2026-10-23 カリフォルニア大学サンディエゴ校（UCSD）
An aerial view of King Range in Humboldt County taken during a 2023 airplane lidar survey conducted by the Air-Sea Interaction Laboratory at Scripps Institution of Oceanography at UC San Diego. Image credit: Nick Statom/Air-Sea Interaction Laboratory.
＜関連情報＞
- https://today.ucsd.edu/story/new-statewide-lidar-study-identifies-hotspots-for-california-coastal-cliff-retreat
- https://www.sciencedirect.com/science/article/pii/S1569843226003493
航空機搭載ライダーと植生フィルタリングを用いたカリフォルニア沿岸崖の地形変化に関する理解の向上（2016年～2023年） Improved understanding of California coastal cliff morphodynamics using airborne lidar and vegetation filtering (2016–2023)
Danghan Xie, Hironori Matsumoto, Zuzanna M. Swirad, Luc Lenain, Adam P. Young
International Journal of Applied Earth Observation and Geoinformation Available online: 28 June 2026
DOI:https://doi.org/10.1016/j.jag.2026.105433
Highlights
- Airborne lidar data were collected across the California coast in 2023.
- Automated workflows were developed to map cliff geometry, erosion, and retreat.
- Ground filtering reduced vegetation-related uncertainty from 70 to 90% to below 20%.
- Cliff retreat and erosion rates were higher in Northern and Central California.
- Statewide cliff face retreat rate averaged 0.06 m/yr during 2016–2023.
Abstract
Coastal cliffs are widespread along California coastlines, yet their erosion remains difficult to quantify at statewide scales because of (1) limited high-resolution data, (2) intensive processing requirements, and (3) challenges in mapping ground elevations beneath vegetation. This study collected airborne lidar data across the California coast in 2023 and compared it with 2016 lidar to evaluate coastal cliff changes. We developed automated approaches to (1) delineate cliff geometry and cliff top retreat, and (2) quantify erosion volume changes and retreat rates at 5-m spacing alongshore. Using ground filtering algorithms, we reduced vegetation-obscured areas from 70–90% to <20%. The results show that mean cliffs are 38 m tall, 55 m wide, and slope at 37°, with height and width generally increasing northward. ∼34.5% of cliffs showed no measurable cliff face retreat change, while statewide retreat averaged 0.06 m/yr and reached a maximum of 10.2 m/yr. Both cliff top and face retreat rates were highest in Northern California. The maximum erosion rate exceeded 1150 m3/m/yr, while the statewide mean erosion and deposition rates were 2.6 m3/m/yr and 0.3 m3/m/yr, respectively. Although taller cliffs experienced higher erosion rates, a negative trend existed between cliff face retreat rate and cliff height for cliffs <100 m. This study provides a framework for statewide cliff change monitoring for improved understanding of coastal hazards across diverse coastal settings.
