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Sahara’s surface transformation forced an abrupt hydroclimate decline and Neolithic culture transition in northern China

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The Innovation 2024年第1期5卷 70-79页

作者： Yandong Hou Hao Long Sumiko Tsukamoto Zhengyao Lu Jie Chen Daniel EIbarra Toru Tamura Qiong Zhang Weiyi Sun Jingran Zhang Lei Gao Manfred Frechen Ji Shen State Key Laboratory of Lake Science and Environment Nanjing Institute of Geography and LimnologyChinese Academy of Sciences(NIGLAS)Nanjing 210008China Leibniz institute for Applied Geophysics(LIAG) Department of Geochronology30655 HannoverGermany Department of Physical geography and Ecosystem Science Lund University22100 LundSweden Key Laboratory of Western China’s Environmental Systems(Ministry of Education) College of Earth and Environmental SciencesLanzhou UniversityLanzhou 730000China College of Atmospheric Sciences Lanzhou UniversityLanzhou 730000China institute at Brown for Environment and Society and Department of Earth Environmentaland Planetary SciencesBrown UniversityProvidenceRI 02912USA Geological Survey of Japan National Institute of Advanced Industrial Science and TechnologyTsukubaIbaraki 305-8567Japan Graduate School of Frontier Sciences University of TokyoKashiwaChiba 277-8561Japan Department of Physical geography and Bolin Centre for Climate Research Stockholm University10691 StockholmSweden School of geography Nanjing Normal UniversityJiangsu Centre for Collaborative Innovation in Geographical Information Resource Development and ApplicationKey Laboratory of Virtual Geographic EnvironmentMinistry of Education of ChinaNanjing 210023China School of geography and Ocean Science Nanjing UniversityNanjing 210023China

The remote forcing from land surface changes in the Sahara is hypothesized to play a pivotal role in modulating the intensity of the East Asian summer monsoon(EASM)through ocean-atmospheric *** modulation has far-reaching consequences,particularly in facilitating societal shifts documented in northern ***,we present a well-dated lake-level record from the Daihai Lake Basin in northern China,providing quantitative assessments of Holocene monsoonal precipitation and the consequent migrations of the northern boundary of the *** reconstruction,informed by a water-and-energy balance model,indicates that annual precipitation reached700 mm during 8–5 ka,followed by a rapid decline to tween 5 and 4 *** shift coherently aligns with a signi550 mm be-ficant300 km northwestward movement of the EASM northern boundary during the Middle Holocene(MH),in contrast to its current *** findings underscore that these changes cannot be entirely attributed to orbital forcing,as corroborated by simulation *** model simulations deployed in our study suggest that the presence of the Green Sahara during the MH significantly strengthened the EASM and led to a northward shift of the monsoon rainfall ***,the Sahara’s reversion to a desert landscape in the late Holocene was accompanied by a corresponding southward retraction of monsoon *** dramatic hydroclimate changes during5–4 ka likely triggered or at least contributed to a shift in Neolithic cultures and societal transformation in northern *** decreasing agricultural productivity,communities transitioned from millet farming to a mixed rainfed agriculture and animal husbandry ***,our findings elucidate not only the variability of the EASM but also the profound implications of a remote forcing,such as surface transformations of the Sahara,on climatic changes and cultural evolution in northern China.

关键词： Holocene monsoon abrupt

Advancing flood susceptibility modeling using stacking ensemble machine learning: A multi-model approach

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Journal of Geographical Sciences 2024年第8期34卷 1513-1536页

作者： YANG Huilin YAO Rui DONG Linyao SUN Peng ZHANG Qiang WEI Yongqiang SUN Shao AGHAKOUCHAK Amir School of geography and Tourism Anhui Normal UniversityWuhu 241002AnhuiChina Changjiang River Scientific Research institute Wuhan 430015China Advanced Interdisciplinary institute of Environment and Ecology Beijing Normal UniversityZhuhai 519087GuangdongChina Hunan institute of Water Resources and Hydropower Research Changsha 410007China State Key Laboratory of Severe Weather Chinese Academy of Meteorological SciencesBeijing 100081China Department of Civil and Environmental Engineering University of California IrvineIrvineCA 92697USA

