Drought-triggered false ring formation in a Mediterranean shrub

Botany ◽  
2010 ◽  
Vol 88 (6) ◽  
pp. 545-555 ◽  
Author(s):  
Carolyn A. Copenheaver ◽  
Holger Gärtner ◽  
Isabelle Schäfer ◽  
Francesco P. Vaccari ◽  
Paolo Cherubini
Keyword(s):  
Mediterranean Region ◽  
Growth Response ◽  
Climate Models ◽  
Ring Formation ◽  
False Rings ◽  
Mediterranean Plants ◽  
Average Rainfall ◽  
The Mediterranean ◽  
Mesic Site ◽  
Mediterranean Shrub

Recently, the Mediterranean region has experienced unprecedented drought. Climate models continue to predict an increase in drought frequency and duration, which increases the importance of quantifying the response of already drought-tolerant Mediterranean plants to increased drought. We examined the wood anatomy and dendroecological features of a Mediterranean shrub, Arbutus unedo L., at a xeric and a mesic site on the Italian island of Elba to identify shrub growth response to drought. Cross-sectional microsections of A. unedo stems were stained, described, and crossdated. Annual ring widths of radial microsections were measured and compared with regional climatic variables. False rings (intra-annual bands of latewood typically formed in response to a specific stressor) were visible in the wood samples when viewing radial microsections under high magnification. False ring formation coincided with below-average rainfall in late summer at the xeric site, and below-average rainfall and high temperatures in spring and summer at the mesic site. If increased drought occurs in the Mediterranean region, it is likely that plants in this region will experience a drought-induced growth response similar to that seen in A. unedo, and slight differences in drought tolerance may become more important as plants compete for moisture under drier conditions.

scholarly journals Seasonal predictability of Mediterranean weather regimes in the Copernicus C3S systems

2021 ◽  
Author(s):  
Ignazio Giuntoli ◽  
Federico Fabiano ◽  
Susanna Corti
Keyword(s):  
Mediterranean Region ◽  
Climate Models ◽  
Reanalysis Data ◽  
Seasonal Predictability ◽  
Economic Implications ◽  
Weather Regimes ◽  
Weather Patterns ◽  
The Mediterranean ◽  
Good Agreement

AbstractSeasonal predictions in the Mediterranean region have relevant socio-economic implications, especially in the context of a changing climate. To date, sources of predictability have not been sufficiently investigated at the seasonal scale in this region. To fill this gap, we explore sources of predictability using a weather regimes (WRs) framework. The role of WRs in influencing regional weather patterns in the climate state has generated interest in assessing the ability of climate models to reproduce them. We identify four Mediterranean WRs for the winter (DJF) season and explore their sources of predictability looking at teleconnections with sea surface temperature (SST). In particular, we assess how SST anomalies affect the WRs frequencies during winter focussing on the two WRs that are associated with the teleconnections in which the signal is more intense: the Meridional and the Anticyclonic regimes. These sources of predictability are sought in five state-of-the-art seasonal forecasting systems included in the Copernicus Climate Change Services (C3S) suite finding a weaker signal but an overall good agreement with reanalysis data. Finally, we assess the ability of the C3S models in reproducing the reanalysis data WRs frequencies finding that their moderate skill increases during ENSO intense years, indicating that this teleconnection is well reproduced by the models and yields improved predictability in the Mediterranean region.

scholarly journals Post-processing of seasonal predictions – Case studies using the EUROSIP hindcast data base

2019 ◽  
Author(s):  
Emmanuel Roulin ◽  
Stéphane Vannitsem
Keyword(s):  
Case Studies ◽  
Mediterranean Region ◽  
Climate Models ◽  
Processing Method ◽  
Post Processing ◽  
Model Combination ◽  
Spring Temperature ◽  
Skill Scores ◽  
The Mediterranean ◽  
The Impact

Abstract. Seasonal predictions from climate models are increasingly invoked in various sectors like water management, energy and transport to cite a few. This study investigates the post-processing of the seasonal predictions of the EUROSIP multi-model system. The hindcasts comprise samples of 23 to 36 years and ensembles of 10 to 28 members depending on the 5 models included. Skill scores both deterministic and probabilistic are calculated in order to compare the impact of the post-processing and help selecting – if any – the multi- or single-model and the post-processing method best suited for a specific location, target season and lead-time. The presence of trends and the cross-validation setting add some complexity to the already heterogeneous database. This study focuses on six cases in Western Europe and the Mediterranean Region. The forecasts of three monthly averages of surface temperature and of sea mean sea level pressure are compared with the corresponding ERA Interim reanalysis data whereas the forecasts of precipitation are evaluated with the rain-gauge data from the Global Precipitation Climatology Centre. The skills of seasonal predictions in the extra-tropics are limited and our results are no exception. There is a significant skill for the spring temperature forecast with model initiation in March for all but one case studies and the skill is extending to the initiation begin of February for Belgium. There is is also a significant skill for the summer temperature for the case studies in the Mediterranean region. For these area, the skill comes in large part from the global warming so that after having de-trended the data, a null improvement cannot be excluded. Autumn temperature in UK and in the Turkey is forecast with some skill as well as winter temperature in UK and Greece. Precipitation is even more difficult to forecast: the two spots where skill scores are significantly positive are Sweden and Greece during winter with initialisation on the first December. It has been shown that multi-model ensemble improve the skills in many cases and that taking into account the longest common period of hindcasts results in better and less uncertain skill scores. For all these cases, the post-processing method and the model or model combination resulting in the best skill score have been selected.

