Characterization of karst conduits by tracer tests for an artificial recharge scheme

Challenged by rapidly changing climate in combination with an increase in anthropogenic pressures, karst groundwater resources in the Old Town of Lijiang (OTLJ), SW China, are diminishing. Higher frequency and longer duration of dried-up periods have been observed at the Heilongtan Park (HP) Springs in recent years. Thus, there is an urgent need for an artificial recharge scheme, aimed at replenishing groundwater in the aquifer and increasing the outflow of the springs to ensure effective water resources management. Evaluation of the scheme feasibility, prior to its implementation, is important. In this study, tracer tests were conducted between the recharge area and receiving springs in order to gain insight into the transport mechanisms of karst groundwater and the structural characteristics of the aquifer. Multiple underground flow paths, exhibiting high conductivity between the recharge area and HP Springs, were revealed by the interpretation of tracer breakthrough curves. Three springs considered as the leakages of the scheme were identified. Moreover, the outflow of springs at HP and OTLJ were predicted to be increased by the artificially recharged water after 9.2 and 12.5 days, respectively. Quantitative analysis of tracer recoveries demonstrates that the springs to be recharged and the springs considered as leakages, respectively, share 45 and 55% of the increased outflow. The feasibility of the scheme has been confirmed by the tracer tests. This report provides references for the evaluation of artificial groundwater recharge and protection strategies, particularly in large and poorly investigated karst spring fields.

     

新疆生态系统健康遥感评估及关键驱动因子研究

作为我国陆地面积最大的省级行政区,新疆维吾尔自治区具有多样的生态系统结构和丰富的动植物物种资源,是我国西北地区重要的生物多样性热点研究区域。通过以新疆维吾尔自治区为研究对象,结合区域特点和定量遥感数据实时、易获取、周期性等优势,选取归一化植被指数、动物物种丰富度、干旱度、人类扰动指数四类单因子指标,依据“活力-组织-恢复力”生态健康评估模型,定量化的构建了新疆以遥感数据为主导的区域综合生态健康遥感评估指数,并进一步基于地理探测器探明不同环境驱动因子对新疆生态健康的影响程度,在县级行政区层面对该方法进行了长时间序列的应用分析和验证。结果表明:(1)新疆生态健康水平以塔里木河—叶尔羌河流域为分界线,北疆生态健康水平明显高于南疆,具有显著的空间分异性和集聚特征。(2)各环境因子对新疆生态健康的影响程度依次为:归一化植被指数(0.645)>人类扰动指数(0.512)>动物物种丰富度(0.414)>干旱度(0.116)。(3)2000—2018年新疆整体生态健康水平呈现逐步攀升的趋势,变化最为显著的区域是在昌吉回族自治州的玛纳斯县、呼图壁县以及昌吉市;阿勒泰地区的福海县和富蕴县。     

Understanding the Soil Temperature Variability at Different Depths: Effects of Surface Air Temperature,Snow Cover,and the Soil Memory

The soil temperature(ST)is closely related to the surface air temperature(AT),but their coupling may be affected by other factors.In this study,significant effects of the AT on the underlying ST were found,and the time taken to propagate downward to 320 cm can be up to 10 months.Besides the AT,the ST is also affected by memory effects-namely,its prior thermal conditions.At deeper depth(i.e.,320 cm),the effects of the AT from a particular season may be exceeded by the soil memory effects from the last season.At shallower layers(i.e.,<80 cm),the effects of the AT may be blocked by the snow cover,resulting in a poorly synchronous correlation between the AT and the ST.In northeastern China,this snow cover blockage mainly occurs in winter and then vanishes in the subsequent spring.Due to the thermal insulation effect of the snow cover,the winter ST at layers above 80 cm in northeastern China were found to continue to increase even during the recent global warming hiatus period.These findings may be instructive for better understanding ST variations,as well as land?atmosphere interactions.     

