scholarly journals Forest Fires in Madeira Island and the Fire Weather Created by Orographic Effects

Atmosphere ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 827
Author(s):  
Flavio T. Couto ◽  
Rui Salgado ◽  
Nuno Guiomar

Understanding the effects of weather and topography on fire spread in specific contexts, such as oceanic islands, is critical for supporting fire prevention and suppression strategies. In this study, we analyse the atmospheric conditions associated with historical forest fires that have occurred over complex terrain in Madeira Island, Portugal. The atmospheric Meso-NH model was used to identify the mesoscale environment during three forest fires events. The model was configured into two nested horizontal domains, the outer domain at 2.5 km resolution and the inner domain at 500 m. The paper brings a comprehensive analysis on the factors favouring the evolution of significant large fires occurring in Madeira Island in August 2010, July 2012 and August 2016. These fire events were selected because they are characterized by their large size (between 324.99 ha and 7691.67 ha) that expanded in a short-time period, threatening people and property in the wildland-urban interfaces. The study highlights that local terrain produce orographic effects that enhance the fire danger over the southern slope during typical summer atmospheric conditions.

2021 ◽  
Author(s):  
Flavio T. Couto ◽  
Nuno Andrade ◽  
Rui Salgado ◽  
Jaime Serra

<p>Drought conditions increase the likelihood of extreme wildfires which result in loss of life and property causing several damages to the society. The extensive study of different real cases is important to better understand the environmental conditions and their impacts on different sectors. The study aims to explore the atmospheric conditions associated with three forest fires occurring in Madeira island using convection-permitting simulations. In addition, the potential impacts on tourism sector is preliminary discussed using media data for one of the episodes when the fires affected the area surrounding the Funchal city, leaving several houses and a five-star hotel destroyed and 3 fatalities at least. Madeira is a Portuguese island located in the North Atlantic Ocean where the forest fires represent a risk for the ecosystems and for the local economy. The tourism is one of the main economic activities of the island. The numerical simulations were performed using the Meso-NH model. It was configured into two domains, the outer domain with 2.5 km resolution, and an inner domain with a resolution of 500 m and capable to better represent the complex terrain characteristic of the mountainous island. The vertical grid was calculated automatically by the model with a total of 50 levels following the terrain. The simulations were performed in a two-way interactive mode, initialized and forced using the European Centre for Medium-Range Weather Forecasts (ECMWF) analysis updated each 6 hours. The forest fires episodes were explored from the atmospheric circulation point of view, using meteorological variables as temperature, relative humidity and wind over the island. The Azores Anticyclone was the typical synoptic system inducing the north-easterly airflow towards the island. As it remains almost stationary, the fair weather is maintained over the region for several days and may lead to drought conditions during summertime. However, the downward motion created by the local orography at the southern slope was evident from the simulations. The combined effect of terrain and atmospheric condition was essential increasing the fire danger by leading the maximum temperatures above 35°C and relative humidity around 15%. Also, by creating the favourable conditions to the fire propagation after their ignition, namely due to the intense gust winds. One episode was marked by the cancellation of several international flights due to the high amount of smoke that affected Funchal, as well as the evacuation of more than 1,000 residents and tourists. The summer season is a critical fire weather period for the Madeira island, and the study contributes to identify fire risk and anticipate fire behaviour in some specific regions of the island. The use of high-resolution simulations is able to indicate the regions more propitious to fires, namely those affected by the highest near surface temperatures and lowest values of relative humidity. Overall, the results also can help in the development of fire risk management practices, as well as promoting a sustainable development, namely of the tourism sector.</p>


