正确认识不同区域能量和水分循环特征是研究局地地气相互作用及准确预测区域天气,气候变化的关键.为了研究属于干旱/半干旱气候的青藏高原(TP)和湿润/半湿润气候的长江流域(YRR)之间地表能量和水分交换的异同,本文对比分析了两个区域8...正确认识不同区域能量和水分循环特征是研究局地地气相互作用及准确预测区域天气,气候变化的关键.为了研究属于干旱/半干旱气候的青藏高原(TP)和湿润/半湿润气候的长江流域(YRR)之间地表能量和水分交换的异同,本文对比分析了两个区域8个不同地表类型(包括高山荒漠,高山草地,(平原)城市和(平原)草地等)观测站点的地表辐射和能量通量数据.结果显示:(1)TP由于高原大气层稀薄且空气洁净,年平均入射短波辐射为251.3W m^(-2),是YRR的1.7倍.加之高原地表反照率高导致反射辐射(59.6 W m^(-2))是YRR的2.87倍.入射及出射的长波辐射为231.5和338.0 W m^(-2),分别为YRR的0.64和0.83.而两个区域的净辐射差异不大;(2)草地站更多的潜热释放使得地表总加热效率高于城市和高山荒漠,TP和YRR的草地站的年平均潜热分别为35.0和38.8 W m^(-2),而植被稀疏且土壤干燥的高山荒漠地区感热最大,年平均感热为42.1 W m^(-2);其次是城市下垫面,其年平均感热为37.7 W m^(-2).研究结果揭示了不同气候背景下典型下垫面地气相互作用特征,为地气相互作用过程深入分析奠定了基础.展开更多
The Wenchuan earthquake has altered the crustal motion characteristics in the eastern margin of the Tibetan Plateau and adjacent regions.Using discontinuous GPS survey data for 2008–2012, the velocity field for the E...The Wenchuan earthquake has altered the crustal motion characteristics in the eastern margin of the Tibetan Plateau and adjacent regions.Using discontinuous GPS survey data for 2008–2012, the velocity field for the Eurasia reference framework has been obtained, and the general trend of contemporary crustal motion after the occurrence of the Wenchuan earthquake has been studied.In addition, using the velocity field, the block movement velocity has been estimated by least-squares fitting.Furthermore, the properties and displacement rates of main faults have been obtained from the differences in velocity vectors of the blocks on both sides of the faults.The results reveal that there are no obvious changes in the general characteristics of crustal motion in this area after the Wenchuan earthquake.The earthquake mainly changed the rate of the movement of the Chuan-Qing block and caused variation in the movement direction of the South China block.The effect of the earthquake on faults is mainly reflected in variations in fault displacement velocity; there is no fundamental change in the properties of fault activity.The displacement rates of the Xianshuihe fault decreased by 3–4 mm/a, the Longmenshan fault increased by 9–10 mm/a, and the northern segment of the Anninghe fault increased by approximately 9 mm/a.Furthermore, the displacement rates of the Minjiang, Xueshan, Huya, Longquanshan, and Xinjin faults increased by 2–3 mm/a.This implies that the effects of the Wenchuan earthquake on crustal movement can mainly be observed in the Chuan-Qing, South China, and N-Chuan-Dian blocks and their internal faults, as well as the Xianshuihe and Longmenshan faults and the northern section of the Anninghe fault.The reason for this is that the Wenchuan earthquake disturbed the kinematic and dynamic balance in the region.展开更多
Because of the large number and remoteness, satellite data, including microwave data and optical imagery, have commonly been used in alpine glaciers surveys. Using remote sensing and Geographical Information System (G...Because of the large number and remoteness, satellite data, including microwave data and optical imagery, have commonly been used in alpine glaciers surveys. Using remote sensing and Geographical Information System (GIS) techniques the paper presents the results of a multitempora satellite glacier extent mapping and glacier changes by glacier sizes in the Mt. Qomolangma region at the northern slopes of the middle Himalayas over the Tibetan Plateau. Glaciers in this region have both retreated and advanced in the past 35 years, with retreat dominating. The glacier retreat area was 3.23 km2 (or 0.75 km2 yr-1) during 1974 and 1976, 8.68 km2 (or 0.36 km2 yr-1) during 1976 and 1992, 1.44 km2 (or 0.12 km2 yr-1) during 1992-2000. 1.14 km2 (or 0.22 km2 yr-1) during 2000-2003, and 0.52 km2 (or 0.07 km2 yr-1) during 2003-2008, respectively. While supra-glacier lakes on the debris-terminus of the Rongbuk Glacier were enlarged dramatically at the same time, from 0.05 km2 in 1974 increased to 0.71 km2 in 2008, which was more than 13 times larger in the last 35 years. In addition, glacier changes also showed spatial differences, for example, glacier retreat rate was the fastest at glacier termini between 5400 and 5700 m a.s.l than at other elevations. The result also shows that glaciers in the middle Himalayas retreat almost at a same pace with those in the western Himalayas.展开更多
