Research on the evolution law of permafrost under the influence of urbanization based on remote sensing technology

The permafrost of Mohe County and its suburbs in the Daxing′an Mountains has been influenced by the urbanization. Remote sensing, GIS technology and numerical simulation was used to study the temperature variations of permafrost with the changes in surface vegetation that cover Mohe County and suburban areas, and the law of permafrost degradation on the study area was analyzed. The research results show that the urban area of the study area increased 114.42%from 2000 to 2016, and the urbanization process is continuing to accelerate. The Normalized Difference Vegetation Index map of 2017 in Mohe County and its suburbs was studied and the maximum proportion of vegetation coverage was different in the four seasons. The numerical calculation model results show that the permafrost temperature change in the study area cyclically fluctuates in a cosine form. The annual variation curve of permafrost temperature gradually decreased and its accompanying phase lag increased with depth. The annual temperature change value with the different depths of the town was greater than the natural ground. The maximum permafrost thawing depths of the town and natural ground were 4.2 m and 2.82 m in 50 a, and the degradation rates of the two permafrost are, respectively, 0.88 cm/a and 0.46 cm/a. These results show that urbanization has accelerated the degradation of permafrost.     

包头数字地震遥测台网子台选址研究

阐述包头数字地震遥测台网空间布局、子台台址的选取原则和台基地质条件,对选取的子台进行背景噪声测试,对拟建台网的地震监控能力和合理性进行评估,为包头数字地震遥测台网建设提供科学、经济的规划方案,以期对国内其他地区地震遥测台网建设、改扩建提供参考。     

持续光照下光强对北极海域芬迪亚历山大藻生长及产毒的影响

以格陵兰岛西部、冰岛沿海和楚科奇海的芬迪亚历山大藻为受试对象,并以缅因湾的芬迪亚历山大藻藻株做为参照,从沉积物或海水中的休眠孢囊或营养细胞中分离到12株目标藻种,并在实验室建立纯培养系。然后对这些地域的藻种在不同光照下生长特性的比较、对毒素含量进行研究,发现芬迪亚历山大藻在持续光照条件下最适的生长光强范围是38—91μmol×m~(–2)×s~(–1)。另外,在所有分离到的12株藻细胞中均未检测到脱氨甲酰基膝沟藻毒素2(dc GTX2),大部分藻细胞都在光强较强时,即生长速率低时表现出更高的细胞毒素含量和毒性。     

Research Methodology for Tourism Destination Resilience and Analysis of Its Spatiotemporal Dynamics in the Post-epidemic Period

As the COVID-19 pandemic continues to spread, the global tourism industry is facing enormous challenges. There is an urgent need to explore an effective path for tourism to recover and revitalize. With the normalization of the epidemic, tourism destinations will pay more attention to the prevention, warning, and coping strategies of the epidemic, and this focus will also be evident in the study of tourism destination resilience in the post-epidemic period. Some studies on the epidemic and the resilience of tourism are currently underway, but few of them are integrated with research on the resilience of tourism destinations in the post-epidemic period, although no systematic research ideas or methods have been found. Based on resilience theory, this paper summarizes the general research ideas and develops an epidemic resilience model suitable for urban tourism destinations. The present study also proposes a set of research methods based on the index system to analyze the resilience and its spatiotemporal dynamic characteristics of tourism destinations in the post-epidemic period. The methodology can be divided into three stages: Firstly, construct the conceptual model and evaluation system for tourism destination resilience; Secondly, select case sites for empirical analysis, measure the resilience of tourism destinations, and analyze the characteristics of spatiotemporal differences and subsequent factors of influence; And finally, establish an adaptive management mechanism for tourism destinations to use in response to the epidemic and in guiding the formulation of post-epidemic recovery policies.     

沙尘暴对天山托木尔峰青冰滩72号冰川环境的影响

基于沙尘暴发生前后在天山托木尔峰青冰滩72号冰川末端采集的7个大气气溶胶样品和在水文断面采集的9个融水径流样品,探讨了沙尘暴事件对天山冰川区大气环境和水环境的影响。结果表明,Ca²⁺和SO₄^2-是青冰滩72号冰川大气和融水径流的主要离子,当沙尘暴发生时,这两种介质中的离子浓度显著升高,而且升高存在同时性。由于影响因素不同,浓度随时间变化的趋势不同,大气环境对沙尘事件的响应能力强,水环境则对温度变化的响应能力更强。通过相关性分析和主成分分析认为,青冰滩72号冰川大气中Ca²⁺、Mg²⁺、Na⁺、K⁺、Cl^-和SO₄^2-主要以自然源为主;NO₃^-和NH₄⁺则以人为源为主。轨迹分析发现,由源于东欧、西伯利亚经中亚南下的冷气团引发的大风降温天气以及区域沙尘暴对冰川区环境有显著影响。     

