上海市降雨变化与灾害性降雨特征分析

降雨是引发城市内涝的关键因素,与公众安全密切相关,分析其特征,能够为内涝防治提供一定参考和依据。上海地区气候条件复杂,深受暴雨、台风等水情灾害影响。依据国家基本气象站-宝山站数据,对上海市近40 a降雨变化和灾害性降雨特征进行了分析。结果表明上海年均降雨量以509 mm/10 a的速率递增。同时,降雨天数的减少较为显著,以3 d/10 a的速率递减。从降雨量和降雨强度的角度,灾害性降雨多为暴雨和短历时强降雨。上海年均暴雨天数为3 d,但雨量可占全年的1/5,大范围暴雨通常由台风引起。近年来,高于排水标准的短历时强降雨出现频次有增多的趋势。汛期作为灾害性降雨的高发期,可作为城市防涝的重点     

我国袋式除尘行业2011年发展综述

综述了2011年我国袋式除尘行业的发展概况;介绍了袋式除尘行业的生产经营状况、技术进展情况以及主要企业的经营和发展情况;详细分析了袋式除尘技术在各行业的应用前景;对袋式除尘行业在发展中存在的主要问题提出了对策和建议,并对行业的发展进行了展望。     

Validation of Satellite Precipitation Adjustment Methodology From Seven Basins in the Continental United States1

Tobin, Kenneth J. and Marvin E. Bennett, 2012. Validation of Satellite Precipitation Adjustment Methodology From Seven Basins in the Continental United States. Journal of the American Water Resources Association (JAWRA) 48(2): 221‐234. DOI: 10.1111/j.1752‐1688.2011.00604.x Abstract: The precipitation science community has expressed concern regarding the ability of satellite‐based precipitation products to accurately capture rainfall values over land. There has been some work that has focused on addressing the deficiencies of satellite precipitation products, particularly on the adjustment of bias. This article outlines a methodology that adjusts satellite products utilizing ground‐based precipitation data. The approach is not a simple bias adjustment, but is a three‐step process that transforms a satellite product based on a ground‐based precipitation product (NEXRAD‐derived Multisensor Precipitation Estimator [MPE] product or rain‐gauge data). The developed methodology was successfully applied to seven moderate‐to‐large sized watersheds from continental United States (CONUS) and northern Mexico over a spectrum of climatic regimes ranging from dry to humid settings. Methodology validation is based on comparison of observed and simulated streamflow generated with SWAT (Soil and Water Assessment Tool) model using unadjusted and adjusted precipitation products as input. Streamflow comparison is based on mass balance error and Nash‐Sutcliffe efficiency coefficient. Finally, the contribution of how adjustment to correct misses, false alarms, and bias impacts adjusted datasets and the potential impact that the adjustment methodology can have on hydrological applications such as water resource monitoring and flood prediction are explored.     

Projections of 21st Century Sierra Nevada Local Hydrologic Flow Components Using an Ensemble of General Circulation Models1

Abstract: Sierra Nevada snowmelt and runoff is a key source of water for many of California’s 38 million residents and nearly the entire population of western Nevada. The purpose of this study was to assess the impacts of expected 21st Century climatic changes in the Sierra Nevada at the subwatershed scale, for all hydrologic flow components, and for a suite of 16 General Circulation Models (GCMs) with two emission scenarios. The Soil and Water Assessment Tool (SWAT) was calibrated and validated at 35 unimpaired streamflow sites. Results show that temperatures are projected to increase throughout the Sierra Nevada, whereas precipitation projections vary between GCMs. These climatic changes drive a decrease in average annual streamflow and an advance of snowmelt and runoff by several weeks. The largest streamflow reductions were found in the mid‐range elevations due to less snow accumulation, whereas the higher elevation watersheds were more resilient due to colder temperatures. Simulation results showed that decreases in snowmelt affects not only streamflow, but evapotranspiration, surface, and subsurface flows, such that less water is available in spring and summer, thus potentially affecting aquatic and terrestrial ecosystems. Declining spring and summer flows did not equally affect all subwatersheds in the region, and the subwatershed perspective allowed for identification for the most sensitive basins throughout the Sierra Nevada.     

