遥感监测土壤湿度综述

遥感技术具有大面积同步观测,时效性、经济性强等特点,为大面积动态监测土壤湿度提供了可能。本文对近年来国内外遥感监测土壤湿度的理论、方法的发展和应用进行了回顾,重点介绍了目前已经比较成熟和广泛应用的基于可见光与热红外波段的植被指数方法以及在干旱、半干旱地区的应用,通过对比分析了各种遥感监测方法的优缺点,指出了土壤湿度遥感监测方法存在的不足,展望了土壤湿度遥感监测方法的发展趋势。     

降雨影响噪声自动监测数据的有效性判定分析

选取北京市近5年夏半年（4—9月）夜间的降雨数据及相关噪声自动监测小时等效声级,对小时雨量与噪声自动监测数据进行数学统计分析,找出影响噪声监测数据的小时雨量值及不同声级受雨噪声影响的雨量限值,作为降雨对噪声自动监测小时等效声级的有效性判定条件。     

建设项目竣工验收现场平行样控制指标研究

依据建设项目竣工环境保护验收中污水监测的要求,通过积累大量验收监测质量检查的实验数据,运用数理统计的方法,以化学需氧量和氨氮两个项目为例,建立了质控数据的评价方法,并确定了现场平行样偏差指标的限値。     

污染源排气自动监测氮氧化物的不确定度分析

使用烟气排放连续监测系统自动监测仪器测定污染源排气中氮氧化物,按照最新的《测量不确定度评定与表示》(JJF1059.1—2012)的要求,测量不确定度评定的要求,首次对其氮氧化物自动监测的不确定度进行分析,得出不确定度报告。     

决策树模型在水环境监测网络中选取代表性样点的应用

地表水体中的硝酸盐污染已经成为全球关注的热点环境问题之一。现今,国内外均建立了相关的监测网络对地表水体的水质实施长期监测,但是却导致大量的监测数据累积,给后续的科学研究工作带来了不便,尤其是在庞大的监测网络中如何选取有代表性样点的研究点则成为急需解决的问题之一。以比利时弗拉芒地区地表水的长期监测物理化学指标为例,利用决策树模型评估地表水样点的硝酸盐污染来源专家分类的有效性,为点位优化提供理论依据。原有监测点位的污染源专家分类和模型输出的可匹配率为80%,优化后监测点位从原有47个点降低到30个点,提高了监测工作效率。     

基于3种时间序列模型的九龙江河流库区藻华预测

湖库富营养化和有害藻华是全球性生态环境问题,藻华预测与早期预警是保障湖库水源地供水安全的关键技术.如何基于高频水生态在线监测数据进行藻华的实时动态预测成为水生态管理领域的重大需求.本研究以福建省九龙江江东库区(水源地)为例,利用3年连续观测的逐时平均总叶绿素a浓度数据,对比研究了SARIMA、Prophet和LSTM(长短期记忆神经网络)3种时间序列模型在藻华(日平均叶绿素a大于15μg·L^-1)预测方面的效果.结果表明：(1)时间序列模型要求参数少,灵活性强,能清晰反映水质特征和未来变化趋势,可弥补传统藻类监测预警方法的局限性;(2)基于深度学习框架的LSTM模型,具有独特的迭代优化算法,对藻类非线性变化特征的识别和预测能力较强,其总叶绿素a逐日预测和7日预测效果均显著优于SARIMA模型和Prophet模型;(3)输入数据长度会在一定程度上影响模型预测效果,最优的输入数据时间长度为7 d;输入数据频率对预测效果也有影响,在预测非藻华日时,小时数据的预测效果优于日频率数据;在预测藻华日时,两种频率数据无显著差异,但日频率数据能更准确识别藻华日特征.总结起来,基于...     

Evaluating Perceived Benefits of Ecoregional Assessments

Abstract: The outcomes of systematic conservation planning (process of assessing, implementing, and managing conservation areas) are rarely reported or measured formally. A lack of consistent or rigorous evaluation in conservation planning has fueled debate about the extent to which conservation assessment (identification, design, and prioritization of potential conservation areas) ultimately influences actions on the ground. We interviewed staff members of a nongovernmental organization, who were involved in 5 ecoregional assessments across North and South America and the Asia‐Pacific region. We conducted 17 semistructured interviews with open and closed questions about the perceived purpose, outputs, and outcomes of the ecoregional assessments in which respondents were involved. Using qualitative data collected from those interviews, we investigated the types and frequency of benefits perceived to have emerged from the ecoregional assessments and explored factors that might facilitate or constrain the flow of benefits. Some benefits reflected the intended purpose of ecoregional assessments. Other benefits included improvements in social interactions, attitudes, and institutional knowledge. Our results suggest the latter types of benefits enable ultimate benefits of assessments, such as guiding investments by institutional partners. Our results also showed a clear divergence between the respondents’ expectations and perceived outcomes of implementation of conservation actions arising from ecoregional assessments. Our findings suggest the need for both a broader perspective on the contribution of assessments to planning goals and further evaluation of conservation assessments.     

气象因素对输变电线路电磁环境的影响

不考虑气象因素的输变电线路的电磁环境预测值与实际值之间有差距,探讨了温度、湿度、风等气象因素对输变电线路电磁环境的影响,并提出减缓措施。结果表明:温度上升,则电磁场强度及无线电干扰强度都会增强;高相对湿度下电磁场强度与湿度成正比,低湿度则无明显影响,湿度对无线电干扰的影响与线路电压有关;风使输电线发生偏移,改变空间电磁场强度。     

Changes in bird‐migration patterns associated with human‐induced mortality

Many bird populations have recently changed their migratory behavior in response to alterations of the environment. We collected data over 16 years on male Great Bustards (Otis tarda), a species showing a partial migratory pattern (sedentary and migratory birds coexisting in the same breeding groups). We conducted population counts and radio tracked 180 individuals to examine differences in survival rates between migratory and sedentary individuals and evaluate possible effects of these differences on the migratory pattern of the population. Overall, 65% of individuals migrated and 35% did not. The average distance between breeding and postbreeding areas of migrant individuals was 89.9 km, and the longest average movement of sedentary males was 3.8 km. Breeding group and migration distance had no effect on survival. However, mortality of migrants was 2.4 to 3.5 times higher than mortality of sedentary birds. For marked males, collision with power lines was the main cause of death from unnatural causes (37.6% of all deaths), and migratory birds died in collisions with power lines more frequently than sedentary birds (21.3% vs 6.3%). The percentage of sedentary individuals increased from 17% in 1997 to 45% in 2012. These results were consistent with data collected from radio‐tracked individuals: The proportion of migratory individuals decreased from 86% in 1997–1999 to 44% in 2006–2010. The observed decrease in the migratory tendency was not related to climatic changes (temperatures did not change over the study period) or improvements in habitat quality (dry cereal farmland area decreased in the main study area). Our findings suggest that human‐induced mortality during migration may be an important factor shaping the migration patterns of species inhabiting humanized landscapes.