Speleothems as recorders of local climate variability and its implications for Maya cultural evolution from a unique cave site on the northern Yucatán Peninsula

The unsteady cultural evolution and final collapse of Maya civilization in Mesoamerica are heavily debated issues and discussion includes the impact of both natural (e.g., droughts, hurricanes, volcanic eruptions) and social disasters (e.g., warfare and unsustainable economy). An increasing number of records point to recurrent multi-year droughts coinciding with hiatuses in construction, periods of temporary urban abandonment and population collapse. Previous reconstructions indicate that environmental conditions and precipitation on the Yucat&#225;n Peninsula were distributed very heterogeneously in space and time and the duration and chronology of events remains uncertain. High resolution environmental reconstructions are, however, mainly based on archives from sites on the southern Yucat&#225;n Peninsula.We have now recovered several stalagmites from Estrella Cave, northern Yucat&#225;n Peninsula, spanning the entire Maya era and reaching even to historical times (&#8722;1100 to 1780 AD). The high precision 230Th/U ages obtained so far from these stalagmites indicate growth rates of up to 160 &#181;m per year, thus offering the potential for annual to decadal climate proxy reconstruction. Here we present 230Th/U based preliminary age models for some of these stalagmites. Based on growth rates, petrographic observations, and trace element to calcium ratios we draw first conclusions on the timing of (recurrent) dry periods around key episodes of Maya cultural evolution, such as the Terminal Classic Period (~800&#8211;1000 AD). Furthermore, these first results show that the incorporation of certain trace elements (Mg, Sr, Ba, P, &#8230;) in these speleothems is strongly related to recharge and hence precipitation above the cave. Moreover, the site also contains unique remains of the Mayan culture, such as paintings, pottery, constructions and even buried skeletons, thus highlighting its significance not only for regional climate reconstruction but also for local archaeology.

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Aerosols over Continental Portugal (1978–1993): their sources and an impact on the regional climate

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-14-31009-2014 ◽

2014 ◽

Vol 14 (22) ◽

pp. 31009-31038

Author(s):

A. L. Morozova ◽

I. A. Mironova

Keyword(s):

Sunshine Duration ◽

Regional Climate ◽

Volcanic Eruptions ◽

Anthropogenic Pollution ◽

Statistical Correlation ◽

Significant Finding ◽

Local Climate ◽

Correlation Models ◽

Aerosol Sources ◽

Absorbing Aerosols

Abstract. Understanding of aerosol sources which affect climate is an important problem open in front of scientists as well as policymakers. The role of aerosols in local climate variability depends on a~balance between aerosol absorbing and scattering particles as well as on variability of environmental conditions. In this paper we investigate variability of aerosol content (both absorbing and scattering UV radiation) over Continental Portugal in dependence on aerosol sources (volcanic eruptions, dust events, wildfires and anthropogenic pollution). The effect of the aerosol on the climate is studied analyzing their contribution to variations of temperature, sunshine duration and precipitation over Portuguese regions. The present analysis is based on a developed modern multiple regression technique allowing us to build the statistical correlation models to determine both the main local aerosol sources and aerosol's influence on the climate of the Continental Portugal during 1978–1993 time period. The analysis allows us to conclude that the main sources driving the variations of the aerosol content over studied locations are wildfires, mineral dust intrusions and anthropogenic pollution. The relations between the aerosol content variations and the atmospheric parameters depend on the level of urbanization of the studied region, the type of aerosol and the season. The most significant finding is the decrease of the daily temperature (and diurnal temperature range) related to the decrease of sunshine duration observed during the summer periods of increased content of the absorbing aerosols in the atmosphere.

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Assessing the impact of large volcanic eruptions of the Last Millennium on Australian rainfall regimes

10.5194/cp-2017-109 ◽

2017 ◽

Author(s):

Stephanie Blake ◽

Sophie C. Lewis ◽

Allegra N. LeGrande

Keyword(s):

El Niño ◽

El Nino ◽

Southern Oscillation ◽

Regional Climate ◽

Volcanic Eruptions ◽

Explosive Volcanism ◽

Climate Forcing ◽

Last Millennium ◽

Precipitation Anomalies ◽

The Impact

Abstract. Explosive volcanism is an important natural climate forcing, impacting global surface temperatures and regional precipitation. Although previous studies have investigated aspects of the impact of tropical volcanism on various ocean-atmosphere systems and regional climate regimes, volcanic eruptions remain a poorly understood climate forcing and climatic responses are not well constrained. In this study, volcanic eruptions are explored in particular reference to Australian precipitation, and both the Indian Ocean Dipole (IOD) and El Nino-Southern Oscillation (ENSO). Using nine realisations of the Last Millennium (LM) with different time-evolving forcing combinations, from the NASA GISS ModelE2-R, the impact of the 6 largest tropical volcanic eruptions of this period are investigated. Overall, we find that volcanic aerosol forcing increased the likelihood of El Nino and positive IOD conditions for up to four years following an eruption, and resulted in positive precipitation anomalies over northwest (NW) and southeast (SE) Australia. Larger atmospheric sulfate loading coincides with more persistent positive IOD and El Nino conditions, enhanced positive precipitation anomalies over NW Australia, and dampened precipitation anomalies over SE Australia.

