基于地面三维激光扫描强度数据的潮滩表层含水量估算

doi:10.12082/dqxxkx.2020.190213

摘要/Abstract

摘要：

大面积潮滩表层含水量的测定是潮滩研究中的难题,传统的测量方法难以同时满足高效和精度的要求。地面三维激光扫描技术凭借其高精度、高分辨率以及主动性强等优点,已经高效运用在潮滩地形研究中。但是,对潮滩含水量进行有效分析,仅利用点云的空间几何信息是不够的,还需要对点云的强度数据进行挖掘。地面激光扫描仪提供了包含目标表面光谱反射特性的点云强度数据,利用强度数据可以有效地进行目标表面特性提取。本文提出了一种新的长距离地面激光扫描仪强度数据改正方法,对入射角和距离效应进行有效改正。利用Riegl VZ-4000长距离地面激光扫描仪建立室内含水量模型并对上海市崇明岛一处潮滩进行测试分析,同时收集26个潮滩沉积物样品并利用传统干湿称重法进行含水量验证计算。结果表明：相比于传统技术,利用改正后的激光强度值估算大面积潮滩沉积物表层含水量是一种精确和高效的方法。改正后的激光强度值与潮滩表层含水量存在幂函数关系,相关系数为0.961,估算精度为91.94%。

关键词: 强度数据, 潮滩, 地面三维激光扫描, 表层含水量, 强度改正, 上海崇明岛

Abstract:

Estimation of surface soil moisture and distributions play a key role in the ecological, environmental, and topographical investigations for intertidal mudflats, which are characteristically wet and periodically submerged by sea water. Unfortunately, existing techniques of large-scale surface moisture monitoring have measurement limitations, and the efficiency and accuracy of traditional methods are difficult to be ensured simultaneously. Thanks to the advantages of high precision, high resolution, and strong flexibility, Terrestrial Laser Scanners (TLSs) have been widely used to study the geomorphological features of intertidal mudflats. However, merely geometrical information is not enough to derive the physical characteristics of a mudflat, it is also necessary to mine intensity data of points cloud. Aside from the 3D points cloud, TLS can record the intensity value of each point, which contains spectral characteristics of the scanned target and is of vital importance to the improvement of TLS data classification and feature extraction. Most TLSs emit near-infrared lasers that can be strongly absorbed by water. Thus, the intensity values of areas with high water moisture are theoretically smaller than those of the regions with low moisture. In this study, the intensity data of TLSs were corrected for the incidence angle and distance effects, and the corrected intensity data were utilized to quantitatively estimate the surface soil moisture of intertidal mudflats. The Riegl VZ-4000 long-distance terrestrial laser scanner with a near-infrared wavelength of 1550 nm was used to establish the indoor moisture model and to conduct a case study of a tidal flat in the Chongming Island, Shanghai, China. Additionally, 26 sediment samples were also collected by the traditional way of gravimetric measurements to get moisture. Results show that there was a power function relationship between the corrected intensity data and surface moisture, with the correction coefficient being 0.961 and the estimation accuracy reaching 91.94%. Our findings show that, compared with the traditional technique (i.e., gravimetric measurements), the corrected intensity data of long-range TLSs are effective for quick, accurate, and detailed estimation of surface soil moisture over large areas.

Key words: intensity data, tidal flat, terrestrial laser scanner, surface moisture, intensity correction, Chongming Island, Shanghai

陈锦, 谭凯, 张卫国. 基于地面三维激光扫描强度数据的潮滩表层含水量估算[J]. 地球信息科学学报, 2020, 22(2): 290-297.DOI:10.12082/dqxxkx.2020.190213

CHEN Jin, TAN Kai, ZHANG Weiguo. Estimation of Surface Moisture of Tidal Flat based on Intensity Data of Terrestrial Laser Scanner[J]. Journal of Geo-information Science, 2020, 22(2): 290-297.DOI:10.12082/dqxxkx.2020.190213

