前期夏季西太平洋暖池热含量对江南春雨的影响及其可能机理

利用GODAS海洋温度资料、中国753站逐日降水资料以及NCEP/NCAR逐日再分析资料讨论了前期夏季西太平洋暖池热含量异常对江南春雨的影响,并通过高低层环流异常解释了其可能过程和机制。研究结果表明:(1)前期夏季暖池区热含量影响春雨的敏感海区位于9°~16°N,150°~166°E,与春雨强度呈显著反相关,前期夏季关键区热含量的显著偏低是春雨异常偏多的强信号。(2)多雨年和少雨年大气环流差值场与夏季暖池热含量(取反号)回归的次年春季大气环流形态基本一致。低层菲律宾海异常反气旋西北侧的暖湿西南气流输送及江南地区高层辐散抽吸运动是造成春雨偏多的直接原因。(3)关键区热含量在前期夏季的异常偏低使低层异常反气旋在其西北侧触发生成,并在菲律宾海附近持续存在(前夏至当年春季),春季引导强盛的西南气流向江南输送水汽;同时,热含量异常偏低在我国大陆东部激发出高层异常气旋并持续维持(前秋至当年春季),导致春季西风急流轴异常南压,高层形成异常辐散中心,形成强烈的抽吸作用,导致江南春雨显著偏多。前夏热含量显著偏高引起江南春雨偏少的过程则与之相反。     

Role of sea ice on satellite-observed chlorophyll-a concentration variations during spring bloom in the East/Japan sea

The relationship between the spring bloom along the Primorye coast and the sea ice of the Tatarskiy Strait in the northern region of the East/Japan Sea, a semi-enclosed marginal sea in the North Pacific, was investigated using the ten-year SeaWiFS chlorophyll-a concentration data and DMSP/SSMI sea ice concentration data from 1998 to 2007. Year-to-year variations in the chlorophyll-a concentrations in the spring were positively correlated with those of the sea ice concentrations in the Tatarskiy Strait in the previous winter with a correlation coefficient of 0.77. Abrupt increases in nutrients, essential for the spring bloom in the upper ocean during spring, were supplied from sea ice-melted waters. Time series of vertical distributions of the nutrients indicated that phosphate concentrations were extremely elevated in the upper ocean (less than 100 m) without any connection to high concentrations in the deep waters below. The water mass from sea ice provided preferable conditions for the spring bloom through changes in the vertical stratification structure of the water columns. Along-coast ratios of stability parameters between two neighboring months clearly showed the rapid progression of the generation of a shallow pycnocline due to fresh water originating from sea ice. This study addressed the importance of the physical environment for biogeochemical processes in semi-enclosed marginal seas affected by local sea ice.     

六盘水市近6a马铃薯全生育期的降水特征及其补充灌溉分析

选取贵州西部六枝特区郎节坝试验区、钟山区大地试验区、水城县前进试验区和盘县坡上试验区共4个不同海拔马铃薯种植区连续6 a(2006—2011年)春薯主要大田生长期(2—9月)逐日降水的观测资料和春薯产量资料,利用降水产量积分回归函数,分析降水变化对春薯产量的影响。结果表明,贵州西部山区降水存在时空分布不均状况,但降水总体呈现出随着海拔高度的升高而增多趋势,同时找出了影响春薯产量不稳定的主要原因。不同区域春薯生长发育过程中的最佳补充灌溉时期不同:郎节坝试验区在播种期到开花期需补充灌溉,大地试验区应分别在播种期和现蕾期到开花期补充灌溉,前进试验区在现蕾期到开花期需补充灌溉,坡上试验区应在开花的始期至盛期补充灌溉。科学、合理的调控措施,有利于提高春薯的产量和质量。     

两次大连春季暴雨的环流特征和诊断分析

利用NCEP/NCAR再分析资料、常规观测资料和大连地区近100个逐时自动气象站雨量资料,对大连地区2007年3月3～5日和2009年4月19～21日两次春季暴雨过程的大尺度环流特征进行了诊断分析,研究了大尺度环流条件对大连地区春季暴雨的影响。结果表明：（1）对流层低层的增温、增湿及中纬度冷空气的侵入,是导致两次春季暴...     