Flood susceptibility modeling is crucial for rapid flood forecasting, disaster reduction strategies, evacuation planning, and decision-making. Machine learning(ML) models have proven to be effective tools for assessing flood susceptibility. However, most previous studies have focused on individual models or comparative performance, underscoring the unique strengths and weaknesses of each model. In this study, we propose a stacking ensemble learning algorithm that harnesses the strengths of a diverse range of machine learning models. The findings reveal the following:(1) The stacking ensemble learning, using RF-XGBCB-LR model, significantly enhances flood susceptibility simulation.(2) In addition to rainfall,key flood drivers in the study area include NDVI, and impervious surfaces. Over 40% of the study area, primarily in the northeast and southeast, exhibits high flood susceptibility, with higher risks for populations compared to cropland.(3) In the northeast of the study area,heavy precipitation, low terrain, and NDVI values are key indicators contributing to high flood susceptibility, while long-duration precipitation, mountainous topography, and upper reach vegetation are the main drivers in the southeast. This study underscores the effectiveness of ML, particularly ensemble learning, in flood modeling. It identifies vulnerable areas and contributes to improved flood risk management.

关键词： flood susceptibility assessment machine learning stacking ensemble learning flood drivers XiangjiangRiverBasin

Formation environment and hydrocarbon potential of the Paleogene Enping Formation coal measures in the ZhuⅠDepression of northern South China Sea

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Acta Oceanologica Sinica 2024年第4期43卷 119-135页

作者： Yuting Yin Lei Lan Dongdong Wang Ying Chen Yan Liu Youchuan Li Zengxue Li Jiamin Liu College of Earth Science and Engineering Shandong University of Science and TechnologyQingdaoShandong 266590China China National Offshore Oil Corporation Research institute Co. Ltd.Beijing 100028China School of geography Earth and Environmental SciencesUniversity of BirminghamBirminghamB152TTUK

The coal-measure source rock in the Chinese sea area plays a significant role as a hydrocarbon source rock,with its genetic environment,development and distribution,and hydrocarbon generation potential serving as essential factors for the exploration of coal-type oil and gas *** study focuses on the coal-measure source rock of the Paleogene Enping Formation in the ZhuⅠDepression,located in the northern South China *** main geological insights obtained are as *** coal measures of the Enping Formation are developed in a warm and wet tropical-subtropical *** development environment of the coal-measure source rock in the Enping Formation includes the braided river delta upper plain peat swamp,characterized by dry forest swamp coal facies with relatively thick coal seams and a small number of *** braided river delta lower plain swamp-interdistributary bay of braided river delta front represents a forest edge-wetland herbaceous swamp coal facies with numerous layers of thin coal seams and poor *** shore swamp corresponds to an open water swamp coal facies with multiple layers of thin coal seams and poor *** organic matter abundance in the braided river delta upper plain is the highest,followed by the braided river delta lower plain-braided river delta front,and the shore-shallow *** organic matter type is predominantly typeⅡ*** evolution analysis suggests that the organic matter has progressed into a substantial oil generation *** hydrocarbon generation potential of the coal-measure source rock in the Enping Formation is the highest in the braided river delta upper plain,followed by the braided river delta lower plain-braided river delta front and the shore-shallow ***,this study proposes three organic facies in the coal-measure source rock of the Enping Formation:upper-plain swamp-dry forest swamp facies,lower plain-interdistributary bay-forest-herbaceous swamp facies,and lake swamp-herbaceo

关键词： coal-measure source rock Paleogene genetic environment hydrocarbon generation characteristic ZhuⅠDepression

Does ash dieback affect the reproductive ecology of Fraxinus excelsior L.?

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Journal of Forestry Research 2024年第2期35卷 54-69页

作者： Anna‑Katharina Eisen Lisa Buchner Barbara Fussi Susanne Jochner‑Oette Physical geography/Landscape Ecology and Sustainable Ecosystem Development Catholic University of Eichstätt-Ingolstadt85072 EichstättGermany Bavarian Office for Forest Genetics(AWG) 83317 TeisendorfGermany

