地下河系统水动态监测网络优化对比分析:以桂林海洋-寨底地下河系统为例     

邹胜章  杨苗清  陈宏峰  朱丹尼  周长松  李录娟  谢浩 《地学前缘》2019,26(1):326-335

基于我国南方地区岩溶发育极不均匀、水位水质动态变化快的特点,通过对信息熵法和防污性能法所得结果的对比,分析在缺少系列监测资料条件下,利用岩溶水系统防污性能评价结果快速布设地下河系统水动态监测网的可行性及其布设原则。根据防污性能评价结果,结合水循环特征,桂林海洋-寨底地下河系统水动态监测网需由17个监测站组成;采用信息熵法对现有35个监测站进行优化后,认为只需要12个监测站就可组成最优监测网,但这12个监测站点与采用防污性能评价法得到的点位完全重合,且均位于防污性能差的地区。对比分析认为,以地下水系统防污性能评价结果布设地下水动态监测网是可行性的,因为岩溶发育区既是防污性能差的地区,也是地下水动态变化快的地区,能充分反映地下河系统水质水量变化。采用防污性能评价法布设地下水动态监测网时,需要充分认识和了解地下河系统水文地质条件和地下河管道结构特征,且需要遵循以下原则:(1)在岩溶发育相对较弱的系统中部(基本上不存在防污性能差的地区)不设置监测站点;(2)在距离地下河出口较近的岩溶发育区内(即防污性能差的地区)监测站点可由地下河出口替代;(3)对于多支管道系统,岩溶发育相对较弱且距离较短的小型支管道上可以不布设监测站,由支管道与主管道交汇处的监测站代替。  相似文献   

Investigation of inner-basin variation: Impact of large reservoirs on water regimes of downstream water bodies     

Xue Dai  Zhongbo Yu  Guishan Yang  Chong-Yu Xu  Rongrong Wan 《水文研究》2021,35(5):e14241

Large dams and reservoirs alter not only the natural flow regimes of streams and rivers but also their flooding cycles and flood magnitudes. Although the effect of dams and reservoirs has been reported for some vulnerable locations, the understanding of the inner-basin variation with respect to the effects remains limited. In this study, we analyse the Three Gorges Dam (TGD) built on the Changjiang mainstream (Yangtze River) to investigate the dam effect variations in the system of interconnected water bodies located downstream. We investigated the effect of flow alterations along the downstream river network using discharge time series at different gauging stations. The river–lake interactions (referring to the interactions between the Changjiang mainstream and its tributary lakes i.e. the Dongting and Poyang lakes) and their roles in modifying the TGD effect intensity were also investigated in the large-scale river–lake system. The results show that the water storage of the tributary lakes decreased after the activation of the TGD. Severe droughts occurred in the lakes, weakening their ability to recharge the Changjiang mainstream. As a consequence, the effect of the TGD on the Changjiang flow increase during the dry season diminished quickly downstream of the dam, whereas its impact on the flow decrease during the wet season gradually exacerbated along the mainstream, especially at sites located downstream of the lake outlets. Therefore, when assessing dam-induced hydrological changes, special attention should be paid to the changes in the storage of tributary lakes and the associated effects in the mainstream. This is of high importance for managing the water resource trade-offs between different water bodies in dam-affected riverine systems.  相似文献   

水文情势、土壤和水电开发对河流湿地中植物的影响研究进展     

杨娇  厉恩华  夏盈  张莹莹  王学雷 《湿地科学》2020,18(1):115-121

开展环境对河流湿地中植物的影响研究,不仅有助于了解河流湿地中植物与生态环境之间的关系,而且对河流湿地中植物的保护和恢复工作具有重要意义。根据近年来发表的环境对河流湿地中植物的影响研究成果,对河流湿地中植物的范围进行了界定,综述了与河流湿地中植物关系密切的水文情势、土壤和水电开发对其的影响,指出未来对河流湿地中植物的影响研究的方向。  相似文献   

Emission of methane and nitrous oxides from agricultural soils and related global warming potentials of Murshidabad District,West Bengal          下载免费PDF全文

