Late-Holocene: Cooler or warmer?

The Holocene ◽  
2021 ◽  
pp. 095968362110191
Author(s):  
Heinz Wanner
Keyword(s):  
Time Series ◽  
Late Holocene ◽  
Early Holocene ◽  
Boreal Summer ◽  
Solar Forcing ◽  
Summer Temperatures

Early studies on the evolution of glaciers argue that the warm Early Holocene transitioned into a Late-Holocene Neoglacial, with numerous glacial advances due to decreasing solar forcing in the boreal summer. The assumption of decreasing temperatures based on the glacier studies was supported by several proxy-based reconstructions as well as by simulations. Under the keyword “Holocene temperature conundrum” this fact is questioned. In particular, it is argued that the proxy studies are biased on time series dominated by a seasonal bias in the form of predominant summer temperatures (mainly marine). After a presentation of the facts, the weaknesses of both hypotheses (cooler or warmer) are briefly presented.

scholarly journals Link between East Asian summer monsoon and sedimentation in river-mouth sandbars since the early Holocene preserved in the Yangtze River subaqueous delta front

2020 ◽  
Vol 95 ◽  
pp. 84-96
Author(s):  
Gang Xu ◽  
Jian Liu ◽  
Marcello Gugliotta ◽  
Yoshiki Saito ◽  
Lilei Chen ◽  
...  
Keyword(s):  
Yangtze River ◽  
Late Holocene ◽  
Asian Summer Monsoon ◽  
Yangtze River Basin ◽  
River Mouth ◽  
Early Holocene ◽  
The Yangtze River ◽  
Delta Front ◽  
The Yangtze River Basin ◽  
Asian Summer

AbstractThis paper presents geochemical and grain-size records since the early Holocene in core ECS0702 with a fine chronology frame obtained from the Yangtze River subaqueous delta front. Since ~9500 cal yr BP, the proxy records of chemical weathering from the Yangtze River basin generally exhibit a Holocene optimum in the early Holocene, a weak East Asian summer monsoon (EASM) period during the middle Holocene, and a relatively strong EASM period in the late Holocene. The ~8.2 and ~4.4 cal ka BP cooling events are recorded in core ECS0702. The flooding events reconstructed by the grain-size parameters since the early Holocene suggest that the floods mainly occurred during strong EASM periods and the Yangtze River mouth sandbar caused by the floods mainly formed in the early and late Holocene. The Yangtze River-mouth sandbars since the early Holocene shifted from north to south, affected by tidal currents and the Coriolis force, and more importantly, controlled by the EASM. Our results are of great significance for enriching both the record of Holocene climate change in the Yangtze River basin and knowledge about the formation and evolution progress of the deltas located in monsoon regions.

scholarly journals Associations between high summer temperatures and cerebrovascular mortality in Astana, Kazakhstan: a time-series analysis

2013 ◽  
Vol 23 (suppl_1) ◽  
Author(s):  
AM Grjibovski ◽  
N Nurgaliyeva ◽  
B Adilbekova ◽  
G Kozhakhmetova ◽  
A Sharbakov ◽  
...  
Keyword(s):  
Time Series ◽  
Time Series Analysis ◽  
Series Analysis ◽  
Summer Temperatures

scholarly journals Identifying global patterns of stochasticity and nonlinearity in the Earth System

2016 ◽  
Author(s):  
Fernando Arizmendi ◽  
Marcelo Barreiro ◽  
Cristina Masoller
Keyword(s):  
Time Series ◽  
Extreme Values ◽  
Surface Air Temperature ◽  
Reanalysis Data ◽  
Earth System ◽  
Entropy Analysis ◽  
Solar Forcing ◽  
The Earth ◽  
Geographical Regions ◽  
Global Patterns

Abstract. By comparing time-series of surface air temperature (SAT, monthly reanalysis data from NCEP CDAS1 and ERA Interim) with respect to the top-of-atmosphere incoming solar radiation (the insolation), we perform a detailed analysis of the SAT response to solar forcing. By computing the entropy of SAT time-series, we also quantify the degree of stochasticity. We find spatial coherent structures which are characterized by high stochasticity and nearly linear response to solar forcing (the shape of SAT time-series closely follows that of the isolation), or vice versa. The entropy analysis also allows to identify geographical regions in which there are significant differences between the NCEP CDAS1 and ERA Interim datasets, which are due to the presence of extreme values in one dataset but not in the other. Therefore, entropy maps are a valuable tool for anomaly detection and model inter-comparisons.

