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Anthropogenic Threats to degraded Forest Land in the Savannahs’ Region of Togo from 1984 to 2020, West Africa

Journal of Geoscience and Environment Protection 2024年第1期12卷 164-179页

作者： Kossi Senyo Ehlui Wouyo Atakpama Henrik von Wehrden Alagie Bah Edinam Kola Christian Anthony-Krueger Hodabalo Egbelou Kokouvi Bruno Kokou Tchaa Boukpessi West Africa Science Service Center on Climate Change and Adapted Land Use (WASCAL) University of the Gambia Banjul Gambia laboratoire de Recherche sur la dynamique des Milieux et des Sociétés Université de Lomé Lomé Togo laboratoire de Botanique et écologie Végétale Département Botanique Faculté des Sciences Université de Lomé Lomé Togo West Africa Plant Red List Authority (WAPRLA) IUCN Species Survival Commission Gland Switzerland Faculty of Sustainability Center of Methods Leuphana University of Lüneburg Lüneburg Germany Center for International Forestry Research and World Agroforestry (CIFOR-ICRAF) Nairobi Kenya laboratoire de Recherche sur la dynamique des Milieux et des Sociétés (LARDYMES) Department of Geography FSHS University of Lomé Lome Togo department of Science Education University of Cape Coast Cape Coast Ghana Institut Togolais de Recherches Agronomiques (ITRA) Lomé Togo laboratoire de Recherches Biogéographiques et d’Etudes Environnementales Department of Geography University of Lome Lome Togo

This study focuses on the landscape dynamics of the savannahs’ region in the far north of Togo. Based on a literature review and satellite images analysis using GIS and remote sensing, the study aims to ascertain the effects of anthropogenic threats on the forest coverage of the Savannahs’ Region between 1984 to 2020. The objective is to clarify the dynamics of land use in the region from 1984 to 2000 and from 2000 to 2020. The findings indicate a significant decline in forest coverage within the region from 1984 to 2020, a trend attributed to land use patterns. Dry forests in the Savannah region are largely converted to farmlands, housing, dry savannahs or agroforestry parks, leading to a steady reduction in forest areas.

关键词： Forest degradation Land Use Land Cover Savannahs Region Togo

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2023: Weather and Climate Extremes Hitting the Globe with Emerging Features

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Advances in Atmospheric Sciences 2024年第6期41卷 1001-1016页

作者： Wenxia ZHANG Robin CLARK Tianjun ZHOU Laurent LI Chao LI Juan RIVERA Lixia ZHANG Kexin GUI Tingyu ZHANG Lan LI Rongyun PAN Yongjun CHEN Shijie TANG Xin HUANG Shuai HU State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China Met Office Hadley Centre Exeter EX13PBUK University of Chinese Academy of Sciences Beijing 100049China laboratoire de Météorologie dynamique CNRSSorbonne UniversitéEcole Normale SupérieureEcole PolytechniqueParis 75230France Max Planck Institute for Meteorology Hamburg 20146Germany Instituto Argentino de Nivología Glaciología Y Ciencias Ambientales(IANIGLA)CCT CONICETMendoza CP 5500Argentina Shanghai Typhoon Institute China Meteorological AdministrationShanghai 200030China Asia-Pacific Typhoon Collaborative Research Center Shanghai 201306China

Globally,2023 was the warmest observed year on record since at least 1850 and,according to proxy evidence,possibly of the past 100000 years.As in recent years,the record warmth has again been accompanied with yet more extreme weather and climate events throughout the world.Here,we provide an overview of those of 2023,with details and key background causes to help build upon our understanding of the roles of internal climate variability and anthropogenic climate change.We also highlight emerging features associated with some of these extreme events.Hot extremes are occurring earlier in the year,and increasingly simultaneously in differing parts of the world(e.g.,the concurrent hot extremes in the Northern Hemisphere in July 2023).Intense cyclones are exacerbating precipitation extremes(e.g.,the North China flooding in July and the Libya flooding in September).Droughts in some regions(e.g.,California and the Horn of Africa)have transitioned into flood conditions.Climate extremes also show increasing interactions with ecosystems via wildfires(e.g.,those in Hawaii in August and in Canada from spring to autumn 2023)and sandstorms(e.g.,those in Mongolia in April 2023).Finally,we also consider the challenges to research that these emerging characteristics present for the strategy and practice of adaptation.

