近20年中国土地利用变化影响区域气候的数值模拟   总被引：2，自引：0，他引：2  

陈海山  李兴  华文剑 《大气科学》2015,39(2):357-369

区域尺度土地利用/土地覆盖变化(LUCC)的气候效应以及土地覆盖数据的不确定性, 一直是LUCC研究不可忽视的关键问题。本研究基于最新的遥感资料, 采用新的区域气候模式RegCM4.0, 探讨了1990年至2010年中国LUCC对区域气候的影响。结果表明, 中国区域LUCC使得局地气温和日较差发生了显著改变, 而降水及低层环流场变化不显著;LUCC的影响存在季节性差异, 其中, 夏秋季响应程度较大且主要体现在边界层内。就LUCC对气候影响的机理各地区有所不同, 华北地区LUCC的气候效应主要受蒸散发作用主导, 而长江流域则由反照率与蒸散发共同作用。这些结果均说明, 较短时间尺度的LUCC气候效应主要体现在其局地范围, 且在不同的季节有所差异。  相似文献   

The Effects of Land Cover Change on Regional Climate over the Eastern Part of Northwest China          下载免费PDF全文

HAN Zhen-Yu  GAO Xue-Jie  SHI Ying  XU Ying 《大气和海洋科学快报》2015,8(3):153-159

A regional climate model(Reg CM4) is employed to investigate the impacts of land use/cover change(LUCC) on the climate over the eastern part of Northwest China(ENW) in the periods of 2001 and 2011. The results indicated that the LUCC in ENW, which was characterized by desert retreat, reforestation, and farmland expansion, led to significant local changes in surface air temperature(within ~0.3°C) and slight regional changes in precipitation(within ~15%) in summer. In the desert retreat area, the net absorbed shortwave radiation had a greater influence than evaporative cooling, leading to increases in the daily mean and maximum temperature. Besides, the daily mean and maximum temperatures increased in the reforestation area but decreased in the farmland expansion area. As surface albedo showed no significant change in these regions, the temperature increase in the reforestation area can be attributed to a decrease in evaporation, while the opposite effect appears to have been the case in the farmland expansion area.  相似文献   

Interannual and Decadal Variations of Surface Solar Radiation over East China in the First Half of the 20th Century          下载免费PDF全文

FEI Ye  XIA Xiang-Ao 《大气和海洋科学快报》2015,8(5)

Variability and long-term trends of sunshine duration(SSD) and total cloud cover(TCC) were studied based on surface observations from 10 meteorological stations over East China in the first half of the 20 th century. The correlation coefficients between SSD and diurnal temperature range(DTR), as well as TCC, were analyzed. SSD experienced a significant increasing trend(0.16 h d-1 per decade) from 1908 to 1936, and the maximum brightening was in autumn(0.33 h d-1 per decade). The good agreement between the variability of SSD and DTR, supported by the correlation coefficient between them of 0.72, implies that the SSD measurements were reliable. TCC showed a decreasing trend(-0.93% per decade) and was significantly inversely related to SSD(-0.74), indicating the variation of SSD was attributable to changes in cloud cover. The result was obviously different to that since the 1960 s, when clouds could not account for the decadal trend of surface solar radiation in China.  相似文献   

Evaluating the economic damage of climate change on global coral reefs     

《Global Environmental Change》2015

This paper evaluates the global economic damage arising from the effects of climate change and associated carbon dioxide concentrations on the loss of coral reefs. We do this by first estimating the effects of sea surface temperature and carbon dioxide concentrations on coral cover. We develop a statistical relationship between coral coverage and sea surface temperature that indicates that the effects are dependent on the temperature range. For example, we find that increasing sea surface temperature causes coral coverage to decrease when sea surface temperature is higher than 26.85 °C, with the estimated reduction being 2.3% when sea surface temperature increases by 1%. In addition, we find that a 1% carbon dioxide increase induces a 0.6% reduction in global coral coverage. We also estimate the resultant loss in economic value based on a meta-analysis of the recreational and commercial value of reef coverage and a crude proportional approach for other value factors. The meta-analysis shows that the coral reef value decreases by 3.8% when coral cover falls by 1%. By combining these two steps we find that the lost value in terms of the global coral reef value under climate change scenarios ranges from US$3.95 to US$23.78 billion annually.  相似文献   

基于GEE的地表覆盖与气候状态关联研究     

陈伟  刘湘媛  曾圣  张华平  毛志芳 《测绘通报》2021,(12):99-104

为探究地表覆盖与气候状态间的关联性,本文选取2019年的Landsat影像数据,结合温度、降水量、PM_2.5浓度3种气候指标,利用GEE平台,结合NDVI、MNDWI、NDBI,采用SVM、RF、CART方法进行地表覆盖分类,探究气候指标与地表覆盖类型分布的关联性;提出了使用3种气候指标构建分类特征进行地表覆盖分类的方法,并通过消融试验分析了气候指标对地表覆盖分类精度的影响。结果表明:①RF有较好的分类结果,总体精度为96.0%;②3种气候指标均能提高地表覆盖分类精度,其中PM_2.5浓度效果最好;③温度与植被、水体关联性较大,PM_2.5浓度与城区、植被关联性较大,降水量与耕地关联性较大。  相似文献   

