In this paper, an updated vegetation map of the permafrost zone in the Qinghai-Tibet Plateau （QTP） was delineated. The vegetation map model was extracted from vegetation sampling with remote sensing （RS） datasets ...In this paper, an updated vegetation map of the permafrost zone in the Qinghai-Tibet Plateau （QTP） was delineated. The vegetation map model was extracted from vegetation sampling with remote sensing （RS） datasets by decision tree method. The spatial resolution of the map is 1 km×1 kin, and in it the alpine swamp meadow is firstly distinguished in the high-altitude areas. The results showed that the total vegetated area in the permafrost zone of the QTP is 1,201,751 km2. In the vegetated region, 50,260 km2 is the areas of alpine swamp meadow, 583,909 km2 for alpine meadow, 332,754 km2 for alpine steppe, and 234,828 km2 for alpine desert. This updated vegetation map in permafrost zone of QTP could provide more details about the distribution of alpine vegetation types for studying the vegetation mechanisms in the land surface processes of highaltitude areas.展开更多
Two models are used to simulate the high-altitude permafrost distribution on the Qinghai-Xizang Plateau. The two models are the “altitude model”, a Gaussian distribution function used to describe the latitudinal zon...Two models are used to simulate the high-altitude permafrost distribution on the Qinghai-Xizang Plateau. The two models are the “altitude model”, a Gaussian distribution function used to describe the latitudinal zonation of permafrost based on the three-dimensional rules of high-altitude permafrost, and the “frost number model”, a dimensionless ratio defined by manipulation of freezing and thawing degree-day sums. The results show that the “altitude model” can simulate the high-altitude permafrost distribution under present climate conditions accurately. Given the essential hypotheses and using the GCM scenarios from HADCM2, the “altitude model” is used for predicting the permafrost distribution change on the Qinghai-Xizang Plateau. The results show that the permafrost on the plateau will not change significantly during 20–50 a, the percentage of the total disappeared area will not be over 19%. However, by the year 2099, if the air temperature increases by an average of 2.91°C on the plateau, the decrease in the area of permafrost will exceed 58%—almost all the permafrost in the southern plateau and in the eastern plateau will disappear.展开更多
Maca （Lepidium meyenii Walp, 2n = 8x = 64）, belonging to the Brassicaceae family, is an economic plant cultivated in the central Andes sierra in Peru （4000-4500 m）. Considering that the rapid uplift of the central...Maca （Lepidium meyenii Walp, 2n = 8x = 64）, belonging to the Brassicaceae family, is an economic plant cultivated in the central Andes sierra in Peru （4000-4500 m）. Considering that the rapid uplift of the central Andes occurred 5-10 million years ago （Ma）, an evolutionary question arises regarding how plants such as maca acquire high-altitude adaptation within a short geological period. Here, we report the high-quality genome assembly of maca, in which two closely spaced maca-specific whole-genome duplications （WGDs; ~6.7 Ma） were identified. Comparative genomic analysis between maca and closely related Brassicaceae species revealed expansions of maca genes and gene families involved in abiotic stress response, hormone signaling pathway, and secondary metabolite biosynthesis via WGDs. The retention and subsequent functional divergence of many duplicated genes may account for the morphological and physiological changes （i.e., small leaf shape and self-fertility） in maca in a high-altitude environment. In addition, some duplicated maca genes were identified with functions in morphological adaptation （i.e., LEAF CURLING RESPONSIVENESS） and abiotic stress response （i.e., GL YClNE-RICH RNA-BINDING PROTEINS and DNA-DAMAGE-REPAIR/TOLERATION2） under positive selection. Collectively, the maca genome provides use- ful information to understand the important roles of WGDs in the high-altitude adaptation of plants in the Andes.展开更多
Long-runout rockslides at high altitude could cause disaster chain in river basins and destroy towns and major infrasturctures.This paper firstly explores the initiation mechanism of high-altitude and long-runout rock...Long-runout rockslides at high altitude could cause disaster chain in river basins and destroy towns and major infrasturctures.This paper firstly explores the initiation mechanism of high-altitude and long-runout rockslides.Two types of sliding-prone geostructure models,i.e.the fault control type in orogenic belt and the fold control type in platform area,are proposed.Then,large-scale experimental apparatus and associated numerical simulations are conducted to understanding the chain-style dynamics of rockslide-debris avalanche-debris flow.The results reveal the fragmentation effects,the rheological behaviors and the boundary layer effect of long-runout avalanche-debris flow.The dynamic character-istics of quasi-static-transition-inertia state and solid-liquid coupling in rapid movement of rockslide-debris avalanche-debris flow are investigated.Finally,the risk mitigation strategy of the non-structure and structure for resilient energy dissipation are illustrated for initiation,transition and deposition zones.The structural prevention and mitigation methods have been successfully applied to the high-altitude and long-runout rockslides in Zhouqu and Maoxian of the Wenchuan earthquake zone,as well as the other major geohazards in Qinghai-Tibet Plateau and its adjacent areas.展开更多
基金supported by the National Natural Science Foundation of China (Grant No.41101055)the Hundred Talents Program of the Chinese Academy of Sciences granted to Tonghua Wu (Grant No.51Y251571)the “National Basic Research Program of China (973 Program)” (Grant No.2010CB951402)
文摘In this paper, an updated vegetation map of the permafrost zone in the Qinghai-Tibet Plateau （QTP） was delineated. The vegetation map model was extracted from vegetation sampling with remote sensing （RS） datasets by decision tree method. The spatial resolution of the map is 1 km×1 kin, and in it the alpine swamp meadow is firstly distinguished in the high-altitude areas. The results showed that the total vegetated area in the permafrost zone of the QTP is 1,201,751 km2. In the vegetated region, 50,260 km2 is the areas of alpine swamp meadow, 583,909 km2 for alpine meadow, 332,754 km2 for alpine steppe, and 234,828 km2 for alpine desert. This updated vegetation map in permafrost zone of QTP could provide more details about the distribution of alpine vegetation types for studying the vegetation mechanisms in the land surface processes of highaltitude areas.