现今中国东北地区地震活动特征与趋势探讨

分析现今中国东北地区地震活动特征,得到几点结论性认识：1）从中国东北地区地震活动期的时间韵律特征和第5活动期的持续时间、地震次数等指标来看,现今中国东北地区地震活动第5活动期已经结束,2018年、2019年吉林松原5.7级、5.1级地震,或标志着中国东北地区进入了第6活动期。2）2013~2019年中国东北地区地震活动主体地区位于松辽盆地和大兴安岭地区,2个地区具有以大兴安岭与松辽盆地的分界线为轴迁移对跳的活动特征。分析5组迁移对跳轨迹认为,未来的地震具有向大兴安岭地区迁移的可能。3）以松辽盆地南缘为界,形成中国东北地区成对地震与非成对地震活动的分界线。1900年以来中国东北地区的成对地震主要发生在松辽盆地和大兴安岭地区,成对地震时间间隔为0.1~37.0个月,距离间隔最远至309.0 km,震级差最大为0.7级。松辽盆地和大兴安岭地区共发生27次5.0级以上地震,其中24次地震具有成对活动性质,成对地震发生率约为89%。成对地震中,发生在松辽盆地的占71%,发生在大兴安岭地区的占29%。成对地震活动规律在松辽盆地和大兴安岭地区具有普适性特征,可作为该区域的预测指标。4）对比2013~2015年和2015~2018年中国东北地区的面应变率结果可见,变化最为显著的区域位于松辽盆地中部,这个区域也是整个中国东北地区变化最为明显的区域,未来仍需关注该区域的地震危险性。5）松辽盆地仍将是中国东北地区浅源地震活动的主体地区。     

丰南市钱家营矿钱供2孔饮用天然矿泉水

钱供２孔矿泉水赋存于奥陶系碳酸盐岩裂隙溶洞中，供水井深１０００ｍ，利用含水段６２３．５～１０００ｍ，为深层含锶型矿泉水，银含量高达４．８１ｍｇ／Ｌ。水化学类型为ＳＯ＿４·ＨＣＯ＿３－Ｃａ·Ｍｇ型水。允许开采量５００ｍ￣３／ｄ。钱家营矿地势平坦，交通方便，水质优良，具有良好的开发前景。     

春夏季青藏高原与伊朗高原地表热通量的时空分布特征及相互联系

伊朗高原和青藏高原热力作用对东亚区域气候具有重要影响。基于1979—2014年欧洲中心ERA-interim月平均再分析地表热通量资料,分析了春、夏季青藏高原与伊朗高原地表热通量的时、空分布特征以及春、夏季青藏高原与伊朗高原地表热通量的关系。结果表明,春、夏季青藏高原与伊朗高原地表热通量在季节、年际和年代际尺度上具有不同的时、空分布特征。对于青藏高原,春、夏季地表感热呈西部大东部小、地表潜热呈东部大西部小;地表感热在春季最大且大于地表潜热,地表潜热在夏季最大且大于地表感热。在年际时间尺度上,春、夏季青藏高原地表热通量异常的年际变化在东、西部不一致,青藏高原西部,地表感热与地表潜热有较强的负相关关系。青藏高原地表感热异常具有很强的持续性,当春季地表感热较强（弱）时,夏季高原地表感热同样较强（弱）。青藏高原东部与西部地表热通量的年代际变化有明显差异,春（夏）季青藏高原东部地表感热呈显著的年代际减弱趋势,1998（2001）年发生年代际转折,由正异常转为负异常;而青藏高原西部地表感热在春季则有显著的增大趋势,2003年发生年代际转折,由负异常转为正异常。青藏高原东部地表潜热仅在春季为显著减弱趋势,2003年出现年代际转折,由正异常转为负异常;青藏高原西部地表潜热在春、夏季都有显著减弱趋势,年代际转折出现在21世纪初,由正异常转为负异常。对于伊朗高原,春、夏季地表热通量的空间分布在整个区域较一致,地表感热在夏季最大,地表潜热在春季大、夏季小,但各季节地表感热都大于地表潜热。相对于青藏高原地表感热,伊朗高原地表感热在各月都更大。在年际时间尺度上,春、夏季伊朗高原各区域地表热通量异常的年际变化较一致;地表感热与潜热有很强的负相关关系;伊朗高原地表感热、潜热异常都具有持续性,当春季地表感热（潜热）通量较强（弱）时,夏季地表感热（潜热）通量同样较强（弱）。伊朗高原北部与南部地表热通量的年代际变化存在差异。其中,春、夏季伊朗高原北部地表感热（潜热）呈显著增强（减弱）趋势,在20世纪末发生了年代际转折,春、夏季北部地表感热（潜热）由负（正）异常转为正（负）异常。而伊朗高原南部春、夏季地表热通量无显著变化趋势,但春季地表感热、潜热与夏季地表感热同样在20世纪末存在年代际转折,地表感热（潜热）由负（正）异常转为正（负）异常。春、夏季两个高原地区地表热通量的关系主要表现为:就春季同期变化而言,伊朗高原地表感热与青藏高原西部地表感热具有同相变化关系,与青藏高原东部地表感热具有反相变化关系,伊朗高原地表潜热与青藏高原东部地表潜热具有同相变化关系;就非同期变化而言,春季伊朗高原地表感热与夏季青藏高原东部地表感热存在反相变化关系。      