新太阳光压模型在GNSS定轨中的应用     

常春涛  慕仁海  程鹏飞  成英燕 《测绘科学》2021,46(2):78-84

太阳光压摄动是影响卫星定轨中重要的误差源,在GNSS导航卫星精密定轨过程中使用最为广泛的光压模型为ECOM模型。为了探究几种ECOM模型及其适用性,该文以超快速星历为起算轨道,分析对比经典ECOM-1模型与最新13参数ECOMC模型对GPS/BDS卫星轨道的影响。结果显示:相较于ECOM-1模型,ECOMC模型在GPS定轨中精度有所提升,特别体现在径向精度提升,单天与三天弧段在径向的解算精度分别提升了12.73%和24.74%;在BDS定轨中,采用ECOMC模型,部分GEO卫星在径向方向单天精度有12.38%的提升,而对于IGSO与MEO卫星二者精度差异不大;分析可得,由于星体结构不对称引起卫星在沿太阳-卫星方向作用的偶数阶短周期谐波扰动,引入卫星-太阳方向偶数阶项的参数估计可提升卫星径向精度。  相似文献   

大光斑波形数据在土地覆盖分类的适用性分析     

马利群  李理  刘俊杰  孙九林  秦奋 《测绘科学》2021,46(3):80-86,95

针对GLAS地学激光测高系统是冰、云和陆地高程卫星(ICESat)的唯一监测工具,能够记录地表光斑内的地物信息,是否能应用于黄土高原土地覆盖分类的问题进行了研究。利用粒子群和最小二乘法相结合的方法对GLAS波形数据进行高斯分解,获取高斯波个数、波形总能量、波形信号起始和信号结束位置4个波形参数;基于波形自动分类方法对黄土高原水体、森林、城市用地、其他地类(裸地、低矮植被等)进行分类。通过基于覆盖相同研究区域的30 m地表覆盖数据(Globe Land30),验证分类的准确性。结果表明,GLAS大光斑波形数据对黄土高原的4种地类能够很好地进行区分,总分类精度高达87.68%,Kappa系数为65.79%。研究表明,GLAS波形数据可以作为获取土地覆盖信息的有效数据源,为研究黄土高原土地覆盖变化提供更丰富的数据支持。  相似文献   

刍议《重庆历史地图集》第二卷的编制     

熊明  杨茂中  成昆凤  刘殊 《测绘地理信息》2021,46(1):123-126

以《重庆历史地图集》第二卷编制的具体情况为例,对图集的开本设计、内容结构设计、封面和版式设计、整体设计、创新源,以及图集编制取得的经验进行了论述,为以后类似图集的编制提供参考。  相似文献   

地层渗透性对岩石强度及机械钻速影响因素分析     

杨谋  孟英峰  李皋  李永杰  徐翔  唐思洪  孙敏 《地质科技情报》2011,30(3):127-131

分析了地层渗透性对井底围压及破岩效率产生的影响,并对地层渗透性进行了分类,在此基础上建立了围压下岩石强度模型;基于压持效率制约了井底净化环境,修正与完善了不同地层渗透性的机械钻速模型,确定了各项参数.应用聚类分析中最优分段法对测井参数与录井参数进行了分类处理并编程获得了单轴下和围压下岩石强度剖面及机械钻速剖面,分别选取...  相似文献   

An experimental study of effect of pre‐existing fabric on deformation of foliated mylonite at high temperature and pressure     

Gui Liu  Yongsheng Zhou  Changrong He  Wenming Yao  Junlai Liu  Yuanyuan Zhang 《Geological Journal》2016,51(1):92-112

We performed deformation experiments on a foliated mylonite under high temperature and pressure conditions in this study. To investigate the effect of pre‐existing fabric on the rheology of rocks, our samples were drilled from natural mylonite with the cylinder axis parallel to the foliation (PAR) and perpendicular to the foliation (PER). We performed 25 tests on seven PAR samples and 21 tests on seven PER samples at temperatures ranging from 600 to 890 °C, confining pressures ranging from 800 to 1400 MPa, and steady‐state strain rates of 1 × 10⁻⁴, 1 × 10⁻⁵ and 2.5 × 10⁻⁶ s⁻¹. In the temperatures of 600–700 °C, the deformation is accommodated by semi‐brittle flow, with the average stress exponent being 6–7 assuming power law flow; in the temperature range of 800–890 °C, deformation is mainly by plastic flow, with an average stress exponent of n = 3 and activation energies of Q = 354 ± 52 kJ/mol (PER and PAR samples). The experimental results show that the strengths of PER samples are higher than those of PAR samples. Deformation microstructures have been studied by optical and electron microscopy. The original foliation of PER samples is destroyed by deformation and replaced by a new foliation, but the deformation of PAR samples followed the original foliation. Electron backscatter diffraction (EBSD) measurements show a strong lattice preferred orientation (LPO) of the quartz c axis fabrics of the starting samples and deformed PER and PAR samples. However, the c axis fabric of quartz in experimentally deformed PER and PAR samples varied with temperature and strain rate is different from that seen in the starting mylonite sample. The initial quartz c axis fabric of the starting mylonite sample has been transformed into a new fabric during experimental deformation. Dehydration melting of biotite and hornblende occurred in both PER and PAR samples at temperatures of 800–890 °C. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献