基于WiFi探针数据的城市出行轨迹提取

为了更便捷地提取城市居民的出行轨迹,从而分析个体的日常空间行为,进而为城市管理的各项措施决策提供数据支撑,本文提出基于WiFi探针数据的城市出行轨迹提取方法,主要解决WiFi探针数据的路网匹配及丢失轨迹重构问题。首先,通过对终端MAC码和时间戳进行多列排序后提取出轨迹记录序列,利用信号强度RSSI值为每条记录提取坐落在路网上的候选点集。其次,设计基于局部评价的算法,对于每一个候选点,利用其前后相邻的几条记录提取的候选点集与其之间的时空关系,先后对其进行时间一致性评价和空间一致性评价,再结合以时间反比动态构建的权函数,得到最终评分;然后将每个候选点集中评分最高的点作为最佳匹配点,至此完成轨迹记录的路网匹配。最后,先采用基于深度优先的路径搜索算法搜索出丢失轨迹上下点之间的所有可行路径,再基于TOPSIS法决策出最优的重构路径。本文以东莞市市中心区域收集的WiFi探针数据为实验数据进行测试,平均每日可提取6万多条轨迹,与其中获取的GPS数据相比较验证了方法的可行性,为城市出行轨迹挖掘提供了新的解决方案。     

新疆和田县大红柳滩一带花岗伟晶岩型稀有金属矿成矿地质特征、成矿时代及找矿方向

大红柳滩一带是帕米尔-昆仑山伟晶岩区中花岗伟晶岩分布最为集中、稀有金属成矿潜力最好的地区。近年来,该地区伟晶岩型稀有金属矿获得一系列找矿突破,引起了广大学者的广泛关注。笔者以新近发现的4处锂矿为重点,对矿床地质特征进行了研究,分析了区域伟晶岩的分带性特征,总结了控矿条件及找矿标志,并利用锡石LA-MC-ICP-MS U-Pb测年法获取含矿伟晶岩的206Pb/207Pb-238U/207Pb等时线年龄为（223±11）Ma（N=44,MSWD=2.1）,207Pb/206Pb-238U/206Pb Tera-Wasserburg谐和年龄为（223.5±7.9）Ma（N=44,MSWD=6.7）,表明伟晶岩的形成时代为晚三叠世,与区域花岗岩的形成时代基本一致。认为大红柳滩地区成矿地质背景、成矿时代及成矿地质特征与川西甲基卡矿田相似,外围及深部找矿潜力巨大。     

基于克里金插值估算区域降水量的抽样方法对比分析——以甘肃省为例

降水数据的空间插值精度由降水的空间变异特征、插值方法和降水观测站分布决定的, 其中, 降水观测站及插值方法的选择尤为重要. 利用空间随机抽样、空间分层抽样和空间三明治抽样等空间抽样方案, 以甘肃省境内的气象站点为研究对象进行抽样分析, 在抽样结果的基础上进行区域降水量克里金插值, 并对比了插值结果精确度. 结果表明: 在较为丰富的先验知识的前提下, 空间三明治抽样所得的区域降水量插值结果的误差项ME(1.97)、MSE(0.0066)和RMSSE(1.0184)都是最优的, 空间分层抽样次之, 空间随机抽样最差. 与另外两种抽样方案相比, 空间三明治抽样是一种使区域误差最小, 适用范围更广, 精确度更高的抽样方法.     

长江中下游典型浅水湖泊表层水体微塑料时空分布特征——以湖北保安湖为例

以湖北保安湖为研究对象,分别于2021年4、7、10月和2022年1月采集表层水样,测定水体中微塑料丰度、粒径、形状、颜色和类型,探究浅水型湖泊表层水体中微塑料的时空分布特征及其影响因素。结果表明,保安湖表层水体微塑料的年平均丰度为(16.20±2.23)items/L。微塑料丰度呈现明显的季节性差异,其中夏季(采样时间7月)平均丰度最低,为(1.40±0.09)items/L。在所有微塑料颗粒中,粒径0.064～1 mm占比最大,为82.57%;黑色和无色微塑料占主导地位,占比分别为36.16%和21.31%;纤维状微塑料分布最广泛,占比达40.01%;聚乙烯(PE)和低密度聚乙烯(LDPE)是最主要的微塑料类型,两者之和占比达46.05%,其次为聚苯乙烯(PS,占比17.2%)、聚对苯二甲酸乙二醇酯(PET,占比8.33%)和聚乙酸乙酯(PVAC,占比8.31%)。统计分析表明,微塑料丰度与湖水水质无显著相关关系。该研究揭示了长江中下游地区典型浅水湖泊微塑料分布现状,为评估类似湖泊微塑料潜在污染风险提供了科学依据。