关键词： weather and climate extremes temperature extremes extreme precipitation drought wildfires

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太平洋十年涛动对全球地表气温变化的影响足迹

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Science Bulletin 2024年第4期69卷 445-448页

作者：梁莉莉 Alan D.Ziegler 陈德亮 Philippe Ciais 李肇新梁时婧王大山徐荣嵘曾振中 School of Environmental Science and Engineering Southern University of Science and TechnologyShenzhen 518055China SUSTech Energy Institute for Carbon Neutrality Southern University of Science and TechnologyShenzhen 518055China Faculty of Fisheries Technology and Aquatic Resources Mae Jo UniversityChiang Mai 50000Thailand Regional Climate Group Department of Earth SciencesUniversity of GothenburgGothenburg 40530Sweden laboratoire des Sciences du Climat et de l’Environnement UniversitéParis-SaclayGif-sur-Yvette 91191France laboratoire de Météorologie dynamique Centre national de la recherche scientifiqueSorbonne UniversitéÉcole Normale SupérieureÉcole PolytechniqueParis 75000France Guangdong Provincial Key Laboratory of Soil and Groundwater Pollution Control School of Environmental Science and EngineeringSouthern University of Science and TechnologyShenzhen 518055China

Sea surface temperature modes have been found to modulate anthropogenic global warming rates on annual and decadal timescales,sometimes leading to periods of“slowdown”despite increasing greenhouse gas emissions^([1]).

关键词：太平洋十年涛动地表气温 greenhouse

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Mapping and Floristic Diversity of the Nakpadjouak Community Forest, Tami Canton, Togo (West Africa)

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Natural Resources 2024年第4期15卷 83-105页

作者： Senyo Kossi Ehlui Christian Anthony-Krueger Edinam Kola Wouyo Atakpama Alagie Bah Henrik von Wehrden Tchaa Boukpessi West Africa Science Service Center on Climate Change and Adapted Land Use WASCAL University of the Gambia Banjul Gambia laboratoire de Recherche sur la dynamique des Milieux et des Socié t&#233s Department of Geography University of Lom&#233 Lome Togo department of Science Education University of Cape Coast Cape Coast Ghana laboratoire de Botanique et É cologie V&#233g&#233tale D&#233partement botanique Facult&#233 des sciences Universit&#233 de Lom&#233 Lome Togo West Africa Plant Red List Authority (WAPRLA) IUCN Species Survival Commission Gland Switzerland Center for International Forestry Research and World Agroforestry (CIFOR-ICRAF) Nairobi Kenya Faculty of Sustainability Center of Methods Leuphana University of L&#252neburg L&#252neburg Germany laboratoire de Recherches Biogé ographiques et d&#8217Etudes Environnementales Department of Geography University of Lome Lome Togo

Since 2015, community forests have been promoted in Togo as an alternative to protect areas from degradation and as a means of contributing to forest landscape restoration. The study focuses on the Nakpadjouak Community Forest (NCF) in Tami (Togo, West Africa) which contributes to community forests sustainable management. It aims in (i) mapping forest ecosystems and analysing their dynamic and (ii) characterizing the floristic diversity of the NCF. The ecosystems were mapped and their dynamic was evaluated based on Google Earth images of 2014 and 2020. Floristic and forestry inventories were carried out using the transect technique in a sample of 20 plots of 50 m × 20 m. The NCF was made up mainly by wooded/shrub savannahs (95.37%) and croplands/fallow (4.63%) in 2014. These two land use types undergone changes over the 6 years prior to 2020. By 2020, the NCF had 3 land use types: wooded/shrub savannahs (77.59%), open forest/wooded savannahs (22.23%), and croplands/fallows (0.18%). A total of 89 plant species belonging to 70 genera and 28 families were recorded within the NCF. The dominant species are: Heteropogon contortus (L.) P.Beauv. and Combretum collinum Fresen. followed by Pteleopsissuberosa Engl. & Diels, Annona senegalensis Pers. The most common species are: Lannea acida A.Rich. s.l., A. senegalensis, Vitellaria paradoxa C.F.Gaertner subsp. paradoxa, C. collinum and Acacia dudgeonii Craib ex Holland. Due to its small area of just 40 hectares and its diverse plant life, this community forest of Savannahs Region is a significant biodiversity hotspot and warrants conservation efforts.