Improving bioavailability of phosphorous from cattle dung by using phosphatase immobilized on natural clay and nanoclay

The high P retention of acidic Andisols makes necessary to increase our technological approaches in pasture management in the animal system production. Here, we evaluated the clay- or nanoclay-acid phosphatase complexes for improving phosphorus mineralization from degraded cattle dung. We implemented an immobilization mechanism of acid phosphatase (AP) using natural clays (allophanic and montmorillonite) and nanoclays as support materials. Also, we evaluated the mineralization of organic P containing in decomposed cattle dung with clay- and nanoclay-AP complexes by incubation studies. Clays and nanoclays were characterized by microscopy techniques as atomic force and confocal-laser scanning microscopy. We found that these support materials stabilized AP by encapsulation. Our results showed that immobilization on allophanic or montmorillonite materials improved both the specific activity (4-48%) and the V_max (28-38%) of AP. Moreover, the enzyme had a better performance when immobilized on clay and nanoclay from Andisol than on montmorillonite materials. Phosphorous mineralization of cattle dung was regulated by water-soluble P present in the dung and P re-adsorption on allophanic materials. However, we were able to detect a potential capacity of AP immobilized on allophanic nanoclays as the best alternative for P mineralization. Further research with initially low water-soluble P containing organic materials is required to quantify the P mineralization potential and bioavailability of P from dung.     

低浓度氨氮废水的离子交换法脱氮

分别研究了沸石的等温吸附模型,改性沸石在交换柱中的穿透与再生,通过化学沉淀法对再生废液中氨氮的回收等。结果显示:60～80目单位重量天然斜发沸石对氨氮的饱和交换容量为4.15 mg/g;30 mg/L的氨氮废水经过交换柱后沸石的穿透吸附容量和平衡吸附容量分别为:4.50 mg/g和4.757 mg/g。化学再生后,用化学沉淀法使再生废液中氨氮由202 mg/L降到16.3 mg/L。     

腾冲县旅游气候适宜度分析研究

基于1981—2010年云南省腾冲县基础气候的数据分析,建立了适用于腾冲县的旅游适宜度指数。结果显示,腾冲县全年的旅游适宜度指数变幅为16.5—24.0,表明全年的气候都适合旅游,其中每年的10月至次年的3月最适宜旅游,4—9月适宜旅游。此外,对合理开发气候旅游资源进行了有针对性的探讨,为地方旅游产业发展规划提供了气象依据。     

基于地统计的区域气象要素空间插值与分布研究

利用地统计学的理论与方法,以黄土高原南部地区为例,分别运用径向基函数法、普通克里格法和反距离权重法对研究区内139个气象台站2010年的年平均气温和年降水量进行了空间插值,并利用交叉检验方法对插值精度进行了评估。评估结果表明,3种空间插值方法对研究区域内的气象要素进行统计内插的效果都较好。对气温来说,径向基函数法最好,其均方根预测误差值仅为2.263,其次是反距离权重法和普通克里格最好,均方根预测误差值分别仅为2.377和2.38;对降水来说,则是普通克里格法最优,均方根预测误差最小,且其标准均方根预测误差值为0.8205,接近于1。由此可见,对年均降水量采用普通克里格插值法的精度较高。     

鸟粪石法回收制肥工业废水中氨氮的中试研究

制肥工业废水中氨氮浓度高,难以直接进行生化反应,采用鸟粪石沉淀法可有效去除并回收氨氮。利用中试反应器回收某制肥工业废水中的氨氮,采用氯化镁与氧化镁作为联用镁源,通过考察不同进料方式、搅拌速度、停留时间等因素的影响,确定了鸟粪石法回收氨氮的最佳工况:采用间歇进水、固体投加镁源的投料方式,搅拌速度300 r/min,停留时间2 h。最佳条件下,氨氮去除率达到93.5%,磷残余率小于0.3%,生成的鸟粪石纯度可达85.6%,砷和铅的质量分数分别为0.0036和0.0008,符合肥料中重金属限值(GB/T 23349-2009),其他重金属均未检出。因此,回收产品有很好的利用价值。经济分析表明磷源是此方法处理成本较高的主要原因。