Dextral-slip in the Nyainqentanglha region of Tibet resulted in oblique underthrusting and granite generation in the Early to Middle Miocene, but by the end of the epoch uplift and extensional faulting dominated. The ...Dextral-slip in the Nyainqentanglha region of Tibet resulted in oblique underthrusting and granite generation in the Early to Middle Miocene, but by the end of the epoch uplift and extensional faulting dominated. The east-west dextral-slip Gangdise fault system merges eastward into the northeast-trending, southeast-dipping Nyainqentanglha thrust system that swings eastward farther north into the dextral-slip North Damxung shear zone and Jiali faults. These faults were took shape by the Early Miocene, and the large Nyainqentanglha granitic batholith formed along the thrust system in 18.3-11.0 Ma as the western block drove under the eastern one. The dextral-slip movement ended at -11 Ma and the batholith rose, as marked by gravitational shearing at 8.6-8.3 Ma, and a new fault system developed. Northwest-trending dextral-slip faults formed to the northwest of the raisen batholith, whereas the northeast-trending South Damxung thrust faults with some sinistral-slip formed to the southeast. The latter are replaced farther to the east by the west-northwest-trending Lhtinzhub thrust faults with dextral-slip. This relatively local uplift that left adjacent Eocene and Miocene deposits preserved was followed by a regional uplift and the initiation of a system of generally north-south grabens in the Late Miocene at -6.5 Ma. The regional uplift of the southern Tibetan Plateau thus appears to have occurred between 8.3 Ma and 6.5 Ma. The Gulu, DamxungYangbajain and Angan graben systems that pass east of the Nyainqentanglha Mountains are locally controlled by the earlier northeast-trending faults. These grabens dominate the subsequent tectonic movement and are still very active as northwest-trending dextral-slip faults northwest of the mountains. The Miocene is a time of great tectonic change that ushered in the modern tectonic regime.展开更多
In this study, a parameterization scheme based on Moderate Resolution Imaging Spectroradiometer (MODIS) data and in-situ data was tested for deriving the regional surface heating field over a heterogeneous landscape...In this study, a parameterization scheme based on Moderate Resolution Imaging Spectroradiometer (MODIS) data and in-situ data was tested for deriving the regional surface heating field over a heterogeneous landscape. As a case study, the methodology was applied to the whole Tibetan Plateau (TP) area. Four images of MODIS data (i.e., 30 January 2007, 15 April 2007, 1 August 2007, and 25 October 2007) were used in this study for comparison among winter, spring, summer, and autumn. The results were validated using the observations measured at the stations of the Tibetan Observation and Research Platform (TORP). The results show the following: (1) The derived surface heating field for the TP area was in good accord with the land-surface status, showing a wide range of values due to the strong contrast of surface features in the area. (2) The derived surface heating field for the TP was very close to the field measurements (observations). The APD (absolute percent difference) between the derived results and the field observations was 〈10%. (3) The mean surface heating field over the TP increased from January to April to August, and decreased in October. Therefore, the reasonable regional distribution of the surface heating field over a heterogeneous landscape can be obtained using this methodology. The limitations and further improvement of this method are also discussed.展开更多
This study was based on the CEOP/CAMP-Tibet observed data at AWS (Automatic Weather Station) of MS3478 in the seasonal frozen soil region of northern Tibetan Plateau from March 2007 to February 2008. The variation c...This study was based on the CEOP/CAMP-Tibet observed data at AWS (Automatic Weather Station) of MS3478 in the seasonal frozen soil region of northern Tibetan Plateau from March 2007 to February 2008. The variation characteristics of PE (potential evapotransph'ation) were analyzed based on the Penman-Monteith method recommended by FAO (the Food and Agriculture Organization of the United Na- lions). The contributions of dynamic, thermal and water factors to PE were discussed, and the wet-dry condition of the plateau region was further studied. The results indicated that daily PE was between 0.52 mm and 6.46 mm for the whole year. Monthly PE was over 107 mm from May to September, but decreased to less than 41 mm from November to February. Annual PE was 1,037.8mm. In the summer, thermal PE was significantly more than dynamic PE, but conversely in the winter. Annual variation of thermal PE was of sine wave pattern. In addition, drought and semi-drought climate lasted for a long time while semi-humid climate was short. The effect of water and dynamic factors on PE varied considerably with the seasons. Annual variation of thermal PE was of sine wave pattern.展开更多