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Large volcanic eruptions as a natural hazard: The impact of the 536/540 CE double event on the atmospheric circulation, surface climate, vegetation and society in Scandinavia

10.5194/egusphere-egu21-12270 ◽

2021 ◽

Author(s):

Evelien van Dijk ◽

Ingar Mørkestøl Gundersen ◽

Manon Bajard ◽

Helge Høeg ◽

Kjetil Løftsgård ◽

...

Keyword(s):

Atmospheric Circulation ◽

Natural Hazard ◽

Volcanic Eruptions ◽

Climate History ◽

Local Climate ◽

Surface Climate ◽

Climate Records ◽

The Impact ◽

Large Volcanic Eruptions ◽

Double Event

Large volcanic eruptions that reach the stratosphere cool the surface climate and impact the atmospheric circulation, feeding back on the local climate. The mid-6th century is an outstanding period in climate history that featured an extreme cold period, including one of the coldest decades in the past 2000 years. It was triggered by the 536/540 CE volcanic double event, creating the strongest decadal volcanic forcing in the last two millennia. During this period societal changes are recorded around the world, like the Great Migration period and the outbreak of the Justinian Plague. However, not a lot is known about the causal relationships between global cooling and societal change. Less is known also, about the impact of the large-scale atmospheric circulation on the regional climate, vegetation and society in Scandinavia after this volcanic double event. Here we aim to improve this understanding by combining global climate and regional growing-degree-day (GGD) modeling with climate proxies and archaeological records from Southeastern Norway.We use PMIP4 past2k runs and the MPI-ESM ensemble simulation of the 6th/7th century (520-680 CE), to analyze the atmospheric circulation, surface climate and vegetation changes as a response to the volcanic double event of 536/540 CE, over Scandinavia, specifically Southeastern Norway. Thereby we focus on the response of the major circulation patterns that influence the climate over Northern Europe: the positive and negative North Atlantic Oscillation, the Scandinavian blocking and the Atlantic ridge. The results of the GDD model, driven with the MPI-ESM model input, are compared to local pollen and climate records and archaeological data (e.g. grave density and settlement records) to shed more light on the local climate, vegetation and society impact. This comparison allows us to better understand how a natural hazard influenced local areas and climate records in Southeastern Norway. This study is part of the VIKINGS project, which focuses on the impact of volcanic eruptions on climate, environment and society in Norway/ Scandinavia.

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Aerosols over continental Portugal (1978–1993): their sources and an impact on the regional climate

Atmospheric Chemistry and Physics ◽

10.5194/acp-15-6407-2015 ◽

2015 ◽

Vol 15 (11) ◽

pp. 6407-6418 ◽

Cited By ~ 1

Author(s):

A. L. Morozova ◽

I. A. Mironova

Keyword(s):

Sunshine Duration ◽

Regional Climate ◽

Volcanic Eruptions ◽

Anthropogenic Pollution ◽

Maximum Temperature ◽

Daily Maximum Temperature ◽

Daily Maximum ◽

Significant Finding ◽

Local Climate ◽

Aerosol Sources

Abstract. Understanding of aerosol sources that affect climate is an ongoing problem facing scientists as well as policymakers. The role of aerosols in local climate variability depends on a balance between light absorbing and scattering particles as well as on variability of environmental conditions. In this paper we investigate variability of aerosol content (both absorbing and scattering ultraviolet radiation) over continental Portugal in connection with aerosol sources (volcanic eruptions, dust events, wildfires and anthropogenic pollution). The effect of the aerosol on the climate is studied analyzing their contribution to variations of temperature, pressure, sunshine duration and precipitation over Portuguese regions. The present analysis is based on a developed modern multiple regression technique allowing us to build the statistical correlation models to determine both the main local aerosol sources and aerosol's influence on the climate of continental Portugal during 1978–1993. The analysis allows us to conclude that the main sources driving the variations of the aerosol content over studied locations are wildfires, mineral dust intrusions and anthropogenic pollution. The relations between the aerosol content variations and the atmospheric parameters depend on the level of urbanization of the studied region, the type of aerosol and the season. The most significant finding is the decrease of the daily maximum temperature (and diurnal temperature range) related to the decrease of sunshine duration observed during the summer periods of increased content of the absorbing aerosols in the atmosphere.

