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Lakes regulate the water and heat exchange between the ground and the atmosphere on different temporal and spatial scales. However, studies of the lake effect in the high-altitude Tibetan Plateau(TP) rarely have been performed until recently, and little attention has been paid to modelling of frozen lakes. In this study, the Weather Research and Forecasting Model(WRF v. 3.6.1) is employed to conduct three numerical experiments in the Ngoring Lake Basin(the original experiment, an experiment with a tuned model, and a no-lake experiment) to investigate the influences of parameter optimization on the lake simulation and of the high-altitude lake on the regional climate. After the lake depth, the roughness lengths, and initial surface temperature are corrected in the model, the simulation of the air temperature is distinctly improved. In the experiment using a tuned model, the simulated sensible-heat flux(H) is clearly improved, especially during periods of ice melting(from late spring to early summer) and freezing(late fall). The improvement of latent-heat flux(LE) is mainly manifested by the sharp increase in the correlation coefficient between simulation and observation, whereas the improvement in the average value is small. The optimization of initial surface temperature shows the most prominent effect in the first year and distinctly weakens after a freezing period. After the lakes become grassland in the model, the daytime temperature clearly increases during the freezing and melting periods; but the nocturnal cooling appears in other stages, especially from September to October. The annual mean H increases by 6.4 times in the regions of the Ngoring Lake and the Gyaring Lake, and the LE declines by 56.2%. The sum of H and LE increases from 71.2 W/m2(with lake) to 84.6 W/m2(no lake). For the entire simulation region, the sum of H and LE also increases slightly. After the lakes are removed, the air temperature increases significantly from June to September over the area corresponding to the two lakes, and an abnormal convergence field appears; at the same time, the precipitation clearly increases over the two lakes and surrounding areas. 相似文献
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创新地理学研究的几个理论问题 总被引：10，自引：4，他引：6
创新地理学是研究人类创新活动与地理环境关系的地域系统,是一门独立的人文地理分支学科,具有交叉学科的性质。其研究的“人类创新活动”是人类活动的最为重要的方面,对智慧的人地关系系统建设具有重要的意义。创新地理学与其他人文地理学的分支学科具有密切的联系,也与政治学、管理学、经济学、政策学、城市规划等学科有关,创新地理学面临的主要任务是：① 创新地理学基本理论的研究;② 创新要素（人才、资本、技术等）在空间的地域分布与组合规律的研究;③ 创新环境、创新生态及评价研究;④ 创新地理测度、创新空间格局与效应的研究;⑤ 创新联系、创新网络及创新集群的研究;⑥ 多尺度的创新体系的研究;⑦ 创新、城市发展与规划的研究。 相似文献
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人口城镇化与土地城镇化协调性测度及优化——以南昌市为例 总被引：7，自引：5，他引：2
人口与土地是城镇化的重要组成部分,分析二者之间状态演化对促进城市健康发展具有重要意义。在界定人口城镇化与土地城镇化二者概念基础上,基于人口构成、人口素质、人口生活、城镇规模、城镇投入、城镇产出等构建评价指标体系,并通过耦合协调模型对省会型城市南昌市2002~2011年两者之间的协调关系进行测度和分析,结果表明：① 人口城镇化指数与土地城镇化指数呈波动变化并持续上涨,城镇发展由土地滞后型向人口滞后型转变;② 人口城镇化与土地城镇化的协调状态由失调衰退区向过渡协调区演进,发展类型则由高度不协调状态向勉强协调状态过渡。在此基础上分析了南昌市人口城镇化速度滞后于土地城镇化速度的原因,指出两者关系主要受到城市发展外在制度与内在基础的共同作用,并认为构建人口与土地城镇化双重优化路径是协调人口城镇化与土地城镇化同步发展的有效途径。 相似文献
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基于不同空间尺度的上海市装备制造业创新网络演化分析 总被引：2，自引：1，他引：1
利用国家重点产业专利信息服务平台,对1986~2012年上海市装备制造业合作发明专利数据进行检索,描绘了城市、区域和国家3个尺度上海市装备制造业的网络空间结构及其演变特征。研究发现,上海市装备制造业创新网络的演化具有明显的阶段性特征,不同因素在不同空间尺度对创新网络的结构演化影响不同。在国家尺度,城市创新能级是主体结网行为的主要影响因素,且随着时间的推进,其重要性越发明显,而地理距离在这之中并不起作用;在区域尺度,主体创新能级的重要性贯穿整个网络发展阶段,而地理邻近的重要性在后期才开始显现;在本地尺度,合作主体间的平均距离急剧缩减,地理邻近的重要性极为突出。最后,针对上海推动产业升级、建设科创中心提出了一些建议。 相似文献
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城市贫困群体主观生活质量研究——以西安市典型社区为例 总被引：5，自引：1，他引：4