Forest tree species reproduction is a key factor in maintaining the genetic diversity of future generations and the stability of forest *** ongoing ash dieback disease could affect the reproductive ecology of Fraxinus excelsior *** have a major impact on the quantity and quality of pollen and *** this study,we investigated pollen production and viability of pollen and seeds of ash trees with different health status from 2018 to *** were collected from 105 trees(pollen production),pollen from 125 trees(pollen viability),and seeds from 53 trees(seed quality)in two seed orchards and in one floodplain forest in southern *** all parameters were examined at every site every *** average pollen production per tree was estimated at 471.2±647.9 billion pollen *** addition,we found that a high number of inflorescences did not equate to high pollen production per *** production of healthy and diseased trees did not differ significantly,although only 47%of severely diseased male trees(vs.72%for healthy trees)produced *** regards to pollen viability,the TTC test showed an average viability of 73%±17%.Overall,there was a slight tendency for diseased trees to have less viable ***,a significant difference could only be calculated for trees in the floodplain *** percentage of germinable seeds in 2018 was 38%in the floodplain forest and 57%in one of the seed *** percentage of viable seeds(TTC test)ranged from 17 to 22%in the orchards in ***-viable seeds were usually heavily infested by *** general,seed quality was not significantly different between healthy and diseased *** results indicate that ash dieback affects flower formation and pollen viability but not pollen production or seed ***,the fact that hardly any flowering was observed,especially for trees that were seriously affected,suggests a negative effect of ash dieback on reproductive per

关键词： Common ash Seed orchard Floodplain forest Pollen production Viability TTC test Seed stratification Phenology

Late Cenozoic uplift of the Liupan Mountains:Evidence from the Neogene loess deposits

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Science China Earth Sciences 2024年第5期67卷 1480-1488页

作者： Zhilin HE Yansong QIAO Zhengtang GUO Chaoqin CHEN Long CHEN Yang FU Ye YANG Yanxia LIANG Xinru LIN Guoqiao XIAO Tao ZHAN Key Laboratory of Cenozoic Geology and Environment Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 100029China institute of Geomechanics Chinese Academy of Geological SciencesBeijing 100081China CAS Center for Excellence in Life and Paleoenvironment Beijing 100044China University of Chinese Academy of Sciences Beijing 100049China institute of Ecological Geology Survey and Research of Heilongjiang Province Harbin 150030China School of geography and Information Engineering China University of GeosciencesWuhan 430078China School of Earth Sciences China University of GeosciencesWuhan 430074China Natural Resources Survey institute of Heilongjiang Province Harbin 150036China

The Liupan Mountains,one of the important mountain ranges in western China,are located on the boundary between the northeastern Tibetan Plateau and the Ordos *** uplift history of the Liupan Mountains remains *** deposits are good tracers of regional tectonic and geomorphic changes,because loess is sensitive to erosion and the formation and preservation of loess requires relatively flat highlands and relatively stable tectonic *** investigated the distribution of Neogene loess deposits on the western piedmont of the Liupan Mountains and examined a near-continuous loess section(Nanping section)on the piedmont alluvial *** of magnetic susceptibility stratigraphy with the QA-ⅠMiocene loess sequence dates this 56-m section covering the interval from~8.1 to 6.2 *** lower boundary age of this section,together with previously reported Zhuanglang red clay(sand-gravel layers with intercalated loess during~9–8 Ma and near-continuous loess during~8–4.8 Ma)and Chaona red clay(~8.1–2.58 Ma),indicates that the Liupan Mountains were uplifted in the late Miocene(~9–8 Ma)and basically formed by~8 Ma,attesting to no intense mountain building since that *** addition,based on the information from the Zhuanglang core and the QA-Ⅰsection,we infer that sizable parts of the Liupan Mountains were uplifted during the late Oligocene–early Miocene and did not experience intense uplift during~22–9 Ma.

关键词： Liupan Mountains Mountain building Neogene Loess Chinese Loess Plateau Late Miocene Late Oligocene–early Miocene

Decline in tree-ring growth of Picea mongolica and its intra-annual eco-physiological responses to drought and CO_(2) enrichment in semi-arid China

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Journal of Forestry Research 2024年第4期35卷 89-101页

作者： Xiaomin Zeng Ping Ni Xiaohong Liu Wenzhi Wang Yao Li Wenchao Wang School of geography and Tourism Shaanxi Normal UniversityXi’an 710119People’s Republic of China The Key Laboratory of Mountain Environment Evolution and Regulation Institute of Mountain Hazards and EnvironmentChinese Academy of SciencesChengdu 610041People’s Republic of China CAS Key Laboratory of Forest Ecology and Management Institute of Applied EcologyChinese Academy of SciencesShenyang 110016People’s Republic of China University of Chinese Academy of Sciences Beijing 100049People’s Republic of China

