对威尼斯古城中心所做的高分辨率卫星监测,为自然沉降和人类活动对该城市过去20年的土地运动的相对贡献做出了估计。这些发现发表在本期Scientific Reports上。
Luigi Tosi、Pietro Teatini和Tazio Strozzi设计了一项研究,来区分威尼斯的自然土地沉降与人类活动诱导的土地运动。抽地下水所产生的影响(这种影响历史上对土地沉降有贡献)几十年前停止了。然而,由于最近发生的海平面变化(这种变化增加了该城市的脆弱性),关于影响威尼斯市中心的土地沉降的可靠、详尽的知识仍然非常重要。作者利用两种不同类型的高分辨率卫星监测(这种监测能显示各个建筑物的微小运动)研究了该市市中心的长期和短期位移。
该研究表明,自然沉降正在以每年大约0.8-1毫米的速度在威尼斯发生,而人类活动目前对土地运动的贡献大约为每年2-10毫米,但只是在非常局部化的(空间)尺度上和短时间尺度上产生这种贡献。作者说,人类造成的变化主要是由以保护历史建筑为目的的保护和重建工作、以及市政工程(包括为稳定运河壁所做的工作)引起的。(生物谷Bioon.com)
生物谷推荐的英文摘要
Scientific Reports doi:10.1038/srep02710
Natural versus anthropogenic subsidence of Venice
Luigi Tosi,Pietro Teatini& Tazio Strozzi
We detected land displacements of Venice by Persistent Scatterer Interferometry using ERS and ENVISAT C-band and TerraSAR-X and COSMO-SkyMed X-band acquisitions over the periods 1992–2010 and 2008–2011, respectively. By reason of the larger observation period, the C-band sensors was used to quantify the long-term movements, i.e. the subsidence component primarily ascribed to natural processes. The high resolution X-band satellites reveal a high effectiveness to monitor short-time movements as those induced by human activities. Interpolation of the two datasets and removal of the C-band from the X-band map allows discriminating between the natural and anthropogenic components of the subsidence. A certain variability characterizes the natural subsidence (0.9 ± 0.7mm/yr), mainly because of the heterogeneous nature and age of the lagoon subsoil. The 2008 displacements show that man interventions are responsible for movements ranging from 10 to 2mm/yr. These displacements are generally local and distributed along the margins of the city islands.