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Climate impact of volcanic eruptions: the sensitivity to eruption season and latitude in MPI-ESM ensemble experiments

Atmospheric Chemistry and Physics ◽

10.5194/acp-21-13425-2021 ◽

2021 ◽

Vol 21 (17) ◽

pp. 13425-13442

Author(s):

Zhihong Zhuo ◽

Ingo Kirchner ◽

Stephan Pfahl ◽

Ulrich Cubasch

Keyword(s):

Southern Hemisphere ◽

Regional Climate ◽

Volcanic Eruptions ◽

Climate Impact ◽

Climate Impacts ◽

Cloud Formation ◽

Radiative Effects ◽

Near Surface ◽

Volcanic Aerosols ◽

The Impact

Abstract. Explosive volcanic eruptions influence near-surface temperature and precipitation especially in the monsoon regions, but the impact varies with different eruption seasons and latitudes. To study this variability, two groups of ensemble simulations are performed with volcanic eruptions in June and December at 0∘ representing an equatorial eruption (EQ) and at 30∘ N and 30∘ S representing Northern and Southern Hemisphere eruptions (NH and SH). Results show significant cooling especially in areas with enhanced volcanic aerosol content. Compared to the EQ eruption, stronger cooling emerges in the Northern Hemisphere after the NH eruption and in the Southern Hemisphere after the SH eruption. Stronger precipitation variations occur in the tropics than in the high latitudes. Summer and winter eruptions lead to similar hydrological impacts. The NH and the SH eruptions have reversed climate impacts, especially in the regions of the South Asian summer monsoon (SASM). After the NH eruption, direct radiative effects of volcanic aerosols induce changes in the interhemispheric and land–sea thermal contrasts, which move the intertropical convergence zone (ITCZ) southward and weaken the SASM. This reduces the moisture transport from the ocean and reduces cloud formation and precipitation in India. The subsequent radiative feedbacks due to regional cloud cover lead to warming in India. After the SH eruption, vice versa, a northward movement of the ITCZ and strengthening of the SASM, along with enhanced cloud formation, lead to enhanced precipitation and cooling in India. This emphasizes the sensitivity of regional climate impacts of volcanic eruptions to eruption latitude, which relates to the dynamical response of the climate system to radiative effects of volcanic aerosols and the subsequent regional physical feedbacks. Our results indicate the importance of considering dynamical and physical feedbacks to understand the mechanism behind regional climate responses to volcanic eruptions and may also shed light on the climate impact and potential mechanisms of stratospheric aerosol engineering.

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Regional Climate Impacts of Irrigation in Northern Italy Using a High Resolution Model

Atmosphere ◽

10.3390/atmos11010072 ◽

2020 ◽

Vol 11 (1) ◽

pp. 72 ◽

Cited By ~ 1

Author(s):

Arianna Valmassoi ◽

Jimy Dudhia ◽

Silvana Di Sabatino ◽

Francesco Pilla

Keyword(s):

Regional Climate ◽

Sensible Heat Flux ◽

Surface Flux ◽

Moisture Flux ◽

Climatic Conditions ◽

Northern Italy ◽

Climate Impacts ◽

Local Conditions ◽

Local Climate ◽

The Impact

Irrigation is crucial for sustaining agriculture in certain regions; however, there are effects on the local climate. Previous studies discussed that the irrigation signal might depend on the geographical region as well as the synoptic and climatic conditions. The work presented here aims to investigate the mechanisms behind changes in the irrigation impact on the local conditions depending on synoptic changes. Different to previous works, this employs convection-permitting simulations. Irrigation processes are parameterized in three different ways depending on the evaporative loss. The region of focus is in northern Italy (Po Valley), which is of interest for both the soil-atmosphere coupling strength and widely used irrigation. The simulation period is Summer 2015 (May–July), which includes a heatwave month (July) and an average month (June). The results show how irrigation prevented the drying out of the soil layers during the heatwave. This influences the surface flux partition differently, by increasing moisture flux and decreasing the sensible heat flux. In general, the irrigation impact magnitude, with respect to the control simulation, is more than double in July compared to June. This study discusses climate implications for the region, such as the impact of widespread irrigation on the vegetation health, the heatwave feedback mechanism, atmospheric pollution, and human heat discomfort.