图/表 11

图1

图2

图3

图4

图5

表1

表2

图6

图7

图8

图9

参考文献 32

[1]	时钟, 陈吉余, 虞志英 . 中国淤泥质潮滩沉积研究的进展[J]. 地球科学进展, 1996,11(6):555-562.
	[ Shi Z, Chen J Y, Yu Z Y . Sedimentation on the intertidal mudflat in china: an overview[J]. Advances in Earth Science, 1996,11(6):555-562. ]
[2]	Stark J, Van O, Meire P , et al. Observations of tidal and storm surge attenuation in a large tidal marsh[J]. Limnology and Oceanography, 2015,60(4):1371-1381.
[3]	Temmerman S, Meire P, Bouma TJ , et al. Ecosystem-based coastal defence in the face of global change[J]. Nature, 2013,504:79-83.
[4]	Teuchies J, Vandenbruwaene W, Carpentier R , et al. Estuaries as filters: The role of tidal marshes in trace metal removal[J]. PLOS One, 2013,8(8):e70381.
[5]	Robert C, Rudolf G, Pual S , et al. Changes in the global value of ecosystem services[J]. Global Environmental Change, 2014,26:152-158.
[6]	任美锷 . 中国淤泥质潮滩沉积研究的若干问题[J]. 热带海洋, 1985(2):6-14.
	[ Ren M E . A study on sedimentation of tidal mud flats of china[J]. Journal of Tropical Oceanography, 1985(2):6-14. ]
[7]	Sarre R . Evaluation of aeolian sand transport equations using intertidal-zone measurements, Saunton Sands, England[J]. Sedimentology, 2006,37(2):385-392.
[8]	Wiggs G, Baird A . The dynamic effects of moisture on the entrainment and transport of sand by wind[J]. Geomorphology, 2004(59):13-30.
[9]	Davidson A, Robin G, Kelvin M , et al. The effect of wind gusts, moisture content and fetch length on sand transport on a beach[J]. Geomorphology, 2005(68):115-129.
[10]	Yang S L, Fan J Q, Shi B W , et al. Remote impacts of typhoons on the hydrodynamics, sediment transport and bed stability of an intertidal wetland in the Yangtze Delta[J]. Journal of Hydrology, 2019,575:755-766.
[11]	Schmutz P, Namikas S, Steven L . Utility of the Delta-T theta probe for obtaining surface moisture measurements from beaches[J]. Journal of Coastal Research, 2011,27(3):478-484.
[12]	韩飞 . 淤泥质海岸潮滩表层沉积特征遥感研究[D]. 南京:南京师范大学, 2015.
	[ Han F . Remote sensing study on surface sedimentary characteristics of coastal tidal flat[D]. Nanjing: Nanjing Normal University, 2015. ]
[13]	Darke I, Ollerhead D . Measurement of beach surface moisture using surface brightness[J]. Journal of Coastal Research, 2009(251):248-256.
[14]	Höfle B, Geist T, Rutzinger M , et al. Glacier surface segmentation using airborne laser scanning point cloud and intensity data[J]. International Archives of Photogrammetry, Remote Sensing and Spatial Information Sciences, 2007(3/W52):195-200.
[15]	Kashani A, Olsen M, Parrish C , et al. A review of LiDAR radiometric processing: From ad hoc intensity correction to rigorous radiometric calibration[J]. Sensors, 2015,15(11):28099-28128.
[16]	Nield J, Wiggs G, Squirrell R . Aeolian sand strip mobility and protodune development on a drying beach: examining surface moisture and surface roughness patterns measured by terrestrial laser scanning[J]. Earth Surface Processes and Landforms, 2011,4(36):513-522.
[17]	Nield J, King J, Jacobs B . Detecting surface moisture in aeolian environments using terrestrial laser scanning[J]. Aeolian Research, 2014(12):9-17.
