Analysis of the spectral response of flourishing-withering vegetation changes based on ground spectral measurements

A structural mode was used to characterize vegetation composition at the plant leaf level and a flourishing-withering ratio was developed. The spectral responses of vegetation with different flourishing-withering ratios were analyzed, the change rates of the chlorophyll and moisture content indices of vegetation with different flourishing-withering ratios were compared, and correlations between the chlorophyll and moisture content indices were analyzed. The results reveal that leaves with an intermediate flourishing-withering ratio can increase the absorption signatures of vegetation and that band ranges of 570–700 nm and 1300–1540 nm can play a role in indicating changes in the flourishing-withering ratios of vegetation; NPQI, NPCI, R₆₉₅/R₄₂₀, R₆₉₅/R₇₆₀, R₇₅₀/R₇₀₀, the peak-value area of red selvedge, the red selvedge amplitude, the ratio between the red selvedge amplitude and the minimum amplitude, and the NDVI of vegetation change regularly with the change in flourishing-withering ratios, and these nine vegetation indices are highly related to the chlorophyll content. Vegetation indexes of NDWI and PRI are very sensitive to the flourishing-withering change in vegetation and are closely related to the moisture content, and the correlation coefficient is higher than 0.9. The derivative of the spectra is more effective in describing changes in the structural mode of vegetation with different flourishing-withering ratios, especially at band ranges of 552–628 nm and 630–686 nm, and it is more sensitive to the mixed flourishing-withering ratios of leaves rather than to the vegetation indices. The red selvedge position in the spectrum is highly related to the chlorophyll content and is not sensitive to changes in the structural mode of mixed flourishing-withering leaves. The red selvedge parameters are sensitive to changes in the flourishing-withering ratio at the peak-value area of the red selvedge amplitude and the ratio between the red selvedge amplitude and the minimum amplitude. The effect of a sand background on the spectrum of withering leaves is higher than that of flourishing leaves; the effect of a sand background increases with increasing proportions of withering leaves, the superposition effect of the sand background on mixed flourishing-withering leaves is about 7% at visible light bands of 400–700 nm and 1300–1540 nm, and is over 10% at the near infrared band range of 700–1300 nm.     

Features and trends of the environmental change in the arid areas in Central Asia

RS-monitoring index systems of ecological environment changes at a large scale, based on empirical data and trends in environmental change in Central Asia, are developed using NOAA and MODIS data. Moreover, with the help of mathematical statistics and GIS spatial analysis, the degrees, hazards and distribution extent of various possible ecological problems are discussed, environmental changes in Central Asia in 1990 and 2005 are separately evaluated, and dynamic changes in the environment in Central Asia over a 15-year period are analyzed. The results reveal that during the 15-year period from 1990 to 2005, areas of degenerated vegetation in Kazakhstan, Uzbekistan, Turkmenistan, Kirghizstan and Tadzhikistan were enlarged by 0.069×10⁵ km², 0.081×10⁵ km², 0.296×10⁵ km², 0.022×10⁵ km² and 0.112×10⁵ km², respectively. The ecological environment in Central Asia was in the state of significant degeneration and even deterioration. This study proves that NOAA and MODIS data can be used to successfully monitor the environment and provide useful results.     

Regional Tectonic Deformation Background and Medium- and Short-Term Precursors to the Minle-Shandan Earthquakes

INTRODUCTIONOnOctober 2 5,2 0 0 3,twoearthquakesofMS6 .1andMS5.8hitMinleandShandanofGansuProvinceinsuccession (at 38.4°N ,1 0 1 .2°E ;and 38.4°N ,1 0 1 .1°E) .Theseismicfaultisthrustandleft lateraltheMinle DamayingfaultwhichstrikesEWandisaffiliatedtot…     

景泰5．9级地震前后的重力变化研究

通过对河西地区重力复测资料进行系统分析,从动态的观点研究了2000年6月6日景泰5．9级地震孕育过程中的重力场演化特征。重力动态图像较清晰地反映了本区重力场的准均匀态→地震孕育的非均匀态→发震的演化过程,还分析研究了特征重力变化与强震活动原关系。     

陆面温度反演算法——劈窗算法的敏感度分析

劈窗算法是目前由热红外遥感图像数据获取陆面温度最主要的方法。由于进行地面像元尺度实时陆面温度同步测量的困难,尚无法直接对现有各劈窗算法进行评判。该文借助于辐射传输模型ＬＯＷＴＲＡＮ－７及其提供的６种标准大气模式,进行模拟计算,分析了６种主要劈窗算法对大气廓线误差和比辐射率的敏感度,作为劈窗算法适用性的一间接判据。     

Study on automatic recognition of the first motion in a seismic event

IntroductionSeismic detection is one of the most effective methods to monitor underground explosions. When an underground explosion is conducted, like an earthquake, it will radiate seismic waves. Stimulating from sources, these seismic waves travel through the Earth(s interior and surface, propagating widespread. These waves can be recorded by seismograph systems on surface. By studying the recorded seismic signals, we can obtain much detailed information on such a seismic event. We can the…     

1—（2—羟基—3,5—二硝基苯）—3—4（4—苯基—2—噻唑）—三氮稀的合成及其与镍的显

合成了新试剂 1 - (2 -羟基 - 3,5-二硝基苯 ) - 3- (4-苯基 - 2 -噻唑 ) -三氮烯 ,研究了在表面活性剂TritonX - 1 0 0存在下 ,它与Ni2 的显色反应。结果表明 ,在 pH 6.0～ 7.5时 ,Ni2 与该试剂形成配合物 ,其最大吸收峰位于 51 5nm处 ,摩尔吸光系数为 1 .0 8× 1 0 5 L·mol- 1 ·cm- 1 。Ni2 在 0～ 0 .4mg/L内符合比尔定律。方法已用于矿物、合金、钢样中微量镍的测定 ,结果与原子吸收法相符 ,相对标准偏差RSD <5% (n =6)     

沉积物中石英E'心的热力学特性及其地质应用意义

对 8个取自南海珠江口盆地XJ33-2 -1井的样品进行了热力学实验 ,使用电子自旋共振 (ESR)技术获取了样品中石英E′心天然状况下的ESR信号强度I1对经热活化技术处理后石英E′心的ESR信号强度I2 的比值。实验结果表明 :每个样品的活化温度不完全相同 ,这与母岩的特性有关 ;I1/I2 值与古地温呈正相关关系 ;I1/I2 值与地层年龄有很强的相关性 ,相关系数高达0 .99。说明I1/I2 值具有古地温指示和地质计时的实际意义。     

就XS—02井压裂情况谈煤层气井完井及增产措施

在对XS-02井完井压裂进行总结的基础上,分析了3种完井方式和3种压裂液在煤层气井中的适应性,结合XS-02井压裂施工的具体情况,解释煤层气井压裂时高滤失和高施工压力的原因,为以后各井的工作提供可参考的依据。