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| 1 | The relationship between NDVI and precipitation on the Tibetan Plateau显示文摘西藏的高原上的 NDVI 的时间、空间的变化,以及在 NDVI 和降水之间的关系,在这份报纸被讨论,由使用 8-km 分辨率从 1982 ~ 1999 的多时间的 NOAA AVHRR-NDVI 数据。每月最大的 NDVI 和每月的降雨被用来分析季节的变化,和年度最大值 NDVI,年度有效降水和成长季节降水(从 4 月到 8 月) 被用来讨论 interannual 变化。在 NDVI 和降雨之间的 NDVI 和关联系数的动态变化为每个象素被计算。结果如下:(1 ) NDVI 在种季节到达了山峰(从 7 月到 9 月) 在西藏的高原上。在高原的北、西方的部分,成长季节是很短的(大约二或三个月) ;但是在里面南部,植被几乎所有一年周围成长了。每月最大的 NDVI 和每月的降雨的关联在不同区域变化了。它在西方、北、南部的部分是弱的,但是在中央、东方的部分强壮。(2 ) NDVI interannual 的空间分发动态变化也是不同的。增加区域主要在南部的西藏山区的灌木大草原地区,西方的四川东方的西藏山区的具球果的森林地区的西方的部分, Kunlun 山区的荒芜的地区的北斜坡的西方的部分和 Himalaya 的南部的斜坡的东南的部分被散布山区常绿树阔叶的森林地区;减少区域主要在 Qaidam 山区的荒芜的地区,东方 Qinghai-Qilian 山区的大草原地区的西方、北的部分,南部的 Qinghai 高冷的草地大草原地区和 Ngari 被散布山区的荒芜大草原、荒芜的地区。在年度有效降雨和年度最大的 NDVI 之间的关联系数的空间分发类似于成长季节降雨和年度最大的 NDVI ,并且与中等植被盖子在草地和草地在 NDVI 和降雨之间有好关系,并且植被上的降雨的效果在森林和荒芜的区域里是小的。 | DING Mingjun ZHANG Yili LIU Linshan ZHANG Wei WANG Zhaofeng BAI Wanqi | 2007 | Journal of Geographical Sciences2007，17，3： | 45 |
| 2 | Extreme drought changes in Southwest China from 1960 to 2009显示文摘从 1960 ~ 2009 在西南中国基于温度的每日的数据和 108 个气象学的车站的降水,我们计算每月、每年的表面潮湿的索引,以及极端干旱频率。根据数据,极端干旱频率在的时间、空间的特征内部年度,内部十,夏天季风时期和冬季季风时期被分析。结果如下被显示。(1 ) 一般来说,西南的四川盆,南部的 Hengduan 山, Guangxi 的南部的海岸和北贵州是极端干旱频率显著地在过去的 50 年里增加了的区域。至于十的变化,从 1960 年代,到 1980 年代,极端干旱频率介绍了一个减少的趋势,当 1990 年代是最湿的十年,整个区域正在变得湿时。在 2000 年代,极端干旱频率快速升起,但是地区性的差别还原剂。(2 ) 在夏天季风时期期间,干旱频率正在成长的极端,通常在四川盆附近发生在高山,最在云南 Guangxi 和塑造扫帚的山分开。高度在极端干旱频率上有影响,是不同的;在冬季季风时期期间,区域是相对湿的,极端干旱频率正在减少。(3 ) 在夏天季风时期期间,突然的变化在 2003 被观察,而突然的变化在冬季季风时期期间在 1989。年度极端干旱频率变化在夏天季风和冬季季风时期期间是突然的变化的重叠。年度极端干旱频率的离开顺序颤动是 quasi-5 年和 quasi-12 年。 | ZHANG Mingjun HE Jinyun WANG Baolong WANG Shengjie LI Shanshan LIU Wenli MA Xuening | 2013 | Journal of Geographical Sciences2013，23，1： | 43 |
| 3 | Spatiotemporal variation in alpine grassland phenology in the Qinghai-Tibetan Plateau from 1999 to 2009显示文摘Plant phenology is the most salient and sensitive indicator of terrestrial ecosystem response to climate change.Studying its change is significantly important in understanding and predicting impressively changes in terrestrial ecosystem.Based on NDVI from SPOT VGT,this paper analyzed the spatiotemporal changes in alpine grassland phenology in Qinghai-Tibetan Plateau from 1999 to 2009.The results are enumerated as follows:(1) The spatial distribution of the average alpine grassland phenology from 1999 to 2009 is closely related to water and heat conditions.Accompanying the deterioration in heat and water conditions from southeast to northwest,the start of growth season(SOG) was delayed gradually,the end of growth season(EOG) advanced slowly,and the length of growth season(LOG) shortened gradually.Elevation played an important role in the regional differentiation of phenology,but a dividing line of approximately 3500 m existed.Below this line,the phenology fluctuated irregularly with altitude change,whereas above the line,the phenology is closely related to altitude change.(2) From 1999 to 2009,SOG of the alpine grassland came earlier by six days per decade(R2=0.281,P=0.093),EOG was late by two days per decade(R2=0.031,P=0.605),and LOG lengthened by eight days per decade(R2=0.479,P=0.018).The early SOG,the late EOG,and the extended LOG mainly occurred at the center and east of the Plateau.SOG in most of the Plateau advanced significantly,especially in the eastern Plateau.(3) The inter-annual phenology changes of the alpine grassland in the Qinghai-Tibetan Plateau exhibited significant differentiation at different elevation and natural zones.The inter-annual changes at high altitude were more complicated than that at low altitude.The most significant phenology changes were found in the eastern Qinghai-Qilian montane steppe zone,and non-significant changes occurred in the Southern Tibet montane shrub-steppe zone. | DING MingJun ZHANG YiLi SUN XiaoMin LIU LinShan WANG ZhaoFeng BAI WanQi | 2013 | Chinese Science Bulletin2013，58，3： | 44 |
