to the largest Common Era volcanic eruptions

2018 ◽  
Author(s):  
Olga V. Churakova ◽  
Marina V. Fonti ◽  
Matthias Saurer ◽  
Sébastien Guillet ◽  
Christophe Corona ◽  
...  
Keyword(s):  
Tree Ring ◽  
Climate Models ◽  
Global Climate ◽  
Sunshine Duration ◽  
Ring Width ◽  
Volcanic Eruptions ◽  
Global Climate Models ◽  
Spatial And Temporal Scales ◽  
Latewood Density ◽  
Common Era

Abstract. Stratospheric volcanic eruptions have far-reaching impacts on global climate and society. Tree rings can provide valuable climatic information on these impacts across different spatial and temporal scales. Here we explore the suitability of tree-ring width (TRW), maximum latewood density (MXD), cell wall thickness (CWT), and δ13C and δ18O in tree-ring cellulose for the detection of climatic changes in northeastern Yakutia (YAK), eastern Taimyr (TAY) and Russian Altai (ALT) sites caused by six largest Common Era stratospheric volcanic eruptions (535, 540, 1257, 1640, 1815 and 1991). Our findings suggest that TRW, MXD, and CWT show strong summer air temperature anomalies in 536, 541–542, 1258–1259 at all study sites. However, they do not reveal distinct and coherent fingerprints after other eruptions. Based on δ13C data, 536 was extremely humid in YAK and TAY, whereas 541 and 542 were humid years in TAY and ALT. In contrast, the 1257 eruption of Samalas likely triggered a sequence of at least two dry summers across all three Siberian sites. No further extreme hydro-climatic anomalies occurred at Siberian sites in the aftermath of the 1991 eruption. Summer sunshine duration decreased significantly in 536, 541–542, 1258–1259 in YAK, and 536 in ALT. Conversely, 1991 was very sunny in YAK. Since climatic responses to large volcanic eruptions are different, and thus affect ecosystem functioning and productivity differently in space and time, a combined assessment of multiple tree-ring parameters is needed to provide a more complete picture of past climate dynamics, which in turns appears fundamental to validate global climate models.

scholarly journals Siberian tree-ring and stable isotope proxies as indicators of temperature and moisture changes after major stratospheric volcanic eruptions

2019 ◽  
Vol 15 (2) ◽  
pp. 685-700 ◽  
Author(s):  
Olga V. Churakova (Sidorova) ◽  
Marina V. Fonti ◽  
Matthias Saurer ◽  
Sébastien Guillet ◽  
Christophe Corona ◽  
...  
Keyword(s):  
Tree Ring ◽  
Global Climate ◽  
Sunshine Duration ◽  
Ring Width ◽  
Volcanic Eruptions ◽  
Climate Dynamics ◽  
Global Climate Models ◽  
Added Value ◽  
Latewood Density ◽  
The Impact

Abstract. Stratospheric volcanic eruptions have far-reaching impacts on global climate and society. Tree rings can provide valuable climatic information on these impacts across different spatial and temporal scales. To detect temperature and hydroclimatic changes after strong stratospheric Common Era (CE) volcanic eruptions for the last 1500 years (535 CE unknown, 540 CE unknown, 1257 CE Samalas, 1640 CE Parker, 1815 CE Tambora, and 1991 CE Pinatubo), we measured and analyzed tree-ring width (TRW), maximum latewood density (MXD), cell wall thickness (CWT), and δ13C and δ18O in tree-ring cellulose chronologies of climate-sensitive larch trees from three different Siberian regions (northeastern Yakutia – YAK, eastern Taimyr – TAY, and Russian Altai – ALT). All tree-ring proxies proved to encode a significant and specific climatic signal of the growing season. Our findings suggest that TRW, MXD, and CWT show strong negative summer air temperature anomalies in 536, 541–542, and 1258–1259 at all studied regions. Based on δ13C, 536 was extremely humid at YAK, as was 537–538 in TAY. No extreme hydroclimatic anomalies occurred in Siberia after the volcanic eruptions in 1640, 1815, and 1991, except for 1817 at ALT. The signal stored in δ18O indicated significantly lower summer sunshine duration in 542 and 1258–1259 at YAK and 536 at ALT. Our results show that trees growing at YAK and ALT mainly responded the first year after the eruptions, whereas at TAY, the growth response occurred after 2 years. The fact that differences exist in climate responses to volcanic eruptions – both in space and time – underlines the added value of a multiple tree-ring proxy assessment. As such, the various indicators used clearly help to provide a more realistic picture of the impact of volcanic eruption on past climate dynamics, which is fundamental for an improved understanding of climate dynamics, but also for the validation of global climate models.

