scholarly journals Old World megadroughts and pluvials during the Common Era

2015 ◽  
Vol 1 (10) ◽  
pp. e1500561 ◽  
Author(s):  
Edward R. Cook ◽  
Richard Seager ◽  
Yochanan Kushnir ◽  
Keith R. Briffa ◽  
Ulf Büntgen ◽  
...  
Keyword(s):  
Mediterranean Basin ◽  
Climate Model ◽  
Internal Variability ◽  
Climate Projections ◽  
Severe Drought ◽  
Old World ◽  
The Common ◽  
The Mediterranean ◽  
Common Era ◽  
The Mediterranean Basin

Climate model projections suggest widespread drying in the Mediterranean Basin and wetting in Fennoscandia in the coming decades largely as a consequence of greenhouse gas forcing of climate. To place these and other “Old World” climate projections into historical perspective based on more complete estimates of natural hydroclimatic variability, we have developed the “Old World Drought Atlas” (OWDA), a set of year-to-year maps of tree-ring reconstructed summer wetness and dryness over Europe and the Mediterranean Basin during the Common Era. The OWDA matches historical accounts of severe drought and wetness with a spatial completeness not previously available. In addition, megadroughts reconstructed over north-central Europe in the 11th and mid-15th centuries reinforce other evidence from North America and Asia that droughts were more severe, extensive, and prolonged over Northern Hemisphere land areas before the 20th century, with an inadequate understanding of their causes. The OWDA provides new data to determine the causes of Old World drought and wetness and attribute past climate variability to forced and/or internal variability.

scholarly journals Dust emission size distribution impact on aerosol budget and radiative forcing over the Mediterranean region: a regional climate model approach

2012 ◽  
Vol 12 (21) ◽  
pp. 10545-10567 ◽  
Author(s):  
P. Nabat ◽  
F. Solmon ◽  
M. Mallet ◽  
J. F. Kok ◽  
S. Somot
Keyword(s):  
Size Distribution ◽  
Radiative Forcing ◽  
Mediterranean Basin ◽  
Climate Model ◽  
Regional Climate ◽  
Dust Emission ◽  
Dust Deposition ◽  
The Mediterranean ◽  
Dust Distribution ◽  
The Mediterranean Basin

Abstract. The present study investigates the dust emission and load over the Mediterranean basin using the coupled chemistry–aerosol–regional climate model RegCM-4. The first step of this work focuses on dust particle emission size distribution modeling. We compare a parameterization in which the emission is based on the individual kinetic energy of the aggregates striking the surface to a recent parameterization based on an analogy with the fragmentation of brittle materials. The main difference between the two dust schemes concerns the mass proportion of fine aerosol that is reduced in the case of the new dust parameterization, with consequences for optical properties. At the episodic scale, comparisons between RegCM-4 simulations, satellite and ground-based data show a clear improvement using the new dust distribution in terms of aerosol optical depth (AOD) values and geographic gradients. These results are confirmed at the seasonal scale for the investigated year 2008. This change of dust distribution has sensitive impacts on the simulated regional dust budget, notably dry dust deposition and the regional direct aerosol radiative forcing over the Mediterranean basin. In particular, we find that the new size distribution produces a higher dust deposition flux, and smaller top of atmosphere (TOA) dust radiative cooling. A multi-annual simulation is finally carried out using the new dust distribution over the period 2000–2009. The average SW radiative forcing over the Mediterranean Sea reaches −13.6 W m−2 at the surface, and −5.5 W m−2 at TOA. The LW radiative forcing is positive over the basin: 1.7 W m−2 on average over the Mediterranean Sea at the surface, and 0.6 W m−2 at TOA.

scholarly journals Tracing historical introductions in the Mediterranean Basin: the success story of the common genet (Genetta genetta) in Europe

2015 ◽  
Vol 17 (6) ◽  
pp. 1897-1913 ◽  
Author(s):  
Philippe Gaubert ◽  
Irene Del Cerro ◽  
Alejandro Centeno-Cuadros ◽  
Francisco Palomares ◽  
Pascal Fournier ◽  
...  
Keyword(s):  
Mediterranean Basin ◽  
Success Story ◽  
Genetta Genetta ◽  
The Common ◽  
The Mediterranean ◽  
The Mediterranean Basin

scholarly journals Future changes in surface ozone over the Mediterranean basin in the framework of the Chemistry-Aerosol Mediterranean Experiment (ChArMEx)

2017 ◽  
Author(s):  
Nizar Jaidan ◽  
Laaziz El Amraoui ◽  
Jean-Luc Attié ◽  
Philippe Ricaud ◽  
François Dulac
Keyword(s):  
Atmospheric Chemistry ◽  
Mediterranean Basin ◽  
Climate Model ◽  
Surface Ozone ◽  
Future Climate Change ◽  
Ensemble Mean ◽  
The Future ◽  
The Mediterranean ◽  
Surface O3 ◽  
The Mediterranean Basin