scholarly journals Seasonal predictability of Mediterranean Weather Regimes in the Copernicus C3S Systems

2021 ◽  
Author(s):  
Ignazio Giuntoli ◽  
Federico Fabiano ◽  
Susanna Corti
Keyword(s):  
Mediterranean Region ◽  
Climate Models ◽  
Reanalysis Data ◽  
Seasonal Predictability ◽  
Economic Implications ◽  
Weather Regimes ◽  
Weather Patterns ◽  
The Mediterranean ◽  
Good Agreement

<p>Seasonal predictions in the Mediterranean region have relevant socio-economic implications, especially in the context of a changing climate. To date, sources of predictability have not been sufficiently investigated at the seasonal scale in this region. To fill this gap, we explore sources of predictability using a weather regimes (WRs) framework. The role of WRs in influencing regional weather patterns in the climate state has generated interest in assessing the ability of climate models to reproduce them.</p><p>We identify four Mediterranean WRs for the winter (DJF) season and explore their sources of predictability looking at teleconnections with sea surface<br>temperature (SST). In particular, we assess how SST anomalies affect the WRs frequencies during winter focussing on the two WRs that are associated with the teleconnections in which the signal is more intense: the Meridional and the Anticyclonic regimes . These sources of predictability are sought in five state-of-the-art seasonal forecasting systems included in the Copernicus Climate Change Services (C3S) suite finding a weaker signal but an overall good agreement with reanalysis data. Finally, we assess the ability of the C3S models in reproducing the reanalysis data WRs frequencies finding that their moderate skill improves during ENSO intense years, indicating that this teleconnection is well reproduced by the models and yields improved predictability in the Mediterranean region.</p>

scholarly journals Regional climate models' performance in representing precipitation and temperature over selected Mediterranean areas

2013 ◽  
Vol 17 (12) ◽  
pp. 5041-5059 ◽  
Author(s):  
R. Deidda ◽  
M. Marrocu ◽  
G. Caroletti ◽  
G. Pusceddu ◽  
A. Langousis ◽  
...  
Keyword(s):  
Climate Change ◽  
Mediterranean Region ◽  
Climate Models ◽  
Hydrological Modeling ◽  
Regional Climate ◽  
Regional Climate Models ◽  
Data Set ◽  
The Mediterranean ◽  
Ensembles Project ◽  
The Eu

Abstract. This paper discusses the relative performance of several climate models in providing reliable forcing for hydrological modeling in six representative catchments in the Mediterranean region. We consider 14 Regional Climate Models (RCMs), from the EU-FP6 ENSEMBLES project, run for the A1B emission scenario on a common 0.22° (about 24 km) rotated grid over Europe and the Mediterranean region. In the validation period (1951 to 2010) we consider daily precipitation and surface temperatures from the observed data fields (E-OBS) data set, available from the ENSEMBLES project and the data providers in the ECA&D project. Our primary objective is to rank the 14 RCMs for each catchment and select the four best-performing ones to use as common forcing for hydrological models in the six Mediterranean basins considered in the EU-FP7 CLIMB project. Using a common suite of four RCMs for all studied catchments reduces the (epistemic) uncertainty when evaluating trends and climate change impacts in the 21st century. We present and discuss the validation setting, as well as the obtained results and, in some detail, the difficulties we experienced when processing the data. In doing so we also provide useful information and advice for researchers not directly involved in climate modeling, but interested in the use of climate model outputs for hydrological modeling and, more generally, climate change impact studies in the Mediterranean region.

Existing areas and past changes of wetland extent in the Mediterranean region: an overview

2012 ◽  
Vol 38 (2) ◽  
pp. 53-66 ◽  
Author(s):  
Christian Perennou ◽  
Coralie Beltrame ◽  
Anis Guelmami ◽  
Pere Tomàs Vives ◽  
Pierre Caessteker
Keyword(s):  
Mediterranean Region ◽  
Wetland Extent ◽  
The Mediterranean

Spatial Distribution of Pre-Warm Front Rainfall in the Mediterranean Area

1988 ◽  
Vol 19 (1) ◽  
pp. 53-64 ◽  
Author(s):  
C. Corradini ◽  
F. Melone
Keyword(s):  
Mediterranean Area ◽  
Compact Structure ◽  
Large Variability ◽  
Air Mass ◽  
Orographic Effects ◽  
Warm Front ◽  
Average Rainfall ◽  
Convective Motions ◽  
Rainfall Type ◽  
The Mediterranean

Evidence is given of the distribution of pre-warm front rainfall at the meso-γ scale, together with a discussion of the main mechanisms producing this variability. An inland region in the Mediterranean area is considered. The selected rainfall type is commonly considered the most regular inasmuch as it is usually unaffected by extended convective motions. Despite this, within a storm a large variability in space was observed. For 90% of measurements, the typical deviations from the area-average total depth ranged from - 40 to 60 % and the storm ensemble-average rainfall rate over an hilly zone was 60 % greater than that in a contiguous low-land zone generally placed upwind. This variability is largely explained in terms of forced uplift of air mass over an envelope type orography. For a few storms smaller orographic effects were found in locations influenced by an orography with higher slopes and elevations. This feature is ascribed to the compact structure of these mountains which probably determines a deflection of air mass in the boundary layer. The importance of this type of analysis in the hydrological practice is also emphasized.

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