A High-Resolution Gravimetric Geoid Model for Kuwait Using the Least-Squares Collocation

A new gravimetric geoid model, the KW-FLGM2021, is developed for Kuwait in this study. This new geoid model is driven by a combination of the XGM2019e-combined global geopotential model (GGM), terrestrial gravity, and the SRTM 3 global digital elevation model with a spatial resolution of three arc seconds. The KW-FLGM2021 has been computed by using the technique of Least Squares Collocation (LSC) with Remove-Compute-Restore (RCR) procedure. To evaluate the external accuracy of the KW-FLGM2021 gravimetric geoid model, GPS/leveling data were used. As a result of this evaluation, the residual of geoid heights obtained from the KW-FLGM2021 geoid model is 2.2 cm. The KW-FLGM2021 is possible to be recommended as the first accurate geoid model for Kuwait.

The 1513 Monte Crenone rock avalanche: numerical model and geomorphological analysis

As a contribution to the knowledge of historical rockslides, this research focuses on the historical reconstruction, field mapping, and simulation of the expansion, through numerical modelling, of the 30 September 1513 Monte Crenone rock avalanche. Earth observation in 2-D and 3-D, as well as direct in situ field mapping, allowed the detachment zone and the perimeter and volume of the accumulation to be determined. Thanks to the reconstruction of the post-event digital elevation model based on historical topographic maps and the numerical modelling with the RAMMS::DEBRISFLOW software, the dynamics and runout of the rock avalanche were calibrated and reconstructed. The reconstruction of the runout model allowed confirmation of the historical data concerning this event, particularly the damming of the valley floor and the lake formation up to an elevation of 390 m a.s.l., which generated an enormous flood by dam breaching on 20 May 1515, known as the “Buzza di Biasca”.

Landslide Trail Extraction Using Fire Extinguishing Model

Landslide trails are important elements of landslide inventory maps, providing valuable information for landslide risk and hazard assessment. Compared with traditional manual mapping, skeletonization methods offer a more cost-efficient way to map landslide trails, by automatically generating centerlines from landslide polygons. However, a challenge to existing skeletonization methods is that expert knowledge and manual intervention are required to obtain a branchless skeleton, which limits the applicability of these methods. To address this problem, a new workflow for landslide trail extraction (LTE) is proposed in this study. To avoid generating redundant branches and to improve the degree of automation, two endpoints, i.e., the crown point and the toe point, of the trail were determined first, with reference to the digital elevation model. Thus, a fire extinguishing model (FEM) is proposed to generate skeletons without redundant branches. Finally, the effectiveness of the proposed method is verified, by extracting landslide trails from landslide polygons of various shapes and sizes, in two study areas. Experimental results show that, compared with the traditional grassfire model-based skeletonization method, the proposed FEM is capable of obtaining landslide trails without spurious branches. More importantly, compared with the baseline method in our previous work, the proposed LTE workflow can avoid problems including incompleteness, low centrality, and direction errors. This method requires no parameter tuning and yields excellent performance, and is thus highly valuable for practical landslide mapping.

Automatic Mapping and Characterisation of Linear Depositional Bedforms: Theory and Application Using Bathymetry from the North West Shelf of Australia

Bedforms are key components of Earth surfaces and yet their evaluation typically relies on manual measurements that are challenging to reproduce. Several methods exist to automate their identification and calculate their metrics, but they often exhibit limitations where applied at large scales. This paper presents an innovative workflow for identifying and measuring individual depositional bedforms. The workflow relies on the identification of local minima and maxima that are grouped by neighbourhood analysis and calibrated using curvature. The method was trialed using a synthetic digital elevation model and two bathymetry surveys from Australia’s northwest marine region, resulting in the identification of nearly 2000 bedforms. The comparison of the metrics calculated for each individual feature with manual measurements show differences of less than 10%, indicating the robustness of the workflow. The cross-comparison of the metrics resulted in the definition of several sub-types of bedforms, including sandwaves and palaeoshorelines, that were then correlated with oceanic conditions, further corroborating the validity of the workflow. Results from this study support the idea that the use of automated methods to characterise bedforms should be further developed and that the integration of automated measurements at large scales will support the development of new classification charts that currently rely solely on manual measurements.

