全球变化知识资源中心

We here investigated the recent (1976-2014) evolution of the Ararat mountain glaciers, paradigmatic of the evolution of ice bodies in Western Asia and the Caucasus. We gathered ice cover maps, including debris cover from different sources, to depict glaciers' extension, and its variation under recent climate patterns. We then gathered data of (daily/monthly) weather variables (temperature, precipitation, snow cover depth) from two local stations managed by Turkish State Meteorological Service, which we subsequently analyzed to assess the presence of significant trends. We used the recently developed, weather-driven glaciological model Poly-Ice, able to mimic distributed ice and snow melt, mass budget, and gravity-driven ice flow of glaciers, to reproduce recent evolution of the Ararat ice bodies. We found a measurable decrease of the area (-2.38km(2), -30% of the initial area, -0.06km(2)year(-1)) of the Ararat glaciers, including loss of ice under debris covered tongue (-1.99km(2), -70% of the initial area), driven by significantly increasing temperature especially in spring (+0.05 degrees Cyear(-1)). Using our Poly-Ice model, we could (i) mechanistically reproduce the response of the glaciers to the changing climate patterns, (ii) confirm faster downwasting ever since the 1990s under increasing temperature, and (iii) highlight decreased winter snow cover at thaw at the highest altitudes ever since the 1990s, further driving ice melt. Such physically based tool will further allow to project forward the dynamics of these glaciers under future climate. Our results are fully consistent with the present know how of glaciers' retreat from Europe to Caucasus, and Central and Southern Asia, and contribute to the ongoing discussion about retreating glaciers worldwide.