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

Abstract

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.

Future Hydrological Regimes in the Upper Indus Basin: A Case Study from a High-Altitude Glacierized Catchment

“…Scientists in the area of glaciology put forward the concept of the Karakoram anomaly to emphasize the difference between substantially unchanged snow and ice cover and glacier stability in the central Karakoram and the general shrinking of eastern Himalayan glaciers in the last few decades (Hewitt 2005;Kääb et al 2012;Bocchiola and Diolaiuti 2013;Gardelle et al 2012;Minora et al 2013). Our simulations for the control period displayed no significant changes in snow or ice cover, ice depth, or instream discharges (not shown), which substantiates the hypothesis of stable behavior underpinning the Karakoram anomaly.…”

“…Topography is represented here by a digital elevation model (DEM), with 30-m spatial resolution, derived from the ASTER mission (JPL 2014) and used to define altitude belts and local weather variables against altitude. Glaciers boundaries from Minora et al (2013) were used.…”

“…An overall decreasing trend in summer mean and minimum temperatures and an increasing trend in winter precipitation in recent decades have been derived from stations in the upper Indus basin (Archer and Fowler 2004;Bocchiola and Diolaiuti 2013), partly explaining the observed stability or thickening of some Karakoram glaciers, as well as the reduced runoff measured by gauging stations in heavily glacierized catchments of the area (e.g., in the Hunza basin ;Hewitt 2005;Archer 2003;Sharif et al 2013). Furthermore, this behavior might be a consequence of the generally high elevation of glaciers' bodies in this area and of the shielding effect of debris coverage and snow layer (also from avalanches) above the glaciers, combined with a possible increase in orographic precipitation leading to the largest accumulation (Scherler et al 2011a;Minora et al 2013).…”

“…The mountain range of the Hindu Kush, Karakoram, and Himalayas (HKH), known as the ''third pole'' of our planet (e.g., Smiraglia et al 2007;Kehrwald et al 2008;Minora et al 2013), contains a large amount of glacier ice, delivering water for agriculture, drinking, and power production. According to recent estimates, more than 50% of the water flowing in the upper Indus basin, in northern Pakistan, is due to snow and ice melt (Immerzeel et al 2010).…”

“…The glacier mass balance budget in the Karakoram positively affected the 2003-08 specific mass balance for the entire HKH region, which was estimated by Kääb et al (2012) into 20.21 6 0.05 m yr 21 of water equivalent. In particular, some studies discuss the expansion and thickening of the largest glaciers, mainly in the central Karakoram, since the 1990s, accompanied by a nonnegligible number of rapid glacier advances (i.e., surge-type phenomena; see, e.g., Diolaiuti et al 2003;Hewitt 2005;Barrand and Murray 2006;Mayer et al 2011;Copland et al 2011;Minora et al 2013).…”