An algorithm to retrieve precipitation with synthetic aperture radar

This paper presents a new type of rainfall retrieval algorithm, called the model-oriented statistical and Volterra integration. It is a combination of the model-oriented statistical (MOS) and Volterra integral equation (VIE) approaches. The steps involved in this new algorithm can be briefly illustrated as follows. Firstly, information such as the start point and width of the rain is obtained through pre-analysis of the data received by synthetic aperture radar (SAR). Secondly, the VIE retrieval algorithm is employed over a short distance to obtain information on the shape of the rain. Finally, the rain rate can be calculated by using the MOS retrieval algorithm. Simulation results show that the proposed algorithm is effective and simple, and can lead to time savings of nearly 50% compared with MOS. An example of application of SAR data is also discussed, involving the retrieval of precipitation information over the South China Sea.     

Variations of methane stable isotopic values from an Alpine peatland on the eastern Qinghai-Tibetan Plateau

Acta Geochimica - Isotopic signature is a powerful tool to discriminate methane (CH4) source types and constrain regional and global scale CH4 budgets. Peatlands on the Qinghai-Tibetan Plateau are...     

西藏普兰石英岩中发现41亿年碎屑锆石

在西藏普兰县石英岩中,利用SHRIMPU-Pb法测年发现4.1Ga碎屑锆石。该年龄为目前中国最老单颗粒碎屑年龄。>4.0Ga锆石两测点的Th/U值介于0.76~0.86之间,属岩浆锆石。这一发现,为研究青藏高原的地质演化提供了重要的年龄数据。     

Effect of nano-MgO on mechanical performance of cement stabilized silty clay

Abstract

A series of direct shear tests were performed on cement-admixed silty clay to investigate the effect of cement content and nano-magnesia (MgO) on its shear strength properties. For each normal stress, shear strength increased with cement content. However, an obvious increment in shear strength was achieved when the cement content was adjusted from 13% to 17%. Both cohesion and friction angle of cemented soil increased with cement content, and exponential function was adopted to correlate both the factors with cement content. For cement content of 10% investigated in this study, the optimum nano-MgO content was 10‰, wherein the cohesion could reach the peak value. The microstructure of the mixture revealed that the structure of the mixture was compacted for the optimum nano-MgO content. However, micro-cracks were formed when the amount of nano-MgO exceeded its optimum content.     

Python脚本在湖南省第三次国土调查数据库自检中的应用

第三次国土调查数据库是第三次国土调查工作的主要成果,是支撑未来自然资源管理各项工作的关键,其质量必须得到充分重视.对数据库进行充分自检并依据自检问题逐一修改,是减少后期工作量、保障第三次国土调查数据库质量的重要手段.本文通过对湖南省第三次国土调查数据库自检内容和方法的分析,梳理了第三次国土调查数据库自检工作存在的不足,...     

IKONOS影像生产1∶10 000地理信息产品的研究

简要介绍了IKONOS卫星遥感影像适用于地理信息产品生产的特点,然后通过试验生产,并与传统的航片相比较,详细分析了利用IKONOS影像作为数据源生产1∶10000基础信息产品在精度、生产流程、工作效率、生产周期、外业工作量和价格等方面的情况。     

基于多源遥感数据的区域生态系统服务价值年际动态监测 ——以中原城市群为例

通过对多源遥感数据在生态系统服务价值（ESV）遥感模型中的尺度效应分析,选择满足最佳空间分辨率和长时间序列的遥感数据,对中原城市群区域2001~2013年的ESV实现了逐年逐像元水平的动态监测。结果表明：该区应用于遥感模型输入数据的最适空间分辨率为30~1 000 m,相对于30 m尺度,其他尺度估算结果的相对偏差均小于0.4%;结合年际动态监测的需求,选择了MODIS数据产品（空间分辨率500 m,时间尺度1 a）作为遥感模型的最佳数据源;研究区ESV总值在研究期内整体上呈显著增长趋势,增速约为8.6亿元/a,但在持续增长过程中经历了3次波动,且表现得越来越剧烈;在空间上,研究区ESV多年均值呈现出明显的不均衡性,表现为从西南向东部递减的趋势。研究表明此方法简单易行,初步实现了区域ESV年际动态监测遥感模型的准业务化运行。