Potential of time‐lapse photography of snow for hydrological purposes at the small catchment scale

Time‐lapse photography provides an attractive source of information about snow cover characteristics, especially at the small catchment scale. The objective of this study was to design and test a monitoring system, which allows multi‐resolution observations of snow cover characteristics. The main aim was to simultaneously investigate the spatio‐temporal patterns of snow cover, snow depth and snowfall interception in the area very close to the camera, and the spatio‐temporal patterns of snow cover in the far range. The multi‐resolution design was tested at three sites in the eastern part of the Austrian Alps (Hochschwab‐Rax region). Digital photographs were taken at hourly time steps between 6:00 and 18:00 in the period November, 2004 to December, 2006. The results showed that the time‐lapse photography allows effective mapping of the snow depths at high temporal resolution in the region close to the digital camera at many snow stake locations. It is possible to process a large number of photos by using an automatic procedure for accurate snow depth readings. The digital photographs can also be used to infer the settling characteristics of the snow pack and snow interception during the day. Although it is not possible to directly estimate the snow interception mass, the photos may indeed give very useful information on the snow processes on and beneath the forest canopy. The main advantage of using time‐lapse photography in the far range of the digital camera is to observe the spatio‐temporal patterns of snow cover over different landscape configurations. The results illustrate that digital photographs can be very useful for parameterising processes such as sloughing on steep slopes, snow deposition in gullies and snow erosion on mountain ridges in a distributed snow model. Copyright © 2011 John Wiley & Sons, Ltd.     

Lichens and mosses moisture content assessment through high‐spectral resolution remote sensing technology: a case study of the Hudson Bay Lowlands,Canada

Assessing moisture contents of lichens and mosses using ground‐based high‐spectral resolution spectrometers offers immense opportunities for a comprehensive monitoring of peatland moisture status by satellite/airborne imagery. This study investigates the impact of various moisture conditions of common subarctic lichen and moss species upon the spectral signatures obtained. The lichens are Cladina stellaris and Cladina rangiferina, and the mosses are Dicranum elongatum and Tomenthypnum nitens. Reflectance and moisture content measurements of these species were made in a laboratory setting, while maintaining the natural moisture conditions of the samples; once the moisture and spectral measurements were complete, the samples were returned to the field and placed in their natural setting, continuously receiving moisture from precipitation and groundwater and losing water through evaporation and drainage. Changes in reflectance of the visible to shortwave infrared (SWIR) range (400–2500 nm) at various moisture contents were examined, as well as the potential of current spectral reflectance indices to evaluate the plants' moisture contents was examined. Results indicate that the SWIR region is useful in identifying variations in plants moisture conditions, while the unique spectral signatures of the lichens and mosses in the visible and near‐infrared range suggest that these species may be detected by satellite and airborne imagery. Of current spectral indices, the normalized difference infrared index (NDII) was most successful in identifying the above plants' moisture content (details are discussed in the paper). Future study should focus on the development of improved moisture content spectral indices, as well as upscaling reflectance data and spectral indices. Copyright © 2010 John Wiley & Sons, Ltd.     

Climate change during the past 1000 years: a high‐temporal‐resolution multiproxy record from a mire in northern Finland

We present a record of peatland development in relation to climate changes and human activities from the Palomaa mire, a remote site in northern Finland. We used fine‐resolution and continuous sampling to analyse several proxies including pollen (for vegetation on and around the mire), testate amoebae (TA; for mire‐wetness changes), oxygen and carbon isotopes from Sphagnum cellulose (δ¹⁸O and δ¹³C; for humidity and temperature changes), peat‐accumulation rates and peat‐colour changes. In spite of an excellent accumulation model (30 ¹⁴C dates and estimated standard deviation of sample ages <1 year in the most recent part), the potential to determine cause–effect (or lead–lag) relationships between environmental changes and biotic responses is limited by proxy‐specific incorporation processes below the actively growing Sphagnum surface. Nevertheless, what emerges is that mire development was closely related to water‐table changes rather than to summer temperature and that water‐table decreases were associated with increasing peat‐accumulation rates and more abundant mire vegetation. A rapid fen‐to‐bog transition occurred within a few years around AD 1960 when the water table decreased beyond the historical minimum, supporting the notion that mires can rapidly shift into bogs in response to allogenic factors. Copyright © 2012 John Wiley & Sons, Ltd.     

基于高分辨率遥感影像的滇池湖滨湿地植被类型监测

利用多源高分辨率遥感影像,结合图像分割与人机交互判实技术,分建设前（2007～2008年）、建设中（2011年）、建设后（2013年）3个时期对滇池湖滨湿地进行植被分布信息提取与面积统计,进而对其演变规律进行分析.结果表明：随着“滇池湖滨生态带工程”的推进,环湖带乔木与灌木、沉浮水植物、草本植物3类湿地群落面积的总和从建设前的120.39 hm2提高至建设中的1747.54 hm2,再到建设后的1868.91 hm2,占总面积的比例分别为5.49％、79.61％和85.14％,湖滨湿地面积显著提升;建设前主要植被类型为作物植被,占总面积的51.98％,建设后缩减至3.87％,逐步演化为自然植被,主要种类为中山杉（Ascendens mucronatum）、芦苇（Phragmites australis）等,群落多样性与景观格局也有了较大改观.     

