A remote sensing model for monitoring soil evaporation based on differential thermal inertia and its validation   总被引：2，自引：0，他引：2  

张仁华  孙晓敏  朱治林  苏红波  唐新斋 《中国科学D辑(英文版)》2003,46(4):342-355

To develop geosciences quantification and multi-dimensional researches will be an inevitable trend in the 21st century. The interaction between the land surface and the atmosphere not only serves as an important component in geosciences quantification, bu…  相似文献   

Sea surface height and transport stream function of the South China Sea from a variable-grid global ocean circulation model   总被引：8，自引：0，他引：8  

魏泽勋  方国洪  崔秉昊  方越  何宜军 《中国科学D辑(英文版)》2003,46(2):139-148

The study on the South China Sea (SCS) circulation has a history of more than 40 years. Nevertheless, the SCS circulation is not fully understood compared with the Bohai Sea, Yellow Sea and East China Sea (ECS). Many numerical studies on the SCS circulati…  相似文献   

山地二维三分量地震资料采集   总被引：3，自引：3，他引：0  

张晓斌  唐建侯  李亚林  唐晓雪 《物探化探计算技术》2003,25(2):125-129

新研制出的一种三分量检波器,尾锥不动,能方便地调节其方位角和水平角,可保证同一测线上的检波器各分量的极性和相位一致,检波器与地面耦合良好;三个分量之间的隔离度大于20dB,保证了道间无串音干扰。三个检波器串联组合,有利于地震信号接收。通过数值模拟拟定出地震测线布设方位和观测系统,在采集试验中开展波场调查、偏移距试验、不同覆盖次数对比,以确定出合理的观测系统和采集参数,在四川山地获得了高质量的三分量地震资料,形成了一套实用的陆上三分量地震资料采集技术。  相似文献   

上海热浪与健康监测预警系统   总被引：21，自引：0，他引：21       下载免费PDF全文

谈建国  林松伯等 《应用气象学报》2002,13(3):356-363

用1989～1998年上海逐日4次气象观测资料,应用美国特拉华大学的SSC天气分类方法确定逐日天气类型,形成了10年逐日天气类型日历。并通过天气类型与死亡率的对比分析,确定MT+类型是上海地区形成热浪的“侵人型”气团,是具有最高死亡率的天气类型。采用逐步回归方法建立了MT+类型下因受热浪侵袭而超正常死亡数的回归方程。在此基础上建立了上海热浪与健康监测预警系统。通过1999年气象和死亡实况资料检验,系统对热浪及因此引起的死亡具有较好的监测和预警效果。  相似文献   

An Origin for the Linear Magnetic Anomalies on Mars through Accretion of Terranes: Implications for Dynamo Timing     

Alberto G. FairénJavier Ruiz  Francisco Anguita 《Icarus》2002,160(1):220-223

The proposed existence of magnetic lineations in the Terra Cimmeria and Terra Sirenum regions of Mars was initially explained by Earth-like sea-floor spreading. Here we argue instead that these lineations could have been formed at a convergent plate margin through collision and accretion of terranes. A similar process produced banded magnetic anomalies, similar in geometry and even in size to those in Earth's North American Cordillera. Because only sparse and generally weak anomalies have been detected in the martian northern lowlands, which could constitute an analog to the terrestrial oceanic crust, it is possible that the magnetic field stopped its activity while crustal recycling was still active in Mars.  相似文献   

Spectroscopy of Loose and Cemented Sulfate-Bearing Soils: Implications for Duricrust on Mars     

Christopher D. CooperJohn F. Mustard 《Icarus》2002,158(1):42-55

The goal of this work is to determine the spectroscopic properties of sulfate in martian soil analogs over the wavelength range 0.3 to 25 μm (which is relevant to existing and planned remotely sensed data sets for Mars). Sulfate is an abundant component of martian soil (up to 9% SO₃ by weight) and apparently exists as a particulate in the soil but also as a cement. Although previous studies have addressed the spectroscopic identity of sulfates on Mars, none have used laboratory mixtures of materials with sulfates at the abundances measured by landed spacecraft, nor have any works considered the effect of salt-cementation on spectral properties of soil materials. For this work we created mixtures of a palagonitic soil (JSC Mars-1) and sulfates (MgSO₄ and CaSO₄·2H₂O). The effects of cementation were determined and separated from the effects of packing and hydration by measuring the samples as loose powders, packed powders, cemented materials, and disaggregated materials. The results show that the presence of particulate sulfate is best observed in the 4-5 μm region. Soils cemented with sulfate exhibit a pronounced restrahlen band between 8 and 9 μm as well as well-defined absorptions in the 4-5 μm region. Cementation effects are distinct from packing effects and disaggregation of cemented samples rapidly diminishes the strength of the restrahlen bands. The results of this study show that sulfate in loose materials is more detectable in the near infrared (4-5 μm) than in the thermal infrared (8-9 μm). However, cemented materials are easily distinguished from loose mixtures in the thermal infrared because of the high values of their absorption coefficient in this region. Together these results suggest that both wavelength regions are important for determining the spatial extent and physical form of sulfates on the surface of Mars.  相似文献   