The main objective of this study is to simulate the potential vegetation types on the basis of environmental parameters.The paper took Barkam County in a mountainous region of the Eastern Tibetan Plateau as the study ...The main objective of this study is to simulate the potential vegetation types on the basis of environmental parameters.The paper took Barkam County in a mountainous region of the Eastern Tibetan Plateau as the study area.The vegetation distribution was mapped in 1994 and 2007 based on TM remote sensing images by object-oriented interpretation method.We overlaid the two maps to find out the vegetation patches which have not changed,and took them as stable types.Fifty per cent of the stable patches were randomly sampled to operate the logistic regression with related environmental parameters;others were used as test data of simulated results.Seven environmental parameters were mapped,including elevation,slope,aspect,surface curvature,solar radiation,temperature and precipitation,based on DEM data and meteorological site data by GIS technology.The relationship between the spatial distribution of vegetation and environmental variables were quantified by logistic regression.The distribution probabilities of each vegetation type were calculated.Finally,the spatial distribution of potential vegetation was simulated.This research can provide a scientific basis for vegetation restoration and ecological construction in this area.展开更多
A regional climate model(RegCM4.3.4) coupled with an aerosol-snow/ice feedback module was used to simulate the deposition of anthropogenic light-absorbing impurities in snow/ice and the potential radiative feedback of...A regional climate model(RegCM4.3.4) coupled with an aerosol-snow/ice feedback module was used to simulate the deposition of anthropogenic light-absorbing impurities in snow/ice and the potential radiative feedback of black carbon(BC) on temperature and snow cover over the Tibetan Plateau(TP) in 1990-2009. Two experiments driven by ERA-interim reanalysis were performed, i.e., with and without aerosol-snow/ice feedback. Results indicated that the total deposition BC and organic matter(OM) in snow/ice in the monsoon season(MayeS eptember) were much more than non-monsoon season(the remainder of the year). The great BC and OM deposition were simulated along the margin of the TP in the non-monsoon season, and the higher deposition values also occurred in the western TP than the other regions during the monsoon period. BC-in-snow/ice decreased surface albedo and caused positive surface radiative forcing(SRF)(3.0-4.5 W m^(-2)) over the western TP in the monsoon season. The maximum SRF(5-6 W m^(-2)) simulated in the Himalayas and southeastern TP in the non-monsoon season. The surface temperature increased by 0.1-1.5℃ and snow water equivalent decreased by 5-25 mm over the TP, which showed similar spatial distributions with the variations of SRF in each season. This study provided a useful tool to investigate the mechanisms involved in the effect of aerosols on climate change and the water cycle in the cryospheric environment of the TP.展开更多
Early Miocene stratigraphy,major structural systems,magmatic emplacement,volcanic eruption,vegetation change and paleo-elevation were analyzed for the Tibetan Plateau after regional geological mapping at a scale of 1...Early Miocene stratigraphy,major structural systems,magmatic emplacement,volcanic eruption,vegetation change and paleo-elevation were analyzed for the Tibetan Plateau after regional geological mapping at a scale of 1:250,000 and related researches,revealing much more information for tectonic evolution and topographic change of the high plateau caused by Indian-Asian continental collision.Lacustrine deposits of dolostone,dolomite limestone,limestone,marl,sandstone and conglomerate of weak deformation formed extensively in the central Tibetan Plateau,indicating that vast lake complexes as large as 100,000-120,000 km2 existed in the central plateau during Early Miocene.Sporopoilen assemblages contained in the lacustrine strata indicate the disappearance of most tropical-subtropical broad-leaved trees since Early Miocene and the flourishing of dark needle-leaved trees during Early Miocene.Such vegetation changes adjusted for latitude and global climate variations demonstrate that the central Tibetan Plateau rose to ca.4,000-4,500 m and the northeastern plateau uplifted to ca.3,500-4,000 m before the Early Miocene.Intensive thrust and crustal thickening occurred in the areas surrounding central Tibetan Plateau in Early Miocene,formed Gangdise Thrust System (GTS) in the southern Lhasa block,Zedong-Renbu Thrust (ZRT) in the northern Himalaya block,Main Central Thrust (MCT) and Main Boundary Thrust (MBT) in the southern Himalaya block,and regional thrust systems in the