利用常规观测、雷达、卫星和NCEP1°×1°再分析资料,从形势场配置、水汽条件、动力机制、能量条件等方面,对铜仁市东部锦江流域2013年9月一次突发致洪暴雨的形成机理进行综合分析。结果表明：500 h Pa上西太平洋副高稳定少...利用常规观测、雷达、卫星和NCEP1°×1°再分析资料,从形势场配置、水汽条件、动力机制、能量条件等方面,对铜仁市东部锦江流域2013年9月一次突发致洪暴雨的形成机理进行综合分析。结果表明：500 h Pa上西太平洋副高稳定少动,阻挡了由贝湖向东移出的低涡槽速度,使槽前引导南下的冷空气在铜仁区域内与中低层低涡切变线结合,形成了此次大暴雨到特大暴雨过程;K指数达到37~39℃,SI指数为-2.36,CAPE值达到1 677.5 J/kg及以上,为暴雨的发生、发展提供了充足的能量基础,当对流有效位能转换为上升运动的能量时,对应了强对流、强降雨天气开始的出现;其TBB强负值中心及高值的雷达回波,在铜仁东部维持是造成锦江流域致洪暴雨形成的主要原因。展开更多
In order to evaluate the effect of subsoiling on the soil physical properties and wheat yield in dry land conditions, this research was conducted in Mamassani area of Fars province in Iran. The experiment was laid dow...In order to evaluate the effect of subsoiling on the soil physical properties and wheat yield in dry land conditions, this research was conducted in Mamassani area of Fars province in Iran. The experiment was laid down in the form of a complete block experimental design with four treatments and four replications for three years. Treatments included： （1） conventional tillage without using subsoiler which was control treatment （So）; （2） using subsoiler with the shank space of 40 cm which was equal to the subsoiling depth （SO; （3） using subsoiler with the shank space of 60 cm which was 1.5 times of the subsoiling depth （S2）; and （4） using subsoiler with the shank space of 80 cm which was 2 times of the subsoiling depth （S3）. Subsoiling depth was set at 40 cm which was the lower limit of the hard pan depth in the soil. Soil cone index, soil bulk density, soil moisture content, wheat yield, and yield components were measured in this study and SAS software was used to analyze the collected data. Results showed that subsoiling decreased the soil bulk density and cone index, and increased water retention of the soil. Results also revealed that applying subsoiler increased wheat yield and yield components in our dry land conditions. Since subsoiling improved soil physical conditions and increases wheat yield, applying subsoiler in such a dry land conditions is therefore recommended. Results of this study also showed that subsoiling with the shank space of 40 cm and 60 cm had better performance compared to the shank space of 80 cm. On the other hand, shank space of 40 cm reduced the subsoiler effective working width and consequently effective field capacity. Therefore, subsoiler with a shank space of 60 cm is recommended for application in dry land soils of our type.展开更多
Granite is one of the most important components of the continental crust on our Earth; it thus has been an enduring studied subject in geology. According to present knowledge, granite shows a great deal of heterogenei...Granite is one of the most important components of the continental crust on our Earth; it thus has been an enduring studied subject in geology. According to present knowledge, granite shows a great deal of heterogeneity in terms of its texture,structure, mineral species and geochemical compositions at different scales from small dike to large batholith. However, the reasons for these variations are not well understood although numerous interpretations have been proposed. The key point of this debate is whether granitic magma can be effectively differentiated through fractional crystallization, and, if so, what kind of crystallization occurred during the magmatic evolution. Although granitic magma has high viscosity because of its elevated SiO2 content, we agree that fractional crystallization is effectively processed during its evolution based on the evidence from field investigation,mineral species and its chemical variations, and geochemical compositions. These data indicate that crystal settling by gravitation is not the only mechanism dominating granitic differentiation. On the contrary, flow segregation or dynamic sorting may be more important. Accordingly, granite can be divided into unfractionated, fractionated(including weakly fractionated and highly fractionated) and cumulated types, according to the differentiation degree. Highly fractionated granitic magmas are generally high in primary temperature or high with various volatiles during the later stage, which make the fractional crystallization much easier than the common granitic melts. In addition, effective magmatic differentiation can be also expected when the magma emplaced along a large scale of extensional structure. Highly fractionated granitic magma is easily contaminated by country rocks due to its relatively prolonged crystallization time. Thus, granites do not always reflect the characteristics of the source areas and the physical and chemical conditions of the primary magma. We proposed that highly fractionated granites are an important sign indicating compositional maturity of the continental crust, and they are also closely related to the rare-elemental(metal) mineralization of W,Sn, Nb, Ta, Li, Be, Rb, Cs, REEs, etc.展开更多
