Identification of droughts and heatwaves in the Western Mediterranean, variability and impacts on vegetation and wildfires using the coupled ORCHIDEE-WRF regional model

2020 ◽  
Author(s):  
Antoine Guion ◽  
Solène Turquety ◽  
Jan Polcher ◽  
Romain Pennel ◽  
Lluis Fita
Keyword(s):  
Extreme Events ◽  
Regional Model ◽  
Western Mediterranean ◽  
Plant Phenology ◽  
Extreme Weather Events ◽  
Area Index ◽  
Fire Weather Index ◽  
Mitigation And Adaptation ◽  
Extreme High Temperature ◽  
The Impact

<p>In line with what is expected in a context of global warming, droughts and heatwaves have increased both in frequency and intensity over the last century. Severe wildfires and vegetation depletion can result from those extreme weather events with considerable economic, social and environmental damages.</p><p>For the development of mitigation and adaptation strategies, there is a need for exhaustive vulnerability assessments, including the impacts of droughts and heatwaves on the Mediterranean environment.</p><p>If heatwave characteristics are well documented, similar studies about droughts are partial. Most of them are focused on meteorological droughts while agronomical ones are more complex to identify.</p><p> </p><p>Using a coupled land surface–atmosphere regional model (ORCHIDEE-WRF) with the integration of plant phenology, we present an analysis of droughts and heatwaves occurring in the Western Mediterranean over the last 40 years. These extreme events are identified using two complementary methods: the Percentile Limit Anomalies (PLA) and the Standardized Precipitation Evapotranspiration Index (SPEI).</p><p>Impact assessment analysis show significant and dominant effect of droughts on plant phenology during summer. Evaluated using the Leaf Area Index (LAI), plant depletion can reach more than 50%. Response to drought depends on the vegetation type (long vs short root system) and biome (temperate vs semi-arid).</p><p>The impact of these extreme events on fire risk will be presented based on calculations of the wildfire meteorological risk (Fire Weather Index) and an analysis of the fire activity observed by the MODIS satellite instrument. We show that, even if extreme high temperature is the dominant cause, drought contributes to an increase of risk. Simultaneous heatwaves and droughts are the worst environmental conditions. The observed burned area can be <span>±</span>4 times greater than during non-extreme conditions and the fire duration <span>±</span>0.25 times longer.</p>

scholarly journals Droughts and heatwaves in the Western Mediterranean: impact on vegetation and wildfires using the coupled WRF-ORCHIDEE regional model (RegIPSL)

2021 ◽  
Author(s):  
Antoine Guion ◽  
Solène Turquety ◽  
Jan Polcher ◽  
Romain Pennel ◽  
Sophie Bastin ◽  
...  
Keyword(s):  
Extreme Events ◽  
Land Surface ◽  
Synergistic Effects ◽  
Regional Model ◽  
Western Mediterranean ◽  
Extreme Weather Events ◽  
Fuel Load ◽  
Burned Area ◽  
Area Index ◽  
The Impact

AbstractDroughts and heatwaves in the Mediterranean can induce plant activity decline and severe wildfires leading to considerable economic, social and environmental damages. This study aims at statistically quantifying the isolated and combined impacts of these extreme events based on a combination of regional land surface-atmosphere modeling and satellite observations of surface properties (MODIS). A simulation by the RegIPSL coupled regional model (ORCHIDEE-WRF) over the 1979–2016 period in the Western Mediterranean is used to identify heatwaves and droughts. After an evaluation of the model performance against surface observations of temperature and precipitation, a spatio-temporal analysis is conducted using specific indicators of extreme events: Percentile Limit Anomalies (PLA) and the Standardized Precipitation Evapotranspiration Index (SPEI). The impact on vegetation and wildfires is assessed using the MODIS observations of Leaf Area Index (LAI), burned area (BA) and fire radiative power (FRP), clustered by simulated extreme weather events. Due to water stress, droughts lead to significant biomass decrease (− 10$$\%$$ % LAI on average and reaching − 23$$\%$$ % in some areas). The isolated effect of heatwaves is smaller ($$\sim$$ ∼  − 3$$\%$$ % LAI) so that the combined effect is dominated by the impact of droughts. Heatwaves and droughts significantly exacerbate wildfire regimes. Through synergistic effects, simultaneous droughts and heatwaves increase BA and FRP by 2.1 and 2.9 times, respectively, compared to normal conditions. By reducing biomass, droughts slightly decrease fuel availability. However, our results show that the inter-annual variation in fire activity is mainly driven by weather conditions rather than fuel load.