Dendroclimatic relationships and possible implications for mountain birch and Scots pine at treeline in northern Sweden through the 21st centuryThis article is a contribution to the series Tree recruitment, growth, and distribution at the circumpolar forest–tundra transition.

2011 ◽  
Vol 41 (3) ◽  
pp. 450-459 ◽  
Author(s):  
Amanda B. Young ◽  
David M. Cairns ◽  
Charles W. Lafon ◽  
Jon Moen ◽  
Laura E. Martin
Keyword(s):  
Tree Ring ◽  
Scots Pine ◽  
Climate Models ◽  
Global Climate ◽  
Ring Width ◽  
Global Climate Models ◽  
The Arctic ◽  
Mountain Birch ◽  
Terrestrial Vegetation ◽  
Northern Sweden

Changing climate in the Arctic is expected to have significant effects on the pattern and distribution of terrestrial vegetation. Species characteristic of specific zones in the mountains of northern Sweden have been shown to migrate up- and down-slope with changes in climate over the Holocene. This study evaluates the potential for Scots pine (Pinus sylvestris L.) to become a treeline dominant at Fennoscandian treelines, replacing mountain birch (Betula pubescens subsp. czerepanovii (Orlova) Hämet-Ahti). Data from paired mountain birch and Scots pine tree-ring chronologies for eight locations in northern Sweden are used to develop climate – tree ring width index (RWI) relationships. Modeled climate–RWI relationships are then used to predict the relative RWI values of the two species under a suite of climate-forcing scenarios using an ensemble of three global climate models. Results indicate that mountain birch and Scots pine RWI are both correlated with summer temperatures, but Scots pine is more likely than mountain birch to be influenced by moisture conditions. Predictions of RWI under future climate conditions indicate that mountain birch is unlikely to be replaced by Scots pine within the next century.

scholarly journals Eco-Physiological Response of Conifers from High-Latitude and -Altitude Eurasian Regions to Stratospheric Volcanic Eruptions

2020 ◽  
pp. 5-24
Author(s):  
Olga V. Churakova (Sidorova) ◽  
Marina V. Fonti ◽  
Alexander V. Kirdyanov ◽  
Vladimir S. Myglan ◽  
Valentin V. Barinov ◽  
...  
Keyword(s):  
Tree Ring ◽  
Physiological Response ◽  
Sunshine Duration ◽  
Ring Width ◽  
Volcanic Eruptions ◽  
Radiation Budget ◽  
Weather Patterns ◽  
Maximum Latewood Density ◽  
Latewood Density ◽  
Temperature Signal

Stratospheric volcanic eruptions have had significant impacts on the radiation budget, atmospheric and surface temperatures, precipitation and regional weather patterns, resulting in global climatic changes. The changes associated with such eruptions most commonly result in cooling during several years after events. This study aimed to reveal eco-physiological response of larch trees from northeastern Yakutia (YAK), eastern Taimyr (TAY) and Altai (ALT) regions to climatic anomalies after major volcanic eruptions CE 535, 540, 1257, 1641, 1815 and 1991 using new multiple tree-ring parameters: tree-ring width (TRW), maximum latewood density (MXD), cell wall thicknesses (CWT), δ13C and δ18O in tree-ring cellulose. This investigation showed that TRW, CWT, MXD and δ18O chronologies recorded temperature signal, while information about precipitation and vapor pressure deficit was captured by δ13C chronologies. Sunshine duration was well recorded in δ18O from YAK and ALT. Tree-ring parameters recorded cold, wet and cloudy summer anomalies during the 6th and 13th centuries. However, significant summer anomalies after Tambora (1815) and Pinatubo (1991) eruptions were not captured by any tree-ring parameters

