scholarly journals Geochemical variability as an indicator for large volume eruptions in volcanic arcs

2021 ◽  
Author(s):  
Gregor Weber ◽  
Tom Sheldrake
Keyword(s):  
Global Climate ◽  
Large Magnitude ◽  
Volcanic Arcs ◽  
The Past ◽  
Plumbing Systems ◽  
Compositional Variability ◽  
Analyse Data ◽  
Melt Composition ◽  
Crustal Magma

Caldera-forming eruptions have the potential to impact global climate and induce drastic socioeconomic change. However, the criteria to identify volcanoes capable of producing large magnitude eruptions in the future are not well constrained. Here we compile and analyse data, revealing that volcanoes which have produced catastrophic caldera-forming eruptions in the past, typically show larger ranges of long-term erupted bulk-rock geochemistry compared to those that have not. This observation suggests that geochemical variability is a measure of a magmatic systems size. Using a 2D thermal model that simulates the growth and evolution of crustal-scale magmatic systems by stochastic injection of dikes and sills, we show that such behaviour is consistent with differences in crustal magma fluxes. Higher injection rates accumulate greater melt volumes in more extensive crustal plumbing systems, leading to more variable distributions of temperatures and thus melt composition. We conclude that compositional variability should be included in the catalogue of criteria to identify volcanic systems with greater probabilities of producing future large eruptions. Importantly, this allows to identify stratovolcanoes with caldera-like geochemical signatures, which have not yet been recognized as systems with greater probabilities of producing large magnitude eruptions.

scholarly journals Global climatology and trends in convective environments from ERA5 and rawinsonde data

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Mateusz Taszarek ◽  
John T. Allen ◽  
Mattia Marchio ◽  
Harold E. Brooks
Keyword(s):  
Large Scale ◽  
Climate Models ◽  
Global Climate ◽  
Convective Available Potential Energy ◽  
Global Climate Models ◽  
Convective Precipitation ◽  
The Past ◽  
The Tropics ◽  
Rawinsonde Data

AbstractGlobally, thunderstorms are responsible for a significant fraction of rainfall, and in the mid-latitudes often produce extreme weather, including large hail, tornadoes and damaging winds. Despite this importance, how the global frequency of thunderstorms and their accompanying hazards has changed over the past 4 decades remains unclear. Large-scale diagnostics applied to global climate models have suggested that the frequency of thunderstorms and their intensity is likely to increase in the future. Here, we show that according to ERA5 convective available potential energy (CAPE) and convective precipitation (CP) have decreased over the tropics and subtropics with simultaneous increases in 0–6 km wind shear (BS06). Conversely, rawinsonde observations paint a different picture across the mid-latitudes with increasing CAPE and significant decreases to BS06. Differing trends and disagreement between ERA5 and rawinsondes observed over some regions suggest that results should be interpreted with caution, especially for CAPE and CP across tropics where uncertainty is the highest and reliable long-term rawinsonde observations are missing.

scholarly journals Changes in the strength and width of the Hadley Circulation since 1871

2012 ◽  
Vol 8 (4) ◽  
pp. 1169-1175 ◽  
Author(s):  
J. Liu ◽  
M. Song ◽  
Y. Hu ◽  
X. Ren
Keyword(s):  
20Th Century ◽  
Global Climate ◽  
Hadley Circulation ◽  
Recent Change ◽  
Early 20Th Century ◽  
Greenhouse Warming ◽  
Long Period ◽  
The Past ◽  
Period Oscillation

Abstract. Recent studies demonstrate that the Hadley Circulation has intensified and expanded for the past three decades, which has important implications for subtropical societies and may lead to profound changes in global climate. However, the robustness of this intensification and expansion that should be considered when interpreting long-term changes of the Hadley Circulation is still a matter of debate. It also remains largely unknown how the Hadley Circulation has evolved over longer periods. Here, we present long-term variability of the Hadley Circulation using the 20th Century Reanalysis. It shows a slight strengthening and widening of the Hadley Circulation since the late 1970s, which is not inconsistent with recent assessments. However, over centennial timescales (1871–2008), the Hadley Circulation shows a tendency towards a more intense and narrower state. More importantly, the width of the Hadley Circulation might have not yet completed a life-cycle since 1871. The strength and width of the Hadley Circulation during the late 19th to early 20th century show strong natural variability, exceeding variability that coincides with global warming in recent decades. These findings raise the question of whether the recent change in the Hadley Circulation is primarily attributed to greenhouse warming or to a long-period oscillation of the Hadley Circulation – substantially longer than that observed in previous studies.

scholarly journals Was the Little Ice Age more or less El Niño-like than the Medieval Climate Anomaly? Evidence from hydrological and temperature proxy data

