Comparing the seasonal variation of parameter estimation of ecosystem carbon exchange between alpine meadow and cropland in Heihe River Basin, northwestern China

Grasslands and agro-ecosystems occupy one-third of the global terrestrial area. However, great uncertainty still exists about their contributions to the global carbon cycle. This study used various com...     

中国旅游科技创新的时空结构、重心轨迹及其影响因素研究

旅游产业是充满众多科技创新与成果转化的社会经济部门。以我国旅游产业相关发明专利、旅游收入、风景名胜区、高校学生数等为分析依据,基于地理集中指数、动态变动指数、空间重心模型和灰色关联分析等方法,对各省区2006—2017年旅游科技创新的时空结构、重心轨迹及其影响因素等进行实证研究。结果表明：时间上,我国旅游科技创新整体上呈波动上升的发展态势,2013年后地理集中度指数开始持续下降;空间上,旅游科技创新在我国呈东高西低、南高北低的分布格局。此外,旅游科技创新的空间重心位于我国华东地区,并呈先由北向南、再由东向西的移动轨迹。最后,科技创新产出、旅游经济水平、科技经费投入、经济宏观环境、科技创新服务、旅游资源禀赋等要素指标均对我国旅游科技创新产生一定影响,但影响程度具有差异。     

县域城镇化水平综合测评及其动力构成分析——以河北省为例

构建县域城镇化综合测评指标体系,包含经济城镇化、就业城镇化、市场城镇化、人口和基础设施城镇化.运用熵值法测算了河北省县域城镇化水平,发现2001-2012年县域城镇化水平处在上升状态,主要表现为人口城镇化、基础设施和农村非农就业的改变,但城镇化发展并未提供较多的城镇就业岗位和促进工业企业营利能力的提升.从多年平均看,人口和基础设施子系统对县域城镇化水平贡献份额最大,市场子系统贡献份额最小,各子系统有不同的时段特征.采用多元回归模型分析了影响县域城镇化水平的动力因素,显示推动力呈现多元化特点,各种动力共同助推县域城镇化水平的提高,但动力大小有差异,依次表现为政府动力、市场动力、社会动力.     

Diurnal Variations of Atmospheric Hydrogen Peroxide Concentrations in Saxony (Germany)

During a 3-year study, gaseous hydrogenperoxide (H₂O₂) concentrations were measuredas part of the SANA project at the Melpitz FieldResearch Station and in the city of Leipzig. Typicaldaily mean H₂O₂ mixing ratios on sunny dayswere 0.15 to 0.25 ppbv with maximum values of 0.3 to0.5 ppbv at Melpitz, and 0.3 to 0.6 ppbv with maximumvalues of 0.4 to 1.0 ppbv in Leipzig. Over the entireperiod of the project the maximum hourly mean valueswere 2.1 ppbv and 5.3 ppbv in Melpitz and Leipzig,respectively. The data were not complete enough to show a trend.Linear regression analysis shows, that ozone(O₃), temperature and solar radiation arepositively correlated with H₂O₂, whereasnitrogen oxides (NO_x), carbon monoxide (CO) andrelative humidity are negatively correlated. Negativecorrelation between H₂O₂ and CO is caused byjoint occurrence of CO with NO_x in exhaust gases.Negative correlation between H₂O₂ andrelative humidity is not necessarily in contradictionto the accelerating effect of water vapour onH₂O₂ formation. The strong positivecorrelation of H₂O₂ with the dew pointdifference however seems to better reflect theinfluence of water vapour. Multiple linear regression analysis (MLRA) of thecomponents measured, indicates the great influence of CO on the formation of H₂O₂ in the gasphase.     

江苏沿江都市区域经济要素空间演化趋势研究

伴随着中国都市区化的快速发展,经济要素在都市区域的空间分布发生着剧烈的变动和重组.为了更为深入地研究都市区域经济要素的空间演化,采用均匀度指数这一数学工具,重点分析江苏沿江都市区域"城市间"(inter-city)经济要素的变动演化趋势.基于总体趋势、分地区比较、主要指标集3个角度分析的基础上,认为江苏沿江都市区域经济要素的空间演化正呈现出日益均匀化的趋势,其中,外资空间分布的日趋均匀化将对都市区域经济与空间发展产生重要影响.     