EH-4电导率成像系统在铝土矿找矿中的应用研究

简要介绍了EH-4电导率成像系统的基本原理和工作方法。在河南省渑池县雷沟铝土矿区的找矿试验中,测试了系统的稳定性、垂向电性分层能力及对矿区典型电性结构的探测能力和复杂条件的适用能力。应用小波多分辨分析的数学方法对实测数据进行了一阶多分辨分解,分离出一阶细节异常和一阶逼近异常。比对矿区ZK808孔资料,说明了一阶细节异常包含了较多的噪声和静态效应,而一阶逼近异常包含有较多的目标地质体的异常信息,从而有效地压制了噪声及静态效应,突出了目标地质体的异常信息。采用一阶逼近数据进行二维联合反演,并将反演结果与矿区地质资料进行对比,肯定了EH-4电导率成像系统在铝土矿勘查中的找矿效果及应用前景。     

激光剥蚀-电感耦合等离子体质谱线扫描技术的空间分辨率研究

激光剥蚀-电感耦合等离子体质谱(LA-ICP-MS)作为一项实用的技术被广泛应用于原位微区分析。在学者们更为关注的元素空间分布问题上,LA-ICP-MS线扫描较单点剥蚀具有更大的优势。线扫描过程中元素的空间分辨率是影响分析结果准确程度的因素之一。每个脉冲间的信号如果严重叠加会导致较低的空间分辨率。文章通过LA-ICP-MS的单脉冲剥蚀实验,研究了合成硅酸盐玻璃标准样品CGSG中不同元素的信号时间结构,及其对线扫描的空间分辨率的影响。结果表明,当激光束斑40 μm时,应用LA-ICP-MS进行线扫描测量空间分辨率能够满足线扫描技术分析的需求。     

准噶尔阜康东部斜坡区中侏罗统头屯河组高分辨 层序地层格架内储集层宏观非均质性研究

应用高分辨层序地层对准噶尔东部阜康东部斜坡区中侏罗统头屯河组进行层序的划分,共划分出1个长期基准面旋回、三个中期基准面旋回和10个短期基准面旋回。在中期层序地层格架下,按照层内非均质性、层间和平面三个级次对各层序进行非均质性剖析,发现储层宏观非均质性具有一定的规律性,主要在MSC2层序内表现明显。MSC2储集砂体的非均质程度最高,基准面上升初期及下降末期,储集砂体厚度较大,物性较好,是勘探开发有利区域。各层序的非均质性主要受到A/S值变化所影响。     

土地利用冲突的时空格局刻画与多情景模拟研究——以长江三角洲城市群为例

科学刻画与模拟土地利用冲突的时空演化格局是精准认知区域土地利用结构进而寻求人地关系协调的基础。采用景观格局指数构建土地利用冲突模型,借助GIS等手段分析长江三角洲城市群1980—2020年间土地利用冲突的时空演化特征,并结合斑块生成土地利用变化模拟模型和多目标规划法多情景模拟2035年的土地利用冲突格局。结果表明：①长江三角洲城市群土地利用冲突受地形等因素影响呈现“北高南低”的分布格局,且在高速城镇化和城市无序蔓延等因素作用下,人地关系趋于不协调发展,土地利用冲突程度逐年加剧。②受人口迁徙和城镇化发展阶段的影响,土地利用冲突的热点区域由乡村空间转移至了城市空间。③在土地利用过程中,耕地是各利益主体争夺的核心区域,也是权衡土地利用冲突的“关键地带”。④可持续发展情景兼顾了经济发展与生态保护两方面的用地需求,是缓和土地利用冲突的一种合理选择。     

文化冲突对中国入境旅游需求的影响

后疫情时代,文化冲突可能会是中国入境旅游需求复苏的突出制约因子。基于2002—2018年联合国世界旅游组织关于66个客源地对中国的入境旅游人次数据和面板数据估计策略,探究了文化冲突对中国入境旅游需求的影响及其机制。结果表明：① 文化冲突显著负向影响中国入境旅游需求;② 文化冲突对中国入境旅游需求影响在不同性别、区域、年龄、目的群组中具有异质性;③ 文化认同是文化冲突影响中国入境旅游需求过程中的机制变量。研究结果能推进入境旅游需求影响因素理论研究,为实现中国入境旅游需求复苏提供新的理论依据和政策参考。     

风积沙漠地区三维地震勘探资料处理中Q补偿应用实例

在有效波组为低频、低噪且地质任务以小构造解释为目标的地区,采用Q补偿技术有利于提高有效波组的主频,达到提高纵向分辨率的目的。以鄂尔多斯某勘探区为例,采用Q值补偿技术,以克服该区沙漠地貌明显的吸收衰减滤波效应问题,提高其地震资料的中、高频成分。通过对Q补偿参数进行测试,发现Q值为50时有效波响应明显。应用结果表明,经Q补偿后,地震时间剖面有效波主频明显提高,DF7、DF8断层在补偿后的地震时间剖面上较补偿前断点更清晰、位置解释误差更少。