scholarly journals Changes in the future summer Mediterranean climate: contribution of teleconnections and local factors

2020 ◽  
Vol 11 (1) ◽  
pp. 161-181 ◽  
Author(s):  
Monika J. Barcikowska ◽  
Sarah B. Kapnick ◽  
Lakshmi Krishnamurty ◽  
Simone Russo ◽  
Annalisa Cherchi ◽  
...  
Keyword(s):  
North Atlantic ◽  
Land Surface ◽  
Arid Regions ◽  
Local Maximum ◽  
Central Mediterranean ◽  
Temperature And Precipitation ◽  
Southern Mediterranean ◽  
Regional Temperature ◽  
Simulated Climate

Abstract. This study analyzes future climate for the Mediterranean region projected with the high-resolution coupled CM2.5 model, which incorporates a new and improved land model (LM3). The simulated climate changes suggest pronounced warming and drying over most of the region. However, the changes are distinctly smaller than those of the CMIP5 multi-model ensemble. In addition, the changes over much of southeast and central Europe indicate very modest warming compared to the CMIP5 projections and also a tendency toward wetter conditions. These differences indicate a possible role of factors such as land surface–atmospheric interactions in these regions. Our analysis also highlights the importance of correctly projecting the magnitude of changes in the summer North Atlantic Oscillation, which has the capacity to partly offset anthropogenic warming and drying over the western and central Mediterranean. Nevertheless, the projections suggest a decreasing influence of local atmospheric dynamics and teleconnections in maintaining the regional temperature and precipitation balance, in particular over arid regions like the eastern and southern Mediterranean, which show a local maximum of warming and drying. The intensification of the heat low in these regions rather suggests an increasing influence of warming land surface on the local surface atmospheric circulation and progressing desertification.

scholarly journals Shortwave forcing and feedbacks in Last Glacial Maximum and Mid-Holocene PMIP3 simulations

2015 ◽  
Vol 373 (2054) ◽  
pp. 20140424 ◽  
Author(s):  
Pascale Braconnot ◽  
Masa Kageyama
Keyword(s):  
Last Glacial Maximum ◽  
Land Surface ◽  
Relative Strength ◽  
Glacial Maximum ◽  
Climate Feedbacks ◽  
Vegetation Feedback ◽  
Last Glacial ◽  
Model Biases ◽  
Simulated Climate

Simulations of the climates of the Last Glacial Maximum (LGM), 21 000 years ago, and of the Mid-Holocene (MH), 6000 years ago, allow an analysis of climate feedbacks in climate states that are radically different from today. The analyses of cloud and surface albedo feedbacks show that the shortwave cloud feedback is a major driver of differences between model results. Similar behaviours appear when comparing the LGM and MH simulated changes, highlighting the fingerprint of model physics. Even though the different feedbacks show similarities between the different climate periods, the fact that their relative strength differs from one climate to the other prevents a direct comparison of past and future climate sensitivity. The land-surface feedback also shows large disparities among models even though they all produce positive sea-ice and snow feedbacks. Models have very different sensitivities when considering the vegetation feedback. This feedback has a regional pattern that differs significantly between models and depends on their level of complexity and model biases. Analyses of the MH climate in two versions of the IPSL model provide further indication on the possibilities to assess the role of model biases and model physics on simulated climate changes using past climates for which observations can be used to assess the model results.

scholarly journals Rebound in Atmospheric Predictability and the Role of the Land Surface

2012 ◽  
Vol 25 (13) ◽  
pp. 4744-4749 ◽  
Author(s):  
Zhichang Guo ◽  
Paul A. Dirmeyer ◽  
Timothy DelSole ◽  
Randal D. Koster
Keyword(s):  
Soil Moisture ◽  
North America ◽  
Air Temperature ◽  
Land Surface ◽  
Early Spring ◽  
Late Spring ◽  
Temperature And Precipitation ◽  
Atmospheric Predictability ◽  
Earth’S Climate

Abstract Total predictability within a chaotic system like the earth’s climate cannot increase over time. However, it can be transferred between subsystems. Predictability of air temperature and precipitation in numerical model forecasts over North America rebounds during late spring to summer because of information stored in the land surface. Specifically, soil moisture anomalies can persist over several months, but this memory cannot affect the atmosphere during early spring because of a lack of coupling between land and atmosphere. Coupling becomes established in late spring, enabling the effects of soil moisture anomalies to increase atmospheric predictability in 2-month forecasts begun as early as 1 May. This predictability is maintained through summer and then drops as coupling fades again in fall. This finding suggests summer forecasts of rainfall and air temperature over parts of North America could be significantly improved with soil moisture observations during spring.