Episodes of drought-induced decline in tree growth and mortality are becoming more frequent as a result of climate warming and enhanced water stress in semi-arid ***,the ecophysiological mechanisms under-lying the impact of drought on tree growth remains *** this study,earlywood and latewood tree-ring growth,δ^(13)C,andδ^(18)O chronologies of Picea mongolica from 1900 to 2013 were developed to clarify the intra-and inter-annual tree-ring growth responses to increasingly fre-quent *** results indicate that annual basal area increment residuals(BAI_(res)),which removed tree age and size effects,have significantly decreased since ***-ever,the decreasing trend of earlywood BAI_(res) was higher than that of *** response analysis suggests that the dominant parameters for earlywood and latewood proxies(BAI_(res),δ^(13)C andδ^(18)O)were drought-related climate variables(Palmer drought severity index,temperature,rela-tive humidity,and vapor pressure deficit).The most signifi-cant period of earlywood and latewood proxies’responses to climate variables were focused on June-July and July-August,***_(res),andδ^(13)C were significantly affected by temperature and moisture conditions,whereasδ^(18)O was slightly *** stomatal conduct-ance due to drought outweighed the influence of increasing CO_(2) on intrinsic water use efficiency(iWUE),and ultimately led to a decline in BAI_(res).Compared to latewood,the faster decreasing BAI_(res) and smaller increasing iWUE of early-wood suggested trees were more vulnerable to water stress in the early growing *** study provides insights into the inter-and intra-annual mechanisms of tree-ring growth in semi-arid regions under rising CO_(2) and climate change.

关键词： Tree growth Drought Water-use efficiency Seasonal differences Stable isotopes

Diatoms as indicators of environmental change in coastal areas:a case study in Lianjiang coast of East China Sea

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Acta Oceanologica Sinica 2024年第8期43卷 47-57页

作者： Tong Li Jihui Zhang Dongling Li Chengxu Zhou Chenxi Liu Hao Xu Bing Song Longbin Sha Donghai Academy Ningbo UniversityNingbo 315211China Department of geography and Spatial Information Techniques Ningbo UniversityNingbo 315211China College of Food Science and Engineering Ningbo UniversityNingbo 315211China State Key Laboratory of Lake Science and Environment Nanjing Institute of Geography and LimnologyChinese Academy of SciencesNanjing 210008China

Owing to the significant differences in environmental characteristics and explanatory factors among estuarine and coastal regions,research on diatom transfer functions and database establishment remains *** study analysed diatoms in surface sediment samples and a sediment core from the Lianjiang coast of the East China Sea,together with environmental *** component analysis of the environmental variables showed that sea surface salinity(SSS)and sea surface temperature were the most important factors controlling hydrological conditions in the Lianjiang coastal area,whereas canonical correspondence analysis indicated that SSS and pH were the main environmental factors affecting diatom *** on the modern diatom species–environmental variable database,we developed a diatom-based SSS transfer function to quantitatively reconstruct the variability in SSS between 1984 and 2021 for sediment core HK3 from the Lianjiang coastal *** agreement between the reconstructed SSS and instrument SSS data from 1984 to 2021 suggests that diatombased SSS reconstruction is reliable for studying past SSS variability in the Lianjiang coastal *** low SSS events in AD 2019,2013,and 1999,together with an increased relative concentration of freshwater diatom species and coarser sediment grain sizes,corresponded to two super-typhoon events and a catastrophic flooding event in Lianjiang ***,a diatom-based SSS transfer function for reconstructing past SSS variability in the estuarine and coastal areas of the East China Sea can be further used to reflect the paleoenvironmental events in this region.

