Thermal simulation of basic volcanic fluid influence on different source rocks

Based on thermal simulation experiment, interactions between volcanic fluids and source rocks were studied. Gas generations in the dry system and fluid system under different temperatures were analyzed. The results showed that the various types of source rocks are similar in composition, containing gaseous C1-C5 hydrocarbons, H2 and CO2 whose gas yields increase with increasing temperature. The gas yield of source rocks of type I is the high- est, followed by type II, and that of source rocks of type III is the lowest, indicating that the yield of hydrocarbon gases is related to their hydrocarbon generating potential. Although the generating potential of type III is the lowest, it can still be regarded as a useful gas source when it is buried deeply enough. The basic volcanic fluid restrains the generation of gaseous hydrocarbons in different types of source rocks, but promotes the generation of inorganic gases.     

The Metastable Phase Equilibria of the MeX-MgCl_2-H_2O Systems

正1 Introduction The Pingluoba brine,which characterized as high concentration with sodium,potassium,boron,lithium,and rubidium,possess great development value.The main composition of the brine can be summarized to the     

中国植物地理学研究进展与展望

中国植物地理学从20世纪20年代初创到当前繁荣经历了100年的发展,近30年来测序技术和生物信息技术的进步,促进了分类、进化和生态等学科交叉融合,中国植物地理学在诸多方面取得了突破性进展,主要包括：① 植物类群和区系在中国整体上按纬度、经度和海拔呈现出规律性;物种丰富度、系统发生多样性和特有性热点集中分布在南部山地,少数分布在北方山地和干旱地区。② 关于大尺度植物多样性格局及形成机制,多数热带起源科的物种多样性格局受冬季低温的限制,而多数温带起源科的物种多样性格局由末次冰期以来的气候变化主导;中国山地植物和群落具有显著的垂直地带性和空间分布异质性,热量因子是中国高山植物区系地理分异的首要气候因子。③ 中国大多数现生被子植物属（约66%）是在中新世及其以后分化;500 mm年等降水线是中国植物区系年龄和植被分区最重要的分界线;中国植物区系、区系中的特征或关键类群的起源和多样化与青藏高原抬升和亚洲季风加强密切相关。未来,时间和空间的结合仍是植物地理学研究的主旋律,类群、群落和区系分化时间的估算及物种分布数据的分辨率是研究者关注的焦点,植物大数据的持续积累和完善将为学科发展提供强大动力和广阔前景。     

基于PLSR的典型沼泽湿地植物叶片性状与光谱模型构建——以三江国家级自然保护区为例

通过植物光学特性测量叶片性状是一种非破坏性的、长期的湿地动态监测方法。选择三江国家级自然保护区多种典型湿地植物为研究对象,探究植物性状与叶片光谱之间的联系。研究表明：叶片氮含量与光谱的模型构建效果最好,模型R²为0.61,均方根误差（RMSE）为2.3862;叶片含水量、叶片磷、可溶性糖、纤维素和木质素含量之和的模型一般,R²在0.38~0.55范围内,RMSE在0.0004~10.7019范围内;淀粉含量拟合效果较差, R²为0.29,RMSE为0.0106。光谱预测重要性的结果表明,可见光与近红外边缘范围内的光谱信息对于叶片含水量、叶片氮含量、叶片磷含量、单位叶面积质量、纤维素和木质素之和、可溶性糖和淀粉的预测具有最高的重要性。     

中国城市流动人口心理融入的地区差异与影响因素

基于2017年流动人口动态监测调查数据,分析了中国城市流动人口心理融入的区域差异和影响因素。结果表明：① 流动人口心理融入处于较高水平;② 流动人口心理融入区域差异显著。东南沿海及少数西部城市心理融入低于全国平均水平,东北、山东和川渝等地区心理融入高于全国平均水平;③ 流动人口心理融入存在空间集聚效应。除川渝地区外,热点区集中于北方地区,冷点区集中于东南地区。④ 拥有房产、雇主身份和较高受教育水平加快流动人口的心理融入;工资收入的增加不利于心理融入,这与相对剥夺感有关;参与“新农合”对流动人口心理融入具有约束效应;暂住证/居住证及基本公共服务均等化是实现心理融入的重要途径。城市经济快速发展利于流动人口心理融入。跨省流动存在抑制作用,经济发展水平、家庭规模和本地居留时间的作用不显著。     