Qaidam,Qilian,West Kunlun and Songpan-Ganzi blocks.Foreland basins formed in Early Miocene along major thrust systems,e.g.the Siwalik basin along MCT,Yalung-Zangbu Basin along GTS and ZRT,southwestern Tarim depression along West Kunlun Thrust,and large foreland basins along major thrust systems in the northeastern margin of the plateau.Intensive volcanic eruptions formed in the Qiangtang,Hoh-Xil and Kunlun blocks,porphyry granites and volcanic eruptions formed in the Nainqentanglha and Gangdise Mts.,and leucogranites and granites formed in the Himalaya and Longmenshan Mts.in Early Miocene.The K2O weight percentages of Early Miocene magmatic rocks in the Gangdise and Himlayan Mts.are found to increase with distance from the MBT,indicating the genetic relationship between regional magmatism and subduction of Indian continental plate in Early Miocene.展开更多
A large number of Eocene-Oligocene alkaline/alkali-rich igneous rocks were developed in the Tuotuohe region of the Qinghai-Tibetan Plateau.In this study,we present zircon U-Pb ages,Hf isotope data,and major and trace ...A large number of Eocene-Oligocene alkaline/alkali-rich igneous rocks were developed in the Tuotuohe region of the Qinghai-Tibetan Plateau.In this study,we present zircon U-Pb ages,Hf isotope data,and major and trace element compositions of the Cenozoic alkaline rocks from the Tuotuohe region in order to constraint the petrogenesis and tectonic evolution history of Qiangtang Block.Zircon U-Pb ages were measured via LA-ICP-MS to be39.6,37.6 and 32.0 Ma.The 39.6 Ma trachyte was characterized by low SiO2 and high K2O and MgO contents.The 37.6 and 32.0 Ma orthophyres show enrichment in SiO2 and K2O,but deficient in MgO.All of the samples belong to the alkaline rocks.These rocks display enrichment in REE,LREE,and LILE,depletion in HFSE,and no obvious Eu anomalies.Geological and geochemical features suggest that there were two possible mechanisms for the origin of the alkaline rocks in the Tuotuohe region:(1)the removed mafic lower crust dropped into the asthenosphere,forming the mix magma(Nariniya trachyte);(2)the upwelling asthenosphere triggered the crustal melting(Nariniya and Zamaqu orthophyre).The Eocene-Oligocene alkaline rocks in the study and adjacent areas are likely to be the result of the same tectonic-magmatic event of deep lithospheric evolution that is the crustal material melting triggered by lithospheric delamination.This conclusion extends the influence scope of lithospheric delamination eastward to the Tuotuohe region(*92°E)from Banda Co(*82°E).展开更多
利用第二次青藏高原科学考察及其他数据,结合5层网格嵌套、高分辨率(最高333 m)的WRF(Weather Research and Forecasting)可分辨云数值模拟,研究了局地山谷风环流在青藏高原东南林芝地区2019年9月17~18日一次地形云和降水形成过程中的...利用第二次青藏高原科学考察及其他数据,结合5层网格嵌套、高分辨率(最高333 m)的WRF(Weather Research and Forecasting)可分辨云数值模拟,研究了局地山谷风环流在青藏高原东南林芝地区2019年9月17~18日一次地形云和降水形成过程中的作用。结果表明,此次降水过程由西风槽天气过境造成,林芝位于西风槽底部,具有弱不稳定层结,云和降水过程呈现明显的午后、傍晚和凌晨三个阶段的变化特征,并且发现局地山谷风环流在这三个阶段的变化中具有重要作用。午后阶段,由于山区强烈的太阳辐射加热,首先产生明显的上坡风和强上谷风环流,在山坡迎风坡受阻挡抬升,并激发出强的地形波,产生了强对流云和降水;傍晚阶段,由于山脉强烈的长波辐射冷却效应,产生的强下坡风在谷底辐合抬升,促进了山谷上空的弱对流、层状云发展;凌晨阶段,下坡风达到最强,产生了强下谷风环流(山风),下坡风在谷底产生强烈的抬升作用,形成深厚的层状云降水过程。展开更多
There is no temperature effect in the southern Tibetan Plateau and South Asia to the south of the Tanggula Mountains. Amount effect has been observed at a few sampling stations accounting for about a half of the stati...There is no temperature effect in the southern Tibetan Plateau and South Asia to the south of the Tanggula Mountains. Amount effect has been observed at a few sampling stations accounting for about a half of the statistical stations. There is notable temperature effect in the middle and northern Tibetan Plateau and its adjacent Central Asia to the north of the Tanggula Mountains. Because vapor directly originates from low-latitude oceans, the relative heavy ( 18O with small variation characterizes the rainfall in South Asia. A sharp depletion of the stable isotopic compositions in precipitation takes place from Kyangjin on the southern slope of the Himalayas to the Tanggula Mountains in the middle plateau. From the Tanggula Mountains to the northern Tibetan Plateau, the ( 18O in precipitation increases with increasing latitude.展开更多
基金supported by the National Natural Science Foundation of China,under the project entitled“The study of land-atmosphere water and heat flux interaction over the complex terrain of the north and south slopes of the Qomolangma region"[grant number 42230610]a Ministry of Science and Technology of China project called“Landatmosphere interaction and its climate effect of the Second Tibetan Plateau Scientific Expedition and Research Program"[grant number 2019QzKK0103]the Youth Innovation Promotion Association of the Chinese Academy of Sciences[2022069].