| 4 | Spatial and temporal variability in the net primary production of alpine grassland on the Tibetan Plateau since 1982显示文摘基于 GIMMS AVHRR NDVI 数据( 8 km 空间分辨率)为 19822000 , SPOT 植被 NDVI 数据( 1 km 空间分辨率)为 19982009 ,并且观察植物生物资源数据, CASA 模型习惯于在高山的草地的变化在西藏的高原( TP )上让主要生产( NPP )赚的模型。这研究将帮助评估高山的草地生态系统的健康条件,并且对高原牧场并且到 TP 上的国家生态的安全躲蔽处的函数的理解的持续开发的提升很重要。NPP 变化的时间空间的特征用空间统计分析被调查,独立根据 physico 地理的因素(自然地区,高度,纬度和经度) ,河盆,和县级的行政区域。处理的数据用一个 ENVI 4.8 平台被执行,当一个 ArcGIS 9.3 和 ANUSPLIN 平台被用来进行空间分析并且印射时。主要结果如下:(1 ) TP 上的高山的草地的 NPP 逐渐地从东南减少到西北,它在降水和温度对应于坡度。从 1982 ~ 2009,在 TP 高山的草地的平均年度全部的 NPP 是 177.2 ?? ?? ? | ZHANG Yili QI Wei ZHOU Caiping DING Mingjun LIU Linshan GAO Jungang BAI Wanqi WANG Zhaofeng ZHENG Du | 2014 | Journal of Geographical Sciences2014，24，2： | 47 |
| 5 | Glacier area variation and climate change in the Chinese Tianshan Mountains since 1960显示文摘基于自从 1960,在中国 Tianshan 山测量的冰河区域变化的统计,到气候变化的冰河区域变化的反应系统地被讨论。作为结果,冰河的全部的区域被 11.5% 在过去的 50 年里减少了,它根据中国(GIC ) 的冰河库存分开的 10 排水盆的冰河区域变化是一个加权的百分比。在中国 Tianshan 山的冰河的区域变化(APAC ) 的年度百分比在学习时期的标准化以后是 0.31% 。APAC 为不同排水盆广泛地变化,但是冰河通常处于快速的撤退的一个国家。根据在中国 Tianshan 山的 14 个气象学的车站,温度和降水以 0.34 整湲椠 ? 潮 ?湵晩牯 m 的率从 1960 ~ 2009 | WANG Shengjie ZHANG Mingjun LI Zhongqin WANG Feiteng LI Huilin LI Yaju HUANG Xiaoyan | 2011 | Journal of Geographical Sciences2011，21，2： | 31 |
| 6 | Sensitivity of surface air temperature change to land use/cover types in China显示文摘Using CRU high resolution grid observational temperature and ERA40 reanalysis surface air temperature data during 1960-1999, we investigated the sensitivity of surface air temperature change to land use/cover types in China by subtracting the reanalysis from the observed surface air temperature (observation minus reanalysis, OMR). The results show that there is a stable and systemic impact of land use/cover types on surface air temperature. The surface warming of each land use/cover type reacted differently to global warming. The OMR trends of unused land (≥0.17℃/decade), mainly comprised by sandy land, Gobi and bare rock gravel land, are obviously larger than those of the other land use/cover types. The OMR over grassland, farmland and construction land shows a moderate decadal warming about 0.12℃ /decade, 0.10℃/decade, 0.12 ℃ /decade, respectively. Woodland areas do not show a significant warming trend (0.06 ℃ /decade). The overall assessment indicates that the surface warming is larger for areas that are barren and anthropogenically developed. The better the vegetation cover, the smaller the OMR warming trend. Responses of surface air temperature to land use/cover types with similar physical and chemical properties and biological processes have no significant difference. The surface air temperature would not react significantly until the intensity of land cover changes reach a certain degree. Within the same land use/cover type, areas in eastern China with intensive human activities exhibit larger warming trend. The results provide observational evidence for modeling research on the impact of land use/cover change on regional climate. Thus, projecting further surface climate of China in regional scale should not only take greenhouse gas increase into account, but also consider the impact of land use/cover types and land cover change. | YANG XuChao ZHANG YiLi LIU LinShan ZHANG Wei DING MingJun WANG ZhaoFeng | 2009 | Science China Earth Sciences2009，52，8： | 21 |