Rescuing Migrants in the Central Mediterranean: The Emergence of a New Civil Humanitarianism at the Maritime Border

2019 ◽  
Vol 64 (4) ◽  
pp. 436-455
Author(s):  
Marta Esperti
Keyword(s):  
Civil Society ◽  
Research Methodology ◽  
Search And Rescue ◽  
International Organization ◽  
Central Mediterranean ◽  
The Social ◽  
Social Meanings ◽  
Humanitarian Space ◽  
First Arrival

The Central Mediterranean is the most deadly body of water in the Mediterranean Sea with at least 15,062 fatalities recorded by International Organization of Migration between 2014 and 2018. This article aims at highlighting the rise of a variety of new civil society actors engaged in the rescue of people undertaking dangerous journeys across the sea in the attempt of reaching the southern European shores. The peculiarity of the humanitarian space at sea and its political relevance are pointed out to illustrate the unfolding of the maritime border management on the Central Mediterranean route and its relation with the activity of the civil society rescue vessels. The theoretical aspiration of the article is to question the role of a proactive civil humanitarianism at sea, discussing the emergence of different political and social meanings around humanitarianism at the EU’s southern maritime border. In recent years, the increasing presence of new citizens-based organizations at sea challenges the nexus between humanitarian and emergency approaches adopted to implement security-oriented policies. This essay draws on the findings of a broader comparative work on a variety of civil society actors engaged in the search and rescue operations on the maritime route between Libya and Europe, focusing in particular on Italy as country of first arrival. The fieldwork covers a period of time going between 2016 and 2018. The research methodology is built on a multisited ethnography, the conduct of semidirective and informal interviews with both state and nonstate actors, and the analysis of various reports unraveling the social and political tensions around rescue at sea on the Central Mediterranean route.

Role of Land-Surface Changes in Arctic Summer Warming

Science ◽  
2005 ◽  
Vol 310 (5748) ◽  
pp. 657-660 ◽  
Author(s):  
F. S. Chapin
Keyword(s):  
Land Surface ◽  
Summer Warming ◽  
Arctic Summer ◽  
Surface Changes

scholarly journals Using hydraulic head, chloride and electrical conductivity data to distinguish between mountain-front and mountain-block recharge to basin aquifers

2018 ◽  
Vol 22 (2) ◽  
pp. 1629-1648 ◽  
Author(s):  
Etienne Bresciani ◽  
Roger H. Cranswick ◽  
Eddie W. Banks ◽  
Jordi Batlle-Aguilar ◽  
Peter G. Cook ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Arid Regions ◽  
South Australia ◽  
Hydraulic Head ◽  
Mountain Front ◽  
Quaternary Aquifers ◽  
Groundwater Systems ◽  
Flow Directions ◽  
Electrical Conductivity Data

Abstract. Numerous basin aquifers in arid and semi-arid regions of the world derive a significant portion of their recharge from adjacent mountains. Such recharge can effectively occur through either stream infiltration in the mountain-front zone (mountain-front recharge, MFR) or subsurface flow from the mountain (mountain-block recharge, MBR). While a thorough understanding of recharge mechanisms is critical for conceptualizing and managing groundwater systems, distinguishing between MFR and MBR is difficult. We present an approach that uses hydraulic head, chloride and electrical conductivity (EC) data to distinguish between MFR and MBR. These variables are inexpensive to measure, and may be readily available from hydrogeological databases in many cases. Hydraulic heads can provide information on groundwater flow directions and stream–aquifer interactions, while chloride concentrations and EC values can be used to distinguish between different water sources if these have a distinct signature. Such information can provide evidence for the occurrence or absence of MFR and MBR. This approach is tested through application to the Adelaide Plains basin, South Australia. The recharge mechanisms of this basin have long been debated, in part due to difficulties in understanding the hydraulic role of faults. Both hydraulic head and chloride (equivalently, EC) data consistently suggest that streams are gaining in the adjacent Mount Lofty Ranges and losing when entering the basin. Moreover, the data indicate that not only the Quaternary aquifers but also the deeper Tertiary aquifers are recharged through MFR and not MBR. It is expected that this finding will have a significant impact on the management of water resources in the region. This study demonstrates the relevance of using hydraulic head, chloride and EC data to distinguish between MFR and MBR.

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