基于ALOS PALSAR数据的山地冰川流速估算方法比较——以喀喇昆仑地区斯克洋坎力冰川为例
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摘要
冰川表面流速是进行冰川动力学和物质平衡研究的关键参数之一。合成孔径雷达(SAR)影像作为能大范围提取山地冰川表面流速的重要数据源,利用其进行冰川流速估算目前主要有差分In SAR(D-In SAR)法、多孔径InSAR(MAI)法和SAR偏移量追踪(offset tracking)法3种。其中,MAI法是为了克服D-In SAR对雷达方位向(along-track)形变不敏感而发展的一种新的In SAR技术。以喀喇昆仑山中部地区的斯克洋坎力冰川为例,选取了2008年2景间隔46 d的L波段ALOS PALSAR数据,利用上述3种方法分别进行冰川流速提取实验,讨论了3种方法在山地冰川表面流速监测中的适用性和局限性。结果表明,D-In SAR和MAI方法都能够精确提取距离向和方位向的冰川流速信息,但对相干性均要求较高;在低相干区域,SAR偏移量追踪方法也能够获取更为可靠的方位向和距离向二维冰川流速的速度场,但该方法在冰川表面特征不明显的地区受到一定限制。
Glacier surface velocity is one of the key parameters of glacier dynamics and mass balance. Synthetic aperture radar( SAR) image is an important data source to derive the glacier surface velocity. Now,methods for estimating glacier velocities mainly include Differential Interferometric techniques( D- In SAR),Multiple Aperture In SAR( MAI) and offset tracking. Among them,MAI is a new In SAR technology to overcome the drawback of D-In SAR which is not sensitive to radar azimuth( along- track) deformation. In this study,two ALOS PALSAR L band images which acquired 46 days apart were selected to derive glacier surface velocities of Skyang glacier in the central Karakoram based on the above three methods. In addition,the applications and limitations of the three methods in detecting glacier surface velocities are discussed. The results show that D- In SAR and MAI methods accurately detect displacements in range and azimuth direction respectively,but they all require high coherence.However,in areas of low coherence,offset tracking method achieves more reliable results; moreover,it can obtain two- dimensional glacier velocity field in both range and azimuth direction. Nevertheless,it is limited in the areas which lack feature points.
Glacier surface velocity is one of the key parameters of glacier dynamics and mass balance. Synthetic aperture radar( SAR) image is an important data source to derive the glacier surface velocity. Now,methods for estimating glacier velocities mainly include Differential Interferometric techniques( D- In SAR),Multiple Aperture In SAR( MAI) and offset tracking. Among them,MAI is a new In SAR technology to overcome the drawback of D-In SAR which is not sensitive to radar azimuth( along- track) deformation. In this study,two ALOS PALSAR L band images which acquired 46 days apart were selected to derive glacier surface velocities of Skyang glacier in the central Karakoram based on the above three methods. In addition,the applications and limitations of the three methods in detecting glacier surface velocities are discussed. The results show that D- In SAR and MAI methods accurately detect displacements in range and azimuth direction respectively,but they all require high coherence.However,in areas of low coherence,offset tracking method achieves more reliable results; moreover,it can obtain two- dimensional glacier velocity field in both range and azimuth direction. Nevertheless,it is limited in the areas which lack feature points.
引文
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[19]刘毅.基于光学遥感影像特征匹配的南极冰川流速测量方法研究[D].上海:同济大学,2014.Liu Y.Method for Glacier Velocity Measurement in Antarctic Based on Feature Matching of Remote Sensing Images[D].Shanghai:Tongji University,2014.
[20]Heid T,Kb A.Evaluation of existing image matching methods for deriving glacier surface displacements globally from optical satellite imagery[J].Remote Sensing of Environment,2012,118:339-355.
[21]张祥松.喀喇昆仑山音苏盖提冰川及其邻近冰川的近期变化[J].冰川冻土,1980,2(3):12-16.Zhang X S.Recent variations of the Insukati glacier and adjacent glaciers in the Karaoram Mountains[J].Journal of Glaciology and Geocryology,1980,2(3):12-16.
[22]Ruan Z X,Guo H D,Liu G D,et al.Glacier surface velocity estimation in the west Kunlun mountain range from L-band ALOS/PALSAR images using modified synthetic aperture radar offsettracking procedure[J].Journal of Applied Remote Sensing,2014,8(1):084595.
[23]Li J,Li Z W,Ding X L,et al.Investigating mountain glacier motion with the method of SAR intensity-tracking:Removal of topographic effects and analysis of the dynamic patterns[J].Earth-Science Reviews,2014,138:179-195.
[24]Quincey D J,Copland L,Mayer C,et al.Ice velocity and climate variations for Baltoro glacier,Pakistan[J].Journal of Glaciology,2009,55(194):1061-1071.
[2]David G V,Josefino C C.Observation:Cryosphere[M]//IPCC.Climate Change 2013:The Physical Science Basis.Contribution of Working GroupⅠto the Fifth Assessment Report of the Intergovernmental Panel on Climate Change.Cambridge:Cambridge University Press,2013.
