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temporal and spatial changes of suspended sediment concentration and resuspension in the Yangtze River estuary

Journal of Geographical Sciences 2003年第4期13卷 498-506页

作者： CHEN Shenliang, ZHANG Guoan, YANG Shilun(State Key Laboratory of Estuarine and Coastal Research, East China Normal University,Shanghai 200062, China) State Key Laboratory of Estuarine and Coastal Research East China Normal University Shanghai China

A detailed analysis of suspended sediment concentration (SSC) variations over a year period is presented using the data from 8 stations in the Yangtze River estuary and its adjacent waters, together with a discussion of the hydrodynamic regimes of the estuary. spatially, the SSC from Xuliujing downwards to Hangzhou Bay increases almost constantly, and the suspended sediment in the inner estuary shows higher concentration in summer than in winter, while in the outer estuary it shows higher concentration in winter than in summer, and the magnitude is greater in the outer estuary than in the inner estuary, greater in the Hangzhou Bay than in the Yangtze River estuary. The sediments discharged by the Yangtze River into the sea are resuspended by marine dynamics included tidal currents and wind waves. temporally, the SSC shows a pronounced neap-spring tidal cycle and seasonal variations. Furthermore, through the analysis of dynamic mechanism, it is concluded that wave and tidal current are two predominant factors of sediment resuspension and control the distribution and changes of SSC, in which tidal currents control neap-spring tidal cycles, and wind waves control seasonal variations. The ratio between river discharge and marine dynamics controls spatial distribution of SSC.

关键词： suspended sediment concentration temporal and spatial changes sediment resuspension Yangtze River estuary

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Surface air temperature change in the Wuyi Mountains,southeast China

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Journal of Mountain Science 2024年第6期21卷 1992-2004页

作者： QIN Yihui WEI Yuxing LU Jiayi MAO Jiahui CHEN Xingwei GAO Lu CHEN Ying LIU Meibing DENG Haijun Institute of Geography Fujian Normal UniversityFuzhou 350117China National Demonstration Center for Experimental Geography Education Fujian Normal UniversityFuzhou 350117China School of Geographical Science Fujian Normal UniversityFuzhou 350117China Fujian Provincial Engineering Research Center for Monitoring and Assessing Terrestrial Disasters Fujian Normal UniversityFuzhou 350117China Laboratory for Humid Subtropical Eco-geographical Processes of the Ministry of Education Fujian Normal UniversityFuzhou 350117China

Detecting changes in surface air temperature in mid-and low-altitude mountainous regions is essential for a comprehensive understanding of warming trend with *** use daily surface air temperature data from 64 meteorological stations in Wuyi Mountains and its adjacent regions to analyze the spatio-temporal patterns of temperature *** results show that Wuyi Mountains have experienced significant warming from 1961 to *** warming trend of the mean temperature is 0.20℃/decade,the maximum temperature is 0.17℃/decade,and the minimum temperature is 0.26℃/*** 1961-1990,more than 63%of the stations showed a decreasing trend in annual mean temperature,mainly because the maximum temperature decreased during this ***,in 1971-2000,1981-2010 and 1991-2018,the maximum,minimum and mean temperatures *** fastest increasing trend of mean temperature occurred in the southeastern coastal plains,the quickest increasing trend of maximum temperature occurred in the northwestern mountainous region,and the increase of minimum temperature occurred faster in the southeastern coastal and northwestern mountainous regions than that in the central ***,this study suggests that elevation does not affect warming in the Wuyi *** results are beneficial for understanding climate change in humid subtropical middle and low mountains.

关键词： Climate change Surface air temperature temporal and spatial changes Mann-Kendall nonparametric test Wuyi Mountains

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黔东南州近10年凝冻特征及灾害风险区划分析

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气候变化研究快报 2024年第5期13卷 1233-1242页

作者：秦畅畅严小冬龙俐梁平朱军王玥彤黔东南州气象局，贵州凯里贵州省气候中心，贵州贵阳

文章选用2011~2020年黔东南州16个国家气象站和500个区域自动站12月~次年2月的气温、降水、相对湿度、雨凇等逐日观测资料，运用模糊信息分配法找出黔东南地区发生凝冻时的气象要素阈值，结合地理信息系统技术GIS，利用实际观测发生雨... 详细信息