Attributing the global increase in permafrost temperatures to human induced climate change

2021 ◽  
Author(s):  
Lukas Gudmundsson ◽  
Josefine Kirchner ◽  
Anne Gädeke ◽  
Eleanor Burke ◽  
Boris K. Biskaborn ◽  
...  
Keyword(s):  
Climate Change ◽  
Large Scale ◽  
Climate Models ◽  
Global Climate ◽  
Volcanic Eruptions ◽  
Global Climate Models ◽  
Anthropogenic Climate Change ◽  
Permafrost Degradation ◽  
Climate Feedbacks ◽  
Permafrost Temperature

<p>Permafrost temperatures are increasing at the global scale, resulting in permafrost degradation. Besides substantial impacts on Arctic and Alpine hydrology and the stability of landscapes and infrastructure, permafrost degradation can trigger a large-scale release of carbon to the atmosphere with possible global climate feedbacks. Although increasing global air temperature is unanimously linked to human emissions into the atmosphere, the attribution of observed permafrost warming to anthropogenic climate change has so far mostly relied on anecdotal evidence. Here we apply a climate change detection and attribution approach to long permafrost temperature records from 15 boreholes located in the northern Hemisphere and simulated soil temperatures obtained from global climate models contributing to the sixth phase of the Coupled Model Intercomparison Project (CMIP6). We show that observed and simulated trends in permafrost temperature are only consistent if the effect of human emissions on the climate system is considered in the simulations. Moreover, the analysis also reveals that neither simulated pre-industrial climate variability nor the effects natural drivers of climate change (e.g. impacts of large volcanic eruptions) suffice to explain the observed trends. While these results are most significant for a global mean assessment, our analysis also reveals that simulated effects of anthropogenic climate change on permafrost temperature are also consistent with the observed record at the station scale. In summary, the quantitative combination of observed and simulated evidence supports the conclusion that anthropogenic climate change is the key driver of increasing permafrost temperatures with implications for carbon cycle-climate feedbacks at the planetary scale.</p>

scholarly journals The influence of decision-making in tree ring-based climate reconstructions

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Ulf Büntgen ◽  
Kathy Allen ◽  
Kevin J. Anchukaitis ◽  
Dominique Arseneault ◽  
Étienne Boucher ◽  
...  
Keyword(s):  
Tree Ring ◽  
Ring Width ◽  
Volcanic Eruptions ◽  
Double Blind ◽  
Reconstruction Process ◽  
Climate Reconstructions ◽  
The Common ◽  
Common Era ◽  
Mean Variance ◽  
Large Volcanic Eruptions

AbstractTree-ring chronologies underpin the majority of annually-resolved reconstructions of Common Era climate. However, they are derived using different datasets and techniques, the ramifications of which have hitherto been little explored. Here, we report the results of a double-blind experiment that yielded 15 Northern Hemisphere summer temperature reconstructions from a common network of regional tree-ring width datasets. Taken together as an ensemble, the Common Era reconstruction mean correlates with instrumental temperatures from 1794–2016 CE at 0.79 (p < 0.001), reveals summer cooling in the years following large volcanic eruptions, and exhibits strong warming since the 1980s. Differing in their mean, variance, amplitude, sensitivity, and persistence, the ensemble members demonstrate the influence of subjectivity in the reconstruction process. We therefore recommend the routine use of ensemble reconstruction approaches to provide a more consensual picture of past climate variability.

Sensitivity of resolved gravity wave momentum fluxes on different background separation methods in a high resolution simulation.