2020 ◽  
Author(s):  
Rui Salgado ◽  
Flavio T. Couto ◽  
Maria Joao Costa

<p>On February 20, 2010, Madeira island was affected by a tragic event of extreme precipitation. The event was marked by huge economical damage estimated in millions of euros, and more than 40 deaths. Before the event, there were not many studies about severe precipitation in Madeira, which were highly motivated after 2010. This work intent is to show some advancements in knowledge of heavy precipitation events (HPE) in Madeira found in the last decade. The Meso-NH model was used with a rather complete parametrization package of several physical processes occurring in the atmosphere and configured into different dimensions. In order to explore the meridional water vapour transport, the total precipitable water field was extracted from the Atmospheric Infrared Sounder (AIRS) data products. In the first set of simulations, the experiments were performed with three horizontal nested domains (9 km, 3 km, and 1 km resolution). The results for the winter 2009-2010 raised two questions about the topic. First, associated with the large scale environment, and the second one linked to orographic effects. In the first case, apart from a cyclone affecting the island, it was identified the presence of atmospheric rivers (ARs) coupled to frontal systems transporting tropical moisture toward the island. For the orographic effects, the simulations at 1km resolution showed maximums of accumulated precipitation in the highlands. Subsequently, the analysis of the precipitation in Madeira highlands over a 10-year period showed dry summers and the highest rainfall amounts in the winters, although with some significant events occurring also in autumn and spring seasons. Furthermore, it was found that tropical moisture transported through the ARs may reach the island with different intensities and orientation during the winter seasons. However, for the 10 winter periods, the ARs were not the sole factor producing HPE in Madeira. In the second set of simulations, the model was configured with a larger domain of 2.5 km resolution and an inner domain of 0.5 km resolution. All the significant events in autumn 2012 were simulated confirming the orographic effect in the accumulated precipitation. The most interesting result found was the occurrence of maximums values in different regions over the island. For example, over the highlands in the central peaks and southern/northern slopes, or in the coastal plain at lowlands. From the simulations it was possible to explain the causes for the distinct rainfall patterns, and the atmospheric environments associated. The variations in the configuration of the ambient flow, jointly with the orographic forcing may produce convection in distinct regions of the island, resulting in different rainfall patterns. Ten years later, the advances in the understanding of significant precipitation in the Madeira is evident. The results show how different events may occur, since the formation or enhancement of the precipitation over the island is totally dependent on the geographic aspects and atmospheric conditions associated with each precipitating event.</p>


Forests ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 294
Author(s):  
Nicholas F. McCarthy ◽  
Ali Tohidi ◽  
Yawar Aziz ◽  
Matt Dennie ◽  
Mario Miguel Valero ◽  
...  

Scarcity in wildland fire progression data as well as considerable uncertainties in forecasts demand improved methods to monitor fire spread in real time. However, there exists at present no scalable solution to acquire consistent information about active forest fires that is both spatially and temporally explicit. To overcome this limitation, we propose a statistical downscaling scheme based on deep learning that leverages multi-source Remote Sensing (RS) data. Our system relies on a U-Net Convolutional Neural Network (CNN) to downscale Geostationary (GEO) satellite multispectral imagery and continuously monitor active fire progression with a spatial resolution similar to Low Earth Orbit (LEO) sensors. In order to achieve this, the model trains on LEO RS products, land use information, vegetation properties, and terrain data. The practical implementation has been optimized to use cloud compute clusters, software containers and multi-step parallel pipelines in order to facilitate real time operational deployment. The performance of the model was validated in five wildfires selected from among the most destructive that occurred in California in 2017 and 2018. These results demonstrate the effectiveness of the proposed methodology in monitoring fire progression with high spatiotemporal resolution, which can be instrumental for decision support during the first hours of wildfires that may quickly become large and dangerous. Additionally, the proposed methodology can be leveraged to collect detailed quantitative data about real-scale wildfire behaviour, thus supporting the development and validation of fire spread models.


2012 ◽  
Vol 12 (7) ◽  
pp. 2225-2240 ◽  
Author(s):  
F. T. Couto ◽  
R. Salgado ◽  
M. J. Costa

Abstract. This paper constitutes a step towards the understanding of some characteristics associated with high rainfall amounts and flooding on Madeira Island. The high precipitation events that occurred during the winter of 2009/2010 have been considered with three main goals: to analyze the main atmospheric characteristics associated with the events; to expand the understanding of the interaction between the island and the atmospheric circulations, mainly the effects of the island on the generation or intensification of orographic precipitation; and to evaluate the performance of high resolution numerical modeling in simulating and forecasting heavy precipitation events over the island. The MESO-NH model with a horizontal resolution of 1 km is used, as well as rain gauge data, synoptic charts and measurements of precipitable water obtained from the Atmospheric InfraRed Sounder (AIRS). The results confirm the influence of the orographic effects on precipitation over Madeira as well as the tropical–extratropical interaction, since atmospheric rivers were detected in six out of the seven cases analyzed, acting as a low level moisture supplier, which together with the orographic lifting induced the high rainfall amounts. Only in one of the cases the presence of a low pressure system was identified over the archipelago.