关键词： diatom transfer function multivariate statistical analysis environmental variable sea surface salinity

Variations of sediment organic phosphorus and organic carbon during the outbreak and decline of algal blooms in Lake Taihu,China

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Journal of Environmental Sciences 2024年第5期139卷 34-45页

作者： Jiehua Wang Xiuling Bai Wenchao Li Pingping Zhang Mengdi Zhang Haoran Wang Yingge Bai College of geography and Environmental Science Henan UniversityKaifeng 475004China Key Laboratory of Geospatial Technology for the Middle and Lower Yellow River Regions(Henan University) Ministry of EducationKaifeng 475004China National Demonstration Center for Environment and Planning Henan UniversityKaifeng 475004China Surrey International institute Dongbei University of Finance and EconomicsDalian 116000China

In this study,sediment organic phosphorus(OP)and organic carbon(OC)in Lake Taihu,China,as well as their relationships,were analyzed during the outbreak and decline of algal blooms(ABs)over a five-month field *** results showed synchronous temporal changes in the sediment OP and OC contents with the development of *** addition,there was a significant positive correlation between the sediment OP and OC(p<0.01),suggesting simultaneous deposition and consumption during the ABs *** sediment OP and OC contents decreased significantly at the early and last stages of the ABs outbreak and increased at the peak of the ABs outbreak and during the ABs *** temporal variation patterns suggest that the sediment OC and OP contents did not consistently increase during the ABs outbreak,even though algae are an important source of organic matter in *** depletion or enrichment of OC and OP in sediments may also depend on the scale of the ABs *** obtained results revealed significant differences in the sediment OC and OP contents between the months(p<0.05).In addition,OP in the sediments was dominated by orthophosphate diester(phospholipids and DNA-P)and orthophosphate monoester during the ABs outbreak and decline,*** active OC contents and proportions in the sediments in the ABs outbreak were significantly lower than those observed in the ABs decline period,demonstrating the significant impacts of the ABs outbreak and decline on the sediment OC and OP in Lake Taihu.

关键词： Algal blooms Organic phosphorus Organic carbon Sediment ^(31)P NMR Lake Taihu

Spatiotemporal changes in sunshine duration and its influential factors in Chongqing,China from 1961 to 2020

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Journal of Mountain Science 2024年第6期21卷 2005-2024页

作者： LI Jun XIA Hongxuan JIANG Jinge XU Weifeng WEN Di XU Junfeng College of geography and Tourism Chongqing Normal UniversityChongqing 401331China Key Laboratory of GIS Application of Chongqing Chongqing 401331China Chongqing Key Laboratory of Earth Surface Processes and Environmental Remote Sensing in Three Gorges Reservoir area Chongqing 401331China institute of Remote Sensing and Earth Sciences School of Institute of Remote Sensing and Earth SciencesSchool of ScienceHangzhou Normal UniversityHangzhou 311121China

The surface solar radiation in most parts of the world has undergone a phenomenon known as global dimming and brightening,characterized by an initial decrease followed by an *** a result,the sunshine duration(SD)has decreased in the past 60 *** the backdrop of global dimming and brightening,SD has decreased to varying degrees in many regions of *** the observed data of SD,cloud amount(total cloud amount and low cloud amount,abbreviated as TCA and LCA),precipitation,and relative humidity(RH)from 34 meteorological stations in Chongqing during the period of 1961-2020,along with a digital elevation model(DEM)with a resolution of 90 m,this study analyzed the spatiotemporal variations and influencing factors of *** analysis employed methods such as linear regression,Mann-Kendall test,wavelet transformation,and DEM-based possible SD distributed *** results showed that the annual SD in Chongqing has significantly decreased over the last 60 years,with a decreasing interannual trend rate(ITR)of 40.4 h/*** for no obvious trend in spring,SD decreased significantly in summer,autumn and winter at the ITR of 21.1 h/10a,8.5 h/10a and 7.5 h/10a,*** abrupt decrease in the annual SD was found in *** difference before and after the abrupt decrease was 177.7 *** difference before and after the abrupt decrease was 177.7 *** annual SD possessed the oscillation period of *** spatial heterogeneity of the mean annual SD during the last 60 years was *** distribution of SD in Chongqing is high in the northeast and low in the *** addition,about 73%of the total area in Chongqing showed a significant and very significant decreasing *** regions with significant changes are mainly concentrated in the regions with altitudes of 200~1000 *** increasing LCA was the main cause of the decrease of the annual SD in the regions with 200-400 m altitude decreased the most and changed the *** LCA is the prim

关键词： Sunshine duration Spatiotemporal changes Mann-Kendall test Wavelet analysis Geodetector model