黄河流域旅游经济与生态环境协调发展时空演变及影响因素探究

基于黄河流域66个中心城市(市、地区、州、盟)旅游经济系统和生态环境系统的面板数据,运用耦合协调模型、空间自相关分析及地理探测器等方法,以2008、2013、2018年为时间节点,对黄河流域旅游经济系统与生态环境系统耦合协调水平的时空演变特征以及影响因素进行探析.结果表明:(1)2008年黄河流域95％的中心城市旅游经...     

海拉尔地震台阵噪声源调查

利用海拉尔地震台阵位置资料,选取台阵半径50 km范围,通过实地摸排和GPS仪定位方法,判断台阵周围有无国际标注的各大噪声源,同时计算噪声源与台阵的距离,分析台阵所属9个子台环境噪声水平,并将现今噪声功率谱与2000年时进行对比,汇总结果,并对台阵环境噪声水平进行评价。结果表明,海拉尔地震台阵周围有6类噪声源,其中工业设施和公共交通对台阵噪声水平的影响集中在高频段,但对监测能力影响不大;根据地震计安放位置与干扰源的最小距离进行评价,得出7个子台噪声源水平达到Ⅰ级台站环境地噪声水平,B₄、B₅子台处于Ⅱ级台站环境地噪声水平,台阵噪声水平总体处于良好状态,不影响仪器的正常运行。     

基于BiLSTM-CRF的中文层级地址分词

中文地址分词是中文地址标准化的基础工作和地理编码的重要手段,同时也是中文分词和地理研究领域中关注的热点问题之一。针对当前中文地址分词方法缺乏地址层级切分和过多依赖词典和特征的问题,本研究结合四词位标注集和中文层级地址特点,构建针对中文层级地址分词的地址标注体系,并提出融合双向长短时记忆网络和条件随机场(BiLSTM-CRF)的中文层级地址分词模型。该模型既考虑了BiLSTM模型能够记忆上下文地址的特性,也保留了CRF算法可以通过转移概率矩阵控制地址标注输出的能力。针对该地址标注体系标注的训练地址样本,分别使用CRF、LSTM、BiLSTM与BiLSTM-CRF模型进行训练对比。结果表明：① 基于中文地址标注体系的模型分词效果更佳,地址标注更为精细,符合实际地址分布情况;② BiLSTM-CRF模型精确度达到93.4%,高于CRF（90.4%）、LSTM（89.3%）和BiLSTM（91.2%）,其整体地址分词性能和各层级地址分词效果相对于其他模型更突出;③ 各模型分词性能与地址层级保持一致,即地址层级越高,分词效果越好。本研究提出的中文地址标注体系和分词模型为开展中文地址标准化工作提供了方法参考,同时也为进一步提升地理编码技术的精准度提供了可能。     

Influence of Late Springtime Surface Sensible Heat Flux Anomalies over the Tibetan and Iranian Plateaus on the Location of the South Asian High in Early Summer

Variation in the location of the South Asian High(SAH) in early boreal summer is strongly influenced by elevated surface heating from the Tibetan Plateau(TP) and the Iranian Plateau(IP). Based on observational and ERA-Interim data,diagnostic analyses reveal that the interannual northwestward–southeastward(NW–SE) shift of the SAH in June is more closely correlated with the synergistic effect of concurrent surface thermal anomalies over the TP and IP than with each single surface thermal anomaly over either plateau from the preceding May. Concurrent surface thermal anomalies over these two plateaus in May are characterized by a negative correlation between sensible heat flux over most parts of the TP(TPSH)and IP(IPSH). This anomaly pattern can persist till June and influences the NW–SE shift of the SAH in June through the release of latent heat(LH) over northeastern India. When the IPSH is stronger(weaker) and the TPSH is weaker(stronger)than normal in May, an anomalous cyclone(anticyclone) appears over northern India at 850 hPa, which is accompanied by the ascent(descent) of air and anomalous convergence(divergence) of moisture flux in May and June. Therefore, the LH release over northeastern India is strengthened(weakened) and the vertical gradient of apparent heat source is decreased(increased)in the upper troposphere, which is responsible for the northwestward(southeastward) shift of the SAH in June.