| 7 | Tectonically deformed coal types and pore structures in Puhe and Shanchahe coal mines in western Guizhou显示文摘To evaluate the effect of tectonic deformation on coal reservoir properties, we provide an analysis of the types of tectonically deformed coal, macroand microscopic deformation and discuss pore structural characteristics and connectivity based on samples from the Puhe and Shanchahe coal mines. Our research shows that the tectonically deformed coal mostly includes cataclastic structural coal, mortar structural coal and schistose structural coal of a brittle deformation series. The major pore structures of different types of tectonically deformed coal are transitional pores and micropores. The pore volumes of macropores and visible fracture pores produced by structural deformations vary over a large range and increase with the intensity of tectonic deformation. Mesopores as connecting passages develop well in schistose structural coal. According to the shapes of intrusive mercury curves, tectonically deformed coal can be divided into parallel, open and occluded types. The parallel type has poor connectivity and is relatively closed; the open type reflects uniformly developed open pores with good connectivity while the occluded type is good for coalbed methane enrichment, but has poor connectivity between pores. | Li Ming Jiang Bo Lin Shoufa Wang Jilin Ji Mingjun Qu Zhenghui | 2011 | Mining Science and Technology2011，21，3： | 19 |
| 8 | Start of vegetation growing season on the Tibetan Plateau inferred from multiple methods based on GIMMS and SPOT NDVI data显示文摘在这研究,我们使用了四个方法从 1982~2012 在西藏的高原( TP )上调查成长季节( SGS )的开始,用从全球库存为研究建模并且印射获得的规范的差别植被索引( NDVI )数据( GIMSS , 19822006 )并且点植被( SPOT-VGT , 19992012 )。用四个方法估计的 SGS 价值沿着纬度或高度的坡度显示出类似的空间模式,但是与在 SGS 日期的重要变化。最大的差异主要在这些区域被发现与最高或最低植被范围。在 1982 和 1998 之间,然而,从四个方法导出的 SGS 值都根据更最近的点 VGT 数据(19992012 ) 显示一个进展趋势,没有 TP 上的 SGS 的连续地进展的趋势。在价值从在 1999 和 2006 之间的 GIMMS 和点导出的 SGS 之间的关联的分析数据来源与问候在趋势表明一致性到并且到使用的四个分析方法。与另外的方法相比,最大的一致性在之间在里面 situ 数据和检索的 SGS 值与方法 3 被获得(NDVI 比率的阀值) 。避免错误在有多样的植被类型和物理环境的一个广阔区域,知道不同植被类型的季节的变化特征是批评的,特别地在有稀少的草地的区域或常绿树森林。 | DING Mingjun LI Lanhui ZHANG Yili SUN Xiaomin LIU Linshan GAO Jungang WANG Zhaofeng LI Yingnian | 2015 | Journal of Geographical Sciences2015，25，2： | 17 |
| 9 | Control of Rice Embryo Development, Shoot Apical Meristem Maintenance, and Grain Yield by a Novel Cytochrome P450显示文摘被子植物种子通常由二主要部分组成:胚胎和内乳。然而,分子的机制 underlyingembryo 和内乳发展仍然保持大部分未知,特别地在米饭,模型谷物。这里,我们报导 identificationand 米饭巨人胚胎(GE ) 基因的功能的描述。GE 的变化在种子导致了一个大胚胎,它被胚鳞房间的过多的扩大引起。embryonic 以后 growthof ge 幼苗严重地由于有缺点的射击被禁止顶端的分裂组织(SAM ) 维护。基于地图的克隆表明 thatGE 编码对 endoplasmic 蜂窝胃局部性的 CYP78A 亚科 P450 monooxygenase。GE 在 scutellar 上皮主要被表示,在胚胎和内乳之间的接口区域。Overexpressionof GE 支持了细胞增长并且提高了米饭植物生长和谷物产量,但是减少了胚胎尺寸,建议 GE 为协调米饭胚胎和内乳开发是批评的。而且,转基因的 Arabidopsis 植物 overexpressing AtCYP78A10,一个 GE 相当或相同的事物,也生产的更大的种子,在一起调整种子 development.Taken 为 P450s 的 CYP78A 亚科暗示一个保存角色,我们的结果显示 GE 在调整胚胎发展和 SAM maintenance.Key 词起关键作用: | Weibing Yang Mingjun Gao Xin Yin Jiyun Liu Yonghan Xu Longjun Zeng Qun Li Shubiao Zhang Junmin Wang Xiaoming Zhang Zuhua He | 2013 | Molecular Plant2013，6，6： | 16 |
| 10 | Glacier area shrinkage in China and its climatic background during the past half century显示文摘在遥感监视的中国的典型区域基于冰河区域变化记录,吗象从 139 的空气温度和 降水的气象学的数据一样驻扎并且 0 ??????????????????????????吠慭吗?? | ZHANG Mingjun WANG Shengjie LI Zhongqin WANG Feiteng | 2012 | Journal of Geographical Sciences2012，22，1： | 14 |