商圈划分中多元市场域的界定与实证

对商业设施的商圈进行科学识别与划分是分析其商业前景、优化商业空间结构的基础。本研究首先提炼和界定了商圈划分的两种类型、四种市场域方法,分别是基于到访比例的邻近型与份额型市场域、基于出行概率的共享型和首位型市场域,通过比较其优劣发现这四种视角仅能反映商圈的某一特征,无法刻画出商圈空间分布全貌。据此,尝试提出了一种新的复合型市场域模型,并应用手机信令数据,以上海市商业中心为例,对其商圈划分进行了实证检验。研究发现：复合型市场域模型可以综合反映空间距离、客流规模和惠顾概率等要素对商圈的影响,可以弥补单一市场域视角下商圈划分方法的不足。与传统邻近型相比,基于复合市场域模型识别划分的商圈不仅重叠度低,而且其空间分布更加符合实际。     

基于层次分析法的黄河上游水源涵养区生态系统恢复力评价——以甘南州、临夏州为例北大核心CSCD

在全球气候变化背景下,人类活动对生态环境质量影响的定量评价是区域生态保护与高质量发展的关键问题。本文基于层次分析法(AHP)和GIS可视化空间分析技术,应用遥感反演的生态系统分类资料和社会经济统计资料等,构建了包含社会经济、土地压力、自然条件3个准则层的生态系统恢复力评价指标体系,结合指标时空尺度无量纲化与综合指数法,进行了甘肃省甘南州、临夏州2000—2020年的生态系统恢复力定量评估。结果表明:研究区域空间尺度生态恢复力范围分别为0.14—0.65(2000年)、0.12—0.72(2005年)、0.07—0.70(2010年)、0.12—0.70(2015年)、0.28—0.82(2020年);甘南生态系统恢复力较高,临夏生态系统恢复力较低,在空间分布上,生态系统恢复力呈现北低南高的总体特征,高生态恢复力的乡镇以草地、森林、灌木生态系统为主,低生态恢复力的乡镇以农田、城镇生态系统为主;在时序变化特征中,生态系统恢复力总体向好,呈现先上升、后下降、最后上升趋势,受人类活动与气候变化共同作用。     

2011—2012年近海北上热带气旋对山东半岛风雨影响的分析

通过对2011年5号热带风暴“米雷”、9号强热带风暴“梅花”和2012年15号台风“布拉万”共3个近海北上热带气旋的对比分析发现,这类热带气旋给山东半岛造成的影响表现出“先雨后风”的特点。在近海北上热带气旋的影响下,山东半岛的降水基本呈东西向阶梯型分布,同量级的雨带基本呈南北向分布,某地区降水的起止时间、降水量峰值和风速极值的出现时段与热带气旋距该地的距离有一定的对应关系。热带气旋中心位置越过30°N和到达距某地区最近距离的时间对该地降雨的起止时间、降雨峰值和风速极值出现的时段具有一定的指示意义。     

Effects of mixing on the subduction of South Pacific waters identified by a simulated passive tracer and its adjoint

Effects of mixing on water mass subduction are analyzed in the South Pacific Ocean. Model simulations using a passive tracer and its adjoint are employed in conjunction with a particle tracking method to distinguish effects of mixing from those of advection. The results show that mixing processes can contribute to as much as 20% of the overall subduction rate in the South Pacific. Of this mixing contribution, about 30% can be attributed to meso-scale eddies, including their associated bolus transport, while the major part (70%) is due to other diabatic processes. The impact of mixing reaches its maximum near the Sub-Antarctic Front, accounting for nearly 30% of the total subduction rate. Consequently, estimates based on tracing particles or on advection alone may significantly underestimate the subduction rate in the South Pacific Ocean.     

Ensemble rainfall forecasting with numerical weather prediction and radar‐based nowcasting models

The overall objective of this study is to improve the forecasting accuracy of the precipitation in the Singapore region by means of both rainfall forecasting and nowcasting. Numerical Weather Predication (NWP) and radar‐based rainfall nowcasting are two important sources for quantitative precipitation forecast. In this paper, an attempt to combine rainfall prediction from a high‐resolution mesoscale weather model and a radar‐based rainfall model was performed. Two rainfall forecasting methods were selected and examined: (i) the weather research and forecasting model (WRF); and (ii) a translation model (TM). The WRF model, at a high spatial resolution, was run over the domain of interest using the Global Forecast System data as initializing fields. Some heavy rainfall events were selected from data record and used to test the forecast capability of WRF and TM. Results obtained from TM and WRF were then combined together to form an ensemble rainfall forecasting model, by assigning weights of 0.7 and 0.3 weights to TM and WRF, respectively. This paper presented results from WRF and TM, and the resulting ensemble rainfall forecasting; comparisons with station data were conducted as well. It was shown that results from WRF are very useful as advisory of anticipated heavy rainfall events, whereas those from TM, which used information of rain cells already appearing on the radar screen, were more accurate for rainfall nowcasting as expected. The ensemble rainfall forecasting compares reasonably well with the station observation data. Copyright © 2012 John Wiley & Sons, Ltd.