scholarly journals A critical assessment of extreme events trends in times of global warming

2022 ◽  
Vol 137 (1) ◽  
Author(s):  
Gianluca Alimonti ◽  
Luigi Mariani ◽  
Franco Prodi ◽  
Renato Angelo Ricci
Keyword(s):  
Time Series ◽  
Extreme Events ◽  
Surface Wind ◽  
Extreme Weather Events ◽  
Global Changes ◽  
Positive Trend ◽  
Precipitation Frequency ◽  
Mitigation And Adaptation ◽  
The Impact ◽  
Response Indicators

AbstractThis article reviews recent bibliography on time series of some extreme weather events and related response indicators in order to understand whether an increase in intensity and/or frequency is detectable. The most robust global changes in climate extremes are found in yearly values of heatwaves (number of days, maximum duration and cumulated heat), while global trends in heatwave intensity are not significant. Daily precipitation intensity and extreme precipitation frequency are stationary in the main part of the weather stations. Trend analysis of the time series of tropical cyclones show a substantial temporal invariance and the same is true for tornadoes in the USA. At the same time, the impact of warming on surface wind speed remains unclear. The analysis is then extended to some global response indicators of extreme meteorological events, namely natural disasters, floods, droughts, ecosystem productivity and yields of the four main crops (maize, rice, soybean and wheat). None of these response indicators show a clear positive trend of extreme events. In conclusion on the basis of observational data, the climate crisis that, according to many sources, we are experiencing today, is not evident yet. It would be nevertheless extremely important to define mitigation and adaptation strategies that take into account current trends.

scholarly journals Advances in Modelling and Prediction on the Impact of Human Activities and Extreme Events on Environments

Water ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1768
Author(s):  
Matteo Rubinato ◽  
Min Luo ◽  
Xing Zheng ◽  
Jaan H. Pu ◽  
Songdong Shao
Keyword(s):  
Climate Change ◽  
Extreme Events ◽  
Human Activities ◽  
Health And Safety ◽  
Coastal Environments ◽  
Complex Flow ◽  
Mitigation And Adaptation ◽  
Wide Range ◽  
The Impact ◽  
Mountainous River

Fast urbanization and industrialization have progressively caused severe impacts on mountainous, river, and coastal environments, and have increased the risks for people living in these areas. Human activities have changed ecosystems hence it is important to determine ways to predict these consequences to enable the preservation and restoration of these key areas. Furthermore, extreme events attributed to climate change are becoming more frequent, aggravating the entire scenario and introducing ulterior uncertainties on the accurate and efficient management of these areas to protect the environment as well as the health and safety of people. In actual fact, climate change is altering rain patterns and causing extreme heat, as well as inducing other weather mutations. All these lead to more frequent natural disasters such as flood events, erosions, and the contamination and spreading of pollutants. Therefore, efforts need to be devoted to investigate the underlying causes, and to identify feasible mitigation and adaptation strategies to reduce negative impacts on both the environment and citizens. To contribute towards this aim, the selected papers in this Special Issue covered a wide range of issues that are mainly relevant to: (i) the numerical and experimental characterization of complex flow conditions under specific circumstances induced by the natural hazards; (ii) the effect of climate change on the hydrological processes in mountainous, river, and coastal environments, (iii) the protection of ecosystems and the restoration of areas damaged by the effects of climate change and human activities.

scholarly journals Human–Environment Natural Disasters Interconnection in China: A Review

Climate ◽  
2020 ◽  
Vol 8 (4) ◽  
pp. 48 ◽  
Author(s):  
Rawshan Ali ◽  
Alban Kuriqi ◽  
Ozgur Kisi
Keyword(s):  
Extreme Events ◽  
Extreme Weather ◽  
Mitigation Measures ◽  
Extreme Weather Events ◽  
Quantitative Review ◽  
Human Environment ◽  
Critical Studies ◽  
Weather Events ◽  
The Impact ◽  
Financial Losses