Soham Biswas  Namita Chakma  Swati Mollah 《Singapore journal of tropical geography》2017,38(3):313-331

Agricultural activities emit substantial amounts of methane (CH4) and nitrous oxides (N2O), the two important greenhouse gases (GHG) with high global warming potentials (GWP). So far, many studies have already been carried out at national and state level, but lack micro‐level (district or block‐level) inventory in India. The present study sheds light on the flux of CH4 and N2O (from all possible sources) from agricultural soil of various blocks in the Murshidabad district, based on the inventory prepared, using the IPCC methodology, with adjusted emission factors and coefficients appropriate for the local level. The economy of the Murshidabad district almost completely rests on agriculture as more than 80 per cent of the population is directly or indirectly dependent on it for their livelihood. Paddy is the dominating crop, cultivated on more than 60 per cent of the gross cropped area. The present work is based on the review of various literature and reports collected from respective state government offices and websites. Results show that CH4 and N2O emission from the agricultural fields are 126.405 Gg and 0.652 Gg respectively for the year 2011?12 with a large scale spatial variation (block‐level) within the district.  相似文献   

1957-2014年库布齐沙漠地面风场特征   总被引：1，自引：1，他引：0  

肖南  董治宝  南维鸽  崔徐甲  李超  肖巍强  李露露 《中国沙漠》2018,38(3):628-636

风对沙漠化过程具有重要影响,起沙风是塑造沙漠地貌格局的主要动力。根据1957-2014年库布齐沙漠周边4个基准气象站的地面风资料,从风速、风向和输沙势等方面分析库布齐沙漠的地面风场特征。结果显示：（1）库布齐沙漠的起沙风频率与平均风速有很高的相关性;（2）年平均风速为2.7 m·s^-1,全年盛行风向为WNW-NW,为中等变率锐双峰风况,合成输沙风向约为310°。4月风速最大,为中等变率环境;8月风速较小,为高变率环境;1月风速最小,为低变率环境。3-6月风速最大,风向集中度一般;11月至翌年2月风速较大,风向集中度高;7-10月风速最小,风向集中度差;（3）20世纪80年代中后期和2007年前后风速、起沙风频率和输沙势发生了较大变化,尤其是2007年前后由减小向增大发展;（4）大气环流和地表粗糙度的改变是库布齐沙漠地面风场变化的重要原因。  相似文献   

An initial scoping of transitional justice for global climate governance     

Sonja Klinsky 《Climate Policy》2018,18(6):752-765

Geopolitical changes combined with the increasing urgency of ambitious climate action have re-opened debates about justice and international climate policy. Tensions about historical responsibility have been particularly difficult and could intensify with increased climate impacts and as developing countries face mounting pressure to take mitigation action. Climate change is not the only time humans have faced historically rooted, collective action challenges involving justice disputes. Practices and tools from transitional justice have been used in over 30 countries across a range of conflicts at the interface of historical responsibility and imperatives for collective futures. Central to this body of theory and experience is the need to reflect both backwards- and forwards-oriented elements in efforts to build social solidarity. Lessons from transitional justice theory and practice have not been systematically explored in the climate context. This article conceptually examines the potential of transitional justice practices to inform global climate governance by looking at the structural similarities and differences between the global climate regime and traditional transitional justice contexts. It then identifies a suite of common transitional justice practices and assesses their potential applicability in the climate context.

POLICY RELEVANCE

• Justice disputes, including about historical responsibility and future climate actions, are long-standing in the climate context and could intensify with increased climate impacts and broadened mitigation pressures.

• Lessons from efforts to use transitional justice mechanisms could provide insight into strategies for balancing recognition of harms rooted in the past, while creating stronger future-oriented collective action.

• Several areas of transitional justice practice including: the combination of amnesties and litigation, truth commissions, reparations and institutional change could provide useful insights for the climate context.

