利用CDOM吸收系数估算太湖水体表层DOC浓度

溶解有机碳(DOC)是水体中最大的有机碳库,在水体碳循环中起着重要作用.有色溶解有机物(CDOM)是DOC的重要组成部分,其吸光作用改变着水下光场结构,是水色遥感监测的重要因子之一,建立两者的联系为利用遥感技术估算湖泊水体表层DOC浓度提供有效的技术方法.基于2010年5月、2011年1月、2011年3月和2011年5月的太湖4期实验数据(183个采样点),利用CDOM特征波长吸收系数[ag(250)和ag(365)]建立多元线性模型估算太湖水体DOC浓度,同时利用2011年8月29日～9月2日的数据(n=27)对模型进行验证评价,并构建了湖泊水体DOC浓度的遥感反演模式.结果表明,该模型能够有效估算太湖水体的DOC浓度;2011年1月DOC和CDOM的源和汇有较大差异,估算效果较差;其他3期数据的模型估算效果显著(R2=0.64,RMSE=14.31%,n=164),并在201108期数据中得到了验证(R2=0.67,RMSE=10.58%,n=27).模型形式虽具有一定的通用性,但系数在不同的水域中有所差异,模型系数的区域化成为下一步研究的重点.     

Assessment of nutrient distributions in Lake Champlain using satellite remote sensing

The introduction of nutrients to lakes causing eutrophic conditions is a major problem around the world. Proper monitoring and modeling are important to effectively manage eutrophication in lake waters. The goal is to develop remote sensing models for nutrients, total phosphorus and total nitrogen, in Lake Champlain. The remote sensing models were created using multivariate linear regression with the unique band combinations of Landsat Enhanced Thematic Mapper Plus （ETM＋） imagery based on the empirical relationship with the field observations. The resulting models successfully showed nutrient distributions in the most eutrophic part of Lake Champlain, Missisquoi Bay, with reasonable adjusted coefficient of determination values （R2 = 0.81 and 0.75 for total phosphorus and total nitrogen, respectively）. The results show the feasibility and the utility of satellite imagery to detect spatial distributions of lake water quality constituents, which can be used to better understand nutrient distributions in Lake Champlain. This approach can be applicable to other lakes experiencing eutrophication assisting decision making when implementing Best Management Practices and other mitigation techniques to lakes.     

基于HJ-1卫星的丹江口库区水质遥感监测研究

丹江口水库作为南水北调中线工程的水源地,其水质安全将直接影响到调水工程的成败。利用不同水质具有不同光谱特征的特点,采用遥感技术对水域水质进行大范围、准确、快速监测。根据丹江口库区2011年3月、7月、2013年3月、9月4景HJ1A/B卫星遥感影像,结合同步的地面实测水质数据,采用经验反演模型对丹江口水库叶绿素a浓度、水体悬浮物浓度和水体透明度进行了定量遥感反演研究。结果显示,由于2011年受到长江中下游区域重大旱情影响,汉江入库流量较小,造成丹江口水域面积减少;同年相比,水体叶绿素a浓度枯水期比丰水期高;2013年相比2011年水体叶绿素a浓度略有上升;丹库、汉库入库口的水体悬浮物浓度要高于其他区域,主要由于入库口的水流量较大,水体扰动较强。入库口区域较高的悬浮物浓度造成水体透明度要低于其他区域,丹库水域面积大,有利于悬浮物沉积,因此丹库水体透明度高于汉库。     

Research evolution on intelligentized technologies for arc welding process

This paper presents some new evolutions of research works in the IRWTL at SJTU on intelligentized technologies for arc welding dynamic process and robot systems, including multi-information sensing of arc welding process, such as characteristic extraction of weld pool image, voltage, current, and sound, arc-spectral features; multi-information fusion algorithms for prediction of weld penetration; intelligentized modeling of welding dynamic process; intelligent control methodology for welding dynamic process; intelligentized technologies for robotic welding, such as guiding and tracking seam technology and intelligent control of weld pool and penetration in robotic welding process; and development of autonomous welding robot system for the special environment. The ideas of intelligentized welding manufacturing technology (IWMT) and intelligentized welding manufacturing engineering (IWME) are presented in this paper for systematization of intending researches and applications on intelligentized technologies for modern welding manufacturing. The studies of intelligentized welding presented in this paper establish the foundation work of intending researches and applications on intelligentized technologies for modern welding manufacturing.     

辽河流域非点源污染空间特征遥感解析

应用遥感技术研究了辽河流域非点源污染发生特征.将环境卫星遥感数据耦合非点源(non-point Source,NPS)污染负荷估算模型,探索基于遥感像元尺度的非点源污染估算方法,目的是分析2010年辽河流域非点源污染特征,从而明确非点源污染的重点防治区和防治措施,为辽河流域水环境污染防治提供技术支持.结果表明,2010年辽河流域总氮排放量为10.3万t,总磷排放量为0.68万t,化学需氧量排放量为13.1万t,氨氮排放量为1.8万t;目前,对于辽河流域主要的非点源污染类型为农业面源;2010年辽河流域面源污染对水质污染的贡献率表现为总氮67.4%,总磷76.4%,化学需氧量39.4%和氨氮21.9%;空间分布上辽河流域的南部是污染最严重的地区,其次是东北部.本研究结合遥感技术发展了以遥感像元为基本模拟单位的非点源污染负荷估算方法,明确了2010年辽河流域的非点源污染产生量和空间分布特征,为辽河流域污染治理防治工作提供了理论依据.     