Abstract. In the framework of the Chemistry and Aerosol Mediterranean Experiment project (ChArMEx, http://charmex.lsce.ipsl.fr), we study the evolution of surface ozone (O3) over the Mediterranean Basin (MB) with a focus on summertime over the time period 2000–2100, using the Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP) outputs from 11 models. We consider three different periods (2000, 2030 and 2100) and the four Representative Concentration Pathways (RCP2.6, RCP4.5, RCP6.0 and RCP8.5) to study the changes in the future ozone trend and its budget. We use a statistical approach to compare and discuss the results of the models. We discuss the behavior of the models that simulate the surface O3 over the MB. The ensemble mean of ACCMIP models simulates very well the annual cycle of surface O3. Compared to measured summer surface O3 datasets, we found that most of the models overestimate surface O3 and underestimate its variability over the most recent period (1990–2010) when independent observations are available. Compared to the reference period (2000), we found a net decrease in the ensemble mean surface O3 over the MB in 2030 (2100) for 3 RCPs: −13 % (−36 %) for RCP2.6, −7 % (−22 %) for RCP4.5 and −11 % (−33 %) for RCP6.0. The surface O3 decrease over the MB for these scenarios is much more pronounced than the relative changes of the tropospheric ozone burden. This is mainly due to the reduction in O3 precursors and to the NOx-limited regime over the MB. For the RCP8.5, the ensemble mean surface O3 is almost constant over the MB from 2000 to 2100. We show how the future climate change and the increase in CH4 concentrations can offset the benefit of the reduction in emissions of O3 precursors over the MB.

Introduction

2020 ◽  
pp. 1-18
Author(s):  
Andrew W. Devereux
Keyword(s):  
Sixteenth Century ◽  
Early Modern ◽  
Mediterranean Basin ◽  
Spanish Empire ◽  
The West ◽  
Old World ◽  
The Caribbean ◽  
The Mediterranean ◽  
Overseas Expansion ◽  
The Mediterranean Basin

This chapter examines the Spanish expansion into the Mediterranean basin during the fifteenth and sixteenth centuries, as the monarchy sought to forge a multicontinental empire at the heart of the Old World. It talks about the fact that the early modern Spanish Empire is often thought of as an Atlantic empire, one that arose as a result of the Castilian colonies of the Caribbean and, later, the American mainland. It also provides a reminder that during the early decades of overseas expansion, Spain looked to the east as much as it did to the west. The chapter seeks to address historical discrepancies by analyzing arguments that fifteenth- and sixteenth-century Spaniards developed in order to justify acts of war and conquest in the context of the Mediterranean. It connects Spain's Mediterranean imperial project to its Atlantic corollary, reviewing the ways in which the Mediterranean experience sometimes informed and influenced Spanish arguments justifying war and conquest in the Americas.

scholarly journals Dust emission size distribution impact on aerosol budget and radiative forcing over the Mediterranean region: a regional climate model approach

2012 ◽  
Vol 12 (7) ◽  
pp. 17835-17886 ◽  
Author(s):  
P. Nabat ◽  
F. Solmon ◽  
M. Mallet ◽  
J. F. Kok ◽  
S. Somot
Keyword(s):  
Size Distribution ◽  
Radiative Forcing ◽  
Mediterranean Basin ◽  
Climate Model ◽  
Regional Climate ◽  
Dust Emission ◽  
Dust Deposition ◽  
The Mediterranean ◽  
Dust Distribution ◽  
The Mediterranean Basin

Abstract. The present study investigates the dust emission and load over the Mediterranean basin using the coupled-chemistry-aerosol regional climate model RegCM-4. The first step of this work focuses on dust particle emission size distribution modeling. We compare a parameterization in which the emission is based on the individual kinetic energy of the aggregates striking the surface to a recent parameterization based on an analogy with the fragmentation of brittle materials. The main difference between the two dust schemes concerns the mass proportion of fine aerosol which is reduced in the case of the new dust parameterization, with consequences for optical properties. At the episodic scale, comparisons between RegCM-4 simulations, satellite and ground-based data show a clear improvement using the new dust distribution in terms of Aerosol Optical Depth (AOD) values and geographic gradients. These results are confirmed at the seasonal scale for the investigated year 2008. A multi-annual simulation is finally carried out using the new dust distribution over the period 2000–2009. This change of dust distribution has sensitive impacts on the simulated regional dust budget, notably dry dust deposition and the regional direct aerosol radiative forcing over the Mediterranean basin. This could clearly modify the possible effects of dust aerosols on the biogeochemical activity and climate of the Mediterranean basin. In particular, we find that the new size distribution produces a higher dust deposition flux, and smaller top of atmosphere (TOA) dust radiative cooling.

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