scholarly journals Millennial variations of atmospheric CO<sub>2</sub> during the early Holocene (11.7–7.4 ka)

2021 ◽  
Author(s):  
Jinhwa Shin ◽  
Jinho Ahn ◽  
Jai Chowdhry Beeman ◽  
Hun-Gyu Lee ◽  
Edward J. Brook
Keyword(s):  
North Atlantic ◽  
Ice Core ◽  
Polar Front ◽  
Equatorial Pacific ◽  
Early Holocene ◽  
Atmospheric Co2 ◽  
Solar Forcing ◽  
Local Climate ◽  
Climate Conditions ◽  
Siple Dome

Abstract. We present a new high-resolution record of atmospheric CO2 from the Siple Dome ice core, Antarctica over the early Holocene (11.7–7.4 ka) that quantifies natural CO2 variability on millennial timescales under interglacial climate conditions. Atmospheric CO2 decreased by ~10 ppm between 11.3 and 7.3 ka. The decrease was punctuated by local minima at 11.1, 10.1, 9.1 and 8.3 ka with amplitude of 2–6 ppm. These variations correlate with proxies for solar forcing and local climate in the South East Atlantic polar front, East Equatorial Pacific and North Atlantic. These relationships suggest that weak solar forcing changes might have impacted CO2 by changing CO2 outgassing from the Southern Ocean and the East Equatorial Pacific and terrestrial carbon storage in the Northern Hemisphere over the early Holocene.

scholarly journals Social inequalities in heat-attributable mortality in the city of Turin, northwest of Italy: a time series analysis from 1982 to 2018

2020 ◽  
Vol 19 (1) ◽  
Author(s):  
Marta Ellena ◽  
Joan Ballester ◽  
Paola Mercogliano ◽  
Elisa Ferracin ◽  
Giuliana Barbato ◽  
...  
Keyword(s):  
Time Series ◽  
Marital Status ◽  
Mortality Risk ◽  
Educational Level ◽  
Social Inequalities ◽  
Attributable Mortality ◽  
Mortality Data ◽  
All Cause Mortality ◽  
Summer Temperatures ◽  
The City

Abstract Background Understanding context specific heat-health risks in urban areas is important, especially given anticipated severe increases in summer temperatures due to climate change effects. We investigate social inequalities in the association between daily temperatures and mortality in summer in the city of Turin for the period 1982–2018 among different social and demographic groups such as sex, age, educational level, marital status and household occupants. Methods Mortality data are represented by individual all-cause mortality counts for the summer months between 1982 and 2018. Socioeconomic level and daily mean temperature were assigned to each deceased. A time series Poisson regression with distributed lag non-linear models was fitted to capture the complex nonlinear dependency between daily mortality and temperature in summer. The mortality risk due to heat is represented by the Relative Risk (RR) at the 99th percentile of daily summer temperatures for each population subgroup. Results All-cause mortality risk is higher among women (1.88; 95% CI = 1.77, 2.00) and the elderly (2.13; 95% CI = 1.94, 2.33). With regard to education, the highest significant effects for men is observed among higher education levels (1.66; 95% CI = 1.38, 1.99), while risks for women is higher for the lower educational level (1.93; 95% CI = 1.79, 2.08). Results on marital status highlighted a stronger association for widower in men (1.66; 95% CI = 1.38, 2.00) and for separated and divorced in women (2.11; 95% CI = 1.51, 2.94). The risk ratio of household occupants reveals a stronger association for men who lived alone (1.61; 95% CI = 1.39, 1.86), while for women results are almost equivalent between alone and not alone groups. Conclusions The associations between heat and mortality is unequal across different aspects of social vulnerability, and, inter alia, factors influencing the population vulnerability to temperatures can be related to demographic, social, and economic aspects. A number of issues are identified and recommendations for the prioritisation of further research are provided. A better knowledge of these effect modifiers is needed to identify the axes of social inequality across the most vulnerable population sub-groups.