文摘利用常规观测、雷达、卫星和NCEP1°×1°再分析资料,从形势场配置、水汽条件、动力机制、能量条件等方面,对铜仁市东部锦江流域2013年9月一次突发致洪暴雨的形成机理进行综合分析。结果表明：500 h Pa上西太平洋副高稳定少动,阻挡了由贝湖向东移出的低涡槽速度,使槽前引导南下的冷空气在铜仁区域内与中低层低涡切变线结合,形成了此次大暴雨到特大暴雨过程;K指数达到37~39℃,SI指数为-2.36,CAPE值达到1 677.5 J/kg及以上,为暴雨的发生、发展提供了充足的能量基础,当对流有效位能转换为上升运动的能量时,对应了强对流、强降雨天气开始的出现;其TBB强负值中心及高值的雷达回波,在铜仁东部维持是造成锦江流域致洪暴雨形成的主要原因。
文摘In order to evaluate the effect of subsoiling on the soil physical properties and wheat yield in dry land conditions, this research was conducted in Mamassani area of Fars province in Iran. The experiment was laid down in the form of a complete block experimental design with four treatments and four replications for three years. Treatments included： （1） conventional tillage without using subsoiler which was control treatment （So）; （2） using subsoiler with the shank space of 40 cm which was equal to the subsoiling depth （SO; （3） using subsoiler with the shank space of 60 cm which was 1.5 times of the subsoiling depth （S2）; and （4） using subsoiler with the shank space of 80 cm which was 2 times of the subsoiling depth （S3）. Subsoiling depth was set at 40 cm which was the lower limit of the hard pan depth in the soil. Soil cone index, soil bulk density, soil moisture content, wheat yield, and yield components were measured in this study and SAS software was used to analyze the collected data. Results showed that subsoiling decreased the soil bulk density and cone index, and increased water retention of the soil. Results also revealed that applying subsoiler increased wheat yield and yield components in our dry land conditions. Since subsoiling improved soil physical conditions and increases wheat yield, applying subsoiler in such a dry land conditions is therefore recommended. Results of this study also showed that subsoiling with the shank space of 40 cm and 60 cm had better performance compared to the shank space of 80 cm. On the other hand, shank space of 40 cm reduced the subsoiler effective working width and consequently effective field capacity. Therefore, subsoiler with a shank space of 60 cm is recommended for application in dry land soils of our type.
基金supported by the National Natural Science Foundation of China (Grant No. 41130313)by the Strategic Priority Research Program (B) of the Chinese Academy of Sciences (Grant No. XDB03010200)
文摘Granite is one of the most important components of the continental crust on our Earth; it thus has been an enduring studied subject in geology. According to present knowledge, granite shows a great deal of heterogeneity in terms of its texture,structure, mineral species and geochemical compositions at different scales from small dike to large batholith. However, the reasons for these variations are not well understood although numerous interpretations have been proposed. The key point of this debate is whether granitic magma can be effectively differentiated through fractional crystallization, and, if so, what kind of crystallization occurred during the magmatic evolution. Although granitic magma has high viscosity because of its elevated SiO2 content, we agree that fractional crystallization is effectively processed during its evolution based on the evidence from field investigation,mineral species and its chemical variations, and geochemical compositions. These data indicate that crystal settling by gravitation is not the only mechanism dominating granitic differentiation. On the contrary, flow segregation or dynamic sorting may be more important. Accordingly, granite can be divided into unfractionated, fractionated(including weakly fractionated and highly fractionated) and cumulated types, according to the differentiation degree. Highly fractionated granitic magmas are generally high in primary temperature or high with various volatiles during the later stage, which make the fractional crystallization much easier than the common granitic melts. In addition, effective magmatic differentiation can be also expected when the magma emplaced along a large scale of extensional structure. Highly fractionated granitic magma is easily contaminated by country rocks due to its relatively prolonged crystallization time. Thus, granites do not always reflect the characteristics of the source areas and the physical and chemical conditions of the primary magma. We proposed that highly fractionated granites are an important sign indicating compositional maturity of the continental crust, and they are also closely related to the rare-elemental(metal) mineralization of W,Sn, Nb, Ta, Li, Be, Rb, Cs, REEs, etc.