地面感热对青藏高原低涡流场结构及发展的作用   总被引：31，自引：9，他引：22  

李国平  赵邦杰  杨锦青 《大气科学》2002,26(4):519-525

考虑热带气旋类青藏高原低涡为受加热和摩擦强迫并满足热成风平衡的轴对称涡旋系统,通过求解线性化的柱坐标系中涡旋模式的初值问题,分析了地面感热对高原低涡流场结构及发展的影响,给出了高原低涡眼壁内、外侧水平流场和垂直流场的结构特征,讨论了低涡发展与其水平尺度、垂直厚度、所处纬度以及热量总体输送系数和加热强度的关系.结果表明:地面感热对低涡的生成及发展具有重要作用,但这种作用是否有利于低涡的发展与低涡中心和感热加热中心的配置有关.  相似文献   

Monitoring of fault healing after the 1999 Kocaeli, Turkey, earthquake     

Keiichi Tadokoro  Masataka Ando  Şerif Bariş  Kin'ya Nishigami  Mamoru Nakamura  S. Balamir Ücer  Akihiko Ito  Yoshimori Honkura  A. Mete Işikara 《Journal of Seismology》2002,6(3):411-417

The North Anatolian fault zone that ruptured during the mainshock of theM 7.4 Kocaeli (Izmit) earthquake of 17 August 1999 has beenmonitored using S wave splitting, in order to test a hypothesisproposed by Tadokoro et al. (1999). This idea is based on the observationof the M 7.2 1995 Hyogo-ken Nanbu (Kobe) earthquake, Japan.After the Hyogo-ken Nanbu earthquake, a temporal change was detectedin the direction of faster shear wave polarization in 2–3 years after the mainshock (Tadokoro, 1999). Four seismic stations were installed within andnear the fault zone at Kizanlik where the fault offset was 1.5 m, about80 km to the east of the epicenter of the Kocaeli earthquake. Theobservation period was from August 30 to October 27, 1999. Preliminaryresult shows that the average directions of faster shear wave polarization attwo stations were roughly parallel to the fault strike. We expect that thedirection of faster shear wave polarization will change to the same directionas the regional tectonic stress reflecting fault healing process. We havealready carried out a repeated aftershock observation at the same site in2000 for monitoring the fault healing process.  相似文献   

Une dépression piézométrique naturelle en hausse au Sahel (Sud-Ouest du Niger)A rising piezometric depression in the Sahel (southwestern Niger)     

Guillaume Favreau  Christian Leduc  Christelle Marlin  Abdou Guéro 《Comptes Rendus Geoscience》2002,334(6):395-401

In southwest Niger, the Continental Terminal water table displays a natural hollow shape about 10 m in depth over an area of 4000 km². A 10-year survey of this hollow aquifer has shown that current recharge is above $\text{20 }\text{mm}\text{yr}{}^{\mathrm{?1}}$. The water table has risen continuously since the 1950–1960s as a result of land clearance. This shows a disequilibrium in the aquifer balance. The long-term recharge rate is estimated by radioisotopes to be around $\text{1 }\text{mm}\text{yr}{}^{\mathrm{?1}}$. This figure fits with the only possible origin of the piezometric depression, i.e. evapotranspiration losses in its centre. To cite this article: G. Favreau et al., C. R. Geoscience 334 (2002) 395–401.  相似文献   

对华北一次特大台风暴雨过程的位涡诊断分析   总被引：59，自引：23，他引：36  

于玉斌  姚秀萍 《高原气象》2000,19(1):111-120

通过对９６０８号台风低压及其外围暴雨位和等熵面上物理量场的分析,揭示了台风低压北上诱发暴雨过程的位涡场的结构及冷空气对暴雨增幅的作用,给出此次暴雨增幅过程的图像。分析表明：对流层低层中高纬度冷空气（高位涡）扩散南下在台风低压环流区附近的“侵入”作用是此次特大暴雨过程的最重要的原因之一;等熵面位涡的分析进一步说明了中高纬地区冷空气的活动状况;对流层高层或平流层低层位涡的下传有利于位势不稳定能量的释放  相似文献