关键词： Community Forest Floristic Diversity Land Use Change Biodiversity Hotspot Tami Savannah Region Togo

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Role of Anthropogenic Climate Change in Autumn Drought Trend over China from 1961 to 2014

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Journal of Meteorological Research 2022年第2期36卷 251-260页

作者： Xuyu ZHANG Jinhua YU Laurent ZXLI Wei LI Key Laboratory of Meteorological Disaster Ministry of Education/Collaborative Innovation Center on Forecast and Evaluation of Meteorological DisastersNanjing University of Information Science&TechnologyNanjing 210044China laboratoire de Météorologie dynamique Centre National de la Recherche ScientifiqueSorbonne UniversitéEcole Normale SupérieureEcole PolytechniqueParis 75252France

Understanding the impact of anthropogenic climate change on drought is of great significance to the prevention of its adverse effects.Two drought indices,standardized precipitation index(SPI)and standardized precipitation evapotranspiration index(SPEI),are used here for the detection and attribution of autumn droughts in China,and for the exploration of the role played by the anthropogenic climate change.SPI is only related to precipitation,but SPEI involves both precipitation and potential evapotranspiration.For their trend’s spatial patterns,the historical simulations(including all forcings,noted as ALL)from 11 models of the Coupled Model Intercomparison Project phase 6,as an ensemble,are able to reproduce their observational counterpart.SPI shows wetting trend in the north of 35°N and drying trend in the south.SPEI shows drying trend in almost whole China.The drying trend in historical simulations ALL is significantly stronger,compared with the counterpart from the accompanying simulations(called NAT)with only natural forcings implemented.This result clearly indicates that anthropogenic climate change plays a dominant role in the enhancement of autumn drought in China.A more rigorous detection work is also performed with the signal’s fingerprint of ALL(and NAT)projected onto the observation and assessed with the background noise from no external-forcing control simulations.The trend pattern signal in ALL is significantly detected in observation for both SPI and SPEI,with a more pronounced signal in SPEI than in SPI,while the signal of NAT is not detected for neither SPI nor SPEI.Finally,extreme droughts(with indices beyond-2)are assessed in terms of probability ratio between ALL and NAT.It is shown that the anthropogenic precipitation change plays a leading role in the south of 35°N,while the anthropogenic temperature change leads in the north.

关键词： drought anthropogenic effect detection and attribution standardized precipitation index(SPI)and standardized precipitation evapotranspiration index(SPEI)

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Intercomparison of multi-model ensemble-processing strategies within a consistent framework for climate projection in China

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Science China Earth Sciences 2023年第9期66卷 2125-2141页

作者： Huanhuan ZHU Zhihong JIANG Laurent LI Wei LI Sheng JIANG Panyu ZHOU Weihao ZHAO Tong LI Key Laboratory of Meteorological Disaster of Ministry of Education Collaborative Innovation Center on Forecast and Evaluation of Meteorological DisasterNanjing University of Information Science and TechnologyNanjing 210044China laboratoire de Météorologie dynamique CNRSSorbonne UniversitéEcole Normale SupérieureEcole PolytechniqueParis 75005France School of Mathematics and Statistics Nanjing University of Information Science and TechnologyNanjing 210044China