2014 ◽  
Vol 11 (6) ◽  
pp. 1449-1459 ◽  
Author(s):  
I. N. Fletcher ◽  
L. E. O. C. Aragão ◽  
A. Lima ◽  
Y. Shimabukuro ◽  
P. Friedlingstein

Abstract. Current methods for modelling burnt area in dynamic global vegetation models (DGVMs) involve complex fire spread calculations, which rely on many inputs, including fuel characteristics, wind speed and countless parameters. They are therefore susceptible to large uncertainties through error propagation, but undeniably useful for modelling specific, small-scale burns. Using observed fractal distributions of fire scars in Brazilian Amazonia in 2005, we propose an alternative burnt area model for tropical forests, with fire counts as sole input and few parameters. This model is intended for predicting large-scale burnt area rather than looking at individual fire events. A simple parameterization of a tapered fractal distribution is calibrated at multiple spatial resolutions using a satellite-derived burnt area map. The model is capable of accurately reproducing the total area burnt (16 387 km2) and its spatial distribution. When tested pan-tropically using the MODIS MCD14ML active fire product, the model accurately predicts temporal and spatial fire trends, but the magnitude of the differences between these estimates and the GFED3.1 burnt area products varies per continent.


2003 ◽  
Vol 8 (2) ◽  
pp. 210-215 ◽  
Author(s):  
Barbara A. Kozikowski ◽  
Thomas M. Burt ◽  
Debra A. Tirey ◽  
Lisa E. Williams ◽  
Barbara R. Kuzmak ◽  
...  

A diverse set of 320 compounds from the Procter & Gamble Pharmaceuticals organic compound repository was prepared as 20-mM DMSO solutions and stored at 4°C under argon in pressurized canisters to simulate a low-humidity environment. The plates were subjected to 25 freeze/thaw cycles while being exposed to ambient atmospheric conditions after each thaw to simulate the time and manner by which compound plates are exposed to the atmosphere during typical liquid-handling and high-throughput screening processes. High-performance liquid chromatography–mass spectrometry with evaporative light-scattering detection was used to quantitate the amount of compound remaining after every 5th freeze/thaw cycle. Control plates were stored either at room temperature under argon or at 4°C under argon without freeze/thaw cycling and were evaluated at the midpoint and the endpoint of the study. The study was conducted over a short time period (i.e., 7 weeks) to minimize the effect of compound degradation over time due to the exposure of the compounds to DMSO.The results from this study will be used to determine the maximum number of freeze/thaw cycles that can be achieved while maintaining acceptable compound integrity.(Journal of Biomolecular Screening 2003:210-215)


2007 ◽  
Vol 16 (2) ◽  
pp. 174 ◽  
Author(s):  
Kerry Anderson ◽  
Gerhard Reuter ◽  
Mike D. Flannigan

The focus of this investigation is to quantify the effects of perturbations in the meteorological data used in a fire-growth model. Observed variations of temperature, humidity, wind speed, and wind direction are applied as perturbations to hourly values within a simulated weather forecast to produce several forecasts. In turn, these are used by a deterministic eight-point fire-growth model to produce an ensemble of possible final fire perimeters. Two studies were conducted to assess the value of applying perturbations. In the first study, fire growth using detailed, one-minute data was compared to growth based on the more commonly used hourly data. Results showed that the detailed weather produced fire growth larger and wider than the hourly based data. By applying perturbations, variations in the flank and back-fire spread were captured by the random-perturbation model while the forward spread fell within the 20 to 30% probability prediction. A sensitivity analysis based on the observed variations showed that wind speed accounted for a 44% difference in area burned, while temperature accounted for only a 16% difference. In the second study, case studies were conducted on four observed forest fires in Wood Buffalo National Park. Results showed that daily fire-growth predictions using simulated weather forecasts over-predicted fire growth using actual hourly weather observations by 27%. Systematic-perturbation models best compensated for this with most fire growth falling within the predicted range of the models (52 out of 63 days).