文摘正确认识不同区域能量和水分循环特征是研究局地地气相互作用及准确预测区域天气,气候变化的关键.为了研究属于干旱/半干旱气候的青藏高原(TP)和湿润/半湿润气候的长江流域(YRR)之间地表能量和水分交换的异同,本文对比分析了两个区域8个不同地表类型(包括高山荒漠,高山草地,(平原)城市和(平原)草地等)观测站点的地表辐射和能量通量数据.结果显示:(1)TP由于高原大气层稀薄且空气洁净,年平均入射短波辐射为251.3W m^(-2),是YRR的1.7倍.加之高原地表反照率高导致反射辐射(59.6 W m^(-2))是YRR的2.87倍.入射及出射的长波辐射为231.5和338.0 W m^(-2),分别为YRR的0.64和0.83.而两个区域的净辐射差异不大;(2)草地站更多的潜热释放使得地表总加热效率高于城市和高山荒漠,TP和YRR的草地站的年平均潜热分别为35.0和38.8 W m^(-2),而植被稀疏且土壤干燥的高山荒漠地区感热最大,年平均感热为42.1 W m^(-2);其次是城市下垫面,其年平均感热为37.7 W m^(-2).研究结果揭示了不同气候背景下典型下垫面地气相互作用特征,为地气相互作用过程深入分析奠定了基础.
基金supported by a geological survey project of the China Geological Survey (No.1212011140013, No.12120113009800)
文摘The Wenchuan earthquake has altered the crustal motion characteristics in the eastern margin of the Tibetan Plateau and adjacent regions.Using discontinuous GPS survey data for 2008–2012, the velocity field for the Eurasia reference framework has been obtained, and the general trend of contemporary crustal motion after the occurrence of the Wenchuan earthquake has been studied.In addition, using the velocity field, the block movement velocity has been estimated by least-squares fitting.Furthermore, the properties and displacement rates of main faults have been obtained from the differences in velocity vectors of the blocks on both sides of the faults.The results reveal that there are no obvious changes in the general characteristics of crustal motion in this area after the Wenchuan earthquake.The earthquake mainly changed the rate of the movement of the Chuan-Qing block and caused variation in the movement direction of the South China block.The effect of the earthquake on faults is mainly reflected in variations in fault displacement velocity; there is no fundamental change in the properties of fault activity.The displacement rates of the Xianshuihe fault decreased by 3–4 mm/a, the Longmenshan fault increased by 9–10 mm/a, and the northern segment of the Anninghe fault increased by approximately 9 mm/a.Furthermore, the displacement rates of the Minjiang, Xueshan, Huya, Longquanshan, and Xinjin faults increased by 2–3 mm/a.This implies that the effects of the Wenchuan earthquake on crustal movement can mainly be observed in the Chuan-Qing, South China, and N-Chuan-Dian blocks and their internal faults, as well as the Xianshuihe and Longmenshan faults and the northern section of the Anninghe fault.The reason for this is that the Wenchuan earthquake disturbed the kinematic and dynamic balance in the region.
基金supported by the National Natural Science Foundation of China (40601056, 40121101)the Special Funds for Major State Basic Research Project (2009CB723901)+4 种基金the Special Science Foundation on Meteorological Project Research for Public Benefit (GYHY(QX)2007-6-18)the Survey Project on Glacier resources and their changes in China (No.2006FY110200)the Opening Fund projects of State Key Laboratory of Remote Sensing Science in the Institute of Remote Sensing Applicationsthe innovative project of Institute of Tibetan Plateau Research (ITPR),CASthrough a cooperation project between the Climate Change Institute, University of Maine supported by the National Oceanic and Atmospheric Administration (NA04OAR4600179) and the Institute of Tibetan Plateau Research (ITPR), CAS
文摘Because of the large number and remoteness, satellite data, including microwave data and optical imagery, have commonly been used in alpine glaciers surveys. Using remote sensing and Geographical Information System (GIS) techniques the paper presents the results of a multitempora satellite glacier extent mapping and glacier changes by glacier sizes in the Mt. Qomolangma region at the northern slopes of the middle Himalayas over the Tibetan Plateau. Glaciers in this region have both retreated and advanced in the past 35 years, with retreat dominating. The glacier retreat area was 3.23 km2 (or 0.75 km2 yr-1) during 1974 and 1976, 8.68 km2 (or 0.36 km2 yr-1) during 1976 and 1992, 1.44 km2 (or 0.12 km2 yr-1) during 1992-2000. 1.14 km2 (or 0.22 km2 yr-1) during 2000-2003, and 0.52 km2 (or 0.07 km2 yr-1) during 2003-2008, respectively. While supra-glacier lakes on the debris-terminus of the Rongbuk Glacier were enlarged dramatically at the same time, from 0.05 km2 in 1974 increased to 0.71 km2 in 2008, which was more than 13 times larger in the last 35 years. In addition, glacier changes also showed spatial differences, for example, glacier retreat rate was the fastest at glacier termini between 5400 and 5700 m a.s.l than at other elevations. The result also shows that glaciers in the middle Himalayas retreat almost at a same pace with those in the western Himalayas.