This study aimed to assess the interrelationship among extreme natural events and their impacts on environments and humans through a systematic and quantitative review based on the up-to-date scientific literature. Namely, the main goal was to add additional knowledge to the existing evidence of the impacts related to floods, droughts, and landslides on humans and the environment in China; this in order to identify knowledge gaps in research and practice to aid in improving the adaptation and mitigation measures against extreme natural events in China. In this study, 110 documents were analyzed in the evaluation of several impacts triggered by extreme events. Records were obtained from Scopus and Web of Science and examined with a text mining instrument to assess the pattern of publications over the years; the problems linked to extreme weather events were investigated, and the study gaps were discussed. This paper extends work by systematically reviewing recent evidence related to floods, droughts, and landslides in China. We listed the critical studies that focused on the impact of extreme events on both humans and the environment described in current reviews. The findings revealed that goods safety, social safety, and financial losses are of significant concern to the scientific community due to extreme natural events, which from our analysis resulted in being more frequent and intense. It is still underdeveloped to implement distant sensing and imaging methods to monitor and detect the impact of severe weather occurrences. There are still significant study gaps in the fields of the effects of extreme weather events. The analysis result shows that extreme events are increased during the time, so more in-depth investigation and efforts on adaptation, mitigation measures, and strategical governance plans are desperately required.

scholarly journals From Atmospheric Waves to Heatwaves: A Waveguide Perspective for Understanding and Predicting Concurrent, Persistent and Extreme Extratropical Weather

2021 ◽  
pp. 1-35
Author(s):  
Rachel H. White ◽  
Kai Kornhuber ◽  
Olivia Martius ◽  
Volkmar Wirth
Keyword(s):  
Climate Change ◽  
Extreme Events ◽  
Rossby Waves ◽  
Extreme Weather Events ◽  
Atmospheric Conditions ◽  
Weather Extremes ◽  
Weather Events ◽  
Circulation Patterns ◽  
Surface Weather ◽  
The Impact

AbstractA notable number of high impact weather extremes have occurred in recent years, often associated with persistent, strongly meandering atmospheric circulation patterns known as Rossby waves. Because of the high societal and ecosystem impacts, it is of great interest to be able to accurately project how such extreme events will change with climate change, and to predict these events on seasonal to subseasonal (S2S) timescales. There are multiple physical links connecting upper atmosphere circulation patterns to surface weather extremes, and it is asking a lot of our dynamical models to accurately simulate all of these. Subsequently, our confidence in future projections and S2S forecasts of extreme events connected to Rossby waves remains relatively low. We also lack full fundamental theories for the growth and propagation of Rossby waves on the spatial and temporal scales relevant to extreme events, particularly under strongly non-linear conditions. By focussing on one of the first links in the chain from upper atmospheric conditions to surface extremes -- the Rossby waveguide -- it may be possible to circumvent some model biases in later links. To further our understanding of the nature of waveguides, links to persistent surface weather events and their representation in models, we recommend: exploring these links in model hierarchies of increasing complexity, developing fundamental theory, exploiting novel large ensemble data sets, harnessing deep learning, and increased community collaboration. This would help increase understanding and confidence in both S2S predictions of extremes and of projections of the impact of climate change on extreme weather events.

Forest management and hotter droughts: tree-growth monitoring during 2018/2019 in northeastern Germany

2021 ◽  
Author(s):  
Roberto Cruz-García ◽  
Leona Frieboese ◽  
Tobias Scharnweber ◽  
Ilse Alejandra Siller-Aguillón ◽  
Johannes Kalbe ◽  
...  
Keyword(s):  
Climate Change ◽  
Tree Growth ◽  
Extreme Events ◽  
Service Providers ◽  
Extreme Weather Events ◽  
Growth Monitoring ◽  
Data Set ◽  
Management Interventions ◽  
Northeastern Germany ◽  
The Impact

