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A new regional vegetation mapping method based on terrain-climate-remote sensing and its application on the qinghai-xizang plateau

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Science China Earth Sciences 2023年第2期66卷 237-246页

作者： Guangsheng ZHOU Hongrui REN Tong LIU Li ZHOU Yuhe JI Xingyang SONG Xiaomin LV State Key Laboratory of Severe Weather Chinese Academy of Meteorological SciencesBeijing100081China Department of Geomatics Taiyuan University of TechnologyTaiyuan030024China

Understanding the impact of climate change on vegetation and its evolution trend requires long-term accurate data on regional vegetation types and their geographical distribution.Currently,land use and land cover types are mainly obtained based on remote sensing information.Little research has been conducted on remote sensing interpretation of vegetation types and their geographical distributions in terms of the comprehensive utilization of remote sensing,climate,and terrain.A new region vegetation mapping method based on terrain-climate-remote sensing was developed in this study,supported by the Google Earth Engine(GEE)and the random forest algorithm,which is a new generation of earth science data and analysis application platform,together with optimal vegetation mapping features obtained from the average impure reduction method and out-of-bag error value,using different information from remote sensing,climate,and terrain.This vegetation of qinghai-xizang plateau with 10 m spatial resolution in 2020 was mapped,in terms of this new vegetation mapping method,Sentinel-2A/B remotely sensed images,climate,and terrain.The accuracy verification of vegetation mapping on the qinghai-xizang plateau showed an overall accuracy of 89.5%and a Kappa coefficient of 0.87.The results suggest that the regional vegetation mapping method based on terrain-climate-remote sensing proposed in this study can provide technical support for obtaining long-term accurate data on vegetation types and their geographical distributions on the qinghai-xizang plateau and the globe.

关键词： Vegetation mapping Random forest algorithm GEE remote sensing qinghai-xizang plateau

Latest Middle Miocene fauna and flora from Kumkol Basin of northern qinghai-xizang plateau and paleoenvironment

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Science China Earth Sciences 2020年第2期63卷 188-201页

作者： Qiang LI Xinying ZHOU Xijun NI Bihong FU Tao DENG Key Laboratory of Vertebrate Evolution and Human Origins Institute of Vertebrate Paleontology and PaleoanthropologyChinese Academy of SciencesBeijing 100044China CAS Center for Excellence in Life and Paleoenvironment Beijing 100044China CAS Center for Excellence in Tibetan plateau Earth Sciences Beijing 100101China University of Chinese Academy of Sciences Beijing 100049China Institute of Remote Sensing and Digital Earth Chinese Academy of SciencesBeijing 100094China

We report 7 mammalian and 16 pollen species from the top of the Shimagou Formation in Kumkol Basin of northern qinghai-xizang plateau, whose age is latest Middle Miocene(about 12.5 Ma). We erect a new species of fossil rodent,Spermophilinus kumkolensis sp. nov. The micromammalian fauna from the Kumkol Basin shares high similarities with contemporary faunas from Europe and northern China, indicating the existence of active zoogeographic exchange between Europe and northern Asia. Trees are dominant in pollen fossils, and herbs and shrubs are minorities. Broadleaved Quercus and Fagus predominate in tree pollens. The flora reconstructed by pollens displays a mixture of evergreen broadleaved forest and dry and warm steppe landscape. Compared to the modern vegetation in Yunnan region, the latest Middle Miocene flora in the Kumkol Basin represents a distinct vertical distribution. The ecotypes of the latest Middle Miocene fauna and flora in the Kumkol Basin,as a whole, are markedly different from those of modern animals and vegetation, the past climate being more suitable than today.

关键词： qinghai-xizang plateau Kumkol Basin Latest Middle Miocene Micromammals Pollen

Structural Variation of an Atmospheric Heat Source over the qinghai-xizang plateau and Its Influence on Precipitation in Northwest China

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Advances in Atmospheric Sciences 2009年第5期26卷 1027-1041页

作者：魏娜巩远发何金海 Shaanxi Provincial Climate Center Center for plateau Atmospheric and Environmental Research Department of Atmospheric Science Chengdu University of Information Technology College of Atmosphere Sciences Nanjing University of Information Science and Technology

