An analysis of the causes of decadal variations of rainfall in Shandong in summer

The precipitation in Shandong in July, August as well as the whole summer (JJA) and the corresponding 500hPa geopotential height fields are analyzed by means of the SVD (singular value decomposition) methodology. It is found that the general circulations in East Asia and the Western Pacific underwent decadal changes around 1979. The geopotential height, in particular over key areas like the South China Sea and the Philippines, increased after 1979. Corresponding to the changes in the geopotential height, the rainfall in Shandong started to decrease around 1979. The synthesized analysis shows that when the geopotential height at 500hPa level decreases in the key areas, the Western Pacific subtropical high shifts northward and an anticyclonic anomalous cell enforces the southerly flow over Shandong-Korea-Japan, Shandong could experience a wet period. A dry period is likely to occur when the geopotential height increases in these key areas, the subtropical high moves southward or expands westward to a great distance, and a cyclonic anomalous cell controls Shandong. Respective conceptual models for the causative mechanism are obtained for the cases of July, August and the whole summer (JJA).     

毛乌素沙地西南缘灌丛沙丘沉积物的粒度和元素特征

对毛乌素沙地白刺(Nitraria tangutorum)灌丛沙丘沉积物粒度和元素特征进行了采样分析.结果表明:灌丛沙丘沉积物来源单一,几乎全部由丘间地物质组成,其粒度和元素特征与丘间地物质极其相似;相对而言,灌丛沙丘沉积物比丘间地物质含有更多粗颗粒物,主要因丘间地可做跃移运动的中沙和细沙更易被灌丛阻挡而堆积;灌丛沙丘沉积物中大部分元素含量比丘间地物质低,主要因这些元素易被淋溶迁移到丘间地富集;灌丛沙丘发育以来,虽然其沉积环境存在波动,但相对稳定,未发生过显著变化.     

生物基可降解聚乳酸(PLA)沙障对沙丘表层沉积物粒度特征的影响

以吉兰泰盐湖北部流沙区铺设8 a的不同规格聚乳酸（PLA）沙障内沉积物为研究对象,利用激光衍射技术分析了沙丘表层0~3 cm沉积物粒度组成,计算并分析平均粒径、标准偏差等粒度参数,探讨了影响障内沉积物相对粗细的关键组分,分析PLA沙障的防沙效益。结果表明：PLA沙障内沉积物以细沙、中沙、极细沙为主。中沙、极细沙、细沙是障内沉积物的关键组分。PLA沙障的阻滞作用使得中沙、粗沙含量百分比升高,细颗粒含量百分比降低,障内沙粒分选性逐渐变差,峰态偏离正态分布,向负偏方向发展,频率分布曲线分布范围变宽,累积频率曲线变缓,表层颗粒组成趋于粗化。1 m×1 m规格PLA沙障内均以积沙为主;沙丘迎风坡和背风坡的2 m×2 m、3 m×3 m沙障内均为积沙状态,丘顶则为风蚀状态。综合考虑沙障铺设成本和防护效果,得出研究区域内2 m×2 m规格PLA沙障整体防沙效益最佳。     

Denitrification potential of marsh soils in two natural saline-alkaline wetlands

Little information is available on denitrification potential of marsh soils in natural saline-alkaline wetlands. The denitrification potentials of an open wetland in the floodplain(Erbaifangzi wetland) and a closed wetland(Fulaowenpao wetland) in backwater areas in Jilin Province of Northeast China were monitored by an anaerobic incubation at 30℃ for 25 days. Our results showed that the relative denitrification index(RDI) increased gradually with incubation time, and showed a rapid increase in the first 5 days of incubation. The RDI values declined quickly from surface soils to subsurface soils and then kept a small change in deeper soils along soil profiles over the incubation time. Denitrification proceeded much faster in the top 20 cm soils of open wetland than in the closed wetland, whereas no significant differences in RDI values were observed in deeper soils between both wetlands. The RDIs were significantly negatively correlated with bulk density and sand content, while a significantly positive correlation with clay content, soil organic matter, total nitrogen and phosphorous. The maximum net NO–3-N loss through denitrification in 1 m depth were higher in the open wetland than the closed wetland with higher soil pH values. Future research should be focused on understanding the influencing mechanisms of soil alkalinity.     

