武汉城市扩张对热场时空演变的影响   总被引：5，自引：3，他引：2  

谢启姣  刘进华  胡道华 《地理研究》2016,35(7):1259-1272

深入分析城市扩张对城市热场时空分布及演变的影响机制,对探求城市热岛效应缓解对策、改善城市生态环境质量意义重大。基于1987年、1996年、2007年和2013年的Landsat影像反演武汉主城区地表温度、提取不透水面值,定量研究两者的关系,探讨城市建设对城市热场空间分布的影响;采用不透水面和正规化地表温度差值影像动态定量1987-2013年武汉城市扩张对热场时空演变的影响机制。结果表明：① 1987-2013年,武汉不透水面不断增加,城市建设强度加强,城市扩张明显,但是不同时期表现出不同的扩张方向、范围和模式。② 城市热岛效应主要发生在相应时期的建成区和武钢工业区,而城市大型水体则表现出明显的“冷廊效应”和“冷岛效应”;1987-1996年、1996-2007年和2007-2013年热状况恶化面积分别为382.0 km²、305.1 km²和105.7 km²,热状况总体呈现恶化趋势。③ 不透水面指数能较好地解释热场空间的异质性,两者回归方程的系数为0.751~0.923,不透水面值每增加0.1,正规化地表温度值会增加0.01~0.02。④ 城市热状况变化从改良极显著、改良较显著、无变化、恶化较显著到恶化极显著,对应的不透水面差值由小到大,城市扩张和城市建设强度加大对恶化城市热环境和加剧城市热岛扩展作用明显。  相似文献   

塔克拉玛干沙漠腹地地表辐射与能量平衡   总被引：4，自引：4，他引：0  

杨帆  王顺胜  何清  霍文  杨兴华  郑新倩  王毅  蔡文军  买买提艾力&#  买买提依明 《中国沙漠》2016,36(5):1408-1418

利用2013年塔克拉玛干沙漠塔中流动沙面地表辐射、土壤热通量、土壤温湿度和湍流通量观测资料,分析了沙漠腹地地表辐射和能量收支特征及闭合状况。结果表明：除潜热通量外,其余地表辐射各分量和能量平衡分量的月平均日变化结果整体均表现为标准的单峰型日循环形态,其中R_s↓与R_s↑变化同步,R_l↑、R_l↓滞后R_s↓0.5 ~ 1 h。各分量均表现出夏季高、春秋季次之、冬季低的季节波动性。干旱和极低的植被覆盖造成沙漠腹地全年潜热通量始终较为微弱,约占净辐射的2.8%,感热通量成为能量的主要消耗形式,约占净辐射的49%。偶尔的降水会刺激潜热通量突然增加。地表反照率相对较高且稳定,日变化呈早晚大、正午小的“U”型趋势,并具有明显的冬季高、夏季低的季节波动性,年均值0.28,月均值0.25~0.32。能量残差各月的日变化也均呈单峰曲线,日出后和日落前能量闭合程度最佳,并出现过闭合现象,全年夏季小,春秋季次之,冬季较大,月平均日峰值5.1~99.9 W·m^-2。土壤表层热储存是影响该地区能量平衡的重要因子之一,考虑表层土壤热存储后,地表能量闭合率达75.3%,能量闭合率夏季 > 春季 > 秋季 > 冬季,白天相比夜间有大幅提升。  相似文献   

采用AutoLISP语言开发辐射取样图件自动生成程序     

周洪生 《铀矿地质》2009,25(1):37-39

采用AutoLISP语言开发了一套辐射取样图件自动生成程序,该程序完全自主开发,能实现取样图自动生成、自动解释功能,大大提高了辐射取样图件绘制的效率,且避免了手工绘图所带来的误差。  相似文献   

白钨矿的原位高压X射线衍射研究     

刘迎新  秦善  李晓东  李延春  刘景 《矿物学报》2009,29(4)

使用金刚石对顶砧高压装置(DAC)和同步辐射光源,对天然白钨矿进行了原位高压能量色散X射线衍射(EDXD)研究,实验最高压力为16.0 GPa.在实验压力范围内观察到了一次白钨矿结构→钨锰铁矿结构的可逆相变:压力小于5.3 GPa时为白钨矿结构(I4_1/a),在5.3～12.3 GPa压力区间内为白钨矿结构与钨锰铁矿结构(P2/c)并存,大于12.3 GPa时完全相变为钨锰铁矿结构.从键长、配位数和配位多面体角度对白钨矿→钨锰铁矿结构的相变机制进行了解释.  相似文献   

关中盆地地下热水接受补给时温度及热储层温度的估算     

胡扬  ;马致远  ;余娟  ;李青  ;张跟全  ;贾旭兵 《西安地质学院学报》2009,(2):173-176

通过对关中盆地地热井中地下热水的同位素和水化学成分分析,结合研究区的地热地质和水文地质条件,进行了地下热水补给时的温度研究,结果表明,关中盆地地下热水接受补给时的温度以西安地区最低,咸阳次之。同时应用Na-K-Mg三角图和水化学平衡温度理论的方法,估算在平衡条件下关中盆地最大热储温度为118℃。热储温度计算结果表明,关中盆地腹部应为中低温热储层。  相似文献   

Geochemistry and SHRIMP geochronology of alkaline rocks of the Zijinshan massif in the eastern Ordos basin, China     

