Long-term canopy dynamics in a large area of temperate old-growth beech (Fagus crenata) forest: analysis by aerial photographs and digital elevation models

2004 ◽  
Vol 92 (6) ◽  
pp. 945-953 ◽  
Author(s):  
YUKO HENBO ◽  
AKEMI ITAYA ◽  
NAOYUKI NISHIMURA ◽  
SHIN-ICHI YAMAMOTO
Keyword(s):  
Digital Elevation Models ◽  
Fagus Crenata ◽  
Aerial Photographs ◽  
Large Area ◽  
Old Growth ◽  
Digital Elevation ◽  
Fagus Crenata Forest

scholarly journals Multitemporal Analysis of Gully Erosion in Olive Groves by Means of Digital Elevation Models Obtained with Aerial Photogrammetric and LiDAR Data

2020 ◽  
Vol 9 (4) ◽  
pp. 260 ◽  
Author(s):  
Tomás Fernández ◽  
José Luis Pérez-García ◽  
José Miguel Gómez-López ◽  
Javier Cardenal ◽  
Julio Calero ◽  
...  
Keyword(s):  
Digital Elevation Models ◽  
Gully Erosion ◽  
Airborne Lidar ◽  
Aerial Photographs ◽  
Lidar Data ◽  
Digital Elevation ◽  
Surface Models ◽  
Olive Groves ◽  
Airborne Lidar Data ◽  
Database Servers

Gully erosion is one of the main processes of soil degradation, representing 50%–90% of total erosion at basin scales. Thus, its precise characterization has received growing attention in recent years. Geomatics techniques, mainly photogrammetry and LiDAR, can support the quantitative analysis of gully development. This paper deals with the application of these techniques using aerial photographs and airborne LiDAR data available from public database servers to identify and quantify gully erosion through a long period (1980–2016) in an area of 7.5 km2 in olive groves. Several historical flights (1980, 1996, 2001, 2005, 2009, 2011, 2013 and 2016) were aligned in a common coordinate reference system with the LiDAR point cloud, and then, digital surface models (DSMs) and orthophotographs were obtained. Next, the analysis of the DSM of differences (DoDs) allowed the identification of gullies, the calculation of the affected areas as well as the estimation of height differences and volumes between models. These analyses result in an average depletion of 0.50 m and volume loss of 85000 m3 in the gully area, with some periods (2009–2011 and 2011–2013) showing rates of 10,000–20,000 m3/year (20–40 t/ha*year). The manual edition of DSMs in order to obtain digital elevation models (DTMs) in a detailed sector has facilitated an analysis of the influence of this operation on the erosion calculations, finding that it is not significant except in gully areas with a very steep shape.

scholarly journals Glacier geomorphometry — an approach for analyzing long-term glacier surface changes using grid-based digital elevation models

1997 ◽  
Vol 24 ◽  
pp. 135-141 ◽  
Author(s):  
Bernd Etzelmüller ◽  
Johan Ludvig Sollid
Keyword(s):  
Thermal Regime ◽  
Digital Elevation Models ◽  
Surface Form ◽  
Glacier Surface ◽  
Mass Losses ◽  
Digital Elevation ◽  
Glacier Dynamics ◽  
Grid Based ◽  
Surface Changes

This paper presents an approach to long-term glacier monitoring. Mathematical surface descriptors, such as altitude, slope and curvature (surface form) are used to classify and quantify glacier surface developments. The analysis is based on photogrammetically derived grid-based digital elevation models over a period of decades. This paper outlines the concept and applies it to five valley glaciers in Spitsbergen, Svalbard, which differ with respect to size, thermal regime and dynamics. The results reflect differences between the glaciers investigated which are attributable to glacier dynamics, in particular concerning the glacier’s possible surge behaviour during a period with retreat and mass losses.

scholarly journals Quality Assessment and Glaciological Applications of Digital Elevation Models Derived from Space-Borne and Aerial Images over Two Tidewater Glaciers of Southern Spitsbergen