Identification of geologic contrasts from landscape dissection pattern: An application to the Cascade Range, Oregon, USA

This paper demonstrates the plausibility of inferring the spatial variability of geology from topographically derived landscape dissection patterns. This enables surveying large regions for spatial variability in geology, for which direct remote sensing is not feasible, by studying variability in dissection pattern, a feature extracted straight off from digital elevation model data. Dissection pattern is obtained automatically by a novel algorithm, especially designed to delineate the valleys with high accuracy in order to reflect spatial variability in dissection density. The dissection pattern is encapsulated by a continuous map of drainage density, a raster variable best suited for showing spatial variability of dissection. Such a map, constructed for the study area in the Cascade Range, Oregon, USA, shows a sharp discontinuity in the dissection pattern, indicating change in underlying geology. Possible factors controlling the dissection pattern such as climate, local and regional slopes, vegetation, and geology are examined, and geology has been found to be the dominant controlling factor. The dissection contrast coincides with the boundary between the Western and High Cascades, two geologic provinces with different rock ages and types. The older and less permeable Western Cascades are associated with denser dissection pattern, whereas the younger and more permeable High Cascades correspond to less dissected pattern. This new mapping method can be applied to locations where topography is the only readily available data, and the generated map could be used to extract previously unknown geologic or environmental information.     

商丘近40 a蒸发量变化特征及原因分析

利用商丘1961-2000年小型蒸发皿蒸发量资料,分析了商丘蒸发量的变化趋势及引起蒸发量变化的因子,结果表明,商丘年、季和月蒸发量均存在明显的下降趋势,影响蒸发量变化的因子主要有风速、日照、相对湿度、水汽压等.     

环境因子对敦煌莫高窟洞窟水分蒸发的影响

环境因子对洞窟水分蒸发有重要影响.在敦煌莫高窟72窟蒸发水分的收集过程中,通过对窟内温度和湿度的控制,分析窟内温湿度对水分蒸发的影响及作用机理,并根据围岩水分蒸发机理,探讨影响水分蒸发的外部环境因子.结果表明,洞窟2.0℃的温度变化即可对水分蒸发产生显著影响,短期内蒸发量可增大1倍以上.温度高、蒸发量大,可导致窟内相对湿度增加,因此目前全球性的气温升高对洞窟文物将产生不利影响.敦煌地区降雨量的增加增大了空气潮湿过程激活壁画盐分的可能.莫高窟所处的地理位置、地热、地形结构、围岩孔隙度和洞窟结构本身对围岩水分蒸发有重要影响.本文从环境因素揭示了莫高窟壁画能够保存至今的关键原因,为今后洞窟文物的更好保护提供了新思路.     

THE CHARACTERISTICS OF GENERAL CIRCULATION, POLAR ICE AND SNOW DAYS / COVER OF EXTREMELY SEVERE COLD MONTHS IN SOUTH CHINA WINTER

The work has made a statistic study of the variations of extremely severe cold winter months in the south of China and general circulation and external forcing factors in preceding periods. The result shows that from the current month to the preceding March the subtropical high in the west Pacific is persistently weak or located more to the east and south. When the summer monsoon is weak in East Asia in the year before, the winter monsoon will be strong in the current year in which the extremely severe cold month occurs. The Asian polar vortex expands in the preceding July, August and September and the current winter. The Tibetan Plateau has fewer days of snow cover in the November and December before the cold month occurs. There is less snow in the Tibetan Plateau in the preceding winter / spring of each extremely severe cold month. There are more polar ice in the polar Region for the 11 months before the current February, especially the previous March through August, and in Region in January ~ November before the current cold month of December but less ice in Region in March ~ August.     

杭州市空气负离子变化特征分析

利用2008—2010年杭州西溪湿地和馒头山空气负离子观测资料,分析了杭州市空气负离子的季、月和日变化特征,以及空气负离子与气象环境因子的相关关系。结果表明,湿地负离子浓度要好于市区;杭州市空气负离子浓度冬季最大,夏季最小;一日中早晨空气负离子浓度最高,15时左右最低;夜间高于白天。空气负离子浓度与温度、日照时数和空气污染物呈负相关,与相对湿度、风速、云量和降雨量呈正相关。