Laser vision: lidar as a transformative tool to advance critical zone science

Abstract

Abstract. Observation and quantification of the Earth's surface is undergoing a revolutionary change due to the increased spatial resolution and extent afforded by light detection and ranging (lidar) technology. As a consequence, lidar-derived information has led to fundamental discoveries within the individual disciplines of geomorphology, hydrology, and ecology. These disciplines form the cornerstones of critical zone (CZ) science, where researchers study how interactions among the geosphere, hydrosphere, and biosphere shape and maintain the "zone of life", which extends from the top of unweathered bedrock to the top of the vegetation canopy. Fundamental to CZ science is the development of transdisciplinary theories and tools that transcend disciplines and inform other's work, capture new levels of complexity, and create new intellectual outcomes and spaces. Researchers are just beginning to use lidar data sets to answer synergistic, transdisciplinary questions in CZ science, such as how CZ processes co-evolve over long timescales and interact over shorter timescales to create thresholds, shifts in states and fluxes of water, energy, and carbon. The objective of this review is to elucidate the transformative potential of lidar for CZ science to simultaneously allow for quantification of topographic, vegetative, and hydrological processes. A review of 147 peer-reviewed lidar studies highlights a lack of lidar applications for CZ studies as 38 % of the studies were focused in geomorphology, 18 % in hydrology, 32 % in ecology, and the remaining 12 % had an interdisciplinary focus. A handful of exemplar transdisciplinary studies demon- Published by Copernicus Publications on behalf of the European Geosciences Union. 2882 A. A. Harpold et al.: Laser vision: lidar as a transformative toolstrate lidar data sets that are well-integrated with other observations can lead to fundamental advances in CZ science, such as identification of feedbacks between hydrological and ecological processes over hillslope scales and the synergistic co-evolution of landscape-scale CZ structure due to interactions amongst carbon, energy, and water cycles. We propose that using lidar to its full potential will require numerous advances, including new and more powerful open-source processing tools, exploiting new lidar acquisition technologies, and improved integration with physically based models and complementary in situ and remote-sensing observations. We provide a 5-year vision that advocates for the expanded use of lidar data sets and highlights subsequent potential to advance the state of CZ science.

Remote sensing of forest pest damage: a review and lessons learned from a Canadian perspective

“…(5) There is tremendous growth in LiDAR data acquisition capabilities from ground, airborne, and spaceborne platforms (Harpold et al 2015). Data from these sensors will require advancements in processing and analysis, linkages to in situ observations, and integration with other remote sensing data as a basis to advance applications (Harpold et al 2015). Some of these advances, including increased data coverage and quality, as well as the use of multispectral or hyperspectral lasers with full-waveform are now in development (Hakala et al 2012;Harpold et al 2015).…”

“…Data from these sensors will require advancements in processing and analysis, linkages to in situ observations, and integration with other remote sensing data as a basis to advance applications (Harpold et al 2015). Some of these advances, including increased data coverage and quality, as well as the use of multispectral or hyperspectral lasers with full-waveform are now in development (Hakala et al 2012;Harpold et al 2015). Repeat multispectral laser scanning has the potential to monitor the changes in the structure and physiology of the tree canopy (Hakala et al 2015) that could be applicable to measurement of insect damage if the costs associated with repeat data acquisition and processing are considered justifiable relative to the information derived.…”

“…The combination of Landsat 8 and Sentinel-2, for example, results in up to eight image acquisitions within a month that greatly increases the potential for acquiring cloud-free images to track disturbances (Zhu et al 2012). (5) There is tremendous growth in LiDAR data acquisition capabilities from ground, airborne, and spaceborne platforms (Harpold et al 2015). Data from these sensors will require advancements in processing and analysis, linkages to in situ observations, and integration with other remote sensing data as a basis to advance applications (Harpold et al 2015).…”

An integrated airborne laser scanning approach to forest management and cultural heritage issues: a case study at Porolissum, Romania

“…Considering the high cost of data acquisition, the most effective approach is to employ the data in as many usage domains as possible. However, the transdisciplinary use of LiDAR data available from a particular area has rarely been accomplished (Harpold et al 2015). In addition to ancient structures mapping, LiDAR provides accurate measurements of numerous forest inventory attributes at a level of detail that is unavailable to traditional forestry measurements (Popescu & Wynne 2004, Wulder et al 2008, Unger et al 2014, facilitates forest road network mapping (White et al 2010, Azizi et al 2014, and the delineation of forest creeks and streams (Wulder et al 2008, Roman et al 2015.…”

Airborne LiDAR and Aerial Imagery to Assess Potential Burrow Locations for the Desert Tortoise (Gopherus agassizii)

“…To our knowledge, LiDAR and aerial image analysis have not been used specifically to assess desert tortoise habitats, with a particular focus on burrows, but they have been used in many ecological and geologic studies [15][16][17][18], including those studying vegetation structure as habitats for other species such as the Black-throated Blue Warbler [19], the Gopher Tortoise [20], and the Red Squirrel [21]. Airborne LiDAR is used today as a standard tool across ecological and geologic fields, providing high-resolution vertical measurements suitable for land management decisions.…”