2019 ◽  
Vol 11 (9) ◽  
pp. 1121 ◽  
Author(s):  
Małgorzata Błaszczyk ◽  
Dariusz Ignatiuk ◽  
Mariusz Grabiec ◽  
Leszek Kolondra ◽  
Michał Laska ◽  
...  
Keyword(s):  
Mass Balance ◽  
Digital Elevation Models ◽  
Control Point ◽  
Aerial Photographs ◽  
Differential Gps ◽  
Tidewater Glaciers ◽  
Digital Elevation ◽  
High Resolution Satellite Images ◽  
Elevation Changes ◽  
Geodetic Mass Balance

In this study, we assess the accuracy and precision of digital elevation models (DEM) retrieved from aerial photographs taken in 2011 and from Very High Resolution satellite images (WorldView-2 and Pléiades) from the period 2012–2017. Additionally, the accuracy of the freely available Strip product of ArcticDEM was verified. We use the DEMs to characterize geometry changes over Hansbreen and Hornbreen, two tidewater glaciers in southern Spitsbergen, Svalbard. The satellite-based DEMs from WorldView-2 and Pléiades stereo pairs were processed using the Rational Function Model (RFM) without and with one ground control point. The elevation quality of the DEMs over glacierized areas was validated with in situ data: static differential GPS survey of mass balance stakes and GPS kinematic data acquired during ground penetrating radar survey. Results demonstrate the usefulness of the analyzed sources of DEMs for estimation of the total geodetic mass balance of the Svalbard glaciers. DEM accuracy is sufficient to investigate glacier surface elevation changes above 1 m. Strips from the ArcticDEM are generally precise, but some of them showed gross errors and need to be handled with caution. The surface of Hansbreen and Hornbreen has been lowering in recent years. The average annual elevation changes for Hansbreen were more negative in the period 2015–2017 (−2.4 m a−1) than in the period 2011–2015 (−1.7 m a−1). The average annual elevation changes over the studied area of Hornbreen for the period 2012–2017 amounted to −1.6 m a−1. The geodetic mass balance for Hansbreen was more negative than the climatic mass balance estimated using the mass budget method, probably due to underestimation of the ice discharge. From 2011 to 2017, Hansbreen lost on average over 1% of its volume each year. Such a high rate of relative loss illustrates how fast these glaciers are responding to climate change.

scholarly journals Evaluation of a gully headcut retreat model using multitemporal aerial photographs and digital elevation models

2013 ◽  
Vol 118 (4) ◽  
pp. 2159-2173 ◽  
Author(s):  
M. A. Campo-Bescós ◽  
J. H. Flores-Cervantes ◽  
R. L. Bras ◽  
J. Casalí ◽  
J. V. Giráldez
Keyword(s):  
Digital Elevation Models ◽  
Aerial Photographs ◽  
Digital Elevation ◽  
Headcut Retreat

scholarly journals Glacier geomorphometry — an approach for analyzing long-term glacier surface changes using grid-based digital elevation models

1997 ◽  
Vol 24 ◽  
pp. 135-141 ◽  
Author(s):  
Bernd Etzelmüller ◽  
Johan Ludvig Sollid
Keyword(s):  
Thermal Regime ◽  
Digital Elevation Models ◽  
Surface Form ◽  
Glacier Surface ◽  
Mass Losses ◽  
Digital Elevation ◽  
Glacier Dynamics ◽  
Grid Based ◽  
Surface Changes

This paper presents an approach to long-term glacier monitoring. Mathematical surface descriptors, such as altitude, slope and curvature (surface form) are used to classify and quantify glacier surface developments. The analysis is based on photogrammetically derived grid-based digital elevation models over a period of decades. This paper outlines the concept and applies it to five valley glaciers in Spitsbergen, Svalbard, which differ with respect to size, thermal regime and dynamics. The results reflect differences between the glaciers investigated which are attributable to glacier dynamics, in particular concerning the glacier’s possible surge behaviour during a period with retreat and mass losses.

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