scholarly journals Climate and Land Cover Trends Affecting Freshwater Inputs to a Fjord in Northwestern Patagonia

2021 ◽  
Vol 8 ◽  
Author(s):  
Jorge León-Muñoz ◽  
Rodrigo Aguayo ◽  
Rafael Marcé ◽  
Núria Catalán ◽  
Stefan Woelfl ◽  
...  

Freshwater inputs strongly influence oceanographic conditions in coastal systems of northwestern Patagonia (41–45°S). Nevertheless, the influence of freshwater on these systems has weakened in recent decades due to a marked decrease in precipitation. Here we evaluate potential influences of climate and land cover trends on the Puelo River (640 m3s–1), the main source of freshwater input of the Reloncaví Fjord (41.5°S). Water quality was analyzed along the Puelo River basin (six sampling points) and at the discharge site in the Reloncaví Fjord (1, 8, and 25 m depth), through six field campaigns carried out under contrasting streamflow scenarios. We also used several indicators of hydrological alteration, and cross-wavelet transform and coherence analyses to evaluate the association between the Puelo River streamflow and precipitation (1950–2019). Lastly, using the WEAP hydrological model, land cover maps (2001–2016) and burned area reconstructions (1985–2019), we simulated future land cover impacts (2030) on the hydrological processes of the Puelo River. Total Nitrogen and total phosphorus, dissolved carbon, and dissolved iron concentrations measured in the river were 3–15 times lower than those in the fjord. Multivariate analyses showed that streamflow drives the carbon composition in the river. High streamflow conditions contribute with humic and colored materials, while low streamflow conditions corresponded to higher arrival of protein-like materials from the basin. The Puelo River streamflow showed significant trends in magnitude (lower streamflow in summer and autumn), duration (minimum annual streamflow), timing (more floods in spring), and frequency (fewer prolonged floods). The land cover change (LCC) analysis indicated that more than 90% of the basin area maintained its land cover, and that the main changes were attributed to recent large wildfires. Considering these land cover trends, the hydrological simulations project a slight increase in the Puelo River streamflow mainly due to a decrease in evapotranspiration. According to previous simulations, these projections present a direction opposite to the trends forced by climate change. The combined effect of reduction in freshwater input to fiords and potential decline in water quality highlights the need for more robust data and robust analysis of the influence of climate and LCC on this river-fjord complex of northwestern Patagonia.

2021 ◽  
Vol 20 (1) ◽  
pp. 115-126
Author(s):  
Tamas Faiz Dicelebica ◽  
Aji Ali Akbar ◽  
Dian Rahayu Jati

Kalimantan Barat memiliki potensi bencana kebakaran hutan dan lahan gambut yang tinggi karena banyaknya titik api dan jenis lahan gambut yang mudah terbakar pada musim kemarau. Tujuan dari penelitian ini adalah untuk memetakan dan menentukan kecenderungan titik pamas dan mengidentifikasi dan mencegah kawasan rawan kebakaran hutan dan lahan gambut dengan data hotspot, peta curah hujan, peta tutupan lahan, peta kesatuan hidrologis gambut, dan peta cekungan air tanah menggunakan Sistem Informasi Geografis atau SIG. Metode overlap digunakan untuk menganalisis kecenderungan titik panas sedangkan Overlay dan Scoring digunakan untuk mengidentifikasi kawasan rawan kebakaran hutan dan lahan. Setelah dilakukan analisis titik panas, terdapat kecenderungan curah hujan pada kelas curah hujan 1.500-3.000 mm/tahun dengan 2.192 kejadian. Perubahan tutupan lahan di kawasan hutan mengalami penurunan sebesar 7,96%. Peningkatan tutupan lahan di kawasan non-hutan sebesar 11,26%, mempengaruhi potensi dan kecenderungan titik api dan bencana kebakaran hutan dan lahan. Kubu Raya memiliki tingkat kerawanan bencana kebakaran pada kelas sangat rawan dengan luasan 0,26%, dan Kapuas Hulu memiliki tingkat kerawanan bencana kebakaran pada kelas tidak rawan dengan luas 0,19%. Kabupaten Ketapang merupakan daerah dengan tingkat pencegahan tertinggi, dengan luas cekungan airtanah sebesar 26,46%.ABSTRACTWest Kalimantan has a high potential for forest and peatland fire disasters due to the high number of hotspots and the type of peatland which burns easily during the dry season. The purpose of this research is to map and determine the trend of hotspots and areas prone to forest and peatland fires and prevent them with hotspot data, rainfall maps, land cover maps, maps of peat hydrological units, and maps of groundwater basins using Geographic Information Systems or GIS. The overlap method is used to analyze the trend of hotspots; meanwhile, Overlay and Scoring are used to identify areas prone to forest and land fires in this research. After analyzing the hotspots, there is a tendency for rainfall with a class of 1,500-3,000mm/year with 2,192 events. Land cover change in forested areas decreased by 7.96%. It increased land cover in non-forest areas by 11.26%, affecting the potential and tendency of hotspots and forest and land fire disasters. Kubu Raya has a fire disaster vulnerability level in the very vulnerable class with an area of 0.26%, and Kapuas Hulu has a fire disaster vulnerability level in the non-prone class with an area of 0.19%. Ketapang Regency is the area with the highest prevention rate, with a groundwater basin area of 26.46%.