[3]黄磊,李震.光学遥感影像的山地冰川运动速度分析方法[J].冰川冻土,2009,31(5):935-940.Huang L,Li Z.Mountain glacier flow velocities analyzed from satellite optical images[J].Journal of Glaciology and Geocryology,2009,31(5):935-940.
[4]Goldstein R M,Engelhardt H,Kamb B,et al.Satellite radar interferometry for monitoring ice sheet motion:Application to an Antarctic ice stream[J].Science,1993,262(5139):1525-1530.
[5]Kenyi L W,Kaufmann V.Measuring rock glacier surface deformation using SAR interferometry[C]//Eighth International Conference on Permafrost.Zürich,2003,1:537-541.
[6]Joughin I,Smith B E,Abdalati W.Glaciological advances made with interferometric synthetic aperture radar[J].Journal of Glaciology,2010,56(200):1026-1042.
[7]李佳.利用SAR技术监测天山托木尔峰区冰川运动[D].长沙:中南大学,2012.Li J.Deriving Surface Motion of Mountain Glaciers in Tian Shan from PLASAR Images[D].Changsha:Central South University,2012.
[8]Bechor N B,Zebker H A.Measuring two-dimensional movements using a single In SAR pair[J].Geophysical Research Letters,2006,33(16):L16311.
[9]Gourmelen N,Kim S W,Shepherd A,et al.Ice velocity determined using conventional and multiple-aperture In SAR[J].Earth and Planetary Science Letters,2011,307(1/2):156-160.
[10]Hu J,Li Z W,Li J,et al.3-D movement mapping of the alpine glacier in Qinghai-Tibetan plateau by integrating D-In SAR,MAI and offset-tracking:Case study of the Dongkemadi glacier[J].Global and Planetary Change,2014,118:62-68.
[11]Bolch T,Buchroithner M,Pieczonka T,et al.Planimetric and volumetric glacier changes in the Khumbu Himal,Nepal,since 1962 using Corona,landsat TM and ASTER data[J].Journal of Glaciology,2008,54(187):592-600.
[12]Rignot E,Mouginot J,Scheuchl B.Ice flow of the Antarctic ice sheet[J].Science,2011,333(6048):1427-1430.
[13]Bindschadler R,Vornberger P,Blankenship D,et al.Surface velocity and mass balance of ice streams D and E,West Antarctica[J].Journal of Glaciology,1996,42(142):461-475.
[14]Strozzi T,Luckman A,Murray T,et al.Glacier motion estimation using SAR offset-tracking procedures[J].IEEE Transactions on Geoscience and Remote Sensing,2002,40(11):2384-2391.
[15]Copland L,Pope S,Bishop M P,et al.Glacier velocities across the central Karakoram[J].Annals of Glaciology,2009,50(52):41-49.
[16]蒋宗立,刘时银,许君利,等.应用SAR特征匹配方法估计音苏盖提冰川表面流速[J].冰川冻土,2011,33(3):512-518.Jiang Z L,Liu S Y,Xu J L,et al.Using feature-tracking of ALOS PALSAR images to acquire the Yengisogat glacier surface velocities[J].Journal of Glaciology and Geocryology,2011,33(3):512-518.
[17]Kimura H,Yamaguchi Y.Detection of landslide areas using satellite radar interferometry[J].Photogrammetric Engineering and Remote Sensing,2000,66(3):337-344.
[18]周建民,李震,李新武.基于ALOS/PALSAR数据雷达干涉测量的中国西部山谷冰川冰流运动规律研究[J].测绘学报,2009,38(4):341-347.Zhou J M,Li Z,Li X W.Research on rules of the valley glacier motion in western China based on ALOS/PALSAR interferornetry[J].Acta Geodaetica et Cartographica Sinica,2009,38(4):341-347.
[19]刘毅.基于光学遥感影像特征匹配的南极冰川流速测量方法研究[D].上海:同济大学,2014.Liu Y.Method for Glacier Velocity Measurement in Antarctic Based on Feature Matching of Remote Sensing Images[D].Shanghai:Tongji University,2014.
[20]Heid T,Kb A.Evaluation of existing image matching methods for deriving glacier surface displacements globally from optical satellite imagery[J].Remote Sensing of Environment,2012,118:339-355.
[21]张祥松.喀喇昆仑山音苏盖提冰川及其邻近冰川的近期变化[J].冰川冻土,1980,2(3):12-16.Zhang X S.Recent variations of the Insukati glacier and adjacent glaciers in the Karaoram Mountains[J].Journal of Glaciology and Geocryology,1980,2(3):12-16.
[22]Ruan Z X,Guo H D,Liu G D,et al.Glacier surface velocity estimation in the west Kunlun mountain range from L-band ALOS/PALSAR images using modified synthetic aperture radar offsettracking procedure[J].Journal of Applied Remote Sensing,2014,8(1):084595.
[23]Li J,Li Z W,Ding X L,et al.Investigating mountain glacier motion with the method of SAR intensity-tracking:Removal of topographic effects and analysis of the dynamic patterns[J].Earth-Science Reviews,2014,138:179-195.
[24]Quincey D J,Copland L,Mayer C,et al.Ice velocity and climate variations for Baltoro glacier,Pakistan[J].Journal of Glaciology,2009,55(194):1061-1071.