流沙地区沙通量的计算与观测初议

本文在总结野外资料的基础上,讨论了局部沙通量系数、断面通量系数与高度、粒径之间的关系,验证计算沙通量-般公式,结果良好。     

Li_2S─B_2O_3（─LiBr）玻璃的结构表征

用ＮＭＲ和ＸＰＳ技术研究了Ｌｉ２Ｓ─Ｂ２Ｏ３（─ＬｉＢｒ）体系硫氧化物玻璃的结构，结果指出，４─配位硼分数Ｎ４仅仅由玻璃Ｌｉ２Ｓ／Ｂ２Ｏ３摩尔比决定．而与ＬｉＢｒ含量无关，这表明Ｌｉ２Ｓ作为变形剂参与了玻璃网络形成，而ＬｉＢｒ仅作为参杂剂溶解于玻璃基体中，并进入网络间隙。含ＬｉＢｒ玻璃７ＬｉＮＭＲ谱运动变窄说明Ｌｉ＋离子是移迁离子．Ｓ２ｐ的ＸＰＳ解析谱证实了玻璃中桥硫和非桥硫的存在．Ｌｉｌｓ结合能值显示出Ｌｉ＋离了迁移的化学环境。     

地理信息系统支持区域土地利用决策的研究

本文以江苏省溧阳县为例,研究地理信息系统技术在区域土地利用多目标规划中的应用,着重探讨地理信息系统支持的区域土地利用决策原理和方法。研究表明,在地理信息系统的支持下,通过单项适宜性评价模型和生产布局决策模型的建立与运行,可以有效地进行研究区合理的土地利用布局和为区域土地管理提供依据。     

祁连山中部亚高山草地作物系数估算

利用Lysimeter蒸散仪于2011-2014年对祁连山中部黑河上游天涝池流域亚高山草地实际蒸散量进行观测。用FAO Penman-Monteith模型对草地参考蒸散量进行估算,根据草地植被高度结合气象数据,以估算日尺度作物系数,以估算的作物系数与模拟的参考蒸散量计算草地实际蒸散量,并用观测值进行验证。结果表明：FAO改进后的作物系数计算方法适合该区域草地作物系数的计算;以FAO Penman-Monteith模型估算的日蒸散量为0.50~7.26 mm,生长季日均蒸散量有年际变化,2011年 > 2014年 > 2012年 > 2013年。总体来看,土壤蒸发总量年际变化不大,影响蒸散量年际变化的主要部分是植被的蒸腾。     

Characteristics and cause analysis of heavy haze in Changchun City in Northeast China

Northeast China has been reported as having serious air pollution in China with increasing occurrences of severe haze episodes. Changchun City, as the center of Northeast China, has longstanding industry and is an important agricultural base. Additionally, Changchun City has a long winter requiring heating of buildings emitting pollution into the air. These factors contribute to the complexity of haze pollution in this area. In order to analyze the causes of heavy haze, surface air quality has been monitored from 2013 to 2015. By using satellite and meteorological data, atmospheric pollution status, spatio-temporal variations and formation have been analyzed. Results indicated that the air quality in 88.9% of days exceeding air quality index(AQI) level-1 standard(AQI 50) according to the National Ambient Air Quality Standard(NAAQS) of China. Conversely, 33.7% of the days showed a higher level with AQI 100. Extreme haze events(AQI 300) occurred frequently during agricultural harvesting period(from October 10 to November 10), intensive winter heating period(from Late-December to February) and period of spring windblown dust(April and May). Most daily concentrations of gaseous pollutants, i.e., NO_2(43.8 μg/m~3), CO(0.9 mg/m~3), SO_2(37.9 μg/m~3), and O_3(74.9 μg/m~3) were evaluated within level-1 concentration limits of NAAQS standards. However, particulate matter(PM_(2.5) and PM10) concentrations(67.3 μg/m~3 and 115.2 μg/m~3, respectively) were significantly higher than their level-1 limits. Severe haze in spring was caused by offsite transported dust and windblown surface soil. Heavy haze periods during fall and winter were mainly formed by intensive emissions of atmospheric pollutants and steady weather conditions(i.e., low wind speed and inversion layer). The overlay emissions of widespread straw burning and coal combustion for heating were the dominant factors contributing to haze in autumn, while intensive coal burning during the coldest time was the primary component of total emissions. In addition, general emissions including automobile exhaust, road and construction dust, residential and industrial activities, have significantly increased in recent years, making heavy haze a more frequent occurrence. Therefore, both improved technological strategies and optimized pollution management on a regional scale are necessary to minimize emissions in specified seasons in Changchun City, as well as comprehensive control measures in Northeast China.