- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Using Combined Close-Range Active and Passive- Remote Sensing Methods to Detect Sinkholes
摘要： In the Dead Sea region of Israel, sinkholes collapse can be observed easily due to the large number of sites. The continuous decrease in Dead Sea level over the last 30 years, caused a substantial increases the sinkhole activity (more than 5,500 sinkholes upper layer collapse). Sinkholes of up to 50 m diameter are found to be clustered in sites with variable characteristics. In this research, we have developed methods for prediction of sinkholes appearance by using mapping and monitoring methods based on active and passive remote-sensing means. These methods are based on measurements from several instruments including field spectrometry, geophysical ground-penetration radar (GPR) and a frequency domain electromagnetic (FDEM) instrument. Field spectrometry was used to compare the spectral signatures of soil samples collected near progressing sinkholes and those taken in regions with no visible occurrence of sinkholes. Active remote sensing showed higher electrical conductivity and soil moisture in the former regions. Measurements were taken at different time points to monitor the progress of an "embryonic" sinkhole. The research steps included (i) review of previous published literature, (ii) mapping of regions with an abundance of sinkholes in various stages, and areas that are vulnerable to them, (iii) data analysis and development of warning indicators, accessible information to the scientific community. The result derived from this research indicates the possibility to build a pre-warning tool to detect the formation of sinkholes.
关键词： Active remote sensing,Spectroscopy,Ground-penetration radar,Sinkhole,Passive remote sensing,Frequency domain electromagnetic
更新于2025-09-23 15:21:01
-
Abrupt Change in Forest Height along a Tropical Elevation Gradient Detected Using Airborne Lidar
摘要： Most research on vegetation in mountain ranges focuses on elevation gradients as climate gradients, but elevation gradients are also the result of geological processes that build and deconstruct mountains. Recent ?ndings from the Luquillo Mountains, Puerto Rico, have raised questions about whether erosion rates that vary due to past tectonic events and are spatially patterned in relation to elevation may drive vegetation patterns along elevation gradients. Here we use airborne light detection and ranging (LiDAR) technology to observe forest height over the Luquillo Mountain Range. We show that models with different functional forms for the two prominent bedrock types best describe the forest height-elevation patterns. On one bedrock type there are abrupt decreases in forest height with elevation approximated by a sigmoidal function, with the in?ection point near the elevation of where other studies have shown there to be a sharp change in erosion rates triggered by a tectonic uplift event that began approximately 4.2 My ago. Our ?ndings are consistent with broad geologically mediated vegetation patterns along the elevation gradient, consistent with a role for mountain building and deconstructing processes.
关键词： long-term ecological research,geology,critical zone observatory,three-dimensional structure,vegetation,10Be,erosion,active remote sensing,tectonics,ecology
更新于2025-09-09 09:28:46