  相似文献   

Interdecadal variation in Korean spring drought in the early 1990s     

《Dynamics of Atmospheres and Oceans》2017

Statistical change-point analysis was applied to a spring time series of the Palmer Drought Severity Index (PDSI) in Korea, and this showed that the total analysis period can be divided into two periods: a wet period (1975–1990) and a dry period (1991–2014). To investigate the deepening of the spring drought in Korea, a difference in the spring means between the 1991–2014 and 1975–1990 periods was analyzed with respect to large-scale environments. In the recent spring, a typical pressure system pattern in winter, which was an anomalous west-high east-low pressure system pattern, was strengthened throughout the troposphere around Korea. Due to the anomalous pressure system pattern, Korea was affected by relatively cold and dry anomalous northerlies. Furthermore, the western North Pacific subtropical high (WNPSH) was not intensified, and thus the supply of warm and moist airs into Korea was further reduced due to the upper-level jet moving further to the south. In order to determine the reason for the development of the anomalous west-high east-low pressure system pattern in East Asia, the difference in spring snow depth between the two periods was analyzed, and the analysis results showed that positive anomalies were predominant throughout most regions in East Eurasia. As a result, in the analysis of the ground heat net flux, negative anomalies were strengthened in most regions in East Eurasia. The cooling effect in the surrounding regions due to the high snow depth in East Eurasia strengthened the anomalous pressure system pattern as a west-high east-low type.  相似文献   

Interdecadal variation of precipitation days in August in the Korean Peninsula     

《Dynamics of Atmospheres and Oceans》2017

The present study examines a climate regime shift in the time series of the number of rainy days during August in the Korean Peninsula. The statistical change-point analysis indicates that a significant shift occurred in the time series around 1998, providing a rationale to divide it into two parts: 1975–1997 for the shorter rainy-day period and 1998–2012 for the longer rainy-day period. To examine the cause of recent rapid increases in the number of days with precipitation in August in the Korean Peninsula, differences in the averages of large-scale environments between the 1998–2012 period and the 1975–1997 period were analyzed.The differences in stream flows showed that anomalous cyclones were reinforced in the East Asian continent while anomalous anticyclones were reinforced in the western North Pacific at all layers of the troposphere. The anomalous anticyclones reinforced in the western North Pacific were associated with the western North Pacific subtropical high (WNPSH) developed a little more toward the Korean Peninsula recently. Consequently, the Korean Peninsula has been affected by anomalous south westerlies that supplied warm and humid airs from low tropical regions to the Korean Peninsula. The vertical thermal instability (warm anomaly at lower-level and cold anomaly at middle and upper-level) developed near the Korean Peninsula. In addition, upper tropospheric jets were reinforced further recently near the Korean Peninsula to provide good environments for development of upward flows. The frequency of TCs that affect the Korean Peninsula in August also increased rapidly since 1998.  相似文献   

海岸沙丘沙运动特征若干问题的研究——以闽江口南岸为例     

陈方  贺辉扬 《中国沙漠》1997,17(4):355-361

在海岸带,沙粒粒径和水分含量是决定沙粒起动风速的最主要因素。闽江口南岸海滩沙的平均粒径为2.0Φ,水分含量多在0.3%~1.0%之间。运用Johnson的经验公式,可计算出海滩沙的起动风速为6~7m/s。这一结果与实际观测值十分吻合。由于海岸环境因素的影响,使得同等条件下海岸带沙粒的起动风速明显大于内陆沙漠沙,而风沙流的输沙率明显小于内陆沙漠沙。海岸带是风速剧变带,在引用陆地气象台站的风速记录分析海岸风况和研究风沙运动规律时,必须对风速进行订正。  相似文献   

目标函数聚类法在地下水动态分类中的应用   总被引：1，自引：0，他引：1  

孙才志  林山杉 《吉林地质》1999,18(2):50-55

地下水动态类型的划分是正确认识研究区水文地质条件与地下水开发利用之间关系的一个重要环节。本文论述了目标函数聚类法的原理与计算过程,并应用该方法对某河流附近的１５个观测孔的水位动态进行分类。分析结果表明该方法具有较高的可靠性与较广的适用性。  相似文献