Impact of intensity variability of the Asian summer monsoon anticyclone on the chemical distribution in the upper troposphere and lower stratosphere          下载免费PDF全文

Kecheng Peng  Jiali Luo  Jiayi Mu  Xiaoqun Cao  Hongying Tian  Lin Shang  Yanan Guo 《大气和海洋科学快报》2022,15(3):100144

During the Asian summer monsoon (ASM) season, the process of stratosphere–troposphere exchange significantly affects the concentration and spatial distribution of chemical constituents in the upper troposphere and lower stratosphere (UTLS). However, the effect of the intensity of the Asian summer monsoon anticyclone (ASMA) on the horizontal distribution of chemical species within and around the ASMA, especially on the daily time scale, remains unclear. Here, the authors use the MERRA-2 reanalysis dataset and Aura Microwave Limb Sounder observations to study the impact of ASMA intensity on chemical distributions at 100 hPa during the ASM season. The intraseasonal variation of ASMA is classified into a strong period (SP) and weak period (WP), which refer to the periods when the intensity of ASMA remains strong and weak, respectively. The relatively low ozone (O₃) region is found to be larger at 100 hPa during SPs, while its mixing ratio is lower than during WPs in summer. In June, analysis shows that the O₃ horizontal distribution is mainly related to the intensity of AMSA, especially during SPs in June, while deep convections also impact the O₃ horizontal distribution in July and August. These results indicate that the intraseasonal variation of the ASMA intensity coupled to deep convection can significantly affect the chemical distribution in the UTLS region during the ASM season.摘要亚洲夏季风期, 平流层–对流层物质交换过程能显著影响上对流层下平流层化学成分的浓度变化和空间分布. 然而, 亚洲夏季风反气旋强度的季节内变化对其内部和周围地区化学成分水平分布的影响尚不清楚. 本文将亚洲夏季风反气旋划分为季节内强周期和弱周期, 发现当亚洲夏季风反气旋更强时, 100 hPa O₃低值区的面积更大, O₃浓度更低. 但是这种影响主要体现在6月份, 7, 8月的O₃水平分布还受东南亚地区深对流的影响. 这些结果表明亚洲夏季风反气旋强度和深对流的季节内变化可以显著影响亚洲夏季风期上对流层下平流层的化学分布.  相似文献   

黄河中下游区域生态需水量研究     

纪书华  赵全升  吴美玲  袁家淼  闫家怡 《海洋湖沼通报》2006,(4):38-43

在生态需水量概念与分类的基础上,以傍黄河流域典型县域为例,采用彭曼-蒙蒂斯(Penman-Monteith)公式和基于水循环理论的方法对该地区的最小生态学需水量进行了估算。两种方法计算的最小生态需水量分别为6.097×108m3、7.018×108m3,平均值为6.56×108m3。计算结果与其它成果比较相差较小,说明该方法是合理的,可以推广应用于其它半干旱、半湿润区域,为区域水资源可持续开发利用的规划和管理提供科学依据。  相似文献   

山东小清河的浮游植物   总被引：2，自引：1，他引：2  

田家怡 《海洋湖沼通报》1995,(1):38-46

对山东小清河全程１３个测点，在春、夏、秋、冬季分析进行了４次调查，共发现浮游植物１４５种，隶属于７门３２科６２属。  相似文献   

山东小清河的轮虫类   总被引：1，自引：1，他引：1  

田家怡 《海洋湖沼通报》1996,(1):38-41

对小清河的轮虫类进行了多年调查，本文报导了轮虫类３７种，特鉴定１种，隶属于９科２２属，其中７种轮虫的山东省新纪录。  相似文献   

代际传递视角下中国城市家庭住房产权获得——基于上海的实证研究     

崔璨  崔军茹  李佳怡 《世界地理研究》2021,30(1):167-178

随着中国城市住房价格大幅上涨,住房可支付性成为青年面临的严峻挑战。尽管越来越多的研究开始关注中国城市住房不平等问题,但大多侧重住房资源分配由国家向市场的转移,相对而言,家庭在住房资源获取中的作用被忽视。本文选取上海市作为研究区域,使用2013年长三角社会变迁调查数据,以上海“80后”青年家庭为研究对象,重点关注夫妻双方父母的住房状况和社会经济属性对青年家庭住房产权获得的影响及性别差异。研究发现,父母户口很大程度上影响着青年家庭的住房结果;不同户口状况的父母住房财富存在较大分化,其影响着年轻家庭可获得的家庭购房资助的数额。与妻子父母相比,丈夫父母的户口状况对青年家庭住房结果的影响更大;而妻子父母在本地且拥有住房产权的双重优势与青年家庭住房产权获得有更强的正向联系。家庭背景对子代住房的影响结合婚姻匹配机制使住房优势或劣势在青年家庭内部累积,或会加剧住房分化现象。  相似文献   

Distribution of dominant zooplankton species along a latitudinal gradient in China sea during spring     