<p> Forests are vital ecosystem service providers and are thought to play an important role as carbon sinks in climate-warming mitigation. Climate change can modify environmental forcing of tree growth, bringing changes in growth performance and ultimately in ecosystem community composition. Thus, studying how trees and forests react to a changing environment is required to preserve and manage them sustainably. It is largely unexplored how extreme weather events, such as the so called “hotter-droughts”, interact with silvicultural interventions (thinning). To address this problem, we explore a monitoring data set from 2017-2020 of three broadleaved species native to the Central European temperate forest (<em>Fagus sylvatica</em> L., <em>Quercus robur</em> L., <em>Betula pendula</em> Roth). To investigate the effect of thinning interventions and weather conditions on intra-annual growth, an experimental gap was created at the end of 2016 in the studied stands. Trees standing next to the gap and others on closed-stand conditions were equipped with band-dendrometers, which were read out bi-weekly throughout the four vegetation periods. The obtained growth-curves were used to compare absolute and relative growth between experimental conditions (gap vs. closed), and non-linear models were fitted to derive the phenology of stem-growth. In general, trees under gap conditions revealed smaller increments than trees in closed stands during the drought years 2018/2019, but especially for 2019. Species differences indicate beech was most sensitive to the extreme summer drought, as expected given the conclusions of several dendroecological studies. The results indicate different sensitivities to extreme events on the years following silvicultural interventions between tree species. As gap-formation occurs also naturally in temperate forests, these results suggest a possible mechanism through which legacy-effects and variability in individual climate responses arise, which can help unravel climatic signals in tree-rings and explain how they are modulated by ecological conditions and management interventions. Monitoring of tree-growth in a high-temporal resolution seems a valuable approach to understand the impact of extreme events and climate change on tree-growth. The obtained insights are relevant for improving sustainable silvicultural management, as the suitability of a species for a site might change upon further warming and more frequent drought spells. We recommend continuing to explore tree-growth at finer time-scales to shed light on species performance under climate change.</p>

scholarly journals Sea extreme events during the last millennium in north-east of Morocco

2014 ◽  
Vol 2 (3) ◽  
pp. 2079-2102 ◽  
Author(s):  
O. Raji ◽  
L. Dezileau ◽  
U. Von Grafenstein ◽  
S. Niazi ◽  
M. Snoussi ◽  
...  
Keyword(s):  
Extreme Events ◽  
Coastal Lagoon ◽  
Western Mediterranean ◽  
Mediterranean Coast ◽  
Extreme Weather Events ◽  
Geochemical Data ◽  
Last Millennium ◽  
North East ◽  
Weather Events ◽  
Storm Deposits

Abstract. The Moroccan Mediterranean coast is located in one of the most vulnerable area to extreme weather events or tsunami hazards. The objective of this research is to reconstruct the historical extreme submersion-events record using sea-induced deposits preserved in coastal lagoon. The Nador lagoon is the largest Moroccan lagoon (115 km2) located along the Western Mediterranean which presents a high cyclogenetic character and is exposed to tsunamis from Alboran Sea. The sandy barrier which separates the lagoon from the Mediterranean Sea is marked by many overwashes, which indicate how intensely has been exposed to the adverse sea events through history. Using the UWITEC coring platform, an undisturbed MC4.5 core (1.15 m long) was successfully sampled in the studied lagoon. To identify sea extreme events, a multi-proxy approach was applied combining sedimentogical and geochemical data. The preliminary results show that the identified paleo-events are concentrated over the last 500 years. The challenge that remains now is to distinguish between the tsunami and the storm deposits.

Impact of Extreme Events on Transportation Infrastructure in Iowa: A Bayesian Network Approach

2018 ◽  
Vol 2672 (48) ◽  
pp. 45-57 ◽  
Author(s):  
Abhijit R. Kulkarni ◽  
Behrouz Shafei
Keyword(s):  
Extreme Events ◽  
Bayesian Belief Networks ◽  
Extreme Weather ◽  
Transportation Infrastructure ◽  
Sensitivity Analyses ◽  
Extreme Weather Events ◽  
Economic Losses ◽  
Climate Projections ◽  
Weather Events ◽  
The Impact

