47 documents found, page 1 of 5
A trained Mask R-CNN model over PlanetScope imagery for very-high resolution su...
Freitas, Pedro; Vieira, Gonçalo; Canário, João; Vincent, Warwick F.; Pina, Pedro; Mora, CarlaSmall water bodies (< 0.01 km2) showing diverse limnological properties occur in great abundance across the boreal forest and tundra landscapes of the Arctic and Subarctic. However, their classification, geographical distribution and collective importance for water, heat, nutrient, contaminant and carbon cycles are still poorly constrained. One important step for better understanding the role and evolution of s...
Vegetation shadow casts impact remotely sensed reflectance from permafrost thaw...
Freitas, Pedro; Vieira, Gonçalo; Mora, Carla; Canário, João; Vincent, Warwick F.Thermokarst lakes and ponds are a common landscape feature resulting from permafrost thaw, but their intense greenhouse gas emissions are still poorly constrained as a feedback mechanism for global warming because of their diversity, abundance, and remoteness. Thermokarst waterbodies may be small and optically diverse, posing specifc challenges for optical remote sensing regarding detection, classifcation, and ...
UAV-based very high resolution point cloud, digital surface model and orthomosa...
Vieira, Gonçalo; Mora, Carla; Pina, Pedro; Ramalho, Ricardo; Fernandes, RuiFogo in the Cabo Verde archipelago of western Africa is one of the most prominent and active ocean island volcanoes on Earth, posing an important hazard both to local populations and at a regional level. The last eruption took place between 23 November 2014 and 8 February 2015 in the Chã das Caldeiras area at an elevation close to 1800ĝ€¯ma.s.l. The eruptive episode gave origin to extensive lava flows that almo...
UAV-based very high resolution point cloud, digital surface model and orthomosa...
Vieira, Gonçalo; Mora, Carla; Pina, Pedro; Ramalho, Ricardo; Fernandes, RuiFogo in the Cabo Verde archipelago off western Africa is one of the most prominent and active ocean island volcanoes on Earth, posing an important hazard both to local populations and at a regional level. The last eruption took place between 23 November 2014 and 8 February 2015 in the Chã das Caldeiras area at an elevation close to 1800 ma.s.l. The eruptive episode gave origin to extensive lava flows that almos...
Penultimate Glacial Cycle glacier extent in the Iberian Peninsula: new evidence...
Vieira, Gonçalo; Palacios, David; Andrés, Nuria; Mora, Carla; Vázquez Selem, Lorenzo; Woronko, Barbara; Soncco, Carmen; Úbeda, Jose; Goyanes, GabrielThe objective of this work is to present a first assessment on the age of the glacial features of the Serra da Estrela, in the central Portugal, Iberian Peninsula (40°19′ N, 7°37′ W, 1993 m), using Cosmic-Ray Exposure dating (in situ cosmogenic 36Cl). A total of 6 samples were dated, 4 extracted from exposed moraine boulders and 2 from glacially polished bedrock surfaces. Despite the low number of samples, the ...
Landscapes and Landforms of Portugal
Vieira, Gonçalo; Zêzere, José; Mora, CarlaLandscapes and Landforms of Portugal volume presents, for the first time, a series of synthesis chapters on landscape highlights of mainland Portugal, covering a wide diversity of geomorphological settings. These are presented with language and graphic styles that try to bridge-the-gap from professional scientists to undergraduate students, while being also accessible to all those interested in the earth scienc...
The climate of Portugal
Mora, Carla; Vieira, GonçaloPortugal shows a Mediterranean climate with, predominantly, a wet cool season and a dry summer. Despite the concentration of the precipitation in winter, there is a high inter-annual variability, resulting from the latitudinal position in the south-western façade of Europe. The prevailing weather conditions are anticyclonic, with Portugal’s seasonality being marked by the influence of either the subtropical ant...
Monitoring recent changes of vegetation in Fildes Peninsula (King George Island...
Miranda, Vasco; Pina, Pedro; Heleno, Sandra; Vieira, Gonçalo; Mora, Carla; E.G.R. Schaefer, CarlosMapping accurately vegetation surfaces in space and time in the ice-free areas of Antarctica can provide important information to quantitatively describe the evolution of their ecosystems. Spaceborne remote sensing is the adequate way to map and evaluate multitemporal changes on the Antarctic vegetation at large but its nature of occurrence, in relatively small and sparse patches, makes the identification very ...
Regime térmico do ar no Alto Vale do Zêzere (serra da Estrela): caso de estudo ...
Mora, CarlaNeste caso de estudo, recolheram-se dados da temperatura do ar em 5 postos termométricos, situados no sector superior do Vale do rio Zêzere, entre o dia 11 e 15 de abril de 2001, num período de estabilidade atmosférica. Os postos foram instalados a várias altitudes e exposições, de forma a conhecer as modificações do campo térmico do ar junto ao solo ao longo do dia. Verificou-se que o gradiente térmico vertica...
Evaluation of the use of very high resolution aerial imagery for accurate ice-w...
Lousada, Maura; Pina, Pedro; Vieira, Gonçalo; Bandeira, Lourenço; Mora, CarlaThe main objective of this paper is to verify the accuracy of delineating and characterizing ice-wedge polygonal networks with features exclusively extracted from remotely sensed images of very high resolution. This kind of mapping plays a key role for quantifying ice-wedge degradation in warming permafrost. The evaluation of mapping a network is performed in this study with two sets of aerial images that are c...