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- Spatial characterization of climatic variables for Arica-Parinacota and
Tarapacá, Chile using topoclimatic analysis
Authors: Luis Morales-Salinas, Giorgio Castellaro, Nora Frederiksen, Luis Felipe Roman Oosrio, Jose Neira Roman, Guillermo Fuentes Jaque, Cristian Escobar Avaria, Felipe Morales
Pages: 39 - 53
Abstract: In the present study, models were developed to determine the monthly and annual spatio-temporal variation of temperature, precipitation, and solar radiation based on topoclimatic analysis of Arica-Parinacota and Tarapacá in northern Chile. To construct the equations of the topoclimatic model, the data from meteorological stations and physiographic factors (latitude, longitude, altitude, and distance to bodies of water) obtained from a digital terrain model with a resolution of 90 m were compiled in a database. The equations of the topoclimatic model were generated by a stepwise regression with a backward selection technique. The equations for average monthly temperature, precipitation, and solar radiation were determined by linear combinations. The results were statistically significant with coefficients of determination greater than 90%, in addition to being greater than the existing climate databases for this area.
PubDate: 2023-02-02
DOI: 10.18172/cig.5473
Issue No: Vol. 49, No. 1 (2023)
- Three decades of remote sensing analysis of forest decline related to
climate change
Authors: José Luis Gallardo-Salazar, Cuauhtémoc Sáenz-Romero, Roberto Lindig-Cisneros, Leonel López-Toledo, José A. Blanco-García, Ángel R. Endara-Agramont
Pages: 69 - 87
Abstract: Climate change is predicted to lead to increasingly intense and hotter droughts, causing physiological weakness followed by forest decline in many regions of the world. Long- and short-range remote sensing (satellites and unmanned aerial vehicles, commonly called drones) can sense drought-induced changes in vegetation. Although several studies have addressed forest decline events, none have analyzed the forest decline attributable to climate change using remote sensing in a concise manner. A bibliometric analysis was carried out to characterize the scientific production reported in the Web of Science repository. The search descriptors were a combination of keywords related to forest decline and remote sensing. The results showed 278 articles published between 1989 and 2021 in 92 journals, with an average annual increase of 31%. A total of 29 nodes and 220 scientific collaboration links were located, mainly led by researchers from USA, Germany and China. Keyword analysis using World-TreeMap reflected the association of different key forest decline phenomena such as drought stress and climate change. Although the use of satellite information to study and understand forest decline has been reported for just over three decades, the most notable feature of the present research was the limited role of drones with only 5 studies. This reveals an area of opportunity to take advantage of the main strengths of drones, i.e., spatial and temporal resolution, low cost compared to manned flights, and centimeter accuracy. Therefore, it is strongly recommended to increase studies to improve the use of multispectral sensors, thermal and LiDAR technology for long-term monitoring of forest decline related to climate change.
PubDate: 2023-05-04
DOI: 10.18172/cig.5639
Issue No: Vol. 49, No. 1 (2023)
- Land cover mapping using remote sensing data in the Apure River Flood
Plain (Venezuela)
Authors: Rosiris Guzmán, Maximiliano Bezada, Inmaculada Rodríguez-Santalla
Pages: 113 - 137
Abstract: The soil cover is a fundamental indicator to identify the factors that act in the development of the geomorphology of an alluvial plain. This coverage is characterized by the control exercised by the vegetation in the hydromorphological processes, as well as the maintenance and stability of the fluvial channels. A record on the distribution of land cover in the middle course of the anastomosed system of the Apure River is presented. The distribution of geomorphological environments in an area of 65 km2 is analyzed from a combination of data from Landsat-8 and Sentinel-2 images, integrated into a Geographic Information System (GIS). A supervised classification was established using the Support Vector Machine and Maximum Likelihood algorithms. The Landsat image was processed through an atmospheric correction, to later calculate the spectral signatures. Six covers were found: a) wooded savannah, b) forest, c) open savannah, d) crops, e) bodies of water, and f) scrub. There are no substantial differences in the reliability achieved with the Support Vector Machines and Maximum Likelihood classification algorithms. It was shown that the woodland cover is the most representative in the study area with a total extension of 5,717.26 ha (39%), out of 14,658.77 ha. The classification presented a global thematic accuracy of 98.08% and a Kappa index of 0.98. As a result, a soil cover cartography was generated from the best classifier, based on the Kappa index. These findings serve as a reference to increase the records of soil cover characterization and can be useful in studies on management and use of the territory, to identify places more susceptible to degradation and propose measures for the management and conservation of water resources, which can be potentially applicable in similar fluvial environments in other latitudes.
