Near- and Middle-Infrared Monitoring of Burned Areas from Space

We describe a methodology to discriminate burned areas and date burning events that use a burn-sensitive (V, W) index system defined in near-/mid-infrared space. Discrimination of burned areas relies on a monthly composite of minimum of W and on the difference between this composite and that of the previous month. The rationale is to identify pixels with high confidence of having burned and aggregate new burned pixels on a contextual basis. Dating of burning events is based on the analysis of time series of W, and searching for the day before maximum temporal separability is achieved. The procedure is applied to the fire of Monchique, a large event that took place in the southwest of Portugal in August 2018. When the obtained pattern of burned pixels is compared against a reference map, the overall accuracy is larger than 99%; the commission and omission errors are lower than 5 and 10%, respectively; and the bias and the Dice coefficient are above 0.95 and 0.9, respectively. Differences between estimated dates of burning and reference dates derived from remote-sensed observations of active fires show a bias of 0.03 day and a root mean square difference of 0.24 day

The compound event that triggered the destructive fires of October 2017 in Portugal

Portugal is regularly affected by destructive wildfires that have severe social, economic, and ecological impacts. The total burnt area in 2017 (∼540,000 ha) marked the all-time record value since 1980 with a tragic toll of 114 fatalities that occurred in June and October events. The local insurance sector declared it was the costliest natural disaster in Portugal with payouts exceeding USD295 million. Here, the 2017 October event, responsible for more than 200,000 ha of burnt area and 50 fatalities is analyzed from a compound perspective. A prolonged drought led to preconditioned cumulative hydric stress of vegetation in October 2017. In addition, on 15 October 2017, two other major drivers played a critical role: 1) the passage of hurricane Ophelia off the Coast of Portugal, responsible for exceptional meteorological conditions and 2) the human agent, responsible for an extremely elevated number of negligent ignitions. This disastrous combination of natural and anthropogenic drivers led to the uncontrolled wildfires observed on 15 October

Hidrologia e dinâmica do oceano costeiro de Portugal na região do Cabo Mondego

Tese de mestrado em Ciências do Mar, apresentada à Universidade de Lisboa, através da Faculdade de Ciências, em 2018No âmbito do projeto de I&D “Interação entre o Afloramento Costeiro e a Corrente de Portugal - CORPAC” contrato nº 804.86.145 da Junta Nacional de Investigação Científica e Tecnologia – JNICT (atual Fundação para a Ciência e a Tecnologia – FCT), realizaram-se três campanhas oceanográficas, CORPAC/87, CORPAC/89 e CORPAC/92, na região do Cabo Mondego. A última campanha CORPAC/92, decorreu de 22 a 29 de janeiro de 1992 e os dados hidrológicos recolhidos ainda não tinham sido processados. Assim, o processamento e análise destes dados constitui o objetivo do presente trabalho. Os dados de temperatura, de salinidade e de pressão foram disponibilizados pelo arquivo de dados do MARE/FCUL (Centro de Ciências do Mar e do Ambiente, Faculdade de Ciências da Universidade de Lisboa). Estes foram obtidos com 79 estações CTD com medições entre a superfície e a profundidade de 2000 m. Através da análise dos perfis de temperatura, de salinidade e de densidade identificou-se a camada de mistura atingindo profundidades de 150-200 m. À superfície a temperatura variou entre 12.0 e 15.5ºC enquanto a salinidade apresentou valores em torno de 36.0. As descargas de água dos rios destacaram-se por valores inferiores de temperatura e salinidade. Os diagramas de dispersão θ/S revelaram a presença das massas de água características do oceano costeiro de Portugal: a Água Central Oriental do Atlântico Norte (ACOAN), a Água Mediterrânica (AM) presente através de dois núcleos AMsup e AMinf e a Água Profunda do Atlântico Norte (APAN). As características da ACOAN estão desviadas relativamente à curva representativa daquela água central definida por Fiúza (1984) apresentando temperaturas mais baixas e/ou salinidades mais elevadas. Este desvio foi detetado em trabalhos anteriores (por ex, Boyer et al., 2005). Através de uma análise da literatura relativa à Água Central no bordo leste do Atlântico Norte conclui-se que este desvio ocorre devido a um aumento da salinidade a estas profundidades. Através da distribuição de propriedades sobre superfícies horizontais foi possível identificar a Corrente Ibérica para o Polo (IPC – Iberian Poleward Current) pelas temperaturas e salinidades mais elevadas (1.0ºC e 0.1, respetivamente). O mesmo padrão foi observado na temperatura da superfície do mar obtida pelo sensor AVHRR para o mês de janeiro de 1992. O cálculo da velocidade geostrófica não se revelou conclusivo na identificação da IPC, podendo dever-se a escolha do nível de referência usado no cálculo da mesma.In the frame of the R&D project “Interação entre o Afloramento Costeiro e a Corrente de Portugal - CORPAC” contract no. 804.86.145 of the Junta Nacional de Investigação Científica e Tecnologia - JNICT (now the Fundação para a Ciência e a Tecnologia - FCT), three oceanographic campaigns, CORPAC/87, CORPAC/89 and CORPAC/92, were carried out in the region of Cape Mondego. The last one, CORPAC/92, took place from 22 to 29 January 1992 and the data gathered during this cruise had not yet been processed. Processing and analysis of the data collected during this cruise represents the objective of this work. Temperature, salinity and pressure data were provided by the data archive of MARE/FCUL (Center for Marine and Environmental Sciences, Faculty of Sciences of the University of Lisbon). These were obtained from 79 CTD stations with measurements between the surface and 2000 m depth. By analysis of the temperature, salinity and density profiles, a mixing layer was identified reaching the depth of 150-200 m. At the surface the temperature ranged between 12.0 and 15.5ºC while salinity presented values around 36.0. River run-off were characterized by lower values of temperature and salinity. θ/S diagrams revealed the presence of water masses characteristic of the coastal ocean of Portugal: the Eastern North Atlantic Central Water (ENACW), the Mediterranean Water (MW) with two cores, MWU and MWL and the North Atlantic Deep Water (NADW). A deviation of the thermohaline characteristics of the ENACW was identified with respect to its representative curve defined by Fiúza (1984) towards lower temperatures and/or higher salinities. This deviation was detected in previous works (e.g., Boyer et al., 2005). Through an analysis of the literature on Central Water of the eastern North Atlantic we concluded that this deviation occurs due to an increase in salinity at these depths. The distribution of properties on horizontal surfaces made possible the identification of the Iberian Poleward Current (IPC) through higher temperature and salinity values (1.0ºC and 0.1, respectively). The same pattern was observed in the sea surface temperature obtained with the AVHRR sensor for the month of January 1992. The calculation of the geostrophic velocity was not conclusive for the identification of IPC, this may be due to the choice of the reference level used in the calculation