2017 ◽  
Vol 13 (3) ◽  
pp. 267-301 ◽  
Author(s):  
Lilo M. K. Henke ◽  
F. Hugo Lambert ◽  
Dan J. Charman
Keyword(s):  
Little Ice Age ◽  
Large Scale ◽  
Global Climate ◽  
Ice Age ◽  
Medieval Climate Anomaly ◽  
Climate Anomaly ◽  
Proxy Data ◽  
The Past ◽  
Proxy Records

Abstract. The El Niño–Southern Oscillation (ENSO) is the most important source of global climate variability on interannual timescales and has substantial environmental and socio-economic consequences. However, it is unclear how it interacts with large-scale climate states over longer (decadal to centennial) timescales. The instrumental ENSO record is too short for analysing long-term trends and variability and climate models are unable to accurately simulate past ENSO states. Proxy data are used to extend the record, but different proxy sources have produced dissimilar reconstructions of long-term ENSO-like climate change, with some evidence for a temperature–precipitation divergence in ENSO-like climate over the past millennium, in particular during the Medieval Climate Anomaly (MCA; AD  ∼  800–1300) and the Little Ice Age (LIA; AD  ∼  1400–1850). This throws into question the stability of the modern ENSO system and its links to the global climate, which has implications for future projections. Here we use a new statistical approach using weighting based on empirical orthogonal function (EOF) to create two new large-scale reconstructions of ENSO-like climate change derived independently from precipitation proxies and temperature proxies. The method is developed and validated using model-derived pseudo-proxy experiments that address the effects of proxy dating error, resolution, and noise to improve uncertainty estimations. We find no evidence that temperature and precipitation disagree over the ENSO-like state over the past millennium, but neither do they agree strongly. There is no statistically significant difference between the MCA and the LIA in either reconstruction. However, the temperature reconstruction suffers from a lack of high-quality proxy records located in ENSO-sensitive regions, which limits its ability to capture the large-scale ENSO signal. Further expansion of the palaeo-database and improvements to instrumental, satellite, and model representations of ENSO are needed to fully resolve the discrepancies found among proxy records and establish the long-term stability of this important mode of climatic variability.

scholarly journals Changes in the strength and width of the Hadley circulation since 1871

2012 ◽  
Vol 8 (2) ◽  
pp. 695-713 ◽  
Author(s):  
J. Liu ◽  
M. Song ◽  
Y. Hu ◽  
X. Ren
Keyword(s):  
20Th Century ◽  
Global Climate ◽  
Hadley Circulation ◽  
Recent Change ◽  
Early 20Th Century ◽  
Greenhouse Warming ◽  
Long Period ◽  
The Past ◽  
Period Oscillation

Abstract. Recent studies demonstrate that the Hadley Circulation has intensified and expanded for the past three decades, which has important implications for subtropical societies and may lead to profound changes in global climate. However, the robustness of this intensification and expansion that should be considered when interpreting long-term changes of the Hadley Circulation is still matters of debate. It also remains largely unknown how the Hadley Circulation has evolved over longer periods. Here we present long-term variability of the Hadley Circulation using the 20th Century Reanalysis. It shows a slight strengthening and widening of the Hadley Circulation since the late 1970s, which is not inconsistent with recent assessments. However, over centennial timescales (1871–2008), the Hadley Circulation shows a tendency towards more intense and narrower state. More importantly, the width of the Hadley Circulation has not yet completed a life-cycle since 1871. The strength and width of the Hadley Circulation during the late 19th and early 20th century show strong natural variability, exceeding variability that coincides with global warming in recent decades. These findings raise the question that the recent change of the Hadley Circulation is primarily attributed to greenhouse warming or a long-period oscillation of the Hadley Circulation substantially longer than that observed in previous studies.

scholarly journals Deep-reaching acceleration of global mean ocean circulation over the past two decades

2020 ◽  
Vol 6 (6) ◽  
pp. eaax7727 ◽  
Author(s):  
Shijian Hu ◽  
Janet Sprintall ◽  
Cong Guan ◽  
Michael J. McPhaden ◽  
Fan Wang ◽  
...  
Keyword(s):  
Kinetic Energy ◽  
Ocean Circulation ◽  
Global Climate ◽  
Circulation System ◽  
The Past ◽  
Tropical Oceans ◽  
Increasing Trend ◽  
Long Term Trend ◽  
Global Mean