Yang Xingke  Chao Huixia  N.I. Volkova  Zheng Menglin  Yao Weihua 《Russian Geology and Geophysics》2009,50(9):751-762

Characteristics of geology, petrology, and geochemistry of the Zijinshan massif were studied in the eastern part of the Ordos basin. Geochemical analysis shows that the massif is characterized by high alkali, relatively high Fe, and low Mg and Ca contents. The rocks are undersaturated in SiO₂, rich in REE (with no Eu anomaly) and belong to the alkaline-peralkaline series. The geologic history of the Zijinshan massif consists of several stages of magmatism. The obtained isotope-geochronological (U-Pb SHRIMP) data show that the magmatic activity climaxed in the interval 150–110 Ma, while the age of 16 zircon grains fitted a narrower interval, 132–125 Ma, i.e., the Early Cretaceous. The younger age corresponds to the middle and late stages of the evolution of the Ordos basin and agrees with a large Early Cretaceous tectonothermal event in North China. This event led to the large-scale uplift of the eastern flank of the Ordos basin, rise of the Lüliang asthenosphere, and to the formation of a large west-sloping monocline. The U-Pb SHRIMP studies have also revealed magmatic zircons of Carboniferous–Permian age, which evidences the multistage character of the thermal process.  相似文献   

High-Pressure Behavior of Copper Carbonate: Data from Malachite     

LIU Yingxin  QIN Shan  LI Haijian  LI Xiaodong  LI Yanchun  LIU Jing 《《地质学报》英文版》2009,83(3):615-617

Abstract: In-situ high-pressure energy dispersive X-ray diffraction experiments of malachite have been performed using diamond anvil cell and synchrotron radiation. The highest recorded pressure is up to 17.4 GPa. The experimental results reveal that malachite experienced two phase transitions at 0.7 and 7.8 GPa, and the last one is reversible.  相似文献   

A Regional Scale Investigation of Climatological Tropical Convection and Precipitation in the Amazon Basin     

《The Professional geographer》2013,65(2):258-271

This study constructs a regional scale climatology of tropical convection and precipitation from more than 15 years of monthly outgoing longwave radiation (OLR) and precipitation data on 2.5°× 2.5° latitude-longitude grid to examine the spatial and temporal patterns and variability of convection and precipitation in the Amazon Basin. A linear regression analysis also detects if any trends exist in the two datasets. The region of study extends from 15°N to 25°S and 30° to 80°W that encompass the Amazon Basin and surrounding fringe areas for the period from January 1979 through December 1995 for the OLR data and up to 1996 for the precipitation dataset. The basin-average mean monthly and seasonal climatology serve as a ‘baseline’ reference for comparison with the full time series of basin-average monthly OLR and precipitation to illustrate the interannual variability and identify anomalous periods of wet and dry conditions. A linear trend analysis of OLR data found small negative values across the Amazon Basin indicating a slight increase in convective activity over the period of study. The analysis of the precipitation time series, however, shows no coincidental increase in precipitation as would be expected with an increase in convective activity. Portions of Rondônia and Mato Grosso, areas that have undergone extensive deforestation, illustrate no trend in precipitation as suggested by GCM simulation results. The only area featuring any large change in precipitation occurs in a small area in the northwestern region of South America where a large positive trend in precipitation exists.  相似文献   

A comparative analysis of DEM‐based models to estimate the solar radiation in mountainous terrain     

J. A. Ruiz‐Arias  D. Pozo‐Vázquez  H. Alsamamra 《International journal of geographical information science》2013,27(8):1049-1076

Daily solar radiation estimates of four up‐to‐date solar radiation models (Solar Analyst, r.sun, SRAD and Solei‐32), based on a digital elevation model (DEM), have been evaluated and compared in a Mediterranean environment characterized by a complex topography. The models' estimates were evaluated against 40 days of radiometric data collected in 14 stations. Analyzed sky conditions ranged from completely overcast conditions to clear skies. Additionally, the role of the spatial resolution of the DEM has been evaluated through the use of two different resolutions: 20 and 100 m. Results showed that, under clear‐sky conditions, the daily solar radiation variability in the study area may be reasonably estimated with mean bias errors under 10% and root mean square error values of around 15%. On the other hand, results proved that the reliability of the estimates substantially decreases under overcast conditions for some of the solar radiation models. Regarding the role of the DEM spatial resolution, results suggested that the reliability of the estimates for complex topography areas under clear‐sky conditions improves using a higher spatial resolution.  相似文献   

An explanation of the large PGA value of 2013 Ms7.0 Lushan earthquake at 51BXD station through topographic analysis     

Zhijun Dai  Xiaojun Li 《地震学报(英文版)》2013,(3):199-205

In Ms7.0 Lushan earthquake, a large amount of strong ground motion recordings were collected. In this paper, we analyze the recordings carefully. The abnor- mality of ground motion recordings is identified through a log linear regression. In the station of 51BXD, the PGA value has exceeded 1 g, which is the biggest peak ground acceleration （PGA） value obtained from all recordings in this earthquake. The log linear relation shows the PGA value in this station is abnormally large. As this station is located on the footage of a hill, the topographic amplifi- cation factor is explored in order to explain this abnor- mality. Through 3D numerical modeling using spectral element method with transmitting boundary conditions, the amplification factor is quantized. In this station, the topo- graphic amplification is highly polarized in the direction of East-West which agrees with the empirical recordings. This research result suggests us in future directionality of topographic amplification should be considered in the aseismic design.  相似文献