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关于举办“2019年度李仪祉讲座系列报告会(二十七)”的通知

作者:     来源:澳门赌钱官网     发布日期:2019-12-10     浏览次数:

  

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报告题目:Field Scale Monitoring of Soil Water Using Actively Heated Fiber Optics

报告人:Asim Biswas博士,University of Guelph

邀请人:李毅 教授、李敏 副教授

报告时间:2019年12月12日(星期四)下午2:30-3:30

报告地点:水建平台网址综合楼208会议室

报告摘要:

A major challenge in understanding the hydrological dynamics is the modeling and measurement of soil water content (SWC) across a range of spatial and temporal scales. A range of point-based sensors has advanced the measurement of SWC at defined points in space or time while remote sensing has been used to estimate SWC at continental to global scales. However, an intermediate spatial scale gap remains where we lack high resolution (both spatial and temporal) SWC data to quantify the patterns and magnitudes of hydrological dynamics and to better assess the performance of various hydrological models. The active heat pulse with fiber optic temperature sensing (AHFO) method has shown the potential to provide SWC data at sub-meter intervals along a fiber optic cable to a distance >10000 meters. This study evaluated the feasibility of AHFO to measure SWC at sub-meter (spatial) and diurnal to seasonal (temporal) scales in laboratory and field. Heat pulses of three minutes duration were applied at a rate of 20 Wm-1 through a helically wrapped fiber optic cable in a sandy soil column before, during, and after irrigation in the laboratory. Heat pulses of five minutes duration were applied at a rate of 7.28 Wm-1 through eighteen fiber optic cable transects installed at three depths (0.05, 0.10 and 0.20 m) at six-hour intervals daily over nearly three months in a cropped field. A distributed temperature sensing (DTS) instrument was used to measure the cumulative temperature increase (Tcum) at locations along the cable. An indirect relationship between Tcum and SWC was developed and validated using the SWC measurements measured by the gravimetric method (laboratory) and calibrated soil water sensors in the field. Spatial and time series data were used to generate maps of SWC. Strong relationships between Tcum and SWC (R20.90) predicted soil water accurately; RMSE of 3 to 4 % for both laboratory and field experiment. Maps of SWC helped to identify wetting bulb formation, movement of the wetting front and changes in the dimensions (wetted radius and depth) of wetting bulbs during irrigation experiment in the laboratory. Further, AFHO method clearly identified the changes in SWC due to rainwater infiltration at diurnal to seasonal temporal scales in the field. Overall, results of this study demonstrated the feasibility of the AFHO method to measure and monitor soil water at small (laboratory soil column) to field scales at high spatial (sub-meter) and sub-hourly to seasonal temporal scales. It also showed the potential to improve water movement models using high-resolution SWC measurements in the future.

报告人简介:

Asim Biswas博士曾先后在加拿大McGill UniversityUniversity of Guelph任职助理教授和副教授。主要研究领域为农业水文学,在包气带水文学、精准农业、土壤水分、热及溶质迁移和空间变异性等方面的研究非常深入,为量化研究土壤水文的相关属性和机制奠定了基础。Asim Biswas博士已发表SCI论文67篇,会议摘要131篇,参编著作1部,专利1项。目前主持科研项目十余项,其中主持项目的经费136万美元;在国际会议和研讨会上邀请发言28次,口头报告84次,海报17幅。指导和合作指导研究生15名。先后获得多向奖励,包括2010年获得加拿大土壤科学学会(CSSS)Bentley 奖;2010-2012年连续获得SSSA年会最佳海报奖,2011年度加拿大地球物理联盟(CGU) 最佳学生论文奖; 2012University of Saskatchewan优秀博士论文奖;2012Kirkham 旅游奖;2014年获美国地球物理联盟(AGU)颁发的Donald L. Turcotte奖;2016年及2018年两次获美国土壤科学学会土壤物理与水文青年科学家奖;2018年获美国土壤科学学会S6分会青年学者奖;2018年获安大略省研究、创新和科学部早期研究员奖等。

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                  2019年12月10日


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