Extension of summer climatic conditions into spring in the Western Mediterranean area

Abstract

From a local point of view, in May/June, there is an important and positive 2 m temperature trend at Palma (Mallorca), which is simultaneous and highly correlated with a strong increase in the 500 hPa geopotential height. This study analyses this fact as well as the observed tendencies in a wider seasonal and geographical context. We confirm the particularly high correlation between 2 m temperature and 500 hPa geopotential during the warm months as opposed to the much weaker correlation in winter. This suggests that mechanisms for thermal changes act differently throughout the year in this region. Besides the direct radiative effect, warm season near‐surface temperatures are linked to the presence of deep anticyclones, which effectively determine the northern edge of the Hadley cell. Accordingly, the strong warming trend in the area of Palma during the warm months of the year is purportedly related to the poleward extension of the Hadley cell. The fact that May/June shows the highest low‐level temperature trend among all bi‐monthly series is a common regional feature over a relatively wide area over the Western Mediterranean. Different geographical patterns emerge in other periods of the year. In July/August, the strongest low‐level warming area drifts to the east‐northeast, towards Ukraine and Russia. Coincidentally, the 500 hPa geopotential tendencies show a coherent pattern, with an intense positive trend ridge over the Western Mediterranean area in May/June, and a displacement of this ridge to the north‐east in July/August. We show the connection between 500 hPa geopotential height and near‐surface temperature by means of a multiple lineal regression that attributes half of the local temperature tendency in Palma to the intensification of a 500 hPa ridge centred over the Western Mediterranean and surroundings.

Spatio-temporal responses of butterflies to global warming on a Mediterranean island over two decades

“…Likewise, warming is not homogeneous throughout the year and in the Mediterranean region the greatest contribution to annual warming occurs in the transition from spring to summer (Garcia, 2015). There is also strong evidence to suggest that summer seasons in the Mediterranean are becoming longer (Bartolini et al ., 2012; Jansà et al ., 2017). In this sense, despite the short climatic period analysed in our study, warming trends (with respect to maximum temperatures) were observed in April, September and December, and also marginally in May.…”

“…Although all five sites were used to define the overall phenology of the species on the island, we only used three with 15–18 years of data for comparisons: (1) Albufera des Grau, an open coastal area with dry meadows and Mediterranean scrub; (2) Santa Catalina, a forested area dominated by evergreen oak and pine forests; and (3) Barranc d’Algendar, a ravine in the south of the island with orchards at the beginning and thick undergrowth further inland. Although the climate is typically Mediterranean throughout the island, with hot-dry summers and mild-wet winters (Jansà et al, 2017), the geomorphology of its ravines generates moister microclimatic conditions that set Barranc d’Algendar apart from the other studied localities.…”

Spatio‐temporal responses of butterflies to global warming on a Mediterranean island over two decades

“…Although all five sites were used to define the overall phenology of the species on the island, we only used three with 15–18 years of data for comparisons: (1) Albufera des Grau, an open coastal area with dry meadows and Mediterranean scrub; (2) Santa Catalina, a forested area dominated by evergreen oak and pine forests; and (3) Barranc d'Algendar, a ravine in the south of the island with orchards at the beginning and thick undergrowth further inland. Although the climate is typically Mediterranean throughout the island, with hot‐dry summers and mild‐wet winters (Jansà et al ., 2017), the geomorphology of its ravines generates moister microclimatic conditions in Barranc d'Algendar.…”

Predictable and Unpredictable Climate Variability Impacts on Optimal Renewable Energy Mixes: The Example of Spain

“…Within Europe, the Mediterranean is an area especially susceptible to some aspects of climate change [7], and has had significantly greater consequences from some of its effects. For instance, the warming effect is stronger in the Mediterranean region [8], as well as unevenly distributed within the months of the year [9]. The United Nations Environment Programme (UNEP) [10] states that there is a need for an investment in renewable energy sources and an increase in their efficiency in the Mediterranean region, due to the need for an equilibrium in the use of food, water and energy.…”