2001-2010 glacier changes in the Central Karakoram National Park: a contribution to evaluate the magnitude and rate of the "Karakoram anomaly"

Abstract. Karakoram is one of the most glacierized region worldwide, and glaciers therein are the main water resource of Pakistan. The attention paid to this area is increasing, because the evolution of its glaciers recently depicted a situation of general stability, known as "Karakoram Anomaly", in contrast to glacier retreat worldwide. Here we focused our attention upon the glacier evolution within the Central Karakoram National Park (CKNP, a newborn park of this region, ca. 12 162 km2 in area) to assess the magnitude and rate of such anomaly. By means of Remote Sensing data (i.e.: Landsat images), we analyzed a sample of more than 700 glaciers, and we found out their area change between 2001 and 2010 is not significant (+27 km2 ± 42 km2), thus confirming their stationarity. We analyzed climate data, snow coverage from MODIS, and supraglacial debris presence, as well as potential (con-) causes. We found a slight decrease of summer temperatures (down to −1.5 °C during 1980–2009) and an increase of wet days during winter (up +3.3 days yr−1 during 1980–2009), possibly increasing snow cover duration, consistently with MODIS data. We further detected considerable supra-glacial debris coverage (ca. 20% of the glacier area which rose up to 31% considering only the ablation area), which could have reduced buried ice melting during the last decade. These results provide further ground to uphold the existence of the Karakoram Anomaly, and present an useful template for assessment of water availability within the glaciers of the CKNP.