| 11 | Changes in temperature extremes in the Yangtze River Basin, 1962-2011显示文摘Based on daily maximum and minimum temperature observed by the China Meteorological Administration at 115 meteorological stations in the Yangtze River Basin from 1962 to 2011,the methods of linear regression,principal component analysis and correlation analysis are employed to investigate the temporal variability and spatial distribution of temperature extremes.Sixteen indices of extreme temperature are selected.The results are as follows:(1) The occurrence of cold days,cold nights,ice days,frost days and cold spell duration indicator has significantly decreased by –0.84,–2.78,–0.48,–3.29 and –0.67 days per decade,respectively.While the occurrence of warm days,warm nights,summer days,tropical nights,warm spell duration indicator and growing season length shows statistically significant increasing trends at rates of 2.24,2.86,2.93,1.80,0.83 and 2.30 days per decade,respectively.The tendency rate of the coldest day,coldest night,warmest day,warmest night and diurnal temperature range is 0.33,0.47,0.16,0.19 and –0.07℃ per decade,respectively.(2) The magnitudes of changes in cold indices(cold nights,coldest day and coldest night) are obviously greater than those of warm indices(warm nights,warmest day and warmest night).The change ranges of night indices(warm nights and cold nights) are larger than those of day indices(warm days and cold days),which indicates that the change of day and night temperature is asymmetrical.(3) Spatially,the regionally averaged values of cold indices in the upper reaches of the Yangtze River Basin are larger than those in the middle and lower reaches.However,the regionally averaged values of most warm indices(except warm spell duration indicator) and growing season length in the middle and lower reaches are larger than those in the upper reaches.(4) The extreme temperature indices are well correlated with each other except diurnal temperature range. | WANG Qiong ZHANG Mingjun WANG Shengjie MA Qian SUN Meiping | 2014 | Journal of Geographical Sciences2014，24，1： | 14 |
| 12 | Assessment of diurnal variation of summer precipitation over the Qilian Mountains based on an hourly merged dataset from 2008 to 2014显示文摘调查日报在在向东北西藏的高原的 Qilian 山的夏天降水的变化,时时,为这个区域的降水数量在 0.1 点用一个时时合并的降水产品在 2008-2014 的夏天期间被分析 ? 湵慦潶慲汢? 諟D禎澞?汣浩瑡 ? 档湡敧椠?? | LIU Xuemei ZHANG Mingjun WANG Shengjie WANG Jie ZHAO Peipei ZHOU Panpan | 2017 | Journal of Geographical Sciences2017，27，3： | 14 |
| 13 | NUMERICAL SIMULATION OF FLOW THROUGH ORIFICE ENERGY-DISSIPATORS IN XIAOLANGDI FLOOD-DISCHAR-GE TUNNEL显示文摘The cavitation of orifi ces is one of the main problems of the Xiaolangdi flood discharge tunnels. Along with the decompression experiment, the flow field was calculated in this paper by using an axis-symmetrical k-ε turbulence model. The calculated pressur e distribution was compared with the measured data and in agreement with each ot her. The calculated results show that few of the cavitation bubbles generating a t the orifice edge can reach the wall under the calculation condition, the force applied on the orifice surface and the flow pattern before the orifice may be i mproved obviously by adding the vortex elimination ring at the upper side of the orifice. | Qu, Jingxue Xu, Weilin Yang, Yongquan Wang, Wei Diao, Mingjun | 2000 | Journal of Hydrodynamics2000，12，3： | 14 |
