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1.
依据渤海湾盆地2000余口测温井的地温梯度数据、地层岩性描述、分层数据以及钻井资料,计算了该盆地各生油岩系底界面的温度。统计结果表明:渤海湾盆地沙河街组大部分凹陷区地层底界面温度介于90℃至150℃,目前仍具有大量生油的温度条件,而在隆起或一些凸起地区,该地层组段温度普遍小于90℃,未能达到生油的温度指标。东营组和孔店组地层也仍具有一定的生油温度条件。研究还表明:地层温度与地层界面埋深密切相关,温度随界面埋深的增大而升高,沉积厚度大的凹陷区地层界面温度大于沉积厚度小的凸起区或斜坡地带,说明地层界面埋深是决定地温高低的主要控制因素,而地温梯度对地层界面温度的影响相对较小。 相似文献
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Desertification is a severe stage of land degradation, manifested by “desert-like” conditions in dryland areas. Climatic conditions together with geomorphologic processes help to mould desert-like soil surface features in arid zones. The identification of these soil features serves as a useful input for understanding the desertification process and land degradation as a whole. In the present study, imaging spectrometer data were used to detect and map desert-like surface features. Absorption feature parameters in the spectral region between 0.4 and 2.5 μm wavelengths were analysed and correlated with soil properties, such as soil colour, soil salinity, gypsum content, etc. Soil groupings were made based on their similarities and their spectral reflectance curves were studied. Distinct differences in the reflectance curves throughout the spectrum were exhibited between groups. Although the samples belonging to the same group shared common properties, the curves still showed differences within the same group.Characteristic reflectance curves of soil surface features were derived from spectral measurements both in the field and in the laboratory, and mean reflectance values derived from image pixels representing known features. Linear unmixing and spectral angle matching techniques were applied to assess their suitability in mapping surface features for land degradation studies. The study showed that linear unmixing provided more realistic results for mapping “desert-like” surface features than the spectral angle matching technique. 相似文献
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On August 5, 2001, Shanghai was struck by a torrential rainfall due to the passage of a tropical depression (TD). The rainfall intensity has been the strongest in recent 50 years. In this paper, a set of mesoscale re-analyses data and the planetary boundary layer observation from a wind profiler are used to understand the possible mechanism of such a heavy rain. Results show that the outburst of a southerly jet in the lower atmosphere triggered the explosive development of cyclonically vertical vorticity in the region with steep potential temperature surfaces in front of the TD; while the cyclonic vorticity increased notably at higher levels due to the small atmospheric vertical stability of westerly currents in the vicinity of Shanghai. The simultaneous sharp development of cyclonic vorticity at different levels should be the main cause for the torrential rainfall. 相似文献
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Jiangsu has the most abundant tidal flat resources among China's coastal provinces.To ease the conflict between the growing population and shrinking usable land and to promote regional sustainable development,large-scale coastal reclamation development activities have been performed in Jiangsu Province since 1949.The present study has integrated multi-source remote sensing images during 1974 to 2012 by using a Multi-point Fast Marching Method(MFMM) to extract the Jiangsu coastal reclamation areas for different time periods.The temporal and spatial patterns of the extent and elevation of the reclamation areas were analysed in order to determine the unused potential for future reclamation.It will provide information necessary to support the development and construction of tidal flats in Jiangsu.Results show that:(1) the reclaimed tidal flats along the Jiangsu coast cover more than 19.86×104 hm2,of which 13.97×104 hm2 is located in Yancheng,4.84×104 hm2 in Nantong,and 1.05×104 hm2 in Lianyungang;(2) the average elevation of the reclaimed Jiangsu tidal flats has gradually decreased over the last 40 years,while those in Dongtai and Rudong have showed particularly accelerated decrease since the 1990s;and(3) in 2012,very few unused tidal flats two meters above the sea level are left along the Jiangsu coast,and mainly concentrated in Yancheng.As there are still reserving some coastal land resources between 0-2 m,providing us with a potential for future development.All of these findings may be useful for researchers and local authorities for the development and utilization of tidal flat resources in Jiangsu. 相似文献
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