南通市大气降水中硫酸根的影响因素研究

随着环境空气污染的日益加重,研究硫酸根与降水中其他因子的相关关系对准确反映大气的质量状况具有重要意义.根据南通市2018年的降水监测数据,采用SPSS统计分析软件对降水中的硫酸根浓度与pH值、电导率以及常见阴、阳离子进行相关性分析,推断出离子的可能来源.通过多元线性回归模型可以对南通的硫酸根离子浓度进行预测.研究为南通...     

生态环境执法事件本体构建研究和实践应用

结合生态环境执法特点,建立生态环境执法事件本体模型,并对执法不同阶段的相关概念进行统一语义约定.该模型通过时间、环境、对象、动作、状态和语言描述六要素来描述执法事件,通过执法事件类、事件类间关系、事件推理规则和事件实例案件的四元组结构进行执法事件的表达.同时,以某热力工程公司运营的锅炉房超标排放烟气污染物的执法案件构建...     

晶析辅助化学沉淀法的研究

在用化学沉淀法处理高浓度氨氮废水的基础上,引入晶析辅助化学沉淀法的思路,即将晶种投加到反应器中,然后从氨氮去除率、生成晶体的粒型、粒径三个方面分析不同晶种对生成晶体的影响,并对生成的磷酸铵镁晶体进行X光衍射分析。得出结论：投加晶种有利于提高氨氮的去除率,但不会明显提高生成晶体的粒径。     

Using SWAT to Model Streamflow in Two River Basins With Ground and Satellite Precipitation Data1

Abstract: Both ground rain gauge and remotely sensed precipitation (Next Generation Weather Radar – NEXRAD Stage III) data have been used to support spatially distributed hydrological modeling. This study is unique in that it utilizes and compares the performance of National Weather Service (NWS) rain gauge, NEXRAD Stage III, and Tropical Rainfall Measurement Mission (TRMM) 3B42 (Version 6) data for the hydrological modeling of the Middle Nueces River Watershed in South Texas and Middle Rio Grande Watershed in South Texas and northern Mexico. The hydrologic model chosen for this study is the Soil and Water Assessment Tool (SWAT), which is a comprehensive, physical‐based tool that models watershed hydrology and water quality within stream reaches. Minor adjustments to selected model parameters were applied to make parameter values more realistic based on results from previous studies. In both watersheds, NEXRAD Stage III data yields results with low mass balance error between simulated and actual streamflow (±13%) and high monthly Nash‐Sutcliffe efficiency coefficients (NS > 0.60) for both calibration (July 1, 2003 to December 31, 2006) and validation (2007) periods. In the Middle Rio Grande Watershed NEXRAD Stage III data also yield robust daily results (time averaged over a three‐day period) with NS values of (0.60‐0.88). TRMM 3B42 data generate simulations for the Middle Rio Grande Watershed of variable qualtiy (MBE = +13 to ?16%; NS = 0.38‐0.94; RMSE = 0.07‐0.65), but greatly overestimates streamflow during the calibration period in the Middle Nueces Watershed. During the calibration period use of NWS rain gauge data does not generate acceptable simulations in both watersheds. Significantly, our study is the first to successfully demonstrate the utility of satellite‐estimated precipitation (TRMM 3B42) in supporting hydrologic modeling with SWAT; thereby, potentially extending the realm (between 50°N and 50°S) where remotely sensed precipitation data can support hydrologic modeling outside of regions that have modern, ground‐based radar networks (i.e., much of the third world).     

GIS‐Based Spatial Precipitation Estimation: A Comparison of Geostatistical Approaches1

Abstract: As one of the primary inputs that drive watershed dynamics, the estimation of spatial variability of precipitation has been shown to be crucial for accurate distributed hydrologic modeling. In this study, a Geographic Information System program, which incorporates Nearest Neighborhood (NN), Inverse Distance Weighted (IDW), Simple Kriging (SK), Ordinary Kriging (OK), Simple Kriging with Local Means (SKlm), and Kriging with External Drift (KED), was developed to facilitate automatic spatial precipitation estimation. Elevation and spatial coordinate information were used as auxiliary variables in SKlm and KED methods. The above spatial interpolation methods were applied in the Luohe watershed with an area of 5,239 km², which is located downstream of the Yellow River basin, for estimating 10 years’ (1991‐2000) daily spatial precipitation using 41 rain gauges. The results obtained in this study show that the spatial precipitation maps estimated by different interpolation methods have similar areal mean precipitation depth, but significantly different values of maximum precipitation, minimum precipitation, and coefficient of variation. The accuracy of the spatial precipitation estimated by different interpolation methods was evaluated using a correlation coefficient, Nash‐Sutcliffe efficiency, and relative mean absolute error. Compared with NN and IDW methods that are widely used in distributed hydrologic modeling systems, the geostatistical methods incorporated in this GIS program can provide more accurate spatial precipitation estimation. Overall, the SKlm_EL_X and KED_EL_X, which incorporate both elevation and spatial coordinate as auxiliary into SKlm and KED, respectively, obtained higher correlation coefficient and Nash‐Sutcliffe efficiency, and lower relative mean absolute error than other methods tested. The GIS program developed in this study can serve as an effective and efficient tool to implement advanced geostatistics methods that incorporate auxiliary information to improve spatial precipitation estimation for hydrologic models.     