| 14 | Climate change in Mt. Qomolangma region since 1971显示文摘Using monthly average, maximum, minimum air temperature and monthly precipitation data from 5 weather stations in Mt. Qomolangma region in China from 1971 to 2004, climatic linear trend, moving average, low-pass filter and accumulated variance analysis methods, the spatial and temporal patterns of the climatic change in this region were analyzed. The main findings can be summarized as follows: (1) There is obvious ascending tendency for the interannual change of air temperature in Mt. Qomolangma region and the ascending tendency of Tingri, the highest station, is the most significant. The rate of increasing air temperature is 0.234 oC/decade in Mt. Qomolangma region, 0.302 oC/decade in Tingri. The air temperature increases more strongly in non-growing season. (2) Compared with China and the global average, the warming of Mt. Qomolangma region occurred early. The linear rates of temperature increase in Mt. Qomolangma region exceed those for China and the global average in the same period. This is attributed to the sensitivity of mountainous regions to climate change. (3) The southern and northern parts of Mt. Qomolangma region are quite different in precipitation changes. Stations in the northern part show increasing trends but are not statistically significant. Nyalam in the southern part shows a decreasing trend and the sudden decreasing of precipitation occurred in the early 1990s. (4) Compared with the previous studies, we find that the warming of Mt. Qomolangma high-elevation region is most significant in China in the same period. The highest automatic meteorological comprehensive observation station in the world set up at the base camp of Mt. Qomolangma with a height of 5032 m a.s.l will play an important role in monitoring the global climate change. | YANG Xuchao ZHANG Yili ZHANG Wei YAN Yuping WANG Zhaofeng DING Mingjun CHU Duo | 2006 | Journal of Geographical Sciences2006，16，3： | 12 |
| 15 | Recent Progress in Dual-Polarization Radar Research and Applications in China显示文摘Dual-polarization(dual-pol)radar can measure additional parameters that provide more microphysical information of precipitation systems than those provided by conventional Doppler radar.The dual-pol parameters have been successfully utilized to investigate precipitation microphysics and improve radar quantitative precipitation estimation(QPE).The recent progress in dual-pol radar research and applications in China is summarized in four aspects.Firstly,the characteristics of several representative dual-pol radars are reviewed.Various approaches have been developed for radar data quality control,including calibration,attenuation correction,calculation of specific differential phase shift,and identification and removal of non-meteorological echoes.Using dual-pol radar measurements,the microphysical characteristics derived from raindrop size distribution retrieval,hydrometeor classification,and QPE is better understood in China.The limited number of studies in China that have sought to use dual-pol radar data to validate the microphysical parameterization and initialization of numerical models and assimilate dual-pol data into numerical models are summarized.The challenges of applying dual-pol data in numerical models and emerging technologies that may make significant impacts on the field of radar meteorology are discussed. | Kun ZHAO Hao HUANG Mingjun WANG Wen-Chau LEE Gang CHEN Long WEN Jing WEN Guifu ZHANG Ming XUE Zhengwei YANG Liping LIU Chong WU Zhiqun HU Sheng CHEN | 2019 | Advances in Atmospheric Sciences2019，36，9： | 12 |
| 16 | Changes in daily extreme precipitation events in South China from 1961 to 2011显示文摘从 0.5 摩敤基于每日的降水吗?? | REN Zhengguo ZHANG Mingjun WANG Shengjie QIANG Fang ZHU Xiaofan DONG Lei | 2015 | Journal of Geographical Sciences2015，25，1： | 10 |
