scholarly journals Modulation of the Occurrence of Heatwaves over the Euro-Mediterranean Region by the Intensity of the Atlantic Multidecadal Variability

2021 ◽  
Vol 34 (3) ◽  
pp. 1099-1114
Author(s):  
Saïd Qasmi ◽  
Emilia Sanchez-Gomez ◽  
Yohan Ruprich-Robert ◽  
Julien Boé ◽  
Christophe Cassou

AbstractThe influence of the Atlantic multidecadal variability (AMV) and its amplitude on the Euro-Mediterranean summer climate is studied in two climate models, namely CNRM-CM5 and EC-Earth3P. Large ensembles of idealized experiments have been conducted in which North Atlantic sea surface temperatures are relaxed toward different amplitudes of the observed AMV anomalies. In agreement with observations, during a positive phase of the AMV both models simulate an increase (decrease) in temperature of 0.2°–0.8°C and a decrease (increase) in precipitation over the Mediterranean basin of 0.1–0.2 mm day−1 (northern half of Europe) compared to a negative phase. Heatwave durations over the Mediterranean land regions are 40% (up to 85% over the eastern regions) longer for a moderate amplitude of the AMV. Lower and higher amplitudes lead to longer durations of ~30% and ~100%, respectively. A comparison with observed heatwaves indicates that the AMV can considerably modulate the current anthropogenically forced response on heatwaves durations depending on the area and on the AMV amplitude. The related anticyclonic anomalies over the Mediterranean basin are associated with drier soils and a reduction of cloud cover, which concomitantly induce a decrease (increase) of the latent (sensible) heat flux, and an enhancement of the downward radiative fluxes over lands. It is found that both tropical and extratropical forcings from the AMV are needed to trigger mechanisms, which modulate the atmospheric circulation over the Euro-Atlantic region. The amplitude of the local climate response over the Mediterranean basin evolves linearly with the amplitude of the AMV. However, the strength of this relationship differs between the models, and depends on their intrinsic biases.

2014 ◽  
Vol 14 (20) ◽  
pp. 11427-11446 ◽  
Author(s):  
P. Ricaud ◽  
B. Sič ◽  
L. El Amraoui ◽  
J.-L. Attié ◽  
R. Zbinden ◽  
...  

Abstract. The space and time variabilities of methane (CH4) total column and upper tropospheric mixing ratios are analysed above the Mediterranean Basin (MB) as part of the Chemical and Aerosol Mediterranean Experiment (ChArMEx) programme. Since the analysis of the mid-to-upper tropospheric CH4 distribution from spaceborne sensors and model outputs is challenging, we have adopted a climatological approach and have used a wide variety of data sets. We have combined spaceborne measurements from the Thermal And Near infrared Sensor for carbon Observations – Fourier Transform Spectrometer (TANSO-FTS) instrument on the Greenhouse gases Observing SATellite (GOSAT) satellite, the Atmospheric InfraRed Spectrometer (AIRS) on the AURA platform and the Infrared Atmospheric Sounder Interferometer (IASI) instrument aboard the MetOp-A platform with model results from the Chemical Transport Model (CTM) MOCAGE, and the Chemical Climate Models (CCMs) CNRM-AOCCM and LMDz-OR-INCA (according to different emission scenarios). In order to minimize systematic errors in the spaceborne measurements, we have only considered maritime pixels over the MB. The period of interest spans from 2008 to 2011 considering satellite and MOCAGE data and, regarding the CCMs, from 2001 to 2010. Although CH4 is a long-lived tracer with lifetime of ~12 years and is supposed to be well mixed in the troposphere, an east–west gradient in CH4 is observed and modelled in the mid-to-upper troposphere with a maximum in the Western MB in all seasons except in summer when CH4 accumulates above the Eastern MB. The peak-to-peak amplitude of the east–west seasonal variation in CH4 above the MB in the upper troposphere (300 hPa) is weak but almost twice as great in the satellite measurements (~25 ppbv) as in the model data (~15 ppbv). The maximum of CH4 in summer above the eastern MB can be explained by a series of dynamical processes only occurring in summer. The Asian monsoon traps and uplifts high amounts of CH4 to the upper troposphere where they build up. The Asian Monsoon Anticyclone redistributes these elevated CH4 amounts towards North Africa and the Middle East to finally reach and descend in the eastern MB. In the lower troposphere, the CH4 variability is mainly driven by the local sources of emission in the vicinity of the MB.