基金Project "Fundamental Research of Cryosphere" supported by the Chinese Academy of Sciences.
文摘Two models are used to simulate the high-altitude permafrost distribution on the Qinghai-Xizang Plateau. The two models are the “altitude model”, a Gaussian distribution function used to describe the latitudinal zonation of permafrost based on the three-dimensional rules of high-altitude permafrost, and the “frost number model”, a dimensionless ratio defined by manipulation of freezing and thawing degree-day sums. The results show that the “altitude model” can simulate the high-altitude permafrost distribution under present climate conditions accurately. Given the essential hypotheses and using the GCM scenarios from HADCM2, the “altitude model” is used for predicting the permafrost distribution change on the Qinghai-Xizang Plateau. The results show that the permafrost on the plateau will not change significantly during 20–50 a, the percentage of the total disappeared area will not be over 19%. However, by the year 2099, if the air temperature increases by an average of 2.91°C on the plateau, the decrease in the area of permafrost will exceed 58%—almost all the permafrost in the southern plateau and in the eastern plateau will disappear.
文摘Maca （Lepidium meyenii Walp, 2n = 8x = 64）, belonging to the Brassicaceae family, is an economic plant cultivated in the central Andes sierra in Peru （4000-4500 m）. Considering that the rapid uplift of the central Andes occurred 5-10 million years ago （Ma）, an evolutionary question arises regarding how plants such as maca acquire high-altitude adaptation within a short geological period. Here, we report the high-quality genome assembly of maca, in which two closely spaced maca-specific whole-genome duplications （WGDs; ~6.7 Ma） were identified. Comparative genomic analysis between maca and closely related Brassicaceae species revealed expansions of maca genes and gene families involved in abiotic stress response, hormone signaling pathway, and secondary metabolite biosynthesis via WGDs. The retention and subsequent functional divergence of many duplicated genes may account for the morphological and physiological changes （i.e., small leaf shape and self-fertility） in maca in a high-altitude environment. In addition, some duplicated maca genes were identified with functions in morphological adaptation （i.e., LEAF CURLING RESPONSIVENESS） and abiotic stress response （i.e., GL YClNE-RICH RNA-BINDING PROTEINS and DNA-DAMAGE-REPAIR/TOLERATION2） under positive selection. Collectively, the maca genome provides use- ful information to understand the important roles of WGDs in the high-altitude adaptation of plants in the Andes.
基金This work was financially supported by National Natural Science Foundation of China(Grant Nos.U2244226,U2244227 and 42177172).
文摘Long-runout rockslides at high altitude could cause disaster chain in river basins and destroy towns and major infrasturctures.This paper firstly explores the initiation mechanism of high-altitude and long-runout rockslides.Two types of sliding-prone geostructure models,i.e.the fault control type in orogenic belt and the fold control type in platform area,are proposed.Then,large-scale experimental apparatus and associated numerical simulations are conducted to understanding the chain-style dynamics of rockslide-debris avalanche-debris flow.The results reveal the fragmentation effects,the rheological behaviors and the boundary layer effect of long-runout avalanche-debris flow.The dynamic character-istics of quasi-static-transition-inertia state and solid-liquid coupling in rapid movement of rockslide-debris avalanche-debris flow are investigated.Finally,the risk mitigation strategy of the non-structure and structure for resilient energy dissipation are illustrated for initiation,transition and deposition zones.The structural prevention and mitigation methods have been successfully applied to the high-altitude and long-runout rockslides in Zhouqu and Maoxian of the Wenchuan earthquake zone,as well as the other major geohazards in Qinghai-Tibet Plateau and its adjacent areas.