2011 ◽  
Vol 22 (06) ◽  
pp. 607-621 ◽  
Author(s):  
KLAUS LICHTENEGGER ◽  
WILHELM SCHAPPACHER

In this paper a stochastic cellular automata model is examined, which has been developed to study a "small" world, where local changes may noticeably alter global characteristics. This is applied to a climate model, where global temperature is determined by an interplay between atmospheric carbon dioxide and carbon stored by plant life. The latter can be released by forest fires, giving rise to significant changes of global conditions within short time.


Author(s):  
Koyu Satoh ◽  
Naian Liu ◽  
Qiong Liu ◽  
K. T. Yang

It is important to examine the behavior of forest fires and city fires to mitigate the property damages and victims by fires. There have been many previous studies on forest fires where the fire spreading patterns were investigated, utilizing artificial satellite pictures of forest fires, together with the use of corresponding weather data and GIS data. On the other hand, large area city fires are very scarce in the world, particularly in modern cities where high-rise concrete buildings are constructed with sufficient open spaces. Thus, the examples of city fires to be referred are few and detailed investigations of city fires are limited. However, there have still been existing old cities where traditional houses built with flammable material such as wood, maybe historically important, only separated with very small open spacing. Fires may freely spread in those cities, once a big earthquake happens there and then water supply for the fire brigade is damaged in the worst case along with the effect of strong wind. There are some fundamental differences between the forest fires and city fires, as the fuel may distribute either continuously or discretely. For instance, in forest fires, the dead fallen leaves, dry grasses and trees are distributed continuously on the ground, while the wooden houses in cities are discretely distributed with some separation of open spacing, such as roads and gardens. Therefore, the wooden houses neighboring the burning houses with some separation are heated by radiation and flames to elevate the temperatures, thus causing the ignition, and finally reaching a large city fire. The authors have studied the forest fire spread and are planning to start a laboratory experiment of city fire spreading. In the preliminary investigation, a numerical study is made to correlate with the laboratory experiment of city fire propagation, utilizing the three-dimensional CFD simulations. Based on the detailed experimental analysis, the authors are attempting to modify the three dimensional CFD code to predict the forest fires and city fires more precisely, taking into account the thermal heating and ignition processes. In this study, some fundamental information on the city fire propagation has been obtained, particularly to know the safe open spacing distances between the houses in the cities and also the wind speed.


2020 ◽  
Author(s):  
Camilla Marie Jensen ◽  
Tobias Erhardt ◽  
Giulia Sinnl ◽  
Hubertus Fischer

<p>Ice sheets are reliable archives of atmospheric impurities such as aerosols and gasses of both natural and anthropogenic origin. Impurity records from Greenland ice cores reveal much information about previous atmospheric conditions and long-range transport in the Northern hemisphere going back more than a hundred thousand years.</p><p>Here we present the data from the upper 1,411 m from the EGRIP ice core, measuring conductivity, dust, sodium, calcium, ammonium, and nitrate. These records contain information about ocean sources, transport of terrestrial dust, soil and vegetation emissions as well as biomass burning, volcanic eruptions, etc., covering approximately the past 15,000 years. This newly obtained data set is unique as it provides the first high-resolution information about several thousands of years of the mid-Holocene period in Greenland that none of the previous impurity records from the other deep Greenland ice cores had managed to cover before due to brittle ice. This will contribute to further understanding of the atmospheric conditions for the pre-industrial period.</p><p>The ammonium record contains peaks significantly higher than the background level. These peaks are caused by biomass burning or forest fires emitting plumes of ammonia large enough so that they can extend to the free troposphere and be efficiently transported all the way to the Greenland ice sheet. Here we present preliminary results of the wild fire frequency covering the entire Holocene, where the wild fires are defined as outliers in the ammonium record of annual means.</p>


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