[18]	Smit Y, Ruessink G, Brakenhoff L , et al. Measuring spatial and temporal variation in surface moisture on a coastal beach with a near-infrared terrestrial laser scanner[J]. Aeolian Research, 2018(31):19-27.
[19]	Soudarissanane S, Lindenbergh R, Menenti M , et al. Scanning geometry: Influencing factor on the quality of terrestrial laser scanning points[J]. ISPRS Journal of Photogrammetry and Remote Sensing, 2011,66(4):389-399.
[20]	Lichti D D, Gordon S J, Tipdecho T . Error models and propagation in directly georeferenced terrestrial laser scanner networks[J]. Journal of Surveying Engineering, 2005,131(4):135-142.
[21]	Lichti D D . Error modelling, calibration and analysis of an AM-CW terrestrial laser scanner system[J]. ISPRS Journal of Photogrammetry & Remote Sensing, 2007,61(5):307-324.
[22]	胡以华 . 激光成像目标侦察[M]. 北京: 国防工业出版社, 2013.
	[ Hu Y H. Laser Imaging Target Reconnaissance[M]. Beijing: National Defense Industry Press, 2013. ]
[23]	杨欧, 刘苍字 . 长江口北支沉积物粒径趋势及泥沙来源研究[J]. 水利学报, 2002(2):79-84.
	[ Yang O, Liu C Z . Analysis on sediment transport patterns and sediment sources of north branch of Changjiang estuary[J]. Journal of Hydraulic Engineering, 2002(2):79-84. ]
[24]	周开胜, 孟翊, 刘苍字 , 等. 长江口北支潮流沉积物磁性特征与沉积环境分析[J]. 海洋通报, 2008(5):47-55.
	[ Zhou K S, Meng Y, Liu C Z , et al. Magnetic properties and sedimentary environment of the Xinglong sand in the north branch, the Yangtze estuary[J]. Marine Science Bulletin, 2008(5):47-55. ]
[25]	李一鸣 . 近三十年来长江口河槽沉积特征及其影响因子研究[D]. 上海:华东师范大学, 2018.
	[ Studies on sediment characteristics and the influencing factors in the Yangtze estuary riverbed during the recent 30 years[D]. Shanghai: East China Normal University, 2018. ]
[26]	谢卫明, 何青, 章可奇 , 等. 三维激光扫描系统在潮滩地貌研究中的应用[J]. 泥沙研究, 2015(1):1-6.
	[ Xie W M, He Q, Zhang K Q , et al. Application of the terrestrial laser scanner to measuring geomorphology in tidal flats and salt marshes[J]. Journal of Sediment Research, 2015(1):1-6. ]
[27]	Davidson R. Introduction to coastal processes and geomorphology[M]. Cambridge: Cambridge University Press, 2010.
[28]	Höfle B, Pfeifer N . Correction of laser scanning intensity data: Data and model-driven approaches[J]. ISPRS Journal of Photogrammetry and Remote Sensing, 2007,62(6):415-433.
[29]	Tan K, Chen J, Qian W , et al. Intensity data correction for long-range terrestrial laser scanners: A case study of target differentiation in an intertidal zone[J]. Remote Sensing, 2019,11(3):331.
[30]	鲁如坤 . 土壤农业化学分析方法[M]. 北京: 中国农业科学技术出版社, 1999.
	[ Lu R K. Analytical methods of soil agricultural chemistry[M]. Beijing: China Agricultural Science Press, 1999. ]
[31]	Smit Y, Ruessink G, Brakenhoff L B , et al. Measuring spatial and temporal variation in surface moisture on a coastal beach with a near-infrared terrestrial laser scanner[J]. Aeolian Research, 2017,31:19-27.
[32]	张东, 李欢, 郑晓丹 . 潮滩表层沉积物含水量的高光谱预测模型与反演分析[J]. 地球信息科学学报, 2013,15(4):581-589.
	[ Zhang D, Li H, Zheng X T . The moisture content prediction model of surface sediment in intertidal flat by hyperspectral remote sensing[J]. Journal of Geo-information Science, 2013,15(4):581-589. ]

阶数	7阶参数	6阶参数	5阶参数	4阶参数
7	1.559	1.399	2.484×10^-2	2.053×10^-4
3阶参数	2阶参数	1阶参数	常数	决定系数
-9.269×10^-7	2.312×10^-9	-2.971×10^-12	1.529×10^-15	0.9814