基于GIS的北京山区优势林分生态位分析

应用生态位理论,以北京山区森林资源为研究对象,分析优势林分的空间分布及其资源利用和环境适应能力的差异。基于GIS方法,建立优势林分空间分布数据库以及资源梯度信息数据库,分别采用Levins公式和Smith公式,在水分、热量、光照和土壤质量4维环境因子梯度上测定了研究区8个优势林分的生态位宽度,采用Pianka公式测定生态位重叠。结果表明:Smith公式考虑资源可利用性,得到的生态位宽度更能客观地反映优势林分资源空间利用程度;研究区各优势林分重叠度普遍较大,反映了对环境要求的相似性及资源共享的趋势性。     

Occurrence and evolution of the Xiaotangshan hot spring in Beijing, China

Thermal groundwater occurs in bedrock aquifers consisting of the dolomite of the Wumishan Group of the Jixianin System and the Cambrian carbonate in the Xiaotangshan geothermal field near the northern margin of the North China Plain, China. The hot water in the geothermal field of basin-type discharges partly in the form of the Xiaotangshan hot spring under natural conditions. The hot water has TDS of less than 600 mg/L and is of Na·Ca-HCO₃ type. The geothermal water receives recharge from precipitation in the mountain area with elevation of about 500 m above sea level to the north of the spring. Thermal groundwater flows slowly south and southeast through a deep circulation with a residence time of 224 years estimated with the Ra–Rn method. The Xiaotangshan hot spring dried up in the middle of the 1980s owing to the increasing withdrawal of the hot water in the geothermal field in the past decades. The water level of the geothermal system still falls continually at an annual average rate of about 2 m, although water temperature changes very little, indicating that the recharge of such a geothermal system of basin-type is limited. Over-exploitation has a dramatic impact on the geothermal system, and reduction in exploitation and reinjection are required for the sustainable usage of the hot water.     

北京房山变质核杂岩的基本特征及其成因探讨

摘要：北京房山变质核杂岩是典型的板内变质核杂岩。由核部的结晶基底及顶部的变余糜棱岩带、固态流变的中间层和脆性剪裂的上部盖层组成三层结构。核部有强力侵位的早白垩世的房山花岗闪长岩株。地壳的韧性伸展表现于下古生界及其前的盖层岩系中,形成于印支期前,反映了强烈的区域古地热异常。印支期的南北向挤压造就了区域构造格局。燕山期的岩浆侵入使变质核杂岩定型。新生代的差异性隆升使核杂岩最终出露地表。幔源热异常、基底热隆及岩浆的强力侵位是核杂岩形成的主要因素．     

北京测震台网台基背景噪声特征

利用Welch算法,选取北京市测震台网28个测震台站地震连续波形中不同时段的无震记录,计算其台基噪声功率谱并进行背景噪声特征的统计分析,结果表明:北京市测震台网各台基噪声背景优势频率各有特征,高低频段噪声功率谱曲线差异大。在1~20Hz频段内,北京地区的背景噪声高值区出现在中心城区附近,低值区出现在北部的琉璃庙、密云和南部的上方山等台站,主要受人为噪声影响;在0.008~0.1Hz频段内,北京所有地区差异不大。     

冬奥赛场卫星和地基微波辐射计气温廓线观测对比和验证

利用探空站数据对北京和张家口冬奥赛场周边地区的地基微波辐射计和FY 4A大气垂直探测仪资料进行验证分析。选取2020年全年FY 4A大气垂直探测仪资料以及2020年12月至2021年3月期间对冬奥赛事有重要影响的寒潮前后、雾霾和沙尘暴这3种不同天气现象下探测得到的气温廓线数据进行个例分析。结果表明：在晴空条件下,地基微波辐射计和FY 4A大气垂直探测仪探测大气垂直气温的精度较高,平均相关系数达到0.97,低层大气（500 hPa以下）较高层大气探测结果的一致性较好;大气污染对探测精度产生一定影响,其中PM2.5产生的影响较小,PM10的提高对FY 4A大气垂直探测仪的探测产生较大影响,尤其是发生沙尘暴时,星载探测仪无法对低层大气进行探测。经过对比和验证,卫星探测作为补充探测手段,可以与地基微波辐射计互相补充,尤其是在空间覆盖和时间分辨率上具备一定优势,但在有云和沙尘暴的天气条件下无法对低层大气开展探测;地基微波辐射计可以对一个地点的大气垂直参数开展不间断的探测,与探空站数据的一致性较高。卫星探测和地基微波辐射计均可以为冬奥赛事提供高时间分辨率的探测数据,为数值天气预报提供有力的数据支撑。     