Climate change adaptation and relevant policy-making need reliable projections of future climate.Methods based on multi-model ensemble are generally considered as the most efficient way to achieve the goal.However,their efficiency varies and inter-comparison is a challenging task,as they use a variety of target variables,geographic regions,time periods,or model pools.Here,we construct and use a consistent framework to evaluate the performance of five ensemble-processing methods,i.e.,multimodel ensemble mean(MME),rank-based weighting(RANK),reliability ensemble averaging(REA),climate model weighting by independence and performance(ClimWIP),and Bayesian model averaging(BMA).We investigate the annual mean temperature(Tav)and total precipitation(Prcptot)changes(relative to 1995–2014)over China and its seven subregions at 1.5 and 2℃warming levels(relative to pre-industrial).All ensemble-processing methods perform better than MME,and achieve generally consistent results in terms of median values.But they show different results in terms of inter-model spread,served as a measure of uncertainty,and signal-to-noise ratio(SNR).ClimWIP is the most optimal method with its good performance in simulating current climate and in providing credible future projections.The uncertainty,measured by the range of 10th–90th percentiles,is reduced by about 30%for Tav,and 15%for Prcptot in China,with a certain variation among subregions.Based on ClimWIP,and averaged over whole China under 1.5/2℃global warming levels,Tav increases by about 1.1/1.8℃(relative to 1995–2014),while Prcptot increases by about 5.4%/11.2%,respectively.Reliability of projections is found dependent on investigated regions and indices.The projection for Tav is credible across all regions,as its SNR is generally larger than 2,while the SNR is lower than 1 for Prcptot over most regions under 1.5℃warming.The largest warming is found in northeastern China,with increase of 1.3(0.6–1.7)/2.0(1.4–2.6)℃(ensemble’s median and range of the 10th–90th percentiles)under 1.5/2℃warmin

关键词： Multi-model ensemble simulation Ensemble-processing strategy Global warming targets Climate projection uncertainty assessment Regional climate change in China

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Paleoclimate and Paleoenvironment of Gonghe Basin, Qinghai-Tibet Plateau, During the Lastdeglacial: Weathering, Erosion and Vegetation Cover Affect Clay Mineral Formation

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Acta Geologica Sinica(English Edition) 2014年第2期88卷 647-660页

作者： SUN Qingfeng Christophe COLIN Faculty of Geography Northwest Normal University laboratoire des Interactions et dynamique des Environnements de Surface (IdeS) UMR 8148CNRS Université de Paris-Sud

With the analysis of the sources and formation mechanism of the clay minerals in the sediment core from the Dalianhai lake in the Gonghe Basin,northeastern Tibet-Qinghai Plateau,clay mineral composition proxies,grain-size and carbonate contents have been employed for high-resolution study in order to reconstruct East Asian Summer Monsoon （EASM） over the northeastern Tibet-Qinghai Plateau during the lastdeglacial.The study also extended to establish a relationship between vegetation cover changes and erosion during the last 14.5 ka with pollen record and clay mineral proxies.Smectite/kaolinite and smectite/（illite＋chlorite） ratios allow us to assess hydrolysis conditions in lowlands and/or physical erosion process in highlands of the Gonghe Basin.Before 12.9 Cal ka BP,both mineralogical ratios show low values indicative of strong physical erosion in the basin with a dominant cold and dry phase.After 12.9 Cal ka BP,an increase in both mineralogical ratios indicates enhanced chemical weathering in the basin associated with a warm and humid climate.The beginning of Holocene is characterized by high smectite/（illite＋chlorite） and smectite/kaolinite ratios that is synchronous as with deposition of many peat laminae,implying the best warm and humid conditions specifically between 8.0 to 5.5 Cal ka BP.The time interval after 5.0 Cai ka BP is characterized by a return to high physical erosion and low chemical weathering with dry climate conditions in the basin.Comparing variations of clay mineral assemblages with previous pollen results,we observe a rapid response in terms of chemical weathering and physical erosion intensity to a modification of the vegetation cover in the basin.

关键词： clay minerals vegetation Gonghe Basin Tibet-Qinghai Plateau Asian monsoon Holocene

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Dynamic characteristics of a cyclic-periodic structure with a piezoelectric network

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Chinese Journal of Aeronautics 2015年第5期28卷 1426-1437页

作者： Li Lin deng Pengcheng Fan Yu School of Energy and Power Engineering Beihang University Collaborative Innovation Center for Advanced Aero-Engine laboratoire de Tribologie et dynamique des Systemes Ecole Centrale de Lyon – 36Avenue Guy de Collongues Ecully 69134 France

This paper deals with a cyclic-periodic structure with a piezoelectric network. In such a system, there is not only mechanical connection but also electrical connection between adjacent periodic sectors. The objective is to learn whether the presence of a piezoelectric network would change the dynamic characteristics of the system. The background of the research is about vibration reduction of a bladed disk in an aero-engine, and the system is simulated by a lumped parameter model. The dynamic equations of the system are derived, and then the analytical solution corresponding to the eigenvalue problem is given. The vibration responses to single traveling wave excitations （EO excitations） and multiple traveling wave excitations （NEO excitations） are studied. The results show that the presence of a piezoelectric network would change the natural frequencies of the system compared with those of the system with the piezoelectric shunt circuit. The forced response is sensitive to the connection type and the elements of the network. An energy analysis of the electro-mechanical coupling system has been performed to understand its dynamic behavior, and the following conclusion is obtained： a vibration reduction to excitations whose primary har- monic component is not zero can be achieved by a parallel piezoelectric network, while a reduction to other excitations should be based on a series piezoelectric network.