NCEP/NCAR reanalysis data and a 47-year precipitation dataset are utilized to analyze the relationship between an atmospheric heat source （hereafter called 〈 Q1 〉） over the qinghai-xizang plateau （QXP） and its surrounding area and precipitation in northwest China. Our main conclusions are as follows：（1） The horizontal distribution of 〈 Q1 〉 and its changing trend are dramatic over QXP in the summer. There are three strong centers of 〈 Q1 〉 over the south side of QXP with obvious differences in the amount of yearly precipitation and the number of heat sinks predominate in the arid and semi-arid regions of northwest China （NWC）, beside the northern QXP with an obvious higher intensity in years with less precipitation. （2） In the summer, the variation of the heat source＇s vertical structure is obviously different between greater and lesser precipitation years in eastern northwest China （ENWC）. The narrow heat sink belt forms between the northeast QXP and the southwestern part of Lake Baikal. In July and August of greater precipitation years, the heating center of the eastern QXP stays nearly over 35°N, and at 400 hPa of the eastern QXP, the strong upward motion of the heating center constructs a closed secondary vertical circulation cell over the northeast QXP （40~ 46~N）, which is propitious to add precipitation over the ENWC. Otherwise, the heating center shifts to the south of 30°N and disappears in July and August of lesser precipitation years, an opposite secondary circulation cell forms over the northeast QXP, which is a disadvantage for precipitation. Meanwhile, the secondary circulation cell in years with more or less precipitation over the ENWC is also related to the heat source over the Lake Baikal. （3） The vertical structure of the heat source over the western QXP has obvious differences between greater and lesser precipitation years in western northwest China in June and July. The strong/weak heat source over the western QXP produces relatively strong/weak ascending motion and correspondingly constructs

关键词： qinghai-xizang plateau atmospheric heat source/sink greater/lesser precipitation years,northwest China

Changes and spatial patterns of the differences between ground and air temperature over the qinghai-xizang plateau

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Journal of Geographical Sciences 2007年第1期17卷 20-32页

作者： ZHANG Wengang LI Shuxun WU Tonghua PANG Qiangqiang The National Field Station for Scientific Observation of Cryosphere Special Environment and Disaster over the North of qinghai-Tibet plateau Golmud 816000 China Cold and Arid Regions Environmental and Engineering Research Institute CAS Lanzhou 730000 China

The difference between ground soil and air temperature （Ts-Ta） was studied by using the data of ground and air temperature of 99 stations over the qinghai-xizang （Tibet） plateau from 1960 to 2000,and its spatial distribution and time changing tendency have been diagnosed by principal component analysis and power spectral analysis methods. The results show that the values of （Ts-Ta） are the maximum in June and the minimum in December. The first three loading eigenvectors, which reflect the main spatially anomalous structure of （Ts-Ta） over the qinghai-xizang plateau, contain the contrary changing pattern between the northwestern and the southeastern regions, the pattern response of the sea level elevation and the geography, and the pattern response of the distribution of the permafrost. There are four patterns of time evolution including the patterns of monotonous increasing or decreasing trends, the basic stability pattern and the parabola pattern with the minimum value. （Ts-Ta） has a periodic variation about 2 years. According to the spatial distribution of the third loading eigenvectors of （Ts-Ta） over the qinghai-xizang plateau in cold season, the permafrost response region and the seasonal frozen ground response region are identified.

关键词： qinghai-xizang plateau difference between ground and air temperature （Ts-Ta） principal component temperature subarea

Late Cenozoic Geology and Paleo-environment Change in the Eastern Edge of qinghai-xizang plateau

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Acta Geologica Sinica(English Edition) 2008年第5期82卷 959-966页

作者： ZHAO Zhizhong QIAO Yansong WANG Shubing YAO Haitao WANG Yan LI Chaozhu FU Jianli LIU Zongxiu LI Mingze MIAO Qi JIANG Fuchu Institute of Geomechanics Chinese Academy ofGeosciences Beijing 100081 China Open Laboratory of Lake Sediment and Environment Chinese Academy of Sciences Nanjing 210008 Jiangsu China

There are late Cenozoic lacustrine deposits and loess and red clay and moraines in eastern edge of the qinghai-xizang plateau. Various genetic sediments recorded rich information on late Cenozoic paleo-environment changes. Xigeda lacustrine formed during 4.2 Ma B.P.-2.6 Ma B.P. There were 9 periodic warm-cold alternations. Eolian deposition in western Sichuan began at 1.15 Ma B.P. The loess-soil sequences recorded successively 14 paleo-monsoon climate cycles. Laterite in Chengdu plain recorded 5 stages of paleoclimatic stages since 1.13 Ma B.P. There was an old glacial period of 4.3 Ma B.P. in eastern qinghai-xizang plateau. During Quaternary, there are 5 extreme paleoclimatic events corresponding with 5 glaciations.

关键词： qinghai-xizang plateau Xigeda lacustrine Loess in western Sichuan Chengdu laterite Quaternary glaciations

Evolution characteristics of Quaternary tectonic stress field in the north and east margin of qinghai-xizang plateau

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Acta Seismologica Sinica(English Edition) 1999年第5期12卷 550-561页

作者：谢富仁张世民窦素芹崔效锋舒塞兵 Institute of Crustal Dynamics China Seismological Bureau Beijing China

By inversion of fault slip data for Quaternary tectonic stress field and the analysis of crustal deformation after lateTeriary. we explaincd the evolution of crustal dynamic about the north and east margin of qinghai-xizang (Tibet)plateau since Miocenc. From middle or late Miocene to early Pleistocene, the tectonic stress field was featured by amaximum principal compression which was coming from the collision of india Plate continued to the boundaryof the plateau. and was basically of reverse faulting type. Since the late period of early Pleistocene, Pleistocene continuedto push northward and the compressional deformation of the plateau interior increased continuously, meanwhile,N W-SE extension appeared on the east side of the plateau. This formed a favorable condition for the interior block offoe plateau to slide towards east and southeast, causing the faults surrounding the plateau to change from thrust tostrike-slip. -The contemporary tectonic stress field was formed from the late period of early Pleistocene and continuedto present. The direction of maximum principal compressional stress rotated clockwise with respect to the previoustectonic stress held. the stress field was mainly of strike-slip type.