2020 ◽  
Author(s):  
Zuzana Procházková ◽  
Petr Šácha ◽  
Aleš Kuchař ◽  
Petr Pišoft ◽  
Christopher Kruse
Keyword(s):  
High Resolution ◽  
Climate Models ◽  
Global Climate ◽  
Internal Gravity Waves ◽  
Complex Problem ◽  
Global Climate Models ◽  
Satellite Observations ◽  
Detection Methods ◽  
Spatial And Temporal Scales ◽  
Resolution Model

&lt;p&gt;Internal gravity waves (GWs) and their interaction with the atmospheric circulation present a complex problem for global climate models (GCMs) due to a variety of spatial and temporal scales involved. GWs and their effects in GCMs are parameterized by employing various simplifications and restrictions&lt;br&gt;(propagation, spectrum). Also, our incomplete knowledge of the GW properties in the real atmosphere complicates the situation. Global (satellite) observations of the GW activity are spatiotemporally sparse, making the quantification of the GW interaction with the circulation hardly possible. Recently, atmospheric models capable of resolving most of the GW spectrum have been emerging due to the increasing performance of computing systems. It is increasingly acknowledged that a combination of various types of observations with dedicated high-resolution, GW resolving, simulations has a potential to provide the most precise information about GWs. This combination will allow us to better understand the uncertainty of satellite observations of GW activity, which in turn will be used to develop new GW parameterizations or in development of GW resolving models.&lt;br&gt;In this study, we will analyze sensitivity of GW momentum flux and its divergence on background separation (and other GW detection) methods and approximations (Boussinesq, anelastic) used in the formulas. We analyze data from high-resolution model simulations produced for an observing system simulation experiment of the ISSI team &quot;New Quantitative Constraints on Orographic GW Stress and Drag&quot; (to be introduced in an invited presentation by Ch. Kruse).&lt;/p&gt;

scholarly journals Long-term summer sunshine/moisture stress reconstruction from tree-ring widths from Bosnia and Herzegovina

2013 ◽  
Vol 9 (1) ◽  
pp. 27-40 ◽  
Author(s):  
S. Poljanšek ◽  
A. Ceglar ◽  
T. Levanič
Keyword(s):  
Tree Ring ◽  
Bosnia And Herzegovina ◽  
Sunshine Duration ◽  
Ring Width ◽  
Volcanic Eruptions ◽  
Moisture Stress ◽  
Interactive Effects ◽  
Historical Sources ◽  
Sunshine Hours ◽  
Tree Ring Data

Abstract. We present the first summer sunshine reconstruction from tree-ring data for the western part of the Balkan Peninsula. Summer sunshine is tightly connected with moisture stress in trees, because the moisture stress and therefore the width of annual tree-rings is under the influence of the direct and interactive effects of sunshine duration (temperature, precipitation, cloud cover and evapotranspiration). The reconstruction is based on a calibrated z-scored mean chronology, calculated from tree-ring width measurements from 7 representative black pine (Pinus nigra Arnold) sites in Bosnia and Herzegovina (BiH). A combined regression and scaling approach was used for the reconstruction of the summer sunshine. We found a significant negative correlation (r = −0.54, p < 0.0001) with mean June–July sunshine hours from Osijek meteorological station (Croatia). The developed model was used for reconstruction of summer sunshine for the time period 1660–2010. We identified extreme summer events and compared them to available documentary historical sources of drought, volcanic eruptions and other reconstructions from the broader region. All extreme summers with low sunshine hours (1712, 1810, 1815, 1843, 1899 and 1966) are connected with volcanic eruptions.

scholarly journals Effects of Memory Biases on Variability of Temperature Reconstructions

2019 ◽  
Vol 32 (24) ◽  
pp. 8713-8731 ◽  
Author(s):  
Lucie J. Lücke ◽  
Gabriele C. Hegerl ◽  
Andrew P. Schurer ◽  
Rob Wilson
Keyword(s):  
Tree Ring ◽  
Climate Models ◽  
Climate Model ◽  
Ring Width ◽  
Volcanic Eruptions ◽  
Ice Age ◽  
Detection And Attribution ◽  
Reconstructed Temperature ◽  
Tree Ring Data ◽  
The Difference