文摘Dextral-slip in the Nyainqentanglha region of Tibet resulted in oblique underthrusting and granite generation in the Early to Middle Miocene, but by the end of the epoch uplift and extensional faulting dominated. The east-west dextral-slip Gangdise fault system merges eastward into the northeast-trending, southeast-dipping Nyainqentanglha thrust system that swings eastward farther north into the dextral-slip North Damxung shear zone and Jiali faults. These faults were took shape by the Early Miocene, and the large Nyainqentanglha granitic batholith formed along the thrust system in 18.3-11.0 Ma as the western block drove under the eastern one. The dextral-slip movement ended at -11 Ma and the batholith rose, as marked by gravitational shearing at 8.6-8.3 Ma, and a new fault system developed. Northwest-trending dextral-slip faults formed to the northwest of the raisen batholith, whereas the northeast-trending South Damxung thrust faults with some sinistral-slip formed to the southeast. The latter are replaced farther to the east by the west-northwest-trending Lhtinzhub thrust faults with dextral-slip. This relatively local uplift that left adjacent Eocene and Miocene deposits preserved was followed by a regional uplift and the initiation of a system of generally north-south grabens in the Late Miocene at -6.5 Ma. The regional uplift of the southern Tibetan Plateau thus appears to have occurred between 8.3 Ma and 6.5 Ma. The Gulu, DamxungYangbajain and Angan graben systems that pass east of the Nyainqentanglha Mountains are locally controlled by the earlier northeast-trending faults. These grabens dominate the subsequent tectonic movement and are still very active as northwest-trending dextral-slip faults northwest of the mountains. The Miocene is a time of great tectonic change that ushered in the modern tectonic regime.
基金performed under the auspices of the Chinese National Key Programme for Developing Basic Sciences (Grant No. 2010CB951701)the Innovation Projects of the Chinese Academy of Sciences (Grant No. KZCX2-YW-Q11-01)+1 种基金the National Natural Science Foundation of China (Grant Nos. 40825015and 40810059006)EU-FP7 project "CEOP-AEGIS"(Grant No. 212921)
文摘In this study, a parameterization scheme based on Moderate Resolution Imaging Spectroradiometer (MODIS) data and in-situ data was tested for deriving the regional surface heating field over a heterogeneous landscape. As a case study, the methodology was applied to the whole Tibetan Plateau (TP) area. Four images of MODIS data (i.e., 30 January 2007, 15 April 2007, 1 August 2007, and 25 October 2007) were used in this study for comparison among winter, spring, summer, and autumn. The results were validated using the observations measured at the stations of the Tibetan Observation and Research Platform (TORP). The results show the following: (1) The derived surface heating field for the TP area was in good accord with the land-surface status, showing a wide range of values due to the strong contrast of surface features in the area. (2) The derived surface heating field for the TP was very close to the field measurements (observations). The APD (absolute percent difference) between the derived results and the field observations was 〈10%. (3) The mean surface heating field over the TP increased from January to April to August, and decreased in October. Therefore, the reasonable regional distribution of the surface heating field over a heterogeneous landscape can be obtained using this methodology. The limitations and further improvement of this method are also discussed.
基金the funding received from the National Key Programme for Developing Basic Sciences of China (2010CB951701)Knowledge Innovation Program of the Chinese Academy of Sciences (KZCX2-YW-Q11-01)+3 种基金Natural Science Foundation of China (40875005)Natural Science Foundation of China for International Cooperation (40810059006)European Commission CEOP-AEGIS (Call FP7-ENV-2007-1 Grant No. 212921)Gansu Science and Technology Key Project (1001JKDA001)
文摘This study was based on the CEOP/CAMP-Tibet observed data at AWS (Automatic Weather Station) of MS3478 in the seasonal frozen soil region of northern Tibetan Plateau from March 2007 to February 2008. The variation characteristics of PE (potential evapotransph'ation) were analyzed based on the Penman-Monteith method recommended by FAO (the Food and Agriculture Organization of the United Na- lions). The contributions of dynamic, thermal and water factors to PE were discussed, and the wet-dry condition of the plateau region was further studied. The results indicated that daily PE was between 0.52 mm and 6.46 mm for the whole year. Monthly PE was over 107 mm from May to September, but decreased to less than 41 mm from November to February. Annual PE was 1,037.8mm. In the summer, thermal PE was significantly more than dynamic PE, but conversely in the winter. Annual variation of thermal PE was of sine wave pattern. In addition, drought and semi-drought climate lasted for a long time while semi-humid climate was short. The effect of water and dynamic factors on PE varied considerably with the seasons. Annual variation of thermal PE was of sine wave pattern.