Agroecological land typification

The minimum required information and the sequence of agroecological land type allocation on the land management territory of the experimental station (ES) located in the forest-steppe of the Priob'ye region of Novosibirsk is described. Two agroecological land types are distinguished: the first type (upland lands) is represented by leached chernozem in combination with common, podzolized and dark-grey forest soils; the second type (slightly erosive lands) is represented by leached chernozem in combination with dark-grey forest soils. Soil cover of ES in both types of lands is represented by leached chernozem (Lch-2-2s), the share of which for the first type is 75.26%, for the second - 76.26% of the total area of the types. The first agroecological land type is characterized by a range of heights from 134 to 165 m. The working areas are located on the slopes between 0 and 3 degrees in relation to the terrain angle. Vertical dissection of the relief averages 1.3 m, horizontal dissection by erosion forms is 0.8 km/km2. The second type of land is characterized by an elevation of 113 to 137 meters above sea level and a slope of 1 to 4 degrees. Vertical dissection of the terrain averages 1.7 m, horizontal dissection by erosion forms 0.9 km/km2. Typification was carried out with the help of a generated Digital Land Use Model (DLM) of the ES based on the analysis of geographical information, remote sensing materials (ERS) and cadastral map. The DLM consists of the following geo-information layers: topography, land cover, digital elevation model (DEM), working areas. The DEM includes information on slope steepness and exposure, vertical and horizontal dissection.

Studi Potensi Daerah Genangan Banjir Pasang (rob) Perairan Meulaboh dengan Sistem Informasi Geografis (SIG) Studi Potensi Daerah Genangan Banjir Pasang (rob) Perairan Meulaboh dengan Sistem Informasi Geografis (SIG) (Kajian Teknis)

Abstrak Kota Meulaboh adalah salah satu daerah di provinsi Nanggroe Aceh Darussalam yang berada di wilayah perairan Lautan Samudra Hindia sebagai sarana Pelabuhan. Pelabuhan Meulaboh sangat berperan penting dalam meningkatkan perekonomian dan memenuhi kebutuhan masyarakat khususnya di Wilayah Kabupaten Aceh Barat. Daerah perairan pantai sangat rentan terhadap banjir pasang (rob) akibat fluktuasi muka air laut dengan kejadian pasang tertinggi (Highest Water Level) yang berpotensi mengakibatkan daerah genangan banjir di sekitar wilayah pemukiman penduduk. Studi penelitian dilakukan untuk menganalisis pemetaan potensi daerah genangan banjir pasang (rob) menggunakan Sistem Informasi Geografis (SIG). Elevasi tinggi pasang surut dianalisis dengan metode Admiralty, penggambaran elevasi kontur permukaan tanah dan banjir pasang (rob) dianalisis berdasarkan data Digital Elevation Model (DEM), dan pemetaan potensi daerah genangan banjir antara elevasi permukaan banjir pasang (rob) dengan peta administratif Kota Meulaboh dilakukan dengan Sistem Informasi Geografis (SIG) yang menggunakan software Arcgis. Hasil penelitian menunjukan elevasi muka air banjir pasang (rob) tertinggi berada di ketinggian 0.78 m di atas permukaan laut rata-rata (MSL) dan mengakibatkan potensi luas daerah genangan banjir mencapai 18.18 Km2. Luas daerah genangan banjir mengakibatkan 11 desa terkena dampak dan mengakibatkan kerugian bagi masyarakat khususnya di wilayah Desa Kampung Pasir, Suak Indrapuri, Suak Raya, dan Suak Nie. Kata-kata Kunci: Meulaboh, pasang surut, admiralty, dan sistem informasi geografis. Abstract Meulaboh City is one of the regions in the province of Nanggroe Aceh Darussalam in the territorial waters Indian Ocean as a port. Meulaboh Port is very important in improving the economy and meeting the needs of the community, especially in the District of West Aceh. Coastal waters are very susceptible to tidal flooding (rob) due to sea level fluctuations with the highest water level which has the potential to cause flooding areas around residential areas. The research study was conducted to analyze the mapping of potential tidal flood areas (rob) using Geographic Information Systems (GIS). Tidal height analysis is carried out using the Admiralty method, depiction of ground surface contour elevation and tidal flooding (rob) is analyzed based on Digital Elevation Model (DEM) data, and mapping of potential inundation areas between tidal flood surface elevations (ROB) with administrative maps of Meulaboh City carried out with a Geographic Information System (GIS) that uses Arcgis software. The results showed that the highest tidal flood water level (rob) was at an altitude of 0.78 m above the mean sea level (MSL) and resulted in the potential area of ​​flood inundation areas reaching 18.18 Km2. The total of ​​flood inundation area affected 11 villages and caused losses to the community, especially in the villages of Kampung Pasir, Suak Indrapuri, Suak Raya, and Suak Nie. Keywords: Meulaboh, tides, admiralty, and geographic information systems.