古尔班通古特沙漠草本植物生物量分配特征

草本植物层片是古尔班通古特沙漠早春生产力的主要贡献者,为深入了解荒漠草本植物在群落水平上对荒漠环境的整体适应性,分析了沙漠中部1 hm2样地中草本植物层片地上与地下生物量分配关系,并验证了草本植物层片生物量与根冠比、物种丰富度以及植株密度之间的关系.结果 表明:(1)类短命植物囊果苔草(Carex physodes)是...     

地震属性参数在煤层厚度预测中的应用对比

高分辨率三维地震勘探能够获得地下空间三维数据体的大量地质信息,为工作区煤层厚度的确定提供依据.通过常用的三种方法谱:矩法、振幅谱平方比法、地震振幅谱和子波振幅谱比法,提取三维地震数据体中地震属性,编制相应的软件程序,对煤层厚度进行预测.研究对比了这三种算法的预测效果,为煤田煤层厚度的预测提供了可靠的参考依据.     

1987—2016年雀儿山冰川变化及其对气候变化的响应

深入了解全球变暖背景下青藏高原东南部海洋型冰川的变化趋势及其对气候变化的响应,对认识不同类型冰川对气候变化的响应方式有重要意义.根据Landsat系列遥感影像和数字高程等数据提取了青藏高原东南部雀儿山地区1987—2016年期间多年的冰川边界,并对其变化过程和特征进行了分析.结果表明:1987—2016年雀儿山地区冰川...     

UFCLS线性光谱混合分析法在遥感图像分类识别中的效果分析

用非监督全约束最小二乘法对线性光谱混合模型进行了反演,通过获得各像元组分的面积比图像来达到对各像元分类的目的。将非监督全约束最小二乘法的分类结果与有限光谱混合分析法的分类结果进行对比,结果表明,无论从分类效果还是计算时间上看,前者都优于后者。     

Hyperspectral imagery for disaggregation of land surface temperature with selected regression algorithms over different land use land cover scenes

Land surface temperature (LST), a key parameter in understanding thermal behavior of various terrestrial processes, changes rapidly and hence mapping and modeling its spatio-temporal evolution requires measurements at frequent intervals and finer resolutions. We designed a series of experiments for disaggregation of LST (DLST) derived from the Landsat ETM + thermal band using narrowband reflectance information derived from the EO1-Hyperion hyperspectral sensor and selected regression algorithms over three geographic locations with different climate and land use land cover (LULC) characteristics. The regression algorithms applied to this end were: partial least square regression (PLS), gradient boosting machine (GBM) and support vector machine (SVM). To understand the scale dependence of regression algorithms for predicting LST, we developed individual models (local models) at four spatial resolutions (480 m, 240 m, 120 m and 60 m) and tested the differences between these using RMSE derived from cross-validated samples. The sharpening capabilities of the models were assessed by predicting LST at finer resolutions using models developed at coarser spatial resolution. The results were also compared with LST produced by DisTrad sharpening model. It was found that scale dependence of the models is a function of the study area characteristics and regression algorithms. Considering the sharpening experiments, both GBM and SVM performed better than PLS which produced noisy LST at finer spatial resolutions. Based on the results, it can be concluded that GBM and SVM are more suitable algorithms for operational implementation of this application. These algorithms outperformed DisTrad model for heterogeneous landscapes with high variation in soil moisture content and photosynthetic activities. The variable importance measure derived from PLS and GBM provided insights about the characteristics of the relevant bands. The results indicate that wavelengths centered around 457, 671, 1488 and 2013–2083 nm are the most important in predicting LST. Nevertheless, further research is needed to improve the performance of regression algorithms when there is a large variability in LST and to examine the utility of narrowband vegetation indices to predict the LST. The benefits of this research may extend to applications such as monitoring urban heat island effect, volcanic activity and wildfire, estimating evapotranspiration and assessing drought severity.     

一种卤水中钾离子含量的快速测定方法

介绍了使用多道能谱仪探测卤水中~(40)K放射出的γ射线,用最小二乘法处理数据,得到卤水中钾离子含量的快速测定方法。采用该测量方法,可提高钾盐生产企业劳动生产率、减少资源浪费。     

中国沿岸相对海面变化的本征分析和预测

利用经验正交函数的方法，将平均海面分解为正交时，空函数积的代数和。采用起主导作用的正交函数进行组合，得到修正的海平面变化值，它消除了某些随机的影响。去掉平均海面主要时间本征函数中的主要周期部分，求得剩余部分的变化率，乘以空间本征函数可得各站平均海面的变化速率，对未来的时间本征函数作出预报，便可得到未来的平均海面预报值。     

Responses of Mean and Extreme Precipitation to Different Climate Forcing Under Radiative-Convective Equilibrium

Understanding the responses of mean and extreme precipitation to climate change is of great importance.Previous studies have mainly focused on the responses to prescribed sea surface warming or warming due to increases of CO2.This study uses a cloud-resolving model under the idealization of radiative-convective equilibrium to examine the responses of mean and extreme precipitation to a variety of climate forcings,including changes in prescribed sea surface temperature,CO2,solar insolation,surface albedo,stratospheric volcanic aerosols,and several tropospheric aerosols.The different responses of mean precipitation are understood by examining the changes in the surface energy budget.It is found that the cancellation between shortwave scattering and longwave radiation leads to a small dependence of the mean precipitation response on forcings.The responses of extreme precipitation are decomposed into three components(thermodynamic,dynamic,and precipitation efficiency).The thermodynamic components for all climate forcings are similar.The dynamic components and the precipitation-efficiency components,which have large spreads among the cases,are negatively correlated,leading to a small dependence of the extreme precipitation response on the forcings.     

应用最优化订正法制作长江上游面雨量预报

利用最优化订正法，通过对MAPS数值降水预报进行订正，制作长江上游六大流域短期面雨量预报。2002年6－10月业务试验表明，长江上游六大流域平均的常规降水面雨量预报准确率比MAPS高19％左右，强降水天气过程的击中率为48％左右，取得了较好的效果。     

Spectral analysis of quasi-stationary sea surface topography from GRACE mission

The mean sea surface height (MSSH) refers to the average of the long-term sea height. The quasi-sea surface topography (QSST) is usually defined as the height difference between the MSSH and the geoid. As to 100 years of time yardstick of geodesy, the time that satellite altimetry data sets spanned is relatively shorter, in this paper, the QSST refers to the residual sea surface height (RSSH) that shows the height dif-ference between MSSH derived from altimetry and the geoid[1]. As w…