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311.
Yuanzhi Zhang Hongtao Duan Hongyan Xi Zhaojun Huang JinYeu Tsou Tingchen Jiang 《大气与海洋》2018,56(4):277-288
AbstractAquatic plants and lake bottoms in optically shallow waters (OSWs) wield great influence on reflectance spectra, resulting in the inapplicability of most existing bio-optical models for water colour remote sensing in lakes. Based on radiative transfer theory and measured spectra from a campaign for Lake Taihu in October 2008, absorption and backscattering coefficients were used to simulate the remote-sensing reflectance, which are considered to be reliable if matched to their measured counterparts. Several cases of measured spectra at different depths, Secchi disk depth transparency, and aquatic plant height and coverage were analyzed thoroughly for spectral properties. The contribution of aquatic plants was evaluated and compared with the measured and simulated remote-sensing reflectance values. This is helpful for removing the influence of aquatic plants and lake bottoms from the spectra and for constructing an improved chlorophyll a retrieval model for OSWs, such as that for Lake Taihu, China. 相似文献
312.
Yaohui Li Cailing Zhao Tiejun Zhang Wei Wang Haixia Duan Yuanpu Liu Yulong Ren Zhaoxia Pu 《Acta Meteorologica Sinica》2018,32(6):896-908
This study examines the impacts of land-use data on the simulation of surface air temperature in Northwest China by the Weather Research and Forecasting (WRF) model. International Geosphere–Biosphere Program (IGBP) landuse data with 500-m spatial resolution are generated from Moderate Resolution Imaging Spectroradiometer (MODIS) satellite products. These data are used to replace the default U.S. Geological Survey (USGS) land-use data in the WRF model. Based on the data recorded by national basic meteorological observing stations in Northwest China, results are compared and evaluated. It is found that replacing the default USGS land-use data in the WRF model with the IGBP data improves the ability of the model to simulate surface air temperature in Northwest China in July and December 2015. Errors in the simulated daytime surface air temperature are reduced, while the results vary between seasons. There is some variation in the degree and range of impacts of land-use data on surface air temperature among seasons. Using the IGBP data, the simulated daytime surface air temperature in July 2015 improves at a relatively small number of stations, but to a relatively large degree; whereas the simulation of daytime surface air temperature in December 2015 improves at almost all stations, but only to a relatively small degree (within 1°C). Mitigation of daytime surface air temperature overestimation in July 2015 is influenced mainly by the change in ground heat flux. The modification of underestimated temperature comes mainly from the improvement of simulated net radiation in December 2015. 相似文献
313.
Marine corrosion and biofouling seriously affect the service life of marine structural materials,resulting in performance failure,enormous economic loss,and even catastrophic safety accidents.It is worthwhile and desirable to develop high-efficiency strategy for anti-corrosion and anti-biofouling.In this paper,superhydrophobic 5083 aluminum alloy(AA5083) surface with micro-nano hierarchical morphology was fabricated through anodization followed by 1 H,1 H,2 H,2 H-perfluorooctyltriethoxysilane(POTS)modification.The surface morphologies,roughness,and chemical compositions were revealed by scanning electron microscopy,atomic force microscopy,and X-ray diffraction.The self-cleaning ability,corrosion resistance and algae adhesion suppression ability of the fabricated surfaces were investigated,indicating an excellent water-proofing,anti-corrosion and anti-biofouling performance.We believe the superhydrophobic creation of metallic materials is expected to have potential applications in marine corrosion and antibiofouling fields. 相似文献
314.
