Research Progresses and Prospect of Chimney Effect about Carbon Cycle in the Karst Cave System   总被引：4，自引：0，他引：4  

Luo Weijun Wang Shijie  Wang Shijie  Liu Xiuming 《地球科学进展》2014,29(12):1333-1340

There is a long history of several decades for the systemic study of global carbon cycles, and many important achievements have been obtained. However, these studies of carbon cycles in the karst area that accounts for about 10% of the entire Earth’s land area were paid attention gradually only in the past twenty. Recent researches suggest that karstification has important effects of the global carbon cycle. At present, scientists have had a very comprehensive and systemic understanding of various factors affecting the carbon cycle in the karst area, and estimated the carbon source or sink. However, unlike non karst area, there are generally many caves and fractures that have various sizes and morphologies in the karst area. These caves and fractures provide gas exchange between epikarst zone and atmosphere with a channel (as a window) in the karst area. There have been few reports about the role of the channel in the carbon cycle in the karst area. Previous studies have shown there is an obvious chimney effect in the karst cave system, which cannot be ignored. However, through the overview of the previous studies on carbon cycle of chimney effect in the karst cave system, we found that there were still many problems need to be further studied, such as the contribution of chimney effect to regional and global atmospheric CO₂; the regional differences, the seasonal changes and its reason (driving force) of chimney effect; the influences of chimney effect on the local ecosystem. With the development of modern science and technology (such as eddy covariance, large aperture scintillation and isotope), it becomes possible to solve the above problems. Therefore, it is necessary to use these advanced means for automatic and continuous monitoring and researching the carbon cycles in the karst cave system, which are of important significance for the researches of carbon cycles in the karst area, even for the global carbon cycle studies.  相似文献   

TRIME-T3用于盐碱地土壤含水量测定的试验研究     

潘延鑫  罗纨  贾忠华  井思媛  李山  武迪 《干旱区地理》2017,40(1):108-113

以陕西省富平县卤泊滩盐碱地改良区为例,在其上游地段选取两块农田为研究对象,布置典型观测断面并埋设测管,运用TRIME-T3法和烘干法对观测断面土壤剖面含水量进行测定,并同步测定土壤含盐量。对两种方法测得的土壤含水量进行对比分析,研究土壤盐分对TRIME-T3法测定的土壤含水量影响以及该方法在盐碱地农田土壤剖面含水量测试中的应用。研究结果显示：（1）TRIME-T3法测量值较烘干法值偏大,但两者之间有较高的相关性,回归分析结果表明可以用y=0.866 3x+0.754 5的线性函数进行校正,校正后的TRIME-T3测量值中将有94.4%的值接近土壤含水量真实值。（2）通过对校正函数进行实例验证,结果表明TRIME-T3标定曲线值与烘干法测定值非常接近,绝对误差<1 cm³·cm^-3,相对误差在5%以下,表明TRIME-T3法通过一定的校正后可以很好地表达该盐碱地农田土壤剖面含水量信息。（3）通过对TRIME-T3测定的含水量与相应含盐量进行分析,发现两者之间的相关性并不显著,表明该方法可适用于盐碱地农田土壤剖面含水量测定。该研究结果可为类似地区盐碱地土壤剖面水分测定技术（TRIME-T3）的应用提供科学依据和理论参考。  相似文献   

Toxic Effects of Copper‐Based and Synthetic Organic Pesticides on Activated Sludge     

Berrak Erol Nalbur  Sevil Çalışkan Eleren  Semih Şahin  Ufuk Alkan 《洁净——土壤、空气、水》2012,40(1):39-44

Toxic effects of five commonly used pesticides on the biomass of a municipal activated sludge system were determined on the basis of the reduction in the oxygen uptake rate (OUR) and specific oxygen uptake rate (SOUR). Toxicity levels of the selected pesticides were determined by employing a modified OECD 209 (Organisation for Economic Cooperation and Development) method which was performed as batch experiments using a respirometer. Copper sulphate (CuSO₄ · 5 H₂O), copper oxychloride (Cu₂Cl(OH)₃), copper calcium oxychloride (CaCu₃Cl₂(OH)₆) as copper‐based pesticides and chlorsulphuron (C₁₂H₁₂ClN₅O₄S), 2,4‐dichlorophenoxyacetic acid (2,4‐D) (C₈H₆Cl₂O₃) as synthetic organic pesticides were selected for the experiments. The EC₅₀ values were determined to be 78, 249 and 281 mg/L for CuSO₄ · 5 H₂O, Cu₂Cl(OH)₃ and CaCu₃Cl₂(OH)₆, respectively. Corresponding values for C₁₂H₁₂ClN₅O₄S and 2,4‐D were 860 and 3664 mg/L, respectively. Results indicated that toxicity effects of copper‐based pesticides were higher than that of synthetic organic pesticides. CuSO₄ · 5 H₂O was found to exert the highest toxicity among the copper‐based pesticides, whereas, C₁₂H₁₂ClN₅O₄S was determined to be the most toxic among the organic pesticides on activated sludge biomass.  相似文献   