| 17 | Changes in air temperature over China in response to the recent global warming hiatus显示文摘The 1998-2012 global wanning hiatus has aroused great public interest over the past several years.Based on the air temperature measurements from 622 meteorological stations in China,the temperature response to the global warming hiatus was analyzed at national and regional scales.We found that air temperature changed-0.221°C/10a during 1998-2012,which was lower than the long-term trend for 1960-1998 by 0.427°C/10a.Therefore,the warming hiatus in China was more pronounced than the global mean.Winter played a domi nant role in the nati on wide warming hiatus,con tributi ng 74.13%,while summer contributed the least among the four seasons.Furthermore,the warming hiatus was spatial heterogeneous across different climate conditions in China.Comparing the three geographic zones,the monsoon region of eastern China,arid region of northwestern China,and high frigid region of the Tibetan Plateau,there was significant cooling in eastern and northwestern China.In eastern China,which contributed 53.79%,the trend magnitudes were 0.896°C/10a in winter and 0.134°C/10a in summer.In the Tibeta n Plateau,air temperature in creased by 0.204°C/10a,indicating a lack of a significant warming hiatus.More broadly,the warming hiatus in China may have been associated with the negative phase of PDO and reduction in sunspot numbers and total solar radiation.Finally,although a warming hiatus occurred in China from 1998 to 2012,air temperature rapidly increased after 2012 and will likely to continuously warm in the next few years. | DU Qinqin ZHANG Mingjun WANG Shengjie CHE Cunwei MA Rong MA Zhuanzhuan | 2019 | Journal of Geographical Sciences2019，29，4： | 9 |
| 18 | Formation mechanism of a smooth, defectfree surface of fused silica optics using rapid CO2 laser polishing显示文摘Surface defects introduced by conventional mechanical processing methods can induce irreversible damage and reduce the service life of optics applied in high-power lasers.Compared to mechanical processing,laser polishing with moving beam spot is a noncontact processing method,which is able to form a defect-free surface.This work aims to explore the mechanism of forming a smooth,defect-free fused silica surface by high-power density laser polishing with coupled multiple beams.The underlying mechanisms of laser polishing was revealed by numerical simulations and the theoretical results were verified by experiments.The simulated polishing depth and machined surface morphology were in close agreement with the experimental results.To obtain the optimized polishing quality,the effects of laser polishing parameters(e.g.overlap rate,pulse width and polishing times)on the polishing quality were experimentally investigated.It was found that the processing efficiency of fused silica materials by carbon dioxide(CO2)laser polishing could reach 8.68 mm2 s−1,and the surface roughness(Ra)was better than 25 nm.Besides,the cracks on pristine fused silica surfaces introduced by initial grinding process were completely removed by laser polishing to achieve a defect-free surface.The maximum laser polishing rate can reach 3.88μm s−1,much higher than that of the traditional mechanical polishing methods.The rapid CO2 laser polishing can effectively achieve smooth,defect-free surface,which is of great significance to improve the surface quality of fused silica optics applied in high-power laser facilities. | Linjie Zhao Jian Cheng Mingjun Chen Xiaodong Yuan Wei Liao Qi Liu Hao Yang Haijun Wang | 2019 | International Journal of Extreme Manufacturing2019，1，3： | 8 |