关键词： qinghai-xizang plateau tectonic stress field crustal deformation

Relocation of earthquakes in northeastern region of qinghai-xizang plateau and characteristics of earthquake activity

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Acta Seismologica Sinica(English Edition) 2000年第3期13卷 257-264页

作者：汪素云高阿甲许忠淮张晓东郭瑛 Institute of Geophysics China Seismological Bureau Beijing China

The northeastern region of qinghai-xizang plateau is the junction part of the qinghai-xizang block, Alxa block and ordos block. To explore tectonic feature of this region 4 study profiles are selected by taking gcological background into consideration. The ML≥3.0 earthquakes located within 40 km on both sides of the selected profiles and ML≥4.0 earthquakes in the studied region have been relocated. Of the 388 relocated earthquakes, 36% shift their previously determined epicenters by more than 5 km. The amount of relocated earthquake with focal depth determination increases 50% more than that before relocation. In this quasi-trijunction region of the northeastem of qinghai-xizang plateau three m≥8 earthqutas occurred historically and microearthquates are quite active at present,implying a strong tectonic activity persists here to the present day.

关键词： qinghai-xizang plateau earthquake focal depth

Effects　on　Asian　Monsoon　of　Gigantic　qinghai－xizang　plateau　and　Western　Pacific　Warm　Pool

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Advances in Atmospheric Sciences 1995年第3期12卷 351-360页

作者：朱乾根胡江林 Nanjing Institute of Meteorology Nanjing

A GCM study is performed of the effects on Asian summer monsoon initiation of the qinghai-xizang plateauand western Pacific warm pool. results show that the plateau, being a prominent sensible heat source, acts as a basicfactor for the formation of the monsoon circulation, the northward transported low-latitude and low-level warm,moist flow in relation to the sensible heating experiences dynamic lifting on the south and east sides of the highland,releasing vast quantities of latent heat through condensation, whereby the monsoon circulation pattern is furthermodulated; the temperature contrast between the Pacific warm pool and the Australian / marine continents serves asanother basic factor for the northern SW summer monsoon genesis over the South-China Sea-the western Pacific,which, however, falls into a category of winter monsoon on a physical basis.

关键词： qinghai-xizang plateau Western Pacific warm pool Sensible heating Formation of Asian summermonsoon

NUMERICAL STUDY ON THE DYNAMIC AND THERMODYNAMIC EFFECTS OF THE qinghai-xizang plateau ON THE SEASONAL TRANSITION IN THE EARLY SUMMER IN EAST ASIA

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Acta meteorologica Sinica 1995年第1期9卷 35-47页

作者：郑庆林吴军 Chinese Academy of Meteorological Sciences Beijing 100081

By employing a five-layer seasonal numerical weather prediction model and utilizing the National Meteorological Center (NMC) objective analysis data on May 10,1991 as the initial field,three numerical experiments——diabatic with orography,adiabatic with orography and adiabatic without orography——have been carried out to investigate the dy- namic and thermodynamic effects of the qinghai-xizang plateau (hereafter the plateau) on the seasonal transition in the early summer in East Asia.The results show that the typical seasonal transition features such as the northward shift of the subtropical westerly jet stream,the adjustment of the long-wave in middle and high latitudes and the changes of the circulation in the lower troposphere can be well simulated,if the dynamic and thermodynamic effects of the plateau are both considered in the model as in the experiment adiabatic with orography.In other two experiments,it is failed to simulate out the seasonal transition features. The results also show that the thermodynamic effect of the plateau acts on the atmosphere as a gradually enhanced heating source in the early summer,which makes the air temperature in 500 hPa over the plateau increase by nearly 10℃ in a month and accelerates the northward shift of the subtropical westerly jet stream about seven latitudes more north- ward in twenty days and helps the shifted jet maintain at the northern periphery of the plateau.It is also helpful to the formation and maintenance of the Lake Balchas trough and the northward and westward extension of the Pacific subtropical high.On the other hand,the dynamic effect of the plateau weakens the northward shift of the subtropical westerly jet stream and barricades the westward extension of the Pacific subtropical high.If only the dynamic effect of the plateau is considered in the model without consideration of the thermodynamic effect of the plateau,not only the shifted jet withdraws southward but also the simulated Lake Balchas trough is 10 longitudes more eastward than that in the diabat

关键词： seasonal transition qinghai-xizang plateau dynamic effect thermodynamic effect