PubDate: 2023-07-14
DOI: 10.18172/cig.5607
Issue No: Vol. 49, No. 1 (2023)
- Essential element vulnerabilities and comprehensive disaster risk
assessment for urban planning and risk management in Azogues, Ecuador
Authors: María Augusta Sacoto Flores, Carlos Sánchez-García
Pages: 163 - 190
Abstract: The comprehensive assessment of disaster risk provides information on the potential adverse effects that could condition the city's processes, due to the interaction and contribution of its components in the development of hazard and vulnerability scenarios. By analyzing the most relevant hazards of the urban environment, identifying the vulnerabilities of the critical elements for the development of the city and the exposure of the elements to hazards; this study focuses on the understanding and holistic assessment of the disaster risk of the city of Azogues in Ecuador, in order to provide information to the local government, institutions and the population, to guide decision-making in urban planning and disaster risk management during all stages of disasters. To this end, a semi-quantitative methodology was applied based on the Multi-criteria Decision Analysis Method, and within this, the Analytic Hierarchy Process method and the heuristic approach and Geographic Information Systems and their tools. The results determined that some elements related to the health, education and supply sectors present certain vulnerabilities, although these are not associated with exposure to hazards. In relation to the most relevant hazards, approximately 7% and 33% of the total study area present high levels of susceptibility to landslides and forest fires, respectively. Finally, it was established that the most important factors affecting landslides are geological aspects and slope; and for forest fires, land use (vegetation) and radiation.
PubDate: 2023-03-28
DOI: 10.18172/cig.5628
Issue No: Vol. 49, No. 1 (2023)
- Vineyards and wine between 1995 and 2019
Authors: Teodoro Lasanta, Estela Nadal Romero, Rubén Sáenz
Pages: 211 - 230
Abstract: Wine production consistently exceeds wine consumption on a global scale, which explains why the wine market is highly demanding, competitive and increasingly international. This paper quantifies the changes (between 1995 and 2019) in wine consumption, production and the international wine market. Traditionally, the international wine sector was managed from Europe, mainly by a group of countries (Spain, France, Italy and Portugal) that concentrated most of the vineyards, production and international trade. Since the end of the 20th century, several countries (USA, Canada, Chile, Argentina, South Africa, Australia and New Zealand) have made strong inroads into the sector, increasing their vineyard surface area and having a significant and growing presence in international markets. On the other hand, other countries (China, Russia, Brazil, India, the Netherlands, Japan, etc.) are emerging in wine consumption. All this has changed the geographical distribution of vineyards and wine production, moving progressively from the "Old World" to the "New World". In 1961, Europe accounted for almost 69% of the world's vineyards, whereas in 2019 it will account for only 50%. On the other hand, wine imports and exports doubled between 1995 and 2019, while the number of wine-producing and wine-consuming countries is increasing. The globalisation of the wine market has driven changes in wine production and winemaking systems, as well as the regulation of international trade to take into account competition from non-EU wines, issues that simply discussed in this paper.
PubDate: 2023-05-18
DOI: 10.18172/cig.5646
Issue No: Vol. 49, No. 1 (2023)
- Past and present Geomorphological hazard and cultural heritage loss in El
Castellar castle scarp (central Ebro Basin, Spain)
Authors: José Luis Peña-Monné, M. Marta Sampietro-Vattuone, Marta Espinalt-Brillas, Francisco J. Gutiérrez-González
Pages: 3 - 22
Abstract: The ruins of the Medieval castle and village of El Castellar are located on an abrupt 1.2-km-long scarp of Miocene gypsums, in the central sector of the Ebro depression. The Medieval remains of the main El Castellar castle are perched on a 100 m cliff on the Ebro River. Considering the historical and geoarchaeological relevance of El Castellar settlement, this investigation aimed to study the geomorphological and paleoenvironmental context of the site during and after the settlement and its later evolution, including its current state. Geomorphological data suggest that in Medieval times its constructions were favored by the MCA environmental conditions. During that times, the Ebro River was located in a centered position on its floodplain, and lateral alluvial fans protected the scarp from basal erosion. Later, during the LIA, great climatic flows and recurrent floods changed the river dynamics and promoted the river channel movement against the scarp, destabilizing its foot and generating large landslides and rockfalls, thus promoting its retreat. The village buildings and castle at the top of the scarp were seriously damaged. For several reasons, the area is not easily accessible, but it still contains a relevant archaeological heritage that deserves to be studied and preserved.
