季节冻土区融雪冻土水热耦合模型研究

为描述季节性冻土地区的积融雪及冻土水热过程,采用能量平衡及水量平衡法建立融雪模型,采用有限体积法离散热传导方程和非饱和土壤水运动方程,并对其交界面处进行耦合处理,从而建立季节冻土区融雪冻土耦合数学模型。结合2005年曲玛莱实测站点的观测资料,从不同角度描述积雪变化,冻土活动层内土壤水热特征,检验模型方法的有效性,为揭示该地区的水文运动规律提供有力的支持。     

Uranium Metallogenic Regionalization and Resource Potential in China

This paper work is within the framework of the project Evaluation on Uranium Resources Potential in China funded by the Chinese Government and many thanks to Prof. Chen Yuchuan, Prof. Ye Tianzhu, Prof. Wang Ruijiang, Mr. Wang Quanmin, Mr. Lü Xiaoming and Mr. Wang Yuqing, etc. for their supports.     

An instructural system model of coastal management to the water related hazards in China

Coastal lowlands have large areas of hazard impact and relatively low capacity of prevention to the water related hazards, which have been indicated by the wide-spread flood hazards, high percentages of land with high flood vulnerability. Increasing propulation pressure and the shift of resources exploitation from land to sea will force more and more coastal lowlands to be developed in the future, further enhancing the danger of water-related hazards. In this paper, the coastal lowlands in the northern Jiangsu province, China, were selected as a case study. The Interpretation Structural Model (ISM) was employed to analyze the direct and indirect impacts among the elements within the system, and thereby, to identify the causal elements, middle linkages, their expression, and relations.     

Flood simulation in the coastal lowlands of northern Jiangsu,China

The coastal lowlands in northern Jiangsu Province, China, is characterized by low relief and low water surface gradient in streams. The flooding stages are commonly lower than the high-tide level and the tidal range is relatively small. All these factors prohibit rapid discharge of floodwater and make the flood regimes here extremely sensitive to the sea level rise. The 1991 Plum Rain was examined, when precipitation was significantly higher than normal. The one-dimensional open-channel non-conservative flow model was used to simulate the stream flow in the channel network of studied area. GIS technology was used to delineate the maximum in undated area by analyzing the DEMs.     

Effects of vegetation cover on summer climate in China during 1982–2001

In this paper, we apply lagged correlation analysis to study the effects of vegetation cover on the summer climate in different zones of China, using NOAA/AVHRR normalized difference vegetation index (NDVI) data during the time period from 1982 to 2001 and climate data of 365 meteorological stations across China (precipitation from 1982 to 2001 and temperature from 1982 to 1998). The results show that there are positive correlations between spring NDVI and summer climate (temperature and precipitation) in most zones of China; these suggest that, when the vegetation cover increases, the summer precipitation will increase, and the lagged correlations show a significant difference between zones. The stronger correlations between NDVI in previous season and summer climate occur in three zones (Mid-temperate zone, Warm-temperate zone and Plateau climate zone), and this implies that vegetation changes have more sensitive feedback effects on climate in the three zones in China.     

罕遇地震作用下直接基于位移设计的局部预应力混凝土框架目标位移控制研究

本文针对罕遇地震作用下,直接基于位移设计的预应力混凝土框架在“防止倒塌”性能水准下结构目标位移不能有效控制的问题进行研究.通过理论分析和预应力混凝土框架结构的设计实例模拟计算,总结出影响结构目标位移有效控制的主要原因有结构承载能力超强和性能点时刻位移模式与设计位移模式误差较大两个方面.结构承载能力超强是影响框架层间位移角有效控制的主要原因,位移模式误差则是通过影响等效单自由度体系的等效目标位移而影响目标位移的有效控制.文中提出了考虑强柱弱梁调整、材料强度取值以及其他构造措施等影响的基底剪力折减计算公式,以及采用结构在性能点时刻的位移模式对设计位移模式进行修正的改进方法,算例表明目标位移和其他各项性能参数的控制均得到了非常明显的改善.     

冻藏龙眼果皮细胞膜透性、PPO活性和酚类物质含量的变化

将“油谭本”龙眼在 - 40℃条件下进行速冻 ,然后转入 - 18℃恒定低温冷库中冻藏 180d。测定了龙眼果实速冻时的冻结曲线、冻藏过程中果皮细胞膜渗透率、果皮内PPO的活性和总酚含量的变化情况。试验结果表明 ,- 40℃的冷冻温度即可满足速冻要求 ;冻藏可以有效地抑制果皮内PPO的活性 ,果皮细胞膜渗透率和总酚含量的变化较小 ,能够较好地保持果实的外观品质。     

存储局域网在基础地理信息系统中的应用研究

介绍了存储局域网结构和特点，探讨了存储局域网在基础地理信息系统中的应用。     

Extended Impact of Cold Air Invasions in East Asia in Response to a Warm South China Sea and Philippine Sea

During boreal winter, the invasion of cold air can lead to remarkable temperature drops in East Asia which can result in serious socioeconomic impacts. Here, we find that the intensity of strong synoptic cold days in the East China Sea and Indochina Peninsula are increasing. The enhanced synoptic cold days in these two regions are attributed to surface warming over the South China Sea and Philippine Sea(SCSPS). The oceanic forcing of the SCSPS on the synoptic cold days in the two regions is veri...     

华南冬末春初降水变异关联主模态及机理

基于1951—2018年再分析资料和观测的降水量资料,采用联合经验正交函数分解的方法,分析了华南冬末春初(2、3月)降水年际变异特征,并讨论了相应的环流背景及物理机制。华南2、3月降水变异的第一关联主模态反映出全区2、3月同相变化,第二模态呈现反相变化。第一模态的降水异常与ENSO关联的热带海温异常分布有关,其导致的西太平洋异常反气旋的维持使得2、3月的降水持续出现同相异常。第二模态的降水异常与中高纬度的大气环流异常有关：2月表现为欧亚遥相关型,3月则表现为北极涛动型。第二模态2、3月位势高度异常型的转变分别与北大西洋的热通量的异常变化及平流层极涡信号的下传有关：当2月北大西洋热通量正异常显著时,500 hPa高度场呈现欧亚遥相关(EU)负位相的分布;平流层极涡异常信号在3月下传达到对流层低层,使得3月对流层极涡增强,有利于北极涛动(AO)正位相的形成。2、3月欧亚大陆上空分别在EU遥相关型和AO型环流异常的影响下,导致了华南地区上空的大气环流的辐合辐散异常,并最终造成2、3月华南的降水量反相异常的出现。