Zhaogang SHAO Xiangang MENG Dagang ZHU Daxing ZHENG Zijiang QIAO Chaobin YANG Jian'en HAN Jia YU Qingwei MENG Rongping L 《Frontiers of Earth Science》2008,2(3):364-377
On the Qinghai-Tibet Plateau there are three super large lakes, the Qinghai Lake, Nam Co and Siling Co, and eleven large lakes,
the Zhari Nam Co, Tangra Yumco, Ayakkum Lake, Banggong Co, Har Lake, Ngoring Lake, Yamzho Yumco, Gyaring Lake, Chibuzhang
Co, Ulan Ul Lake and the Ngangla Ringco. The authors studied the changes of these major lakes in the past 25 years, based
on interpretations of the MSS images obtained during the middle 1970s and ETM+ images obtained in the late 1990s or at the beginning of the 21st century. The study shows that: the areas of the Har Lake
andNgoring Lake have remained relatively stable; the areas of the Qinghai Lake, Zhari Nam co, Tangra Yumco, Ayakkum Lake,
Gyaring Lake, Ulan Ul Lake and Ngangla Ringco have been reduced to varying degrees, of which the areas of the Qinghai Lake
and Ulan Ul Lake have decreased most sharply by 60.60 km2 and 59.80 km2 respectively; the areas of the Nam Co, Siling Co and Bangong Co have increased more or less, of which the area of the Siling
Co has increased most sharply by 140.42 km2. The analysis on the changes in areas of major lakes has provided new materials for the study of the lake evolution, climatic
change and environmental variation on the Qinghai-Tibet Plateau.
__________
Translated from Geological Bulletin of China, 2007, 26(12): 1633–1645 [译自: 地质通报] 相似文献
315.
利用涡度、风场,结合地形,对2000-07-11-14日陕西省大范围降水形成洪灾的成因进行了初步探讨,揭示了大降水与主急流东移后的弱急流有密切关系,得出:低层源源不断的水汽、高空弱冷空气以及地面上风切变和特殊地形的共同影响,地表植被破坏严重,是造成这场洪灾暴雨的主要成因。 相似文献
316.
317.
Jianjun Liu C.-G. Duan M. M. Ossowski W. N. Mei R. W. Smith J. R. Hardy 《Physics and Chemistry of Minerals》2001,28(8):586-590
The order-disorder phase transitions in NaNO3 and CaCO3 are simulated by molecular dynamics. The simulations are based on the potentials calculated from the Gordon–Kim modified
electron gas formalism extended to molecular ions. We successfully reproduced the transition temperature T
c
and the abnormally large c axis thermal expansion observed in experiment. The phase transitions in NaNO3 and CaCO3 were found to be initiated by ±60 and ±180° reorientation of the NO3 and CO3 ions about the c axis. The orientations of NO3 and CO3 ions are continuous with six preferred calcite-type orientations above the phase-transition temperature.
Received: 30 January 2001 / Accepted: 11 May 2001 相似文献
318.
兰州阿干镇及其外围中生代地层 总被引:6,自引:0,他引:6
兰州阿干镇及其外围中生代地层有大西沟组、阿干镇组、铁冶沟组和河口群。我们在这四个地层单位中采到了不同丰富程度的孢粉,并在前二组中采到了丰富的植物化石。本文报道的孢粉是这一地区内的首次报道。 大西沟组 孢子以Osmundacidites Wellmanii为主,混有少量繁盛于晚三叠世的Taeniae-sporites sp.;植物属我国北方Coniopteris-Phoenicopsis植物群早期组合。时代为早侏罗世。 阿干镇组 孢粉中Cyathidites minor和Cycadopites typicus含量丰富;植物属我国北方Coniopteris phoenicopsis植物群晚期组合。时代属中侏罗世,并大致属Bathonian期。 铁冶沟群 下部的孢粉以Cycthidites minor居优势,上部没见化石。整个铁冶沟群的时代暂定为中—晚侏罗世。 河口群 下岩组内海金砂科的孢子多见,Cicatricosisporites sp.、Schinaeoisporites sp.仅少量存在。时代为早白垩世。 经过研究,我们在验证前人对四个地层单位时代归宿的同时,进一步认为阿干镇组可大致属于Bathonian期。 相似文献
319.
Shao-bo Duan 《GeoJournal》1992,27(1):133-133
Fourth Asian Urbanization Conference 相似文献
320.
古汉山井田地下水同位素组成特征研究 总被引:1,自引:0,他引:1
根据古汉山井田地下水中~3H、D、~(18)O和~(13)C等资料,建立了该井田鉴别主要含水层地下水的同位素标志,并对冲积层水、奥陶纪石灰岩水和煤系薄层石灰岩水之间的关系,以及矿井充水条件,做出了判断,为今后矿井基建、采矿中判别突水来源,提供了依据。 相似文献