2020 ◽  
Author(s):  
Donato Summa ◽  
Fabio Madonna ◽  
Emanuele Tramutola ◽  
Fabrizio Marra ◽  
Benedetto De Rosa ◽  
...  

<p>The planetary boundary layer height (PBL) is a critical variable in many applications such as NWP, air quality and climate models. The study of the PBL involves several process and parameters: exchange of momentum, heat, water vapour and tracers from the surface to the free atmosphere therefore,  PBL representation in numerical  models is difficult to achieve and observation are used to improve the quality of the implemented parameterizations.</p><p>This presentation will illustrate a climatology of the height of the PBL and its trend since 1978 to present at different in the Mediterranean Basin.</p><p>The height of the PBL is calculated using the maximum vertical gradient of potential temperature  (θ) obtained from radio Station belonging to the IGRA (Integrated Global Radiosonde) archive related in the Europe Region) and to GRUAN network (GCOS Reference Upper Air Network).  </p><p>The IGRA consists of quality-controlled radiosonde observations of temperature, humidity, and wind at stations across all continents. The earliest year of data is 1905, and the data are updated on a daily basis. Record length, vertical extent and resolution, and availability of variables varies among stations and over time. The GRUAN is an international reference observing network of sites measuring essential climate variables above Earth's surface, designed to fill an important gap in the current global observing system. GRUAN measurements are providing long-term, high-quality climate data records from the surface, through the troposphere, and into the stratosphere. </p><p>An estimate of uncertainty will be also discussed and correlated with the recent climate changes at the global scale and in the Mediterranean Basin.</p>


Author(s):  
Joshua M. White

This book offers a comprehensive examination of the shape and impact of piracy in the eastern half of the Mediterranean and the Ottoman Empire’s administrative, legal, and diplomatic response. In the late sixteenth and seventeenth centuries, piracy had a tremendous effect on the formation of international law, the conduct of diplomacy, the articulation of Ottoman imperial and Islamic law, and their application in Ottoman courts. Piracy and Law draws on research in archives and libraries in Istanbul, Venice, Crete, London, and Paris to bring the Ottoman state and Ottoman victims into the story for the first time. It explains why piracy exploded after the 1570s and why the Ottoman state was largely unable to marshal an effective military solution even as it responded dynamically in the spheres of law and diplomacy. By focusing on the Ottoman victims, jurists, and officials who had to contend most with the consequences of piracy, Piracy and Law reveals a broader range of piratical practitioners than the Muslim and Catholic corsairs who have typically been the focus of study and considers their consequences for the Ottoman state and those who traveled through Ottoman waters. This book argues that what made the eastern half of the Mediterranean basin the Ottoman Mediterranean, more than sovereignty or naval supremacy—which was ephemeral—was that it was a legal space. The challenge of piracy helped to define its contours.


Author(s):  
Matthew D. C. Larsen

The concept of textual unfinishedness played a role in a wide variety of cultures and contexts across the Mediterranean basin in antiquity and late antiquity. Chapter 2 documents examples of Greek, Roman, and Jewish writers reflecting explicitly in their own words about unfinished texts. Many writers claimed to have written unfinished texts on purpose for specific cultural reasons, while others claimed to have written texts that slipped out of their hands somehow with their permission.


Author(s):  
Madadh Richey

The alphabet employed by the Phoenicians was the inheritor of a long tradition of alphabetic writing and was itself adapted for use throughout the Mediterranean basin by numerous populations speaking many languages. The present contribution traces the origins of the alphabet in Sinai and the Levant before discussing different alphabetic standardizations in Ugarit and Phoenician Tyre. The complex adaptation of the latter for representation of the Greek language is described in detail, then some brief attention is given to likely—Etruscan and other Italic alphabets—and possible (Iberian and Berber) descendants of the Phoenician alphabet. Finally, it is stressed that current research does not view the Phoenician and other alphabets as inherently simpler, more easily learned, or more democratic than other writing systems. The Phoenician alphabet remains, nevertheless, an impressive technological development worthy, especially by virtue of its generative power, of detailed study ranging from paleographic and orthographic specifications to social and political contextualization.


Insects ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 472
Author(s):  
Fabio Verneau ◽  
Mario Amato ◽  
Francesco La La Barbera

Starting in 2008 and lasting up until 2011, the crisis in agricultural and, in particular, cereal prices triggered a period of riots that spread from the Mediterranean basin to the rest of the world, reaching from Asia to Central America and the African continent. [...]


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