华北平原典型工业城市秋、冬季大气细颗粒物污染特征     

钱若芷  田密  陈阳  赵晴  彭超  石光明  杨复沫 《地球化学》2021,50(1):1-11

济宁市是位于华北平原大气污染传输通道上的工业城市,为研究其秋、冬季细颗粒物(PM2.5)的污染特征,在市区的3个站点进行了PM2.5的同步滤膜采样.采样期为2018年10月15日至2019年1月31日,涵盖非采暖期和采暖期(自2019年11月15日始),共270个小流量滤膜样品.研究结果表明,济宁市秋、冬季PM2.5平...  相似文献   

T639和EC模式对内蒙古主要天气系统的预报性能检验   总被引：2，自引：0，他引：2  

荀学义  孟雪峰  王学强  胡英华  金迎春  赵斐  拓彦军  张旭 《气象科技》2014,42(5):832-838

利用2012年T639和EC模式500hPa高度场预报产品及ECMWF客观再分析资料,采用天气学检验方法,对内蒙古主要天气影响系统之西风槽、贝加尔湖冷涡、蒙古冷涡和东北冷涡数值产品的预报性能进行检验。检验结果表明:T639和EC模式产品对内蒙古影响系统具有较好的预报性能,36h内的预报性能更为显著。EC模式产品预报准确率优于T639模式产品,但对内蒙古东部地区影响系统的预报稳定性相对较差。T639模式产品在36h的预报能力比较高,对影响系统的生成时间、槽线位置、移动速度及中心强度4项检验指标预报准确率均在80%以上。EC模式预报产品,48h内对影响系统4项检验指标预报准确率均在80%以上。随着预报时效延长,T639和EC模式产品预报能力均有所下降。两套模式产品与实况相关系数空间分布在各时效均具有显著的相关关系,并且对应相关系数空间分布,T639和EC模式产品标准差的大值中心与相关系数的低值中心基本一致。  相似文献   

青藏高原雪冰中碳质气溶胶含量变化   总被引：7，自引：0，他引：7  

刘先勤  王宁练  姚檀栋  徐柏青  赵华标  贺建桥  郭学军 《地学前缘》2006,13(5):335-341

文中采用供氧两步加热的方法对过滤到石英膜上的雪冰中碳质气溶胶含量进行分析,其中有机碳(OC)和元素碳(EC)分别在340和650℃的条件下进行热解、氧化分离,生成的CO2转化成CH4并由气相色谱仪氢火焰离子化检测器(FID)检测其含量。空白测试表明,该系统的OC本底值为(0·50±0·04)(1σ)μgC,EC为(0·38±0·04)(1σ)μgC。利用这套分析系统对青藏高原8条冰川的34个雪冰和降水样品中OC和EC的含量进行了测试。结果表明,在青藏高原雪冰中OC和EC含量自东向西、自北向南呈明显的下降趋势(西昆仑除外)。在高原东北部EC的质量分数相对较高,平均为79·2ng·g-1;在喜马拉雅西段EC的质量分数最低,平均为4·3ng·g-1。在冰川表面,雪的融化使雪冰中碳质气溶胶聚集,并导致其含量明显升高,该过程降低了雪表面的反照率,加速了冰川的消融。  相似文献   

基于ECMWF细网格、GRAPES _MESO的短时强降水潜势预报和检验          下载免费PDF全文

吴迎旭  孟莹莹  周一  李兴权  刘松涛  吴岩 《沙漠与绿洲气象(新疆气象)》2021,15(5):30-40

摘要：利用2016-2018年6-8月ECMWF细网格、GRAPES _MESO、黑龙江省822个自动站资料研究黑龙江省6-8月短时强降水（一般短时强降水和极端短时强降水）的预报方法和各项影响因子指标与他们之间的融合。采用双线插值法或临近格点法、分位数法、配料法、排除法、多重分析法，形成以水汽、不稳定、抬升为框架的客观预报方法。研究发现，强降水的环境背景不仅受限于各物理因子阈值，也与他们之间融合密切相关。各因子间存在一定旬差异和日较差，夜间与水汽相关的各阈值明显大于白天，白天热力不稳定性高于夜间。6月中上旬与水汽含量相关的各因子阈值小于其他时段。从检验结果上看，由于强降水的突发性、局地形和研究方法以及模式本身的特性，预报的空报率非常大，漏报率较低，TS评分最低且随着分布密度的降低而降低。一般强降水检验中，两种模式点对点检验的TS评分为0.015左右，14km和40km点对面检验夜间TS评分约0.03和0.08。极端强降水检验中，两种模式点对点检验TS评分约0.004，14km和40km点对面检验准确率约分别为0.005和0.02。7月份由于强降水分布密度相对较大，检验效果也相对较好。一般性强降水EC细网格TS评分高于GRAPES_MESO，而极端强降水检验TS评分刚好相反。  相似文献