扁椭球形雨滴和冰粒后向散射实验与理论研究

本文介绍了对扁椭球形雨滴和冰（雹）粒散射能力的实验模拟和测量技术，报告了一个系列扁水(冰)椭球后向散射截面的实验测量结果；并用扩张边界条件法(EBCM)计算出相应的理论值，用Mie公式计算出等容积球形后向散射截面。将实验结果与理论计算作了综合对比分析，得到了若干有用的结论。     

微波炉在重量法测定硫中的应用

采用玻璃砂芯坩埚过滤BaSO_4沉淀,微波炉代替马弗炉恒重坩埚、沉淀,重量法测定了矿石中的硫。方法准确,精密度好。微波炉不需预先升温,加热6min可达恒重,省时、省电。     

基于地基微波辐射计资料对成都双流机场两次雷雨过程的分析

利用地基微波辐射计资料,比较了2017年7月成都双流机场的两次雷雨过程,根据天气形势分为"两高切变"和"东高西低"2类,在此基础上分析微波辐射计要素变化特征,结果表明:在垂直方向0～10 km,以相对湿度达到80%来区分干区和湿区,则两次过程前3 h,相对湿度在垂直方向均呈现"上下干、中间湿"三层结构,并早于近地层前2 h达到饱和状态;过程期间相对湿度呈现"上干、下湿"两层结构;过程结束后湿层抬高,低层变干。两次过程水汽含量充沛,保持在70 kg/m~2以上,峰值超过85 kg/m~2。每一次中阵雨发生后水汽含量都会短暂回落,但仍高于过程前的数值,不足2 h后再次发生中阵雨。由0℃线高度变化可知,降水过程中,暖区(温度≥0℃)内相对湿度≥90%;云中液态水含量主要分布于6 km以下,温度在0℃以上的液态水占比很高,故两次过程以暖云降水为主。雷雨前1 h左右有"低层气温上升,0℃层抬升,K指数、CAPE指数也明显增大"的典型特征。降水发生在相对湿度、水汽总含量、云中液态水含量和稳定度指数快速增长的波峰中。     

Spectral index determination between 408 MHz and 5 GHz in the northern sky

We present the joint analysis of two 5-GHz interferometric surveys of the northern sky, taken with different baselines. The two surveys were carried out on the Jodrell Bank 5-GHz interferometer based at Manchester. The Maximum Entropy Method is used to check the consistency of the two surveys and the final two-dimensional maps are used, together with low-frequency full sky surveys, to put constraints on the Galactic spectral index. It is found that synchrotron emission is the dominant process at high Galactic latitudes below 5 GHz.     

Space-time soil wetness variations monitoring by a multi-temporal microwave satellite records analysis

In the last few years, remote sensing observations have become a useful tool for providing hydrological information, including the quantification of the main physical characteristics of the catchment, such as topography and land use, and of its variables, like soil moisture or snow cover. Moreover, satellite data have also been largely used in the framework of hydro-meteorological risk mitigation.Recently, an innovative Soil Wetness Variation Index (SWVI) has been proposed, using data acquired by the microwave radiometer AMSU (Advanced Microwave Sounding Unit) which flies aboard NOAA (National Oceanic and Atmospheric Administration) satellites.SWVI is based on a general approach for multi-temporal satellite data analysis (RAT - Robust AVHRR Techniques). This approach exploits the analysis of long-term multi-temporal satellite records in order to obtain a former characterization of the measured signal, in term of expected value and natural variability, providing a further identification of signal anomalies by an automatic, unsupervised change-detection step. Such an approach has already demonstrated, in several studies carried out on extreme flooding events which occurred in Europe in the past few years, its capability in reducing spurious effects generated by natural/observational noise. In this paper, the proposed approach is applied to the analysis of the flooding event which occurred in Europe (primarily in NW Spain) in June 2000. Results obtained, in terms of reliability as well as efficiency in space-time monitoring of soil wetness variation, are presented. Future prospects, in terms of exportability of the methodology on the new dedicated satellite missions, like ESA-SMOS and NASA-HYDROS, are also discussed.     

微波消解-等离子体发射光谱法同时测定水中硅铁钠

讨论使用电感耦合等离子体发射光谱法测定水样中si、Fe、Na时，四种水样前处理方法对测试结果的影响。提出采用HNO3^-HF体系微波消解、H3BO3掩蔽HF的方法前处理水样，用等离子体发射光谱法可同时准确快速地测定水中Si、Fe、Na三种元素的含量。5次测定的相对标准偏差小于4％，加标回收率为89．2％-106％。     

微波辅助化学反应制备纳米高岭石

为提高高岭石比表面积、孔隙率和吸附容量，利用微波辅助化学反应制备了尿素-高岭石复合物，进一步微波辐射使层状高岭石完全剥离并粉碎，经分散后得到了纳米高岭石。利用傅立叶红外光谱仪（FT-IR）、X射线粉晶衍射仪（XRD）、扫描电镜（SEM）和透射电镜（硎）进行了过程中样品结构、形貌和尺寸方面的表征。结果表明：同等条件下，通过微波辅助剥离并粉碎层状高岭石，时间只需30min，约为单一球磨的1／20，分散后的纳米高岭石平均粒径约为150nm。     

多频率多极化地表辐射参数化模型

发展了针对对地观测系统被动微波辐射计AMSR-E应用的裸露地表辐射模型。首先，利用1993年法国INRA地面试验数据对AIEM在宽波段高频率和大角度的辐射信号模拟能力进行评价。验证结果表明，AIEM模型模拟值与地面实测数据吻合很好，说明AIEM模型能很好模拟宽波段和大角度的辐射信号。在此基础上，用AIEM模型建立了一个针对AMSR-E传感器参数配置．包含各种地表粗糙度和介电特性的裸露地表辐射模拟数据库。利用AIEM模拟数据和地面实测数据对目前人们使用的半经验地表模型进行了比较和分析，发展了多频率多极化的地表辐射参数化模型——Qp模型。该模型中，地表粗糙度对辐射信号的影响通过粗糙度参数Qp来表示。参数Qp可简单表示为均方根高度与相关长度的比值（s／l）。从Qp模型与AIEM模型模拟的发射率比较结果来看，它们之间的绝对误差很小，不超过10^-3因而，本文发展的参数化模型可用作模拟地表辐射的前向模型，如用于估算AMSR-E传感器的亮温值，同时模型的发展有利于提高人们对辐射机制的理解和认识。     

被动微波反演裸露区土壤水分综述

被动微波具有全天候、穿透性以及不受云的影响等特征,使其在反演土壤水分时具有很大的优势。通过研究发现,被动微波遥感是反演土壤水分的各种技术中最有效的方法之一。概括了主要的被动微波传感器并从被动微波遥感的原理出发,针对被动微波遥感裸露区地表随机粗糙面的模型以及土壤水分反演算法作了简要介绍。     

A Low-Sidelobe, High Frequency Corrugated Feed Horn for CMB Observations

We have produced a prototype broadband, low-sidelobe conical corrugated feed horn suitable for measurements of the Cosmic Microwave Blackground (CMB) radiation in the frequency band 120–150 GHz. The antenna is a first prototype for the Low Frequency Instrument array in ESA's PLANCK mission, a space project dedicated to CMB anisotropy mesurements in the 30–900 GHz range. We describe the fabrication method, based on silver electro-formation, and present the two-dimensional antenna beam pattern measured at 140 GHz with a milimeter-wave automated scalar test range. The beam has good symmetry in the E and H planes with a far sidelobe level approaching –60 dB at angles 80°. An upper limit to the return loss was measured to be –21 dB.