Ocean circulation redistributes Earth’s energy and water masses and influences global climate. Under historical greenhouse warming, regional ocean currents show diverse tendencies, but whether there is an emerging trend of the global mean ocean circulation system is not yet clear. Here, we show a statistically significant increasing trend in the globally integrated oceanic kinetic energy since the early 1990s, indicating a substantial acceleration of global mean ocean circulation. The increasing trend in kinetic energy is particularly prominent in the global tropical oceans, reaching depths of thousands of meters. The deep-reaching acceleration of the ocean circulation is mainly induced by a planetary intensification of surface winds since the early 1990s. Although possibly influenced by wind changes associated with the onset of a negative Pacific decadal oscillation since the late 1990s, the recent acceleration is far larger than that associated with natural variability, suggesting that it is principally part of a long-term trend.

scholarly journals Precipitation conditions at the mountain study site of Bílý Kříž (the Beskids Mts.) during the past 20 years

Beskydy ◽  
2017 ◽  
Vol 10 (1-2) ◽  
pp. 9-16
Author(s):  
Irena Marková ◽  
Dalibor Janouš ◽  
Filip Holata
Keyword(s):  
Climate Change ◽  
Global Climate Change ◽  
Hydrological Cycle ◽  
Global Climate ◽  
Standardized Precipitation Index ◽  
Heavy Rain ◽  
The Past ◽  
Precipitation Characteristics ◽  
The Standardized Precipitation Index

Expected global climate change can cause changes in several hydrological cycle processes, such as the intensity and frequency of precipitation, river flows, evapotranspiration rates, soil moisture, and groundwater recharge. Precipitation conditions have been observed at the mountain study site of Bílý Kříž (the Beskids Mts., Czech Republic) since 1989. This paper presents the analysis of long-term (1997–2016) precipitation conditions at this study site. Comparison of selected long-term mean precipitation characteristics with mean precipitation characteristics for the 1997–2016 period reported differences in only some parameters. The number of days without precipitation was slightly increasing. No statistically significant trend was found for the number of days with heavy rain. The study site was changed from being a per-humid to humid type as indicated by Lang’rain factor. More dry periods were determined at the past decade according to the standardized precipitation index.

scholarly journals Reference Upper-Air Observations for Climate: From Concept to Reality

2016 ◽  
Vol 97 (1) ◽  
pp. 123-135 ◽  
Author(s):  
G. E. Bodeker ◽  
S. Bojinski ◽  
D. Cimini ◽  
R. J. Dirksen ◽  
M. Haeffelin ◽  
...  
Keyword(s):  
Data Streams ◽  
Global Climate ◽  
Climate Variables ◽  
Global Networks ◽  
Network Expansion ◽  
The Past ◽  
Reference Quality ◽  
Process Studies ◽  
Coordination Meeting

Abstract The three main objectives of the Global Climate Observing System (GCOS) Reference Upper-Air Network (GRUAN) are to provide long-term high-quality climate records of vertical profiles of selected essential climate variables (ECVs), to constrain and calibrate data from more spatially comprehensive global networks, and to provide measurements for process studies that permit an in-depth understanding of the properties of the atmospheric column. In the five years since the first GRUAN implementation and coordination meeting and the printing of an article (Seidel et al.) in this publication, GRUAN has matured to become a functioning network that provides reference-quality observations to a community of users. This article describes the achievements within GRUAN over the past five years toward making reference-quality observations of upper-air ECVs. Milestones in the evolution of GRUAN are emphasized, including development of rigorous criteria for site certification and assessment, the formal certification of the first GRUAN sites, salient aspects of the GRUAN manual and guide to operations, public availability of GRUAN’s first data product, outcomes of a network expansion workshop, and key results of scientific studies designed to provide a sound scientific foundation for GRUAN operations. Two defining attributes of GRUAN are 1) that every measurement is accompanied by a traceable estimate of the measurement uncertainty and 2) that data quality and continuity are maximized because network changes are minimized and managed. This article summarizes how these imperatives are being achieved for existing and planned data products and provides an outlook for the future, including expected new data streams, network expansion, and critical needs for the ongoing success of GRUAN.

scholarly journals Heat stored in the Earth system: Where does the energy go? The GCOS Earth heat inventory team

2020 ◽  
Author(s):  
Karina von Schuckmann ◽  
Lijing Cheng ◽  
Matthew D. Palmer ◽  
Caterina Tassone ◽  
Valentin Aich ◽  
...  
Keyword(s):  
Global Climate ◽  
Atmospheric Composition ◽  
Global Ocean ◽  
Earth System ◽  
Heat Gain ◽  
The Past ◽  
The Earth ◽  
International Assessment ◽  
Composition Changes