Holocene dune activity and environmental change in the prairie parki and and boreal forest, central Saskatchewan, Canada

The Holocene ◽  
2006 ◽  
Vol 16 (1) ◽  
pp. 17-29 ◽  
Author(s):  
Stephen A. Wolfe ◽  
Jeff Ollerhead ◽  
David J. Huntley ◽  
Olav B. Lian
Keyword(s):  
Environmental Change ◽  
Boreal Forest ◽  
Great Plains ◽  
Late Holocene ◽  
Early Holocene ◽  
Aeolian Activity ◽  
Landscape Response ◽  
Response To Environmental Change ◽  
Holocene Activity ◽  
Dune Activity

Past aeolian activity was reconstructed at four dunefields in the prairie parkland and boreal forest of central Saskatchewan to elucidate landscape response to environmental change. Optical ages from stabilized dunes in the boreal transition ecoregion indicate two episodes of activity. The first, at about 11 ka, corresponds to a period of early-Holocene parkland and grassland cover following deglaciation and drainage after about 13.0 ka, and brief establishment of boreal forest. The second, between about 7.5 and 5 ka, corresponds to a period of mid-Holocene parkland-grassland cover. Optical ages from dunefields in the prairie parkland primarily record mid-Holocene activity, between about 7.5 and 4.7 ka, corresponding to a period of grassland cover, with some reworking continuing into the late Holocene. Although this area was deglaciated by about 13.5 ka, there is no evidence of early-Holocene dune activity, suggesting that mid-Holocene activity may have reworked earlier deposits here. Consequently, much of the morphology and stratigraphy observed in these dunefields are associated with mid-Holocene activity, likely associated with increased aridity and reduced vegetation cover at that time. This study provides the most northerly evidence of mid-Holocene dune reactivation on the Great Plains, lending support to the assertion that aeolian activity was widespread at that time.

Holocene climate variations from Zhuyeze terminal lake records in East Asian monsoon margin in arid northern China

2010 ◽  
Vol 74 (1) ◽  
pp. 46-56 ◽  
Author(s):  
Hao Long ◽  
ZhongPing Lai ◽  
NaiAng Wang ◽  
Yu Li
Keyword(s):  
Late Holocene ◽  
Asian Monsoon ◽  
East Asian Monsoon ◽  
East Asian ◽  
Northern China ◽  
Optically Stimulated Luminescence ◽  
Early Holocene ◽  
Climate Variations ◽  
The Holocene ◽  
Geomorphic Features

AbstractZhuyeze palaeolake is a terminal lake situated in the arid northern China in the East Asian monsoon margin. In order to examine the Holocene palaeoclimatic change in the East Asian monsoon margin, Qingtu Lake section (QTL) from Zhuyeze palaeolake is sampled in high resolution. Palaeoclimatic proxies such as grain size, carbonate, TOC, C/N and δ13C of organic matter, were analyzed; eleven 14C samples and six optically stimulated luminescence (OSL) samples were dated to provide chronological control. We also investigated the geomorphic features of lake shorelines in this area. The results show that the climate was warm and dry in early-Holocene (9.5–7.0 cal ka BP), cool and humid in mid-Holocene (7.0–4.8 cal ka BP), and increasingly drier in late-Holocene (since 4.8 cal ka BP). Comparisons of our records with other records in adjacent areas, as well as with the records in the Asian monsoon areas, suggested that changes in effective moisture was synchronous in East Asian monsoon marginal zone (i.e. the pattern of dry early-Holocene, humid mid-Holocene, and aridity-increasing late-Holocene), and that the moisture optimum during the Holocene was out-of-phase between Asian monsoon margin and Asian monsoonal dominated region, possibly due to the high temperature at that time.