基金The National Key Technology Research and Development ProgramExternal Cooperation Program of the Chinese Academy of Sciences[grant number GJHZ0954]+1 种基金National Basic Research Program of China[grant number 2005CB422006]National Natural Science Foundation of China[grant number 40901057]
文摘The main objective of this study is to simulate the potential vegetation types on the basis of environmental parameters.The paper took Barkam County in a mountainous region of the Eastern Tibetan Plateau as the study area.The vegetation distribution was mapped in 1994 and 2007 based on TM remote sensing images by object-oriented interpretation method.We overlaid the two maps to find out the vegetation patches which have not changed,and took them as stable types.Fifty per cent of the stable patches were randomly sampled to operate the logistic regression with related environmental parameters;others were used as test data of simulated results.Seven environmental parameters were mapped,including elevation,slope,aspect,surface curvature,solar radiation,temperature and precipitation,based on DEM data and meteorological site data by GIS technology.The relationship between the spatial distribution of vegetation and environmental variables were quantified by logistic regression.The distribution probabilities of each vegetation type were calculated.Finally,the spatial distribution of potential vegetation was simulated.This research can provide a scientific basis for vegetation restoration and ecological construction in this area.
基金supported by National Nature Science Foundation of China (41301061)Chinese Academy of Sciences (KJZD-EW-G03-04)China Meteorological Administration Special Public Welfare Research Fund (GYHY201306019)
文摘A regional climate model(RegCM4.3.4) coupled with an aerosol-snow/ice feedback module was used to simulate the deposition of anthropogenic light-absorbing impurities in snow/ice and the potential radiative feedback of black carbon(BC) on temperature and snow cover over the Tibetan Plateau(TP) in 1990-2009. Two experiments driven by ERA-interim reanalysis were performed, i.e., with and without aerosol-snow/ice feedback. Results indicated that the total deposition BC and organic matter(OM) in snow/ice in the monsoon season(MayeS eptember) were much more than non-monsoon season(the remainder of the year). The great BC and OM deposition were simulated along the margin of the TP in the non-monsoon season, and the higher deposition values also occurred in the western TP than the other regions during the monsoon period. BC-in-snow/ice decreased surface albedo and caused positive surface radiative forcing(SRF)(3.0-4.5 W m^(-2)) over the western TP in the monsoon season. The maximum SRF(5-6 W m^(-2)) simulated in the Himalayas and southeastern TP in the non-monsoon season. The surface temperature increased by 0.1-1.5℃ and snow water equivalent decreased by 5-25 mm over the TP, which showed similar spatial distributions with the variations of SRF in each season. This study provided a useful tool to investigate the mechanisms involved in the effect of aerosols on climate change and the water cycle in the cryospheric environment of the TP.
基金supported by the China Geological Survey under grants Nos.1212011120185 and 1212011221111the Ministry of Science and Technology of China under grant 2006DFB21330
文摘Early Miocene stratigraphy,major structural systems,magmatic emplacement,volcanic eruption,vegetation change and paleo-elevation were analyzed for the Tibetan Plateau after regional geological mapping at a scale of 1:250,000 and related researches,revealing much more information for tectonic evolution and topographic change of the high plateau caused by Indian-Asian continental collision.Lacustrine deposits of dolostone,dolomite limestone,limestone,marl,sandstone and conglomerate of weak deformation formed extensively in the central Tibetan Plateau,indicating that vast lake complexes as large as 100,000-120,000 km2 existed in the central plateau during Early Miocene.Sporopoilen assemblages contained in the lacustrine strata indicate the disappearance of most tropical-subtropical broad-leaved trees since Early Miocene and the flourishing of dark needle-leaved trees during Early Miocene.Such vegetation changes adjusted for latitude and global climate variations demonstrate that the central Tibetan Plateau rose to ca.4,000-4,500 m and the northeastern plateau uplifted to ca.3,500-4,000 m before the Early Miocene.Intensive thrust and crustal thickening occurred in the areas surrounding central Tibetan Plateau in Early Miocene,formed Gangdise Thrust System (GTS) in the southern Lhasa block,Zedong-Renbu Thrust (ZRT) in the northern Himalaya block,Main Central Thrust (MCT) and Main Boundary Thrust (MBT) in the southern Himalaya block,and regional thrust systems in the Qaidam,Qilian,West Kunlun and Songpan-Ganzi blocks.Foreland basins formed in Early Miocene along major thrust systems,e.g.the Siwalik basin along MCT,Yalung-Zangbu Basin along GTS and ZRT,southwestern Tarim depression along West Kunlun Thrust,and large foreland basins along major thrust systems in the northeastern margin of the plateau.Intensive volcanic eruptions formed in the Qiangtang,Hoh-Xil and Kunlun blocks,porphyry granites and volcanic eruptions formed in the Nainqentanglha and Gangdise Mts.,and leucogranites and granites formed in the Himalaya and Longmenshan Mts.in Early Miocene.The K2O weight percentages of Early Miocene magmatic rocks in the Gangdise and Himlayan Mts.are found to increase with distance from the MBT,indicating the genetic relationship between regional magmatism and subduction of Indian continental plate in Early Miocene.