Abstract. Human-induced atmospheric composition changes cause a radiative imbalance at the top-of-atmosphere which is driving global warming. This Earth Energy Imbalance (EEI) is a fundamental metric of climate change. Understanding the heat gain of the Earth system from this accumulated heat – and particularly how much and where the heat is distributed in the Earth system – is fundamental to understanding how this affects warming oceans, atmosphere and land, rising temperatures and sea level, and loss of grounded and floating ice, which are fundamental concerns for society. This study is a Global Climate Observing System (GCOS) concerted international effort to update the Earth heat inventory, and presents an updated international assessment of ocean warming estimates, and new and updated estimates of heat gain in the atmosphere, cryosphere and land over the period 1960–2018. The study obtains a consistent long-term Earth system heat gain over the past 58 years, with a total heat gain of 393 ± 40 ZJ, which is equivalent to a heating rate of 0.42 ± 0.04 W m−2. The majority of the heat gain (89 %) takes place in the global ocean (0–700 m: 53 %; 700–2000 m: 28 %; > 2000 m: 8 %), while it amounts to 6 % for the land heat gain, to 4 % available for the melting of grounded and floating ice, and to 1 % for atmospheric warming. These new estimates indicate a larger contribution of land and ice heat gain (10 % in total) compared to previous estimates (7 %). There is a regime shift of the Earth heat inventory over the past 2 decades, which appears to be predominantly driven by heat sequestration into the deeper layers of the global ocean, and a doubling of heat gain in the atmosphere. However, a major challenge is to reduce uncertainties in the Earth heat inventory, which can be best achieved through the maintenance of the current global climate observing system, its extension into areas of gaps in the sampling, as well as to establish an international framework for concerted multi-disciplinary research of the Earth heat inventory. Earth heat inventory is published at DKRZ (https://www.dkrz.de/) under the doi: https://doi.org/10.26050/WDCC/GCOS_EHI_EXP (von Schuckmann et al., 2020).

scholarly journals Temperature conditions at the mountain study site of Bílý Kříž (the Beskids Mts.) during the past 20 years

Beskydy ◽  
2017 ◽  
Vol 10 (1-2) ◽  
pp. 113-122
Author(s):  
Irena Marková ◽  
Dalibor Janouš ◽  
Ondřej Nezval
Keyword(s):  
Air Temperature ◽  
Global Climate Change ◽  
Global Climate ◽  
Growth Season ◽  
Temperature Changes ◽  
Temperature Characteristics ◽  
The Past ◽  
Temperature Conditions ◽  
Mean Annual Air Temperature

Global climate change (including temperature changes) had already observable effects on the environment and humanity. Air temperature characteristics have been observed at the mountain study site of Bílý Kříž (the Beskids Mts., Czech Republic) since 1989. This paper presents an analysis of long-term (1997–2016) air temperature conditions at this study. Comparison is made of selected long-term mean air temperature characteristics with mean air temperature characteristics for the period 1997–2016. The results show slightly increasing air temperature, as indicated not only by values for mean annual air temperature but also by changes in number of extreme days (summer, tropical, ice, etc.) and occurrence of hot period. Moreover, the length of the growth season has increase slightly.

Late-Holocene fluctuations of monsoonal Qiangyong Glacier, southern Tibetan Plateau

The Holocene ◽  
2021 ◽  
pp. 095968362110032
Author(s):  
Xiaolong Zhang ◽  
Baiqing Xu ◽  
Jiule Li ◽  
Ying Xie ◽  
Gerd Gleixner
Keyword(s):  
Tibetan Plateau ◽  
Late Holocene ◽  
Global Climate ◽  
The Tibetan Plateau ◽  
Temperature Changes ◽  
The Past ◽  
Physiochemical Parameters ◽  
Continuous Record ◽  
Southern Tibetan Plateau

Glaciers on the Tibetan Plateau (TP) are reliable water sources for Asia. Continuously high-resolution and high-accuracy long-term glacier fluctuations have been examined to improve the reliability of predictions regarding future TP glacier behavior under global climate change. In this study, we analyzed physiochemical parameters in typical glaciolacustrine sediments to reconstruct multidecadal activities of the monsoonal Qiangyong Glacier over the past ~2500 years. The results show that the glacier advanced most strongly during 560 BC–AD 100, followed by AD 1050–1850 and AD 600–850. It retreated most severely during AD 1850–present, followed by AD 100–600 and AD 850–1050. This continuous record corresponds well with changes in the temperature and regional precipitation before the Current Warm Period, exhibiting “warm-humid-retreat” and “cold-dry-advance” patterns. This indicates that temperature changes, rather than precipitation variations, control the monsoonal glaciers at the southern TP at multidecadal to centennial scales. As global warming continues, although the precipitation on the southern TP is projected to increase, the mass loss of TP monsoonal glaciers is expected to continue.

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