Environmental Engineering Reference
In-Depth Information
Figure 9.3 The evolution of the SPEI (Standardized Precipitation Evapotranspiration Index) in
each of the six mountain ranges, obtained from the average climate series in each mountainous
region. A falling trend in SPEI is observed in all regions, and this is most apparent and sustained
in the Pyrenees, Apennines and the Atlas
In summary, Mediterranean mountains will become significantly warmer and
drier during this century, with the western Mediterranean mountains suffering the
greatest decreases in moisture conditions.
9.3 Cryosphere changes in the Mediterranean mountains
Warming temperatures and a generalized tendency to lower precipitation has led to
consistent changes in snowfall and the snowpack extent in mountainous Mediter-
ranean areas, although this trend is not specific to Mediterranean mountains. For
example, Marty (2008) found a marked decrease in snow accumulation in the
Alps during the last two decades, separated from previous accumulation values
by an abrupt change that occurred around 1980. A decrease since the 1940s in
the duration of snow cover has been reported for the Iberian Peninsula (Sanz-
Elorza et al., 2003), and in the Spanish Pyrenees. Lopez-Moreno (2005) showed
a clear trend of decrease from 1950 to 2000, associated with a fall in precipi-
tation and atmospheric circulation changes, during February and March (Lopez-
Moreno and Vicente-Serrano, 2007). Changes in snowpack have been noticeably
greater at low altitudes as a consequence of the rising of the 0 C isotherm (Beniston
et al., 2003).
Warmer temperatures and reduced snow accumulation during winter and spring
have caused a marked retreat of glaciers in the Mediterranean region. Smaller
glaciers in the Apennines and Pyrenees have retreated dramatically and they
Search WWH ::




Custom Search