附加系统参数的多时相InSAR时空建模和形变估计

轨道误差和长波大气延迟组成的系统误差是影响InSAR形变监测精度的重要因素之一.传统方法在空间域对干涉图的系统误差建模,容易导致长波形变和系统误差相混淆.本文在时空域利用附加系统参数对系统误差建模,同时根据观测值质量对差分相位观测值定权,采用附加系统参数的加权最小二乘法估计形变参数和系统误差,实现了长波形变和系统误差的分离.模拟实验结果表明,在形变与系统误差的空间变化特性完全一致的极端情况下,本文方法能实现两者的有效分离,估计的形变速率均方根误差比传统方法降低了98.8%.ASAR数据实验显示当形变尺度较小且分散分布时,本文方法和传统方法得到的结果相似;当形变在研究区内表现为长波变化时,本文方法比传统方法估计的形变结果更为稳健.     

环境伦理观与可持续旅游行为研究进展

环境伦理观是促进人与环境和谐发展的核心理念,对可持续旅游行为具有积极的指导作用。本文通过对中英文主流数据库期刊的文献回顾,对环境伦理观的理论内涵、影响因素以及环境伦理观对可持续旅游行为的影响进行系统梳理。结果表明：环境伦理观的概念体系主要包括环境道德、环境情感和环境信念三要素。现有研究往往不区分环境道德和环境信念,对环境情感的度量往往缺乏统一标准,导致研究结果不一致。对环境伦理观具有直接影响力的是价值观理论,社会文化因素、宗教因素、教育水平、媒体和广告影响、政策、国内和国际移民经历等因素也有一定的作用。西方对环境伦理观与可持续旅游行为进行了大量的定性和定量研究,而国内以概念性研究居多,既有研究中往往仅关注旅游中的环境行为,对可持续旅游行为关注较少,缺乏对这一特定行为的概念界定,因此,未来应在以下几个方面加强研究：①对环境伦理观理论内涵的度量;②对环境伦理观影响因素的研究;③对可持续旅游行为的界定和度量;④文化因素对于环境伦理观和可持续旅游行为的影响;⑤运用定量和定性研究方法探求环境伦理观对可持续旅游行为的作用机理和影响,为促进生态文明建设提供理论支撑和实证研究。     

Stochastic modeling for time series InSAR: with emphasis on atmospheric effects

Despite the many applications of time series interferometric synthetic aperture radar (TS-InSAR) techniques in geophysical problems, error analysis and assessment have been largely overlooked. Tropospheric propagation error is still the dominant error source of InSAR observations. However, the spatiotemporal variation of atmospheric effects is seldom considered in the present standard TS-InSAR techniques, such as persistent scatterer interferometry and small baseline subset interferometry. The failure to consider the stochastic properties of atmospheric effects not only affects the accuracy of the estimators, but also makes it difficult to assess the uncertainty of the final geophysical results. To address this issue, this paper proposes a network-based variance–covariance estimation method to model the spatiotemporal variation of tropospheric signals, and to estimate the temporal variance–covariance matrix of TS-InSAR observations. The constructed stochastic model is then incorporated into the TS-InSAR estimators both for parameters (e.g., deformation velocity, topography residual) estimation and uncertainty assessment. It is an incremental and positive improvement to the traditional weighted least squares methods to solve the multitemporal InSAR time series. The performance of the proposed method is validated by using both simulated and real datasets.     

Dynamic analysis of emergency inter-organizational communication network under public health emergency: a case study of COVID-19 in Hubei Province of China

Storm surge induced by hurricane is a major threat to the Gulf Coasts of the United States. A numerical modeling study was conducted to simulate the storm surge during Hurricane Michael, a category 5 hurricane that landed on the Florida Panhandle in 2018. A high-resolution model mesh was used in the ADCIRC hydrodynamic model to simulate storm surge and tides during the hurricane. Two parametric wind models, Holland 1980 model and Holland 2010 model, have been evaluated for their effects on the accuracy of storm surge modeling by comparing simulated and observed maximum water levels along the coast. The wind model parameters are determined by observed hurricane wind and pressure data. Results indicate that both Holland 1980 and Holland 2010 wind models produce reasonable accuracy in predicting maximum water level in Mexico Beach, with errors between 1 and 3.7%. Comparing to the observed peak water level of 4.74 m in Mexico Beach, Holland 1980 wind model with radius of 64-knot wind speed for parameter estimation results in the lowest error of 1%. For a given wind model, the wind profiles are also affected by the wind data used for parameter estimation. Away from hurricane eye wall, using radius of 64-knot wind speed for parameter estimation generally produces weaker wind than those using radius of 34-knot wind speed for parameter estimation. Comparing model simulated storm tides with 17 water marks observed along the coast, Holland 2010 wind model using radius of 34-knot wind speed for parameter estimation leads to the minimum mean absolute error. The results will provide a good reference for researchers to improve storm surge modeling. The validated model can be used to support coastal hazard mitigation planning.

     

制约我县甘蔗高产的关键因素及其对策

泰和县甘蔗种植面积近年来已达1926hmZ,占总耕地面积的4％,占旱地面积的29％,系仅次于粮油之外的第三大种植作物。虽然现在甘蔗平均产量已达458t／hm’,但与兴国、困县、南康、信丰等省内高产地区相比,我们的产量还比较低;且产量的年际变化较大,高、低产年每htn相差16．5t之多。究其原因,我们认为除栽培管理外,气候是其主要制约因素。1甘蔗的生育过程我县甘蔗通常在3月上旬惊蛰前后埋种,此期间若晴天日数多、10cm地温回暧早且较稳定,经20d左右,于当月底休眠芽便可萌动破土出苗;若遇阴雨天气多、地温回升馒,出苗期要延迟到清…     

淮河流域瓦埠湖流域水体污染研究与现状评价(2011-2015年)

瓦埠湖位于淮河中游南岸,属于淮河流域最大的湖泊.根据2011年8月-2015年12月对瓦埠湖湖区3个监测点位、入（出）湖河流4个监测断面的水质监测数据,选用内梅罗水污染指数法和单因子指数法,以总氮、总磷、铵态氮和高锰酸盐指数为评价指标对瓦埠湖湖区水体和主要入（出）湖河流水质现状进行评价,结果表明：瓦埠湖湖区总体水质状况为轻度污染、Ⅳ类水质,其主要污染源为农业面源污染和生活污染;部分入湖河流受农业氮、磷污染的影响水质较差,其中庄墓河污染情况最为严重.因此,必须加强流域的水环境综合整治工作,控制农业面源污染对流域水环境的影响.     

2017年华西秋雨异常偏多的环流特征及其成因分析

利用NCEP/NCAR再分析数据集和国家气候中心整编的2 000多站逐日降水资料,对导致2017年华西秋季降水异常偏多的大气环流特征及其成因进行分析.结果表明,2017年秋季500 hPa位势高度上欧亚中高纬地区维持一脊一槽环流型,斯堪的那维亚半岛上空有一强大的高压脊,乌拉尔山以东—巴尔喀什湖有一深槽,西太平洋副热带高...