关键词： Cyclic-periodic structures Electro-mechanical dynamicbehavior Energy analysis Piezoelectric networks Vibration reduction

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Diagnosing the Dynamic and Thermodynamic Effects for the Exceptional 2020 Summer Rainy Season in the Yangtze River Valley

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Journal of Meteorological Research 2022年第1期36卷 26-36页

作者： Na WEN Shujie LIU Laurent Z.X.LI College of Atmospheric Sciences Nanjing University of Information Science&TechnologyNanjing 210044China Key Laboratory of Meteorological Disaster of Ministry of Education Nanjing University of Information Science&TechnologyNanjing 210044China Qingdao Engineering Technology Research Center for Meteorological Disaster Prevention Qingdao Meteorological BureauQingdao 266003China laboratoire de Météorologie dynamique Centre National de la Recherche ScientifiqueSorbonne UniversitéEcole Normale SupérieureEcole PolytechniqueParis 75252France

An exceptional rainy season occurred in the Yangtze River valley of eastern China in June-July 2020.The relative importance of the dynamic and thermodynamic effects on this unusual event is evaluated through the budget equations of moisture and moist static energy(MSE).The moisture budget analysis suggests that the thermodynamic effect contributes to the precipitation anomaly by 8.5%through the advection of abnormal water vapor by mean vertical motion,while the dynamic effect,related to water vapor advection by anomalous vertical motion,has the dominant contribution.The MSE budget analysis further reveals that the anomalous vertical motion is both constrained by the dynamic effect related to changes in atmospheric circulation and the thermodynamic effect related to changes of the atmospheric thermal state,with a ratio of thermodynamic versus total effects estimated at 45.3%.The dynamic effect is linked to the advection of warm and humid air by the abnormal southwesterly wind,which is related with an anomalous anticyclone over the Philippine Sea.The thermodynamic effect is partly induced by the positive advection of anomalous MSE(mainly latent energy)by the mean vertical motion.This analysis of the dynamic and thermodynamic effects is useful to understand the underlying physical mechanisms leading to the unusual rainy season in the Yangtze River valley in summer 2020.It is also helpful to put forward a few speculations on the potential role of global warming whose primary effect is,after all,to change the thermal state of the atmosphere.

关键词： exceptional rainfall Yangtze River valley global warming dynamic and thermodynamic effects

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Hysteresis and the nonlinear equivalent piezoelectric coefficient of MFCs for actuation

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Chinese Journal of Aeronautics 2017年第1期30卷 88-98页

作者： Xue Zheng Li Lin M.N.Ichchou Li Chao School of Energy and Power Engineering Beihang University Beijing China Collaborative Innovation Center for Advanced Aero-Engine Beijing China laboratoire de Tribologie et dynamique des Systemes (LTDS) UMR 5513 Ecole Centrale de Lyon Ecully France

The hysteretic behavior and nonlinearity of the equivalent material coefficient of macro fiber composites（MFC） under staircase input conditions are investigated using the Preisach model.Based on a database of first order reversal curves, formulas are derived to predict the hysteresis of strain output and nonlinearity of the equivalent piezoelectric coefficient of MFCs. Formulae are verified by comparing the predicted strains with the measured strains of three MFC specimens,which are driven by a random sequence of staircase voltage inputs. The coefficients obtained by the formulae and experimentation coincide. Further results indicate that the equivalent piezoelectric strain coefficient depends greatly on the value of drive voltage across the entire input range, and the coefficient is asymmetric across the negative and positive input ranges. deflection testing of an MFC composite cantilever demonstrates the importance of taking the nonlinearity of the equivalent piezoelectric coefficient into consideration in the application of actuation.

关键词： Hysteresis Macro fiber composite Nonlinear piezoelectric coef-ficients Piezoelectric materials Preisach model

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