北京房山应急水源地地下水数值模拟及河流渗漏量预测

以北京房山岩溶水应急水源地为例,采用等效连续介质体概化地下水流系统,建立地下水流数值模型,评价地下水源汇项,分析地下水系统特征。运用MODFLOW中的河流（渠）子程序包,刻画地表河流和泉水与地下水的交换关系。经参数识别和验证,计算结果与实测数据拟合较好,能够比较准确的模拟水源地岩溶水系统。模拟和预测结果表明,水源地地区地下水与地表水联系密切,应急开采后,地下水系统由向河流排泄转变为河流渗漏补给地下水,可为应急水源地合理开发利用提供科学依据。     

北京市地质灾害状况及制定地质环境管理办法论证

论文从北京市自然地质背景和资源现状出发，根据目前资源开采中存在的地质环境问题、地质灾害程度以及地质环境发展趋势，论述了北京应尽快制定、颁布与实施地质环境管理办法的必要性、迫切性、可行性和相关依据。北京市主要有崩塌、滑坡、泥石流、地面沉降等地质灾害以及矿山环境污染，而针对这些问题开展的监测预报工作还很少。纵观北京市社会、经济及资源的利用与发展，已逐步显现出地质灾害、矿山环境等地质环境问题对社会经济发展带来的诸多困扰。目前地质灾害及地质环境管理的现状都显示出本市地质环境监测与预报工作还很薄弱，相应的法律、法规建设也不健全。因此，制定地质环境管理办法已迫在眉睫，应使地质环境管理有法可依，改善目前地质环境，保证北京市社会经济可持续发展。     

基于手机数据的北京市城市与近郊交互模式挖掘

在城镇化进程中,城市与近郊之间通过职住、货运、游憩等活动产生越来越紧密的交互联系,对于这些交互联系的准确识别和定量刻画,是理解城乡空间关系的重要手段,也能为城市的资源有效配置与合理规划提供重要的现状信息。本文通过对全北京在一日之内的手机信令数据所反映的人群移动轨迹的深入分析,融合城市的POI信息形成顾及人类活动时空信息的空间交互类型推断。以北京市为例,对城市中心与近郊之间远距离的强交互进行定性、定量和定位的探索。本文发现了北京市多尺度下空间交互模式和距离衰减规律,判断了城乡异常交互类型,对比了城乡之间和城市内部的交互模式的异同,以及基于交互类型视角提取了城乡异常交互的空间特征。研究认为,基于手机信令数据,利用停留点提取和高斯核密度估计的空间交互类型推断有效地发现了北京市周末的远距离出行类型特点,提取了其空间交互强度和空间特征,揭示了基于人类活动的北京市周末城乡交互模式。     

Driving forces and their interactions of built-up land expansion based on the geographical detector – a case study of Beijing,China

Scientific interpretation of the driving forces of built-up land expansion is essential to urban planning and policy-making. In general, built-up land expansion results from the interactions of different factors, and thus, understanding the combined impacts of built-up land expansion is beneficial. However, previous studies have primarily been concerned with the separate effect of each driver, rather than the interactions between the drivers. Using the built-up land expansion in Beijing from 2000 to 2010 as a study case, this research aims to fill this gap. A spatial statistical method, named the geographical detector, was used to investigate the effects of physical and socioeconomic factors. The effects of policy factors were also explored using physical and socioeconomic factors as proxies. The results showed that the modifiable areal unit problem existed in the geographical detector, and 4000 m might be the optimal scale for the classification performed in this study. At this scale, the interactions between most factors enhanced each other, which indicated that the interactions had greater effects on the built-up land expansion than any single factor. In addition, two pairs of nonlinear enhancement, the greatest enhancement type, were found between the distance to rivers and two socioeconomic factors: the total investment in fixed assets and GDP. Moreover, it was found that the urban plans, environmental protection policies and major events had a great impact on built-up land expansion. The findings of this study verify that the geographical detector is applicable in analysing the driving forces of built-up land expansion. This study also offers a new perspective in researching the interactions between different drivers.