PubDate: 2022-07-15
DOI: 10.18172/cig.5204
Issue No: Vol. 49, No. 1 (2022)
- Present climate of lake Montcortès (Central Pyrenees): paleoclimatic
relevance and insights on future warming
Authors: Valentí Rull, Javier Sigró, Teresa Vegas-Vilarrúbia
Pages: 23 - 38
Abstract: The varved sediments of the Pyrenean Lake Montcortès (Pallars Sobirà, Lleida) embody a unique continuous high-resolution (annual) paleoarchive of the last 3000 years for the circum-Mediterranean region. A variety of paleoclimatic and paleoecological records have been retrieved from these uncommon sediments that have turned the lake into a regional reference. Present-day geographical, geological, ecological and limnological features of the lake and its surroundings are reasonably well known but the lack of a local weather station has prevented characterization of current climate, which is important to develop modern-analog studies for paleoclimatic reconstruction and to forecast the potential impacts of future global warming. Here, the local climate of the Montcortès area for the period 1955-2020 is characterized using a network of nearby stations situated along an elevational transect in the same river basin of the lake. The finding of statistically significant elevational gradients for average temperature and precipitation (-0.59 °C and 82 mm per 100 m elevation, respectively) has enabled to estimate these parameters and their seasonal regime for the lake site. The estimated average annual temperature is 9.7±0.8 °C and the estimated total annual precipitation is 1031±34 mm, in average. A representative climograph has been shaped with these data that can serve as a synthetic descriptive and comparative climatic tool. The same analysis has provided climatic data for modern-analog studies useful to improve the interpretation of sedimentary records in climatic and ecological terms. In addition, the seasonal slope shifting of the climatic elevational gradients has been useful to gain insights about possible future climatic trends under a warming scenario
PubDate: 2022-07-08
DOI: 10.18172/cig.5412
Issue No: Vol. 49, No. 1 (2022)
- A performance assessment of gridded snow products in the Upper Euphrates
Authors: Esteban Alonso-González, Juan Ignacio López-Moreno, M. Cansaran Ertaş, Aynur Şensoy, Ali Arda Şorman
Pages: 55 - 68
Abstract: Snow observations are important in many mountain areas to quantify the water stored in snowpacks and to predicting runoff during the melting period. In this study we compare the performance of five different regional-scale gridded snow products to reproduce snow water equivalent (SWE) in the Upper Euphrates region (Karasu Basin, 10,275 km2), with observations from automatic weather stations in the catchment through Taylor diagrams. The products compared are the ERA5, ERA5-Land, MERRA-2, snow data from a dynamical downscaling of ERA-5 (period 2000-2018) and SWE generated from microwave satellite data (SWE-E(H13) period 2013-2015 product of the EUMETSAT H SAF project). The H13 product presented deficiencies in terms of not being able to reproduce the spatial and temporal variability of the snowpack. ERA-5 and, in particular, ERA-Land products, at 30 and 9 km grid size, respectively, showed good performance in reproducing snow evolution compared to four available observation sites. MERRA2 at 50 km resolution showed lower skills compared to the above-mentioned products. Resulting snow data from WRF at 10 km resolution did not show any improvement with respect to the global datasets. The impossibility of testing different configurations due to the lack of observations to compare and the computational constraints to test different parametrizations may be the reasons to explain the low performance although they remain speculative. All the gridded datasets showed good performance in reproducing snow duration over the basin, compared to remotely sensed data. Results highlight ERA-Land dataset as a very promising tool for regional snow studies in mountainous regions with limited observations, in a cost-effective way.
