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511.
内蒙古典型草原与荒漠草原NDVI对气象因子的响应 总被引:2,自引:2,他引:0
分析了内蒙古典型草原与荒漠草原NDVI的变化,探讨了干旱对NDVI的影响,建立了NDVI与气象因子的回归模型。结果表明:2000-2016年内蒙古典型草原与荒漠草原NDVI呈现波动变化,变异较小。干旱对典型草原区的羊草(Leymus chinensis)群落与大针茅(Stipa grandis)群落NDVI影响显著(P<0.05);与正常年份相比,干旱导致羊草群落与大针茅群落NDVI降低约23%。5-8月降水量和干燥度指数影响内蒙古典型草原羊草群落与大针茅群落NDVI;荒漠草原区羊草+短花针茅(Stipa breviflora)群落与沙生针茅(Stipa plareosa)群落NDVI的主要影响因子分别为年均气温与5-8月平均气温;5-8月降水量和年均气温是影响典型草原和荒漠草原NDVI的重要因子。基于气象因子的NDVI回归模型能够较好地对区域NDVI进行估测。生长季降水是影响典型草原NDVI的关键因素,而气温显著影响荒漠草原NDVI。在未来气候变化的背景下,内蒙古典型草原NDVI对干旱的响应会更加敏感。 相似文献
512.
We use the Richardson-Lucy deconvolution algorithm to extract one-dimensional(1 D) spectra from Large Sky Area Multi-Object Fiber Spectroscopic Telescope(LAMOST) spectrum images. Compared with other deconvolution algorithms, this algorithm is much faster. The application on a real LAMOST image illustrates that the 1 D spectrum resulting from this method has a higher signal-to-noise ratio and resolution than those extracted by the LAMOST pipeline. Furthermore, our algorithm can effectively suppress the ringings that are often present in the 1 D resulting spectra generated by other deconvolution methods. 相似文献
513.
Creating appropriate colour schemes is challenging for both novice and experienced cartographers. This paper introduces an artificial bee colony (ABC) algorithm to automatically create various colour schemes. Colour scheme creation is treated as a constrained search problem in a continuous colour space. We considered the gamut of the target device and a series of cartographic rules, such as convention, discrimination, contrast, perceptual uniformity and brightness mirror, in the ABC algorithm and presented detailed initialization, fitness definition, local exploration, and global exploration methods for creating qualitative, sequential and diverging colour schemes. The proposed method is evaluated with a case study, and the results indicate that compared with the brute force search method, the proposed method can create satisfying colour schemes of similar quality but significantly improved efficiency. 相似文献
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Zhang Wenguang Meng Jingyi Liu Bo Zhang Shichun Zhang Jing Jiang Ming Lv Xianguo 《水文研究》2017,31(11):1990-1999
Precipitation is usually the primary source of water for the hydrological cycle in a semiarid area. However, dew occurs frequently and affects water circulation dramatically in the west of Jilin Province in China. Measurements of the amount of dew formed and precipitation were carried out from July 2012 to October 2013 in the Momoge Natural Reserve. The results indicated that moisture from primary precipitation in the summer originated from the East Asian monsoon and was affected by the atmospheric circulation in the middle and high latitudes of Eurasia in the winter. The dew amount was approximately 19.44 mm (approximately 5% of the total rainfall amount), consisting of the evapotranspiration in the local area and atmospheric moisture. Dew also supplies nutrients to the local vegetation. The maximum contribution of total nitrogen, total phosphorus, and potassium in unit corn area could reach 288.60, 27.46, and 291.63 mg/m2 in half a month, respectively. The wind speed, relative humidity, and lowest temperature were the primary factors that dramatically affected dew formation and amount. As an additional source of fresh water, dew not only had a positive impact on the ecosystem in arid and semiarid zones but also played an important role in the local water cycle and other ecological processes. This research has important implications for water circulation and land use management. 相似文献
520.
Chen Jian Zhu Yubo Lv Lei Huang Hairong 《Geotechnical and Geological Engineering》2022,40(6):3211-3224
Geotechnical and Geological Engineering - The fluctuation in reservoir water level is one of the key external factors affecting the stability of slopes. Finite element models are established for... 相似文献