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Mixed NNLO QCD×electroweak corrections of $$ \mathcal{O} $$(Nfαsα) to single-W/Z production at the LHC

Journal of High Energy Physics ◽

10.1007/jhep12(2020)201 ◽

2020 ◽

Vol 2020 (12) ◽

Author(s):

Stefan Dittmaier ◽

Timo Schmidt ◽

Jan Schwarz

Keyword(s):

Z Bosons ◽

Leading Order ◽

Current Standard ◽

Gauge Invariant ◽

Mass Distributions ◽

Self Energy ◽

Electroweak Gauge Boson ◽

First Results ◽

Invariant Part ◽

The Impact

Abstract First results on the radiative corrections of order $$ \mathcal{O} $$ O (Nfαsα) are presented for the off-shell production of W or Z bosons at the LHC, where Nf is the number of fermion flavours. These corrections comprise all diagrams at $$ \mathcal{O} $$ O (αsα) with closed fermion loops, form a gauge-invariant part of the next-to-next-to-leading-order corrections of mixed QCD×electroweak type, and are the ones that concern the issue of mass renormalization of the W and Z resonances. The occurring irreducible two-loop diagrams, which involve only self-energy insertions, are calculated with current standard techniques, and explicit analytical results on the electroweak gauge-boson self-energies at $$ \mathcal{O} $$ O (αsα) are given. Moreover, the generalization of the complex-mass scheme for a gauge-invariant treatment of the W/Z resonances is described for the order $$ \mathcal{O} $$ O (αsα). While the corrections, which are implemented in the Monte Carlo program Rady, are negligible for observables that are dominated by resonant W/Z bosons, they affect invariant-mass distributions at the level of up to 2% for invariant masses of ≳ 500 GeV and are, thus, phenomenologically relevant. The impact on transverse-momentum distributions is similar, taking into account that leading-order predictions to those distributions underestimate the spectrum.

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Urban Climates and Climate Change

Annual Review of Environment and Resources ◽

10.1146/annurev-environ-012320-083623 ◽

2020 ◽

Vol 45 (1) ◽

pp. 411-444 ◽

Cited By ~ 1

Author(s):

Valéry Masson ◽

Aude Lemonsu ◽

Julia Hidalgo ◽

James Voogt

Keyword(s):

Climate Change ◽

Climate Modeling ◽

Regional Climate ◽

Urban Climate ◽

Regional Climate Modeling ◽

Climate Impact ◽

Local Climate ◽

Urban Climatology ◽

Recent Developments ◽

Global Agenda

Cities are particularly vulnerable to extreme weather episodes, which are expected to increase with climate change. Cities also influence their own local climate, for example, through the relative warming known as the urban heat island (UHI) effect. This review discusses urban climate features (even in complex terrain) and processes. We then present state-of-the-art methodologies on the generalization of a common urban neighborhood classification for UHI studies, as well as recent developments in observation systems and crowdsourcing approaches. We discuss new modeling paradigms pertinent to climate impact studies, with a focus on building energetics and urban vegetation. In combination with regional climate modeling, new methods benefit the variety of climate scenarios and models to provide pertinent information at urban scale. Finally, this article presents how recent research in urban climatology contributes to the global agenda on cities and climate change.

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Cooling Efficiencies of a NiTi-Based Cooling Process

Volume 1: Development and Characterization of Multifunctional Materials; Modeling, Simulation and Control of Adaptive Systems; Integrated System Design and Implementation ◽

10.1115/smasis2013-3249 ◽

2013 ◽

Cited By ~ 6

Author(s):

Marvin Schmidt ◽

Andreas Schütze ◽

Stefan Seelecke

Keyword(s):

Solid State ◽

Thermodynamic Analysis ◽

Cooling System ◽

Analysis Method ◽

Efficiency Ratio ◽

Cooling Process ◽

First Results ◽

Work Input ◽

Underlying Mechanisms ◽

The Impact

Energy saving and environmental protection are topics of growing interest. In the light of these aspects alternative refrigeration principles become increasingly important. Shape memory alloys (SMA), especially NiTi alloys, generate a large amount of latent heat during solid state phase transformations, which can lead to a significant cooling effect in the material. These materials do not only provide the potential for an energy-efficient cooling process, they also minimize the impact on the environment by reducing the need for conventional ozone-depleting refrigerants. Our paper, presenting first results obtained in a project within the DFG Priority Program SPP 1599 “Ferroic Cooling”, focuses on the thermodynamic analysis of a NiTi-based cooling system. We first introduce a suitable cooling process and subsequently illustrate the underlying mechanisms of the process in comparison with the conventional compression refrigeration system. We further introduce a graphical solution to calculate the energy efficiency ratio of the system. This thermodynamic analysis method shows the necessary work input and the heat absorption of the SMA in stress/strain- or temperature/entropy-diagrams, respectively. The results of the calculations underline the high potential of this solid-state cooling methodology.

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