| 19 | A Prototype Regional GSI-based EnKF-Variational Hybrid Data Assimilation System for the Rapid Refresh Forecasting System:Dual-Resolution Implementation and Testing Results显示文摘A dual-resolution(DR) version of a regional ensemble Kalman filter(EnKF)-3D ensemble variational(3DEnVar) coupled hybrid data assimilation system is implemented as a prototype for the operational Rapid Refresh forecasting system. The DR 3DEnVar system combines a high-resolution(HR) deterministic background forecast with lower-resolution(LR) EnKF ensemble perturbations used for flow-dependent background error covariance to produce a HR analysis. The computational cost is substantially reduced by running the ensemble forecasts and EnKF analyses at LR. The DR 3DEnVar system is tested with 3-h cycles over a 9-day period using a 40/13-km grid spacing combination. The HR forecasts from the DR hybrid analyses are compared with forecasts launched from HR Gridpoint Statistical Interpolation(GSI) 3D variational(3DVar)analyses, and single LR hybrid analyses interpolated to the HR grid. With the DR 3DEnVar system, a 90% weight for the ensemble covariance yields the lowest forecast errors and the DR hybrid system clearly outperforms the HR GSI 3DVar.Humidity and wind forecasts are also better than those launched from interpolated LR hybrid analyses, but the temperature forecasts are slightly worse. The humidity forecasts are improved most. For precipitation forecasts, the DR 3DEnVar always outperforms HR GSI 3DVar. It also outperforms the LR 3DEnVar, except for the initial forecast period and lower thresholds. | Yujie PAN Ming XUE Kefeng ZHU Mingjun WANG | 2018 | Advances in Atmospheric Sciences2018，35，5： | 7 |
| 20 | Vegetation change in the Mt. Qomolangma Nature Reserve from 1981 to 2001显示文摘Based on the NOAA AVHRR-NDVI data from 1981 to 2001, the digitalized China Vegetation Map (1:1,000,000), DEM, temperature and precipitation data, and field investiga- tion, the spatial patterns and vertical characteristics of natural vegetation changes and their influencing factors in the Mt. Qomolangma Nature Reserve have been studied. The results show that: (1) There is remarkable spatial difference of natural vegetation changes in the Mt. Qomolangma Nature Reserve and stability is the most common status. There are 5.04% of the whole area being seriously degraded, 13.19% slightly degraded, 26.39% slightly im- proved, 0.97% significantly improved and 54.41% keeping stable. The seriously and slightly degraded areas, which mostly lie in the south of the reserve, are along the national bounda- ries. The areas of improved vegetation lie in the north of the reserve and the south side of the Yarlung Zangbo River. The stable areas lie between the improved and degraded areas. Degradation decreases with elevation. (2) Degeneration in the Mt. Qomolangma Nature Re- serve mostly affects shrubs, needle-leaved forests and mixed forests. (3) The temperature change affects the natural vegetation changes spatially while the integration of temperature changes, slopes and aspects affects the natural vegetation change along the altitude gradi- ents. (4) It is the overuse of resources that leads to the vegetation degeneration in some parts of the Mt. Qomolangma Nature Reserve. | ZHANG Wei ZHANG Yili WANG Zhaofeng DING Mingjun YANG Xuchao LIN Xuedong LIU Linshan | 2007 | Journal of Geographical Sciences2007，17，2： | 7 |
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