Jiayi Xu  Zhaoli Xu  Qian Gao 《中国海洋大学学报(英文版)》2016,15(3):502-508

Dominant species of zooplankton community vary with latitude. Though China possesses a vast coastal area in northwestern Pacific, studies on the latitudinal dominant species gradient are rare. We collected zooplankton samples from Haizhou Bay(34.56?–35.19?N, 119.51?–120.30?E), Yueqing Bay(28.14?–28.38?N, 121.10?–121.21?E) and Dongshan Bay(23.65?–23.90?N, 117.45?–117.60?E) in May 2012 and May 2013 to preliminarily characterize the latitudinal dominant species distribution. All the samples were collected vertically using a 0.505 mm mesh plankton net with 0.8 m in mouth diameter from bottom to surface. Calanus sinicus, Aidanosagitta crassa, Labidocera euchaeta, Zonosagitta nagae, Acartia pacifica and Paracalanus parvus were found to be dominant. C. sinicus was the most dominant species and the unique one occurred in all three bays. With latitude decreasing, both the abundance and proportion of C. sinicus declined sharply. Cluster analysis showed that the 6 dominant species could be divided into 3 groups, based on their occurrences in the three bays. Our results suggested that the distribution of dominant species along the coast of China has a significant latitudinal gradient. C. sinicus which widely distributes in the coastal water of the northwestern Pacific can well adapt to the temperature at different latitudes. The high abundance in Haizhou Bay indicated that C. sinicus was an exemplary warm-temperate species, and more commonly occurs in the north of China seas. The ecological characteristics of dominant species change from warm-temperate type in high-latitudinal bays to warm water type in low-latitudinal bays.  相似文献   

Direct and indirect effects of rainfall and vegetation coverage on runoff,soil loss,and nutrient loss in a semi-humid climate     

Jiayi Huo  Changjun Liu  Xinxiao Yu  Lihua Chen  Wenge Zheng  Yuanhui Yang  Changwen Yin 《水文研究》2021,35(1):e13985

Soil and nutrient loss play a vital role in eutrophication of water bodies. Several simulated rainfall experiments have been conducted to investigate the effects of a single controlling factor on soil and nutrient loss. However, the role of precipitation and vegetation coverage in quantifying soil and nutrient loss is still unclear. We monitored runoff, soil loss, and soil nutrient loss under natural rainfall conditions from 2004 to 2015 for 50–100 m² runoff plots around Beijing. Results showed that soil erosion was significantly reduced when vegetation coverage reached 20% and 60%. At levels below 30%, nutrient loss did not differ among different vegetation cover levels. Minimum soil N and P losses were observed at cover levels above 60%. Irrespective of the management measure, soil nutrient losses were higher at high-intensity rainfall (Imax30>15 mm/h) events compared to low-intensity events (p < 0.05). We applied structural equation modelling (SEM) to systematically analyze the relative effects of rainfall characteristics and environmental factors on runoff, soil loss, and soil nutrient loss. At high-intensity rainfall events, neither vegetation cover nor antecedent soil moisture content (ASMC) affected runoff and soil loss. After log-transformation, soil nutrient loss was significantly linearly correlated with runoff and soil loss (p < 0.01). In addition, we identified the direct and indirect relationships among the influencing factors of soil nutrient loss on runoff plots and constructed a structural diagram of these relationships. The factors positively impacting soil nutrient loss were runoff (44%–48%), maximum rainfall intensity over a 30-min period (18%–29%), rainfall depth (20%–27%), and soil loss (10%–14%). Studying the effects of rainfall and vegetation coverage factors on runoff, soil loss, and nutrient loss can improve our understanding of the underlying mechanism of slope non-point source pollution.  相似文献   

Determination of Mohr–Coulomb Shear Strength Parameters from Generalized Hoek–Brown Criterion for Slope Stability Analysis     

Jiayi Shen  S. D. Priest  M. Karakus 《Rock Mechanics and Rock Engineering》2012,45(1):123-129

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A Simplified Failure Criterion for Intact Rocks Based on Rock Type and Uniaxial Compressive Strength   总被引：2，自引：1，他引：1  

Jiayi Shen  Rafael Jimenez  Murat Karakus  Chaoshui Xu 《Rock Mechanics and Rock Engineering》2014,47(2):357-369

The uniaxial compressive strength (UCS) of intact rock, which can be estimated using relatively straightforward and cost-effective techniques, is one of the most practical rock properties used in rock engineering. Thus, constitutive laws to represent the strength and behavior of (intact) rock frequently use it, along with additional intrinsic rock properties. Although triaxial tests can be employed to obtain best-fit failure criterion parameters that provide best strength predictions, they are more expensive and require time-consuming procedures; as a consequence, they are often not readily available at early stages of a project. Based on the analysis of an extensive triaxial test database for intact rocks, we propose a simplified empirical failure criterion in which rock strength at failure is expressed in terms of confining stress and UCS, with a new parameter which can be directly estimated from the UCS for a specified rock type in the absence of triaxial test data. Performance of the proposed failure criterion is then tested for validation against experimental data for eight rock types. The results show that strengths of intact rock estimated by the proposed failure criterion are in good agreement with experimental test data, with small discrepancies between estimated and measurements strengths. Therefore, the proposed criterion can be useful for preliminary (triaxial) strength estimation of intact rocks when triaxial tests data are not available.  相似文献   

中国城市洪涝实时预报研究:现状与挑战     

林珲  吴贤宇  潘家祎  邹海波 《测绘学报》2022,51(7):1306-1316

全球气候变化和快速城市化打破了城市降水—汇水—排水原有的平衡,加剧了中国城市洪涝问题,造成了巨大的生命和财产损失。因此,亟须探索精确、高效的城市洪涝预报方法,提高城市防洪抗灾能力,降低灾害损失影响。然而,城市气象水文过程的复杂性使得城市洪涝实时预报研究面临诸多挑战。本文梳理了我国城市洪涝频发的原因,总结了国内城市洪涝实时预报研究在数据和模型方面的进展,指出了当前研究面临的问题和挑战,并对未来的发展趋势进行了展望,以期为我国城市防洪减灾研究和工作提供参考依据。  相似文献