Abstract Quantifying past climate variation and attributing its causes improves our understanding of the natural variability of the climate system. Tree-ring-based proxies have provided skillful and highly resolved reconstructions of temperature and hydroclimate of the last millennium. However, like all proxies, they are subject to uncertainties arising from varying data quality, coverage, and reconstruction methodology. Previous studies have suggested that biological-based memory processes could cause spectral biases in climate reconstructions. This study determines the effects of such biases on reconstructed temperature variability and the resultant implications for detection and attribution studies. We find that introducing persistent memory, reflecting the spectral properties of tree-ring data, can change the variability of pseudoproxy reconstructions compared to the surrogate climate and resolve certain model–proxy discrepancies. This is especially the case for proxies based on ring-width data. Such memory inflates the difference between the Medieval Climate Anomaly and the Little Ice Age and suppresses and extends the cooling in response to volcanic eruptions. When accounting for memory effects, climate model data can reproduce long-term cooling after volcanic eruptions, as seen in proxy reconstructions. Results of detection and attribution studies show that signals in reconstructions as well as residual unforced variability are consistent with those in climate models when the model fingerprints are adjusted to reflect autoregressive memory as found in tree rings.

scholarly journals Empirical values and assumptions in the convection of numerical models

2021 ◽  
Author(s):  
Anahí Villalba-Pradas ◽  
Francisco J. Tapiador
Keyword(s):  
Climate Models ◽  
Prediction Models ◽  
Numerical Models ◽  
Global Climate ◽  
Weather Prediction ◽  
Global Climate Models ◽  
Spatial And Temporal Scales ◽  
Weather Events ◽  
Wide Range ◽  
Convection Schemes

Abstract. Convection influences climate and weather events over a wide range of spatial and temporal scales. Therefore, accurate predictions of the time and location of convection and its development into severe weather are of great importance. Convection has to be parameterized in Numerical Weather Prediction models, Global Climate Models, and Earth System Models (NWPs, GCMs, and ESMs) as the key physical processes occur at scales much lower than the model grid size. The convection schemes described in the literature represent the physics by simplified models that require assumptions about the processes and the use of a number of parameters based on empirical values. The present paper examines these choices and their impacts on model outputs and emphasizes the importance of observations to improve our current understanding of the physics of convection.

Quantification of peatland-mediated feedbacks to the climate system

2020 ◽  
Author(s):  
Nitin Chaudhary ◽  
Wenxin Zhang ◽  
Guy Schurgers ◽  
Susan Page ◽  
Sebastian Westermann
Keyword(s):  
Carbon Cycle ◽  
Land Surface ◽  
Climate Models ◽  
Global Climate ◽  
Global Climate Models ◽  
Carbon Accumulation ◽  
Land Use Patterns ◽  
Shallow Water Table ◽  
Spatial And Temporal Scales ◽  
The Earth

&lt;p&gt;Peatlands are important carbon reserves in the terrestrial ecosystem and cover 3% of the terrestrial land surface. Peatlands have stored around 350-500 Petagrams [10&lt;sup&gt;15&lt;/sup&gt;] of carbon over the last thousands of years, comprising around 30% of the present-day soil organic carbon pool. Peatlands share many characteristics with upland mineral soils and non-peat wetland ecosystems. However, they constitute a unique ecosystem type with many special characteristics, such as a shallow water table depth, carbon-rich soils, a unique vegetation cover, spatial heterogeneity, anaerobic biogeochemistry and permafrost in the high latitude regions (&gt;45&amp;#176;N). The recent changes in climate and land-use patterns have disturbed the Earth&amp;#8217;s climate-carbon cycle equilibrium. These changes trigger some potentially important land-surface feedbacks, which will further modify the Earth&amp;#8217;s climate. The ongoing changes in peatland carbon balance as a result of climate warming have the potential for strong positive and negative feedbacks to climate, but these impacts are poorly constrained. To assess the importance of these feedbacks, the interactions between the peatland carbon cycle and climate should be taken into account. However, the absence of peatlands in current Earth system models limits our understanding of the peatland-mediated feedbacks at different scales. LPJ-GUESS peatland-vegetation model showed a reasonable demonstration of capturing the right carbon accumulation rates and permafrost dynamics at different spatial and temporal scales and will be further improved and employed to quantify the hypothesized peatland-mediated feedbacks when coupled with regional/global climate models.&lt;/p&gt;

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