2013 ◽  
Vol 34 (11) ◽  
pp. 4008-4024 ◽  
Author(s):  
Pedro Sarmento ◽  
Cidália C. Fonte ◽  
Mário Caetano ◽  
Stephen V. Stehman

Land ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 443
Author(s):  
Evidence Chinedu Enoguanbhor ◽  
Florian Gollnow ◽  
Blake Byron Walker ◽  
Jonas Ostergaard Nielsen ◽  
Tobia Lakes

Land use planning as strategic instruments to guide urban dynamics faces particular challenges in the Global South, including Sub-Saharan Africa, where urgent interventions are required to improve urban and environmental sustainability. This study investigated and identified key challenges of land use planning and its environmental assessments to improve the urban and environmental sustainability of city-regions. In doing so, we combined expert interviews and questionnaires with spatial analyses of urban and regional land use plans, as well as current and future urban land cover maps derived from Geographic Information Systems and remote sensing. By overlaying and contrasting land use plans and land cover maps, we investigated spatial inconsistencies between urban and regional plans and the associated urban land dynamics and used expert surveys to identify the causes of such inconsistencies. We furthermore identified and interrogated key challenges facing land use planning, including its environmental assessment procedures, and explored means for overcoming these barriers to rapid, yet environmentally sound urban growth. The results illuminated multiple inconsistencies (e.g., spatial conflicts) between urban and regional plans, most prominently stemming from conflicts in administrative boundaries and a lack of interdepartmental coordination. Key findings identified a lack of Strategic Environmental Assessment and inadequate implementation of land use plans caused by e.g., insufficient funding, lack of political will, political interference, corruption as challenges facing land use planning strategies for urban and environmental sustainability. The baseline information provided in this study is crucial to improve strategic planning and urban/environmental sustainability of city-regions in Sub-Saharan Africa and across the Global South, where land use planning faces similar challenges to address haphazard urban expansion patterns.


2021 ◽  
Vol 13 (12) ◽  
pp. 2301
Author(s):  
Zander Venter ◽  
Markus Sydenham

Land cover maps are important tools for quantifying the human footprint on the environment and facilitate reporting and accounting to international agreements addressing the Sustainable Development Goals. Widely used European land cover maps such as CORINE (Coordination of Information on the Environment) are produced at medium spatial resolutions (100 m) and rely on diverse data with complex workflows requiring significant institutional capacity. We present a 10 m resolution land cover map (ELC10) of Europe based on a satellite-driven machine learning workflow that is annually updatable. A random forest classification model was trained on 70K ground-truth points from the LUCAS (Land Use/Cover Area Frame Survey) dataset. Within the Google Earth Engine cloud computing environment, the ELC10 map can be generated from approx. 700 TB of Sentinel imagery within approx. 4 days from a single research user account. The map achieved an overall accuracy of 90% across eight land cover classes and could account for statistical unit land cover proportions within 3.9% (R2 = 0.83) of the actual value. These accuracies are higher than that of CORINE (100 m) and other 10 m land cover maps including S2GLC and FROM-GLC10. Spectro-temporal metrics that capture the phenology of land cover classes were most important in producing high mapping accuracies. We found that the atmospheric correction of Sentinel-2 and the speckle filtering of Sentinel-1 imagery had a minimal effect on enhancing the classification accuracy (< 1%). However, combining optical and radar imagery increased accuracy by 3% compared to Sentinel-2 alone and by 10% compared to Sentinel-1 alone. The addition of auxiliary data (terrain, climate and night-time lights) increased accuracy by an additional 2%. By using the centroid pixels from the LUCAS Copernicus module polygons we increased accuracy by <1%, revealing that random forests are robust against contaminated training data. Furthermore, the model requires very little training data to achieve moderate accuracies—the difference between 5K and 50K LUCAS points is only 3% (86 vs. 89%). This implies that significantly less resources are necessary for making in situ survey data (such as LUCAS) suitable for satellite-based land cover classification. At 10 m resolution, the ELC10 map can distinguish detailed landscape features like hedgerows and gardens, and therefore holds potential for aerial statistics at the city borough level and monitoring property-level environmental interventions (e.g., tree planting). Due to the reliance on purely satellite-based input data, the ELC10 map can be continuously updated independent of any country-specific geographic datasets.


2021 ◽  
Vol 36 ◽  
pp. 100837
Author(s):  
Mou Leong Tan ◽  
Yi Lin Tew ◽  
Kwok Pan Chun ◽  
Narimah Samat ◽  
Shazlyn Milleana Shaharudin ◽  
...  

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