Geochemical time series from lake sediments of the Central Asia as chronologic evidence of environmental change over the Late Holocene

2006 ◽  
Vol 25 (S1) ◽  
pp. 6-6
Author(s):  
Andrey V. Daryin ◽  
Ivan A. Kalugin ◽  
Lubov G. Smolyaninova ◽  
Konstantin V. Zolotarev ◽  
Elena G. Vologina ◽  
...  
Keyword(s):  
Time Series ◽  
Environmental Change ◽  
Central Asia ◽  
Lake Sediments ◽  
Late Holocene

scholarly journals Atmospheric methane control mechanisms during the early Holocene

2017 ◽  
Vol 13 (9) ◽  
pp. 1227-1242 ◽  
Author(s):  
Ji-Woong Yang ◽  
Jinho Ahn ◽  
Edward J. Brook ◽  
Yeongjun Ryu
Keyword(s):  
Late Holocene ◽  
Climate Changes ◽  
Gradual Increase ◽  
Early Holocene ◽  
Anthropogenic Emissions ◽  
Control Mechanisms ◽  
Atmospheric Methane ◽  
Tropical Wetlands ◽  
Human Influence ◽  
Siple Dome

Abstract. Understanding processes controlling the atmospheric methane (CH4) mixing ratio is crucial to predict and mitigate future climate changes in this gas. Despite recent detailed studies of the last  ∼  1000 to 2000 years, the mechanisms that control atmospheric CH4 still remain unclear, partly because the late Holocene CH4 budget may be comprised of both natural and anthropogenic emissions. In contrast, the early Holocene was a period when human influence was substantially smaller, allowing us to elucidate more clearly the natural controls under interglacial conditions more clearly. Here we present new high-resolution CH4 records from Siple Dome, Antarctica, covering from 11.6 to 7.7 thousands of years before 1950 AD (ka). We observe four local CH4 minima on a roughly 1000-year spacing, which correspond to cool periods in Greenland. We hypothesize that the cooling in Greenland forced the Intertropical Convergence Zone (ITCZ) to migrate southward, reducing rainfall in northern tropical wetlands. The inter-polar difference (IPD) of CH4 shows a gradual increase from the onset of the Holocene to  ∼  9.5 ka, which implies growth of boreal source strength following the climate warming in the northern extratropics during that period.

Predicting the Cloud Patterns for the Boreal Summer Intraseasonal Oscillation Through a Low-Order Stochastic Model

2015 ◽  
Vol 1 (1) ◽  
Author(s):  
Nan Chen ◽  
Andrew J. Majda
Keyword(s):  
Time Series ◽  
Stochastic Model ◽  
Brightness Temperature ◽  
Large Scale ◽  
Hidden Variables ◽  
Boreal Summer ◽  
Ensemble Spread ◽  
Nonlinear Stochastic Model ◽  
Non Gaussian ◽  
Cloud Patterns

AbstractWe assess the predictability limits of the large-scale cloud patterns in the boreal summer intraseasonal variability (BSISO), which are measured by the infrared brightness temperature, a proxy for convective activity. A recent developed nonlinear data analysis technique, nonlinear Laplacian spectrum analysis (NLSA), is applied to the brightness temperature data, defining two spatial modes with high intermittency associated with the BSISO time series. Then a recent developed data-driven physics-constrained low-ordermodeling strategy is applied to these time series. The result is a four dimensional system with two observed BSISO variables and two hidden variables involving correlated multiplicative noise through the nonlinear energyconserving interaction. With the optimal parameters calibrated by information theory, the non-Gaussian fat tailed probability distribution functions (PDFs), the autocorrelations and the power spectrum of the model signals almost perfectly match those of the observed data. An ensemble prediction scheme incorporating an effective on-line data assimilation algorithm for determining the initial ensemble of the hidden variables shows the useful prediction skill in the non-El Niño years is at least 30 days and even reaches 55 days in those years with regular oscillations and the skillful prediction lasts for 18 days in the strong El Niño year (year 1998). Furthermore, the ensemble spread succeeds in indicating the forecast uncertainty. Although the reduced linear model with time-periodic stable-unstable damping is able to capture the non-Gaussian fat tailed PDFs, it is less skillful in forecasting the BSISO in the years with irregular oscillations. The failure of the ensemble spread to include the truth also indicates failure in quantification of the uncertainty. In addition, without the energy-conserving nonlinear interactions, the linear model is sensitive with parameter variations. mcwfnally, the twin experiment with nonlinear stochastic model has comparable skill as the observed data, suggesting the nonlinear stochastic model has significant skill for determining the predictability limits of the large-scale cloud patterns of the BSISO.

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