文章选用2011~2020年黔东南州16个国家气象站和500个区域自动站12月~次年2月的气温、降水、相对湿度、雨凇等逐日观测资料，运用模糊信息分配法找出黔东南地区发生凝冻时的气象要素阈值，结合地理信息系统技术GIS，利用实际观测发生雨凇日数、过程发生频次、过程平均最低气温、最长持续天数4个指标来界定实际发生凝冻的等级并进行风险区划。结果表明：判断黔东南地区形成凝冻天气的标准为日平均气温≤1.0℃、日最高气温≤4.0℃、日最低气温≤0℃、相对湿度≥80%，利用该阈值去寻找满足上述条件区域站发生凝冻的日数，建立凝冻时间序列，最后将凝冻划分为高、较高、中、低4个风险等级。

关键词：凝冻时空变化 GIS 风险区划 Freezing temporal and spatial changes GIS Risk Zoning

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Future variation of land surface temperature in the Yangtze River Basinbasedon CMIP6 model

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International Journal of Digital Earth 2023年第1期16卷 2776-2796页

作者： Jinlian Liu Hanya Tang Fengqin Yan Shiwei Liu Xuguang Tang Zhi Ding Pujia Yu Chongqing Jinfo Mountain Karst Ecosystem National Observation and Research Station School of Geographical SciencesSouthwest UniversityChongqingPeople’s Republic of China State Key Laboratory of Resources and Environmental Information System Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijingPeople’s Republic of China Chongqing Key Laboratory of Karst Environment School of Geographical SciencesSouthwest UniversityChongqingPeople’s Republic of China

In recent years,past changes in global and regional land surface temperatures(LST)have been well studied,however,future LST changes have been largely ignored owing to data *** this study,three climate variables of CMIP6,namely air temperature(AT),precipitation(Pre),and leaf area index(LAl),were spatially corrected using the Delta downscaling *** this basis,by combining MODIS LST,elevation,slope and aspect,a random forest(RF)model was built to calculate the LST from 2022 to *** absolute variability(AV)and Mann-Kendall(M-K)tests were used to quantitatively detect interannual and seasonal LST changes in different Shared Socioeconomic Pathways(SSPs)*** results showed that the AV value increased successively from SSP1-2.6 to SSP2-4.5 and then to *** with the base period(2003-2021),the increment in interannual,spring,summer and autumn LST during 2022-2100 was mainly between 1 and 2°℃under *** interannual and seasonal LST were spatially characterized by significant warming over large areas,and the increasing was the fastest under *** results indicate that,in the future,LST will increase further over large areas,especially in winter.

关键词： temporal and spatial changes Delta downscaling Random forest Global warming

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temporal and spatial variation of cloud cover in arid regions of Central Asia in the last 40 years

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Research in Cold and Arid Regions 2023年第2期15卷 66-72页

作者： KaiLiang Zhao GuoFeng Zhu LiYuan Sang JiaWei Liu Lei Wang YuWei Liu YuanXiao Xu XinRui Lin WenHao Zhang LinLin Ye College of Geography and Environmental Science Northwest Normal UniversityLanzhouGansu 730070China Shiyang River Ecological Environment Observation Station Northwest Normal UniversityLanzhouGansu 730070China Lanzhou Sub-Center Remote Sensing Application CenterMinistry of AgricultureLanzhouGansu 730000China

Water resources are one of the key factors restricting the development of arid areas,and cloud water resources is an important part of water *** arid region of central Asia is the core region of the current national green silk road construction,and is the largest arid region in the *** on cloud cover data of ECMWF,the current study analyzed temporal and spatial characteristics of cloud properties in arid regions of Central Asia between 1980 and *** findings show that:(1)From the point of view of spatial distribution,total cloudiness in arid regions of Central Asia was low in the south and high in the *** distribution of high cloud frequency and medium cloud frequency was higher in the south and lower in the north,while low cloud frequency distribution was low in the south and high in the north.(2)In terms of time,the variation of cloud cover and cloud type frequency had obvious seasonal *** winter to spring,cloud cover increased,and the change of cloud type frequency *** spring to summer,cloud cover continued to increase and the change of cloud type frequency increased *** cover began to decrease from summer to autumn,and the change of cloud type frequency also decreased.(3)Generally,average total cloud cover decreased in most of central Asia,and high and medium cloud cover increased while low cloud cover *** study provides a reference for the rational development of cloud resources in the region.

关键词： Central Asia Cloud cover temporal and spatial changes Cloud type frequency

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