Investigations of long-term and seasonal scale variations of flow velocity and frontal position of outlet glaciers in Greenland utilizing multi-temporal Landsat imagery

利用多时相 Landsat 图像研究格陵兰岛冰川出口流速和锋面位置的长期和季节性尺度变化

基本信息

批准号：
258481807
负责人：
Professor Dr.-Ing. Martin Horwath, since 11/2015
金额：
--
依托单位：
Professur für Geodätische Erdsystemforschung
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2014
资助国家：
德国
起止时间：
2013-12-31 至 2016-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/258481807?language=en
关键词：
Investigations long term seasonal scale

项目摘要

For more than a decade, the cryosphere with its glacier regions have been affected by large changes. Many of the outlet glaciers of the Greenland Ice Sheet currently show accelerated flow velocities and a significant surface lowering while sustaining a substantial retreat. In particular, marine-terminating glaciers show a dynamic behavior which is not included in current predictions of the future sea-level change. Thus, the marine-terminating outlet glaciers and their influencing factors at the ice-ocean-boundary are the major research object within the proposal. In the time period between 1972 and 2012 flow velocity fields are available for more than 300 outlet glaciers along the margin of the Greenland Ice Sheet. In addition, information about the frontal position as well as their temporal changes are available for more than 100 glaciers. Within the project term both flow velocity and frontal positions of the glaciers are to be extended using satellite data of Landsat7 and Landsat8. Moreover, satellite data of the Sentinel mission expected to start in 2012 will be incorporated. Long-term and seasonal scale variations of flow velocity and the position of the glacier front as well as their interrelation will be investigated using this large data archive. Special focus will be given on the dynamic processes acting at the ice-ocean boundary. This includes the investigation of the impact of the ice mélange in the proglacial fjord on the stability of the frontal position and on the flow velocity. To analyze regional patterns of synchronous glacier changes information about both the annual cycle of sea-ice formation and sea-surface temperatures derived from MODIS data will be incorporated. In the area of North and Northeast Greenland the long-term evolution of the flow velocity as well as changes of the terminus position for more than four decades will be studied. In particular, the effect of observed long-term changes of the sea ice and fast ice formation on the stability of the glacier front accompanied by an ice shelf will be investigated. All available flow-velocity fields will be used to identify surge events of outlet glaciers and their relation to changes of the frontal position and to changes of the spatial-temporal variability of the flow regime.

十多年来，冰冻圈及其冰川区域受到了巨大变化的影响，格陵兰冰盖的许多出口冰川目前显示出流速加快和表面显着降低，同时持续大幅退缩。终止冰川表现出动态行为，目前对未来海平面变化的预测并未包含在内，因此，冰海边界的海洋终止出口冰川及其影响因素是主要的。 1972 年至 2012 年期间，格陵兰冰盖边缘的 300 多个出口冰川的流速场可用。此外，还可以获得有关锋面位置及其时间变化的信息。在项目期限内，将使用 Landsat7 和 Landsat8 的卫星数据扩展冰川的流速和锋面位置。预计将于 2012 年启动的哨兵任务的数据将被纳入其中，利用这一大型数据档案来研究流速和冰川锋位置的长期和季节性变化以及它们之间的相互关系。作用于冰海边界的动态过程，包括研究前冰川峡湾中的冰混合物对锋面位置稳定性和流速的影响，以分析同步冰川的区域模式。来自 MODIS 数据的海冰形成年度周期和海面温度的变化信息将纳入格陵兰岛北部和东北部地区流速的长期演变以及流速的变化。特别是，将研究四十多年来观测到的海冰的长期变化和快速冰形成对冰架伴随的冰川前缘稳定性的影响。速度场将用于识别出口的喘振事件冰川及其与锋面位置变化和流态时空变化变化的关系。