PubDate: 2022-11-04
DOI: 10.18172/cig.5275
Issue No: Vol. 49, No. 1 (2022)
- Analysis of the functional diversity of the herbaceous stratum in a
‘dehesa’ ecosystem using in situ hyperspectral proximal sensing
Authors: Carlos Gonzalo, Vicente Burchard-Levine, Víctor Rolo, Rosario González-Cascón, Gerardo Moreno, M. Pilar Martín
Pages: 89 - 111
Abstract: The aim of this paper is the estimation of functional diversity (FD) of the herbaceous stratum in a ‘dehesa’ ecosystem using hyperspectral data obtained with an ASD FieldSpec® 3 (Analytical Spectral Devices Inc., Boulder, CO, EE. UU.) spectroradiometer. Optical data were correlated with biophysical variables (specific leaf area (SLA), above-ground biomass (AGB), leaf area index (LAI) and nitrogen content (N%)) and traditional diversity indices (Shannon and Evenness) and functional diversity indices (FDis) using as predictor variables: a) vegetation indices (VIs) and simple regression methods, and b) spectral bands and Partial Least Squares Regression (PLSR). Correlations, especially with biophysical variables, improved substantially when using hyperspectral information (R2 >0.6, rRMSE <0.1), which confirms the interest of the spectral dimension to estimate the functional diversity of a complex ecosystem such as semi-arid grasslands.
PubDate: 2022-06-28
DOI: 10.18172/cig.5325
Issue No: Vol. 49, No. 1 (2022)
- Vulnerability and environmental risk in the Sierra Otomí Tepehua
(Hidalgo, México)
Authors: Patricia Catalina Medina-Pérez, Héctor Jesús Tapia-Fernández, Antonio Castillo-Martínez
Pages: 139 - 161
Abstract: Extreme geomorphological and hydrometeorological events cause landslides (gravitational processes) in vulnerable and marginalized communities, where the risk and effects of a natural disaster reduce responsiveness to environmental adversities. In the state of Hidalgo (Mexico) exists dangers as slope instability and processes of massive removal of soil, but in some municipalities of the Sierra Otomí-Tepehua (SOT) does not exist a municipal instrument that provides information on high-risk localities. This study evaluated landslide risk in 220 localities located in three municipalities of the Sierra Otomí-Tepehua region (SOT) using information from the 2020 national census. A geospatial analysis was built in localities with landslide risk, further social vulnerability was evaluated in 33 localities located on hillsides, and the Social Vulnerability Index of Housing (IVSV) was determined. 109 localities with a high and very high level of social vulnerability were identified due to the physical condition of the dwellings located in areas with landslide risk. Finally, risk map of landslides was developed through multi-criteria analysis to focus on mitigate and prevent disasters in the most vulnerable localities of the SOT.
PubDate: 2022-11-02
DOI: 10.18172/cig.5393
Issue No: Vol. 49, No. 1 (2022)
- Evaluation of the quality of the Voluntary Geographic Information for the
road network in Bogotá D.C
Authors: Luis A. Niño Beltran, Aquiles E. Darghan Contreras, Libia D. Cangrejo Aljure, Edwin F. Grisales Camargo
Pages: 191 - 210
Abstract: The production of Voluntary Geographic Information has been growing considerably and continues to be an active area of research. However, the lack of knowledge about the quality of information generated on a voluntary and participatory basis raises challenges and questions about its use. In the review carried out for the Colombian case, no studies related to the subject were identified; consequently, this study is presented on the evaluation of the quality of this type of information on the road network of Bogotá with respect to completeness, positional accuracy and thematic accuracy. This evaluation was carried out by means of a semi-automatic process that uses a mobile buffer and the centroid of the roads to make the corresponding comparisons between two data sources. The results found reveal that the method used allowed to compare up to 85.0% of the data, and that the OpenStreetMap mesh has a completeness of 85.4%, over the entire area of Bogotá. A positional accuracy of 3.98 m and a thematic accuracy related to the percentage of error in the attributes: Road hierarchy, direction of flow and road naming of 35.8%, 15.0% and 34.6% respectively. The quality evaluated through completeness, positional and thematic accuracy in synergistic terms is deficient with respect to the minimum quality levels established in the standard data model, however, the evaluation for each of the attributes shows an acceptable quality in terms of completeness and thematic accuracy.
PubDate: 2022-08-25
DOI: 10.18172/cig.5280
Issue No: Vol. 49, No. 1 (2022)
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