澳洲冷空气活动与长江中下游降水的联系分析

利用澳洲范围700 hPa温度场的再分析资料和长江中下游降水资料,通过谱分析方法,试析了澳洲冷空气活动对我国长江中下游主汛期降水的影响,并进一步分析了西太平洋副热带高压在此中起的作用。研究结果表明：在我国夏季,澳洲变温与涝年长江中下游主汛期的降水都具有77 d的周期,两者存在着77 d周期的遥相关,同时在77 d的周期两者呈现同位相振荡。也就表明在77 d的周期澳洲冷高压变动时经73 d后影响长江中下游降水。同时也得出澳洲冷高压强时,西太平洋副热带高压北移,长江中下游受西太平洋副热带高压控制,晴天少雨;澳洲冷高压弱时,西太平洋副热带高压南落,长江中下游处西太平洋副热带高压边缘,多降水天气。以上结论对长江中下游降水预报有一定的指示意义。     

洪泽湖流域洪涝灾害演变趋势及其与El Nio事件关系

为分析洪泽湖流域洪涝灾害在千年尺度序列上的演变趋势,采用统计历史洪涝记录的方法,分析了气候变化背景下洪涝灾害的响应过程,探讨了洪泽湖流域洪涝灾害同El Nio事件的关系。结果表明：近1 000 a来洪泽湖流域洪涝灾害的频度总体是趋于上升的,这种变化趋势同气候变化的趋势是一致的。研究结果显示：公元1000~1400年洪涝记录偏少,同我国东部地区尤其是中世纪暖期出现的一次200 a以上的干旱化过程有较好的对应性。1400~1800年是洪泽湖流域洪涝的多发期,这一事实同我国东部1550~1850年小冰期期间总体偏湿的环境特征相一致。分析洪涝灾害变化同El Nio事件对应性关系表明：在El Nio事件年及其次年是洪泽湖流域洪涝的多发年份。这可能是由于El Nio事件通过改变西太平洋副高的强度与位置,以及大气环流形势而引起的降水异常所致。了解洪泽湖流域洪涝的演变趋势及其同El Nio的关系对于长期防灾减灾策略具有重要的参考意义。     

湖北省降水变化分析

全面分析了湖北省７２个气象台站自建站有观测记录以来的降水资料后,发现全省降水差异较大,分布不均;不同年代之间降水变化亦存在一定的差异。东部和江汉平原６０,７０年代偏少,８０,９０年代偏多,鄂北,三峡河谷和鄂西南５０,７０和９０年代偏少,６０,８０年代偏多,全省平均为７０年你偏少,８０年代偏多。１９８０年以来东部地区降水偏多,降大雨以上的日数增多,西部地区则相反。     

四种再分析资料与长江中下游地区降水观测资料的对比研究

为了获得对中国区域降水刻画能力较好的再分析资料,以长江中下游地区为例,将PREC/L、CMAP、GPCP及NCEP2四种再分析降水资料与台站降水观测资料进行了多年和逐年平均的年、季、月降水量距平的时空相关分析和方差分析,比较了再分析资料对该区降水刻画能力的差异。首先对该区域的观测资料、CMAP、GPCP及NCEP2资料进行插值,使所有资料具有相同的空间分辨率,在此基础上比较再分析资料与观测资料年、季、月平均的降水变化特征。结果表明,四种再分析资料与观测资料的距平相关系数（均方根误差）由大到小（由小到大）的变化次序为：PREC/L→CMAP→GPCP→NCEP2,四种再分析资料均能较好地刻画出长江中下游地区降水的时空分布特征,尤以PREC/L资料对该区域降水变化的时空演变规律描述得最好。最后,利用PREC/L资料与观测资料对该区域降水的时空特征进行了相关分析、EOF分析和功率谱分析,结果显示夏季平均降水量具有23和31年的显著周期,EOF分析的前两个模态的时间变化分别具有23和28年的显著周期,这些显著周期都通过了95％的红噪声检验.     

Nitrogen interception in floodwater of rice field in Taihu region of China

A field experiment located in Taihu Lake Basin of China was conducted,by application of urea or a mixture of urea with manure, to elucidate the interception of nitrogen(N)export in a typical rice field through"zero-drainage water management"combined with sound irrigation,rainfall forecasting and field drying,N concentrations in floodwater rapidly declined before the first event of field drying after three split fertilizations,and subsequently tended to retum to the background level.Before the first field drying,total particulate nitrogen(TPN)was the predominant N form in floodwater of plots with no N input,dissolved inorganic nitrogen(DIN)on plots that received urea only,and dissolved organic nitrogen(DON)on plots treated with the mixture of urea and manure.Thereafter TPN became the major form.No N export was found from the rice field,but total nitrogen(TN)of 15.8 kg/hm~2 was remained,mainly due to soil N sorption.The results recommended the zero-drainage water management for full-scale areas for minimizing N export.