基金supported by the National Basic Research Program of China[grant numbers 2016YFC0202001 and 973Program 2014CB441200]the National Natural Science Foundation of China[grant numbers 41375036 and41305076]
基金supported by Dr. Huo Liang, College of Earth Science, Jilin Universitysupported by colleagues in Qinghai Geological Survey+1 种基金the Qinghai Fifth Geological and Mineral Exploration Institutefunded by the National Natural Science Foundation of China (Grant No. 41402060)
文摘A large number of Eocene-Oligocene alkaline/alkali-rich igneous rocks were developed in the Tuotuohe region of the Qinghai-Tibetan Plateau.In this study,we present zircon U-Pb ages,Hf isotope data,and major and trace element compositions of the Cenozoic alkaline rocks from the Tuotuohe region in order to constraint the petrogenesis and tectonic evolution history of Qiangtang Block.Zircon U-Pb ages were measured via LA-ICP-MS to be39.6,37.6 and 32.0 Ma.The 39.6 Ma trachyte was characterized by low SiO2 and high K2O and MgO contents.The 37.6 and 32.0 Ma orthophyres show enrichment in SiO2 and K2O,but deficient in MgO.All of the samples belong to the alkaline rocks.These rocks display enrichment in REE,LREE,and LILE,depletion in HFSE,and no obvious Eu anomalies.Geological and geochemical features suggest that there were two possible mechanisms for the origin of the alkaline rocks in the Tuotuohe region:(1)the removed mafic lower crust dropped into the asthenosphere,forming the mix magma(Nariniya trachyte);(2)the upwelling asthenosphere triggered the crustal melting(Nariniya and Zamaqu orthophyre).The Eocene-Oligocene alkaline rocks in the study and adjacent areas are likely to be the result of the same tectonic-magmatic event of deep lithospheric evolution that is the crustal material melting triggered by lithospheric delamination.This conclusion extends the influence scope of lithospheric delamination eastward to the Tuotuohe region(*92°E)from Banda Co(*82°E).
文摘利用第二次青藏高原科学考察及其他数据,结合5层网格嵌套、高分辨率(最高333 m)的WRF(Weather Research and Forecasting)可分辨云数值模拟,研究了局地山谷风环流在青藏高原东南林芝地区2019年9月17~18日一次地形云和降水形成过程中的作用。结果表明,此次降水过程由西风槽天气过境造成,林芝位于西风槽底部,具有弱不稳定层结,云和降水过程呈现明显的午后、傍晚和凌晨三个阶段的变化特征,并且发现局地山谷风环流在这三个阶段的变化中具有重要作用。午后阶段,由于山区强烈的太阳辐射加热,首先产生明显的上坡风和强上谷风环流,在山坡迎风坡受阻挡抬升,并激发出强的地形波,产生了强对流云和降水;傍晚阶段,由于山脉强烈的长波辐射冷却效应,产生的强下坡风在谷底辐合抬升,促进了山谷上空的弱对流、层状云发展;凌晨阶段,下坡风达到最强,产生了强下谷风环流(山风),下坡风在谷底产生强烈的抬升作用,形成深厚的层状云降水过程。
基金This work was supported by the National Key Research Project (Grant No. 1998040802) the CASKnowledge Innovation Program (Grant No. KZCX2-301), CAREERI Foundation (Grant No. TZ2000-02) and LICCRE Program (Grant No. BX2001-3).
文摘There is no temperature effect in the southern Tibetan Plateau and South Asia to the south of the Tanggula Mountains. Amount effect has been observed at a few sampling stations accounting for about a half of the statistical stations. There is notable temperature effect in the middle and northern Tibetan Plateau and its adjacent Central Asia to the north of the Tanggula Mountains. Because vapor directly originates from low-latitude oceans, the relative heavy ( 18O with small variation characterizes the rainfall in South Asia. A sharp depletion of the stable isotopic compositions in precipitation takes place from Kyangjin on the southern slope of the Himalayas to the Tanggula Mountains in the middle plateau. From the Tanggula Mountains to the northern Tibetan Plateau, the ( 18O in precipitation increases with increasing latitude.