岩溶区峰丛洼地植被指数的克里格分析

为了全面掌握岩溶区峰丛洼地植被指数(NDVI)的空间分布状况,解决岩溶区峰丛洼地遥感影像山体阴影区域NDVI信息"缺失"的问题,对广西平果县果化生态重建示范区内的典型峰丛洼地非阴影区域NDVI进行了提取.利用地统计学的方法对NDVI的空间结构特征进行了分析,并对山体阴影区的NDVI进行了预测与验证.结果表明,研究区域NDVI主要受到内在因子的作用,具有强烈的空间自相关性,自相关距离为300 m;Kriging插值结果表明,研究区域NDVI的均值为0.196,在空间分布上表现为条带状和斑块状分布,NDVI高值区域主要分布在峰丛坡度>25°的山体区域,低值区域主要分布在峰丛坡度<25°的山脚和洼地等区域;Kriging插值验证结果表明,研究区域NDVI具有非常高的预测精度,能很好地估计山体阴影区NDVI,为岩溶区生态环境监控、石漠化评估提供了新的思路与方法.     

基于遥感数据反演技术的东海海洋环境谱编制

通过卫星遥感数据的大规模反演技术,获取了研究区域海洋环境要素的时空分布。研制了多通道温湿度综合测量仪,通过实测结果与反演结果的对比,验证了该方法的可信性和可行性。以我国东海海域5a的卫星遥感数据为基础,通过反演计算出该海域的温度、湿度和盐雾分布,编制出适用的海洋环境谱。     

近20 a中国省会及以上城市空间形态演变

以多时相、多波段的Landsat TM/ETM+遥感影像为数据源,利用NDBI-SAVI指数提取1990-2010年中国35个省会及以上城市的建设用地信息,通过计算紧凑度和形状指数,研究城市扩张状况,并借助雷达图来分析城市扩张的方向。结果表明:从城市扩张速度来看,东部城市总体上扩张速度高于中部和西部,其中4个直辖市的扩张速度普遍高于其它城市;扩张速度相对较慢的城市多分布在华北和西北等重工业或河谷型城市。从空间形态变化上看,两时期35个城市的形状大都集中于正方形与矩形之间,只有少数城市形状为菱形、星形、H形或X形。综合来看,近20 a中35个城市形状指数的平均值增加,而标准差减小,城市形态趋于复杂;同时,城市紧凑度的平均值减小。有15个城市的紧凑度增加,20个城市的紧凑度减小。城区往往趋向于少数几个方向扩张,"摊大饼"式的扩张不多见。     

环境监测中遥感技术的运用探究

目前,遥感技术已被广泛使用于大气污染、水污染、地面污染等环境污染的监测工作中,在环境检测工作中遥感技术有速度快、成本低、范围广、长期进行动态监测等优势。经过不断的发展遥感技术越来越新颖,有热红外遥感技术、微波遥感监测技术和可见光-反射红外遥感技术。     

Situational Waste in Landscape Watering: Residential and Business Water Use in an Urban Utah Community1

Abstract: Landscape water conservation is an important issue for municipalities throughout the Western United States, and especially in Utah as rapid growth strains existing water supplies. We conducted interdisciplinary research in Layton, Utah, that aimed at understanding patterns of landscape water use among households and businesses. The research project involved three basic tasks. First, a landscape “water budget” was developed by producing a calibrated and classified mosaic of landscape type and area from airborne multispectral digital imagery, integrating this information with Layton City parcel boundary data to determine landscape vegetated areas per lot, and estimating irrigation needs derived from reference evapotranspiration (ETo) obtained using weather data for the Salt Lake City metropolitan region. Second, utilizing Layton water billing data, water use for each household and business was identified and categorized as “conserving,”“acceptable” or “wasteful” by determining how much the water applied varied from actual landscape plant need. Third, surveys were administered to a random stratified sample of households and businesses in the study area to investigate various factors that were hypothesized to be predictive of wasteful watering practices. This paper primarily focuses on analysis of the household and business survey data, which explores factors affecting urban landscape water use from a human behavioral perspective. We found that the most significant factors predicting actual water use were the type of irrigation system and whether the location was a household or business. Attitudinal and motivational characteristics were not consistently associated with water use. We found that wasteful watering is the result of many factors embedded in the complex context of urban landscapes. This implies that water conservation programs should identify potential wasteful users through analyses of water billing data and direct water conservation measures at these users by focusing on site‐specific evaluations and recommendations. Water audits or water checks are one such tool that some communities have employed to help people understand and assess the quantity of water needed by and applied to their landscapes. This approach provides an opportunity to evaluate situational constraints at particular locations and design appropriate strategies for reducing water waste.