Iowa’s roadway network is an important part of the state’s transportation infrastructure and plays a critical role in the functionality and economic development of the entire state. This network primarily consists of three interstate highways that pass through Iowa, connecting it to the neighboring states and eventually Canada. Various businesses are located near this roadway network and rely on it for everyday operation. In recent years, however, the growth of agricultural and biofuel industries has intensified the demand on the roads and bridges in Iowa. The state’s roads and bridges have also witnessed a number of flooding events, which have caused extensive traffic disruptions and economic losses. Thus, it is imperative to develop a fundamental approach to evaluate the impact of extreme events on the transportation infrastructure of Iowa and other similar states. Towards this goal, the current study investigates the existing condition of Iowa’s transportation infrastructure, possibility of occurrence of extreme weather events, and scenarios that may lead to the failure of transportation infrastructure components. For this purpose, the capabilities of Bayesian belief networks are utilized to quantify the effects of extreme precipitation and extreme temperature on the performance of transportation infrastructure and then predict the probability of damage to roads and bridges. This will be achieved through the identification of the most influential factors using a set of sensitivity analyses, assessment of overall vulnerability with evidence-based propagation analyses, and quantification of response to extreme weather events, taking into consideration climate projections.

Chasing the phantom: biogeography and conservation of Vipera latastei-monticola in the Maghreb (North Africa)

2018 ◽  
Vol 39 (2) ◽  
pp. 145-161 ◽  
Author(s):  
Inês Freitas ◽  
Soumia Fahd ◽  
Guillermo Velo-Antón ◽  
Fernando Martínez-Freiría
Keyword(s):  
North Africa ◽  
Habitat Degradation ◽  
Conservation Status ◽  
Western Mediterranean ◽  
Niche Modelling ◽  
Habitat Transformation ◽  
Mountain Ranges ◽  
Management Actions ◽  
Suitable Space ◽  
The Impact

Abstract The Maghreb region (North Africa) constitutes a major component of the Mediterranean Basin biodiversity hotspot. During the last centuries, a consistent human population growth has led to an unprecedented rate of habitat transformation and loss in the region and thus, threatening its biodiversity. The Western Mediterranean viper Vipera latastei-monticola inhabits humid and subhumid areas in the main mountain ranges of the Maghreb, facing such threatening factors; however, its elusive character and rarity hindered data collection for distinct biological purposes. Here, we study the biogeographical patterns and conservation status of the Maghrebian V. latastei-monticola resulting from recent sampling campaigns in Morocco and Tunisia. We update species distribution, and integrate phylogeographic and ecological niche modelling analyses at both species and lineage level to identify suitable areas, and to evaluate the impact of anthropogenic transformation and level of protection of their suitable space. We identified four highly divergent mitochondrial lineages, including a new lineage endemic to the Western High Atlas, with allopatric distributions and restricted to mountain ranges, supporting the role of mountains as past climatic refugia. Despite the remoteness of suitable areas, we report widespread habitat degradation and identify the low effectiveness of the current protected areas system in preserving the species and lineages range. Our study shows the urgent need to apply management actions for the long-term conservation of this vulnerable species and suggests a revaluation of the specific status of V. monticola, as these populations likely represent an ecotype of V. latastei.

scholarly journals Urban Heat Islands and Thermal Comfort: A Case Study of Zorrotzaurre Island in Bilbao

2021 ◽  
Vol 13 (11) ◽  
pp. 6106
Author(s):  
Irantzu Alvarez ◽  
Laura Quesada-Ganuza ◽  
Estibaliz Briz ◽  
Leire Garmendia
Keyword(s):  
Thermal Comfort ◽  
Heat Waves ◽  
Urban Environments ◽  
Urban Heat Islands ◽  
Extreme Weather Events ◽  
Climate Index ◽  
Physiological Equivalent Temperature ◽  
Heat Islands ◽  
The North ◽  
The Impact

This study assesses the impact of a heat wave on the thermal comfort of an unconstructed area: the North Zone of the Island of Zorrotzaurre (Bilbao, Spain). In this study, the impact of urban planning as proposed in the master plan on thermal comfort is modeled using the ENVI-met program. Likewise, the question of whether the urbanistic proposals are designed to create more resilient urban environments is analyzed in the face of increasingly frequent extreme weather events, especially heat waves. The study is centered on the analysis of temperature variables (air temperature and average radiant temperature) as well as wind speed and relative humidity. This was completed with the parameters of thermal comfort, the physiological equivalent temperature (PET) and the Universal Temperature Climate Index (UTCI) for the hours of the maximum and minimum daily temperatures. The results demonstrated the viability of analyzing thermal comfort through simulations with the ENVI-met program in order to analyze the behavior of urban spaces in various climate scenarios.

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