2009年大连春季强对流雨雪天气过程分析

2009年4月15日大连出现了春季最晚的降雪天气。利用常规资料、自动气象站和雷达等多种资料及中尺度模式MM5对这次强对流雨雪天气过程进行了分析和模拟,结果表明,200hPa急流、500hPa贝加尔湖冷槽南压形成的冷涡、中低层南支槽前水汽输送以及地面冷锋是产生大连春季强对流雨雪天气的环流背景;中层干冷空气叠加在低层暖湿层...     

Asynchrony of spring phytoplankton response to temperature driver within a spatial heterogeneity bay of Three-Gorges Reservoir, China

The increased air temperature is expected to have important driver on spring phytoplankton dynamics. To test whether spatial heterogeneity modifies the synchronous responses of phytoplankton to regional temperature driver, we evaluate temporal coherences for physical factors (temperature, water stability and non-algal light extinction), nutrients (nitrogen, phosphorus and silicon), and biomass and density of phytoplankton by Pearson correlation analysis and synchrony for phytoplankton community dynamics by Mantel test and nonmetric multi-dimensional scaling (NMS), during spring bloom (February 23–April 28, 2005) within Xiangxi Bay, a high spatial gradient bay of Three-Gorges Reservoir (China). The high level of temporal coherences for surface water temperature (r = 0.946, p < 0.01) and relative water column stability (r = 0.750, p < 0.01) were found between pair sites (A and B), in which the increase trends occurred with increase in regional air temperature during the study period. However, the low synchrony for phytoplankton dynamics were indeed observed between Site A and B, especially for the density of common dominant taxa (Cyclotella spp.: r = 0.155, p = 0.388) and community structure (Mantel test: r = 0.351). Moreover, the local habitat characteristics such as nutrient (nitrogen and phosphorus) and non-algal light extinction showed low levels of temporal coherence. It indicated that local community of phytoplankton varies rather independently within the single lentic bay with high spatial heterogeneity and that dispersal of algal organisms among locations cannot overwhelm out these local dynamics. Contrary to many studies, the present results argued that, in a small geographic area (i.e., a single reservoir bay of approximately 24 km length), spatial gradients also may influence spring phytoplankton response to regional temperature driver.     

陕西华清池温泉热储温度的估算

本文以华清池泉水化学成分为例,采用水—岩化学平衡计算的方法,进行了热储温度估算。根据9种矿物平衡温度的统计结果,得出华清池温泉深部热储温度为53.44±6.11℃。这和温泉附近几个热水孔的温度测定结果是基本一致的。     

水溶液中各化学组分可能存在式形分配及Eh值的计算方法

本文在参阅Crerar D.A.等人的资料的基础上,比较系统地论述了水溶液中各种化学组分可能存在形式分配及Eh值的计算方法。文章从对施实计算所需的原始数据的说明开始,主要从以下几个方面说明了计算方法:1.热力学问题的数学描述;2.问题的数值解;3.活度系数的校正;4.迭代步骤;5.Eh值的计算。文中以华清池温泉水化学分析资料为例,分别给出了此资料在12℃和42℃时的计算结果。由于分析技术和计算方法的误差,Eh值的计算结果存在一定的偏离,这也可能是由于给定温度下水中某些组分间存在着非平衡而引起的。     

Chemistry of springwater in Almora, Central Himalaya, India

 A field study was conducted to assess variations in physico-chemical characteristics of water of the springs located within the boundary of a Central Himalayan town where the springwater is used for drinking purposes. Monitoring of 12 springs was carried out for three seasons (winter, summer and monsoon). The results indicate direct influence of unplanned sewage disposal on the springwater quality as reflected by significant regional variations in the concentration of nitrates, chlorides, sulfates, sulfides and electrical conductivity. Population density varies within the town from 3110 to 14 137 persons/km^–2 and has direct relationship with water quality. Springs located in the densely populated area had higher concentrations of all these compounds. Concentrations of nitrates up to 60 ppm were observed in some springs, making water unsuitable for human consumption. No significant changes were observed in springwater quality during different seasons. Received: 3 February 1995 · Accepted: 27 February 1996