基于调查问卷和半结构式访谈的数据,以西安市典型社区贫困群体的主观生活质量为研究对象,分别采用语义差别法研究生活环境感知、熵权TOPSIS 法测算主观满意度、关联网络法分析生活感受特征。结果表明：① 贫困群体对生活环境感知存在局限性,感知能力较差,大多数人群感知结果偏向于正,形成主观感知与客观事实存在偏差的特征。② 贫困群体对生活质量感知较为敏感。就生活质量主观满意度而言,贫困群体主观满意度不高,离各指标的最优状态还相差甚远。4个典型地区贫困人群的主观满意度同处于中等偏低水平。就生活质量感受特征而言,贫困群体对其生活状况的感受整体上是消极的和负面的,生活的不满主要与工作状况、薪资水平密切相关,生活的满意感主要与邻里关系及交通条件等有关。③ 不同类型社区贫困群体感知差异显著,形成原因与典型社区的规划建设背景、所处地理位置、现有功能定位等因素有关。 相似文献
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Hydrological service is a hot issue in the current researches of ecosystem service, particularly in the upper reaches of mountain rivers in dry land areas, where the Qilian Mountain is a representative one. The Qilian Mountain, where forest, shrubland and grassland consist of its main ecosystems, can provide fresh water and many other ecosystem services, through a series of eco-hydrological process such as precipitation interception, soil water storage, and fresh water provision. Thus, monitoring water regulation and assessing the hydrological service of the Qilian Mountain are meaningful and helpful for the healthy development of the lower reaches of arid and semi-arid areas. In recent 10 years, hydrological services have been widely researched in terms of scale and landscape pattern, including water conservation, hydrological responses to afforestation and their ecological effects. This study, after analyzing lots of current models and applications of geographical information system (GIS) in hydrological services, gave a scientific and reasonable evaluation of mountain ecosystem in eco-hydrological services, by employing the combination of international forefronts and contentious issues into the Qilian Mountain. Assessments of hydrological services at regional or larger scales are limited compared with studies within watershed scale in the Qilian Mountain. In our evaluation results of forest ecosystems, it is concluded that long-term observation and dynamic monitoring of different types of ecosystem are indispensable, and the hydrological services and the potential variation in water supplement on regional and large scales should be central issues in the future research. 相似文献
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Pan Yongjie Lyu Shihua Li Suosuo Gao Yanhong Meng Xianhong Ao Yinhuan Wang Shujin 《Theoretical and Applied Climatology》2017,127(3-4):1011-1022
Soils containing gravel (particle size ≥2 mm) are widely distributed over the Qinghai–Tibet Plateau (QTP). Soil mixed with gravel has different thermal and hydrological properties compared with fine soil (particle size <2 mm) and thus has marked impacts on soil water and heat transfer. However, the most commonly used land models do not consider the effects of gravel. This paper reports the development of a new scheme that simulates the thermal and hydrological processes in soil containing gravel and its application in the QTP. The new scheme was implemented in version 4 of the Community Land Model, and experiments were conducted for two typical sites in the QTP. The results showed that (1) soil with gravel tends to reduce the water holding capacity and enhance the hydraulic conductivity and drainage; (2) the thermal conductivity increases with soil gravel content, and the response of the temperature of soil mixed with gravel to air temperature change is rapid; (3) the new scheme performs well in simulating the soil temperature and moisture—the mean biases of soil moisture between the simulation and observation reduced by 25–48 %, and the mean biases of soil temperature reduced by 9–25 %. Therefore, this scheme can successfully simulate the thermal and hydrological processes in soil with different levels of gravel content and is potentially applicable in land surface models.
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