Abstract | Studies on recent climate trends from the Himalayan
range are limited, and even completely absent at
high elevation ( >5000ma.s.l.). This study specifically explores
the southern slopes of Mt. Everest, analyzing the
time series of temperature and precipitation reconstructed
from seven stations located between 2660 and 5600ma.s.l.
during 1994-2013, complemented with the data from all
existing ground weather stations located on both sides of
the mountain range (Koshi Basin) over the same period.
Overall we find that the main and most significant increase
in temperature is concentrated outside of the monsoon period.
Above 5000ma.s.l. the increasing trend in the time
series of minimum temperature (C0.072 C yr?1) is much
stronger than of maximum temperature (C0.009 C yr?1),
while the mean temperature increased by C0.044 C yr?1.
Moreover, we note a substantial liquid precipitation weakening
(?9.3mmyr?1) during the monsoon season. The annual
rate of decrease in precipitation at higher elevations is
similar to the one at lower elevations on the southern side
of the Koshi Basin, but the drier conditions of this remote
environment make the fractional loss much more consistent
(?47% during the monsoon period). Our results challenge
the assumptions on whether temperature or precipitation is
the main driver of recent glacier mass changes in the region.
The main implications are the following: (1) the negaive
mass balances of glaciers observed in this region can be
more ascribed to a decrease in accumulation (snowfall) than
to an increase in surface melting; (2) the melting has only
been favoured during winter and spring months and close
to the glaciers terminus; (3) a decrease in the probability
of snowfall (?10 %) has made a significant impact only at
glacier ablation zone, but the magnitude of this decrease is
distinctly lower than the observed decrease in precipitation;
(4) the decrease in accumulation could have caused the observed
decrease in glacier flow velocity and the current stagnation
of glacier termini, which in turn could have produced
more melting under the debris glacier cover, leading to the
formation of numerous supraglacial and proglacial lakes that
have characterized the region in the last decades. |
Authors | Salerno F., Guyennon N., Thakuri S., Viviano G., Romano E., Vuillermoz E., Cristofanelli P., Stocchi P., Agrillo G., Ma Y., Tartari G. |
Text | 340154 2015 10.5194/tc 9 1229 2015 Scopus 2 s2.0 84935035490 ISI Web of Science WOS WOS 000360659200015 climate change; hymalaia; temperature trend Weak precipitation, warm winters and springs impact glaciers of south slopes of Mt. Everest central Himalaya in the last two decades 1994 2013 Salerno F., Guyennon N., Thakuri S., Viviano G., Romano E., Vuillermoz E., Cristofanelli P., Stocchi P., Agrillo G., Ma Y., Tartari G. National Research Council, Water Research Institute, Brugherio IRSA CNR , Italy; National Research Council, Water Research Institute, Roma IRSA CNR , Italy; National Research Council, Institute of Atmospheric Sciences and Climate ISAC CNR Bologna, Italy; Ev K2 CNR Committee, Via San Bernardino, 145, Bergamo 24126, Italy; Institute of Tibetan Plateau Research, Chinese Academy of Science, Beijing, China; Studies on recent climate trends from the Himalayan range are limited, and even completely absent at high elevation >5000ma.s.l. . This study specifically explores the southern slopes of Mt. Everest, analyzing the time series of temperature and precipitation reconstructed from seven stations located between 2660 and 5600ma.s.l. during 1994 2013, complemented with the data from all existing ground weather stations located on both sides of the mountain range Koshi Basin over the same period. Overall we find that the main and most significant increase in temperature is concentrated outside of the monsoon period. Above 5000ma.s.l. the increasing trend in the time series of minimum temperature C0.072 C yr 1 is much stronger than of maximum temperature C0.009 C yr 1 , while the mean temperature increased by C0.044 C yr 1. Moreover, we note a substantial liquid precipitation weakening 9.3mmyr 1 during the monsoon season. The annual rate of decrease in precipitation at higher elevations is similar to the one at lower elevations on the southern side of the Koshi Basin, but the drier conditions of this remote environment make the fractional loss much more consistent 47% during the monsoon period . Our results challenge the assumptions on whether temperature or precipitation is the main driver of recent glacier mass changes in the region. The main implications are the following 1 the negaive mass balances of glaciers observed in this region can be more ascribed to a decrease in accumulation snowfall than to an increase in surface melting; 2 the melting has only been favoured during winter and spring months and close to the glaciers terminus; 3 a decrease in the probability of snowfall 10 % has made a significant impact only at glacier ablation zone, but the magnitude of this decrease is distinctly lower than the observed decrease in precipitation; 4 the decrease in accumulation could have caused the observed decrease in glacier flow velocity and the current stagnation of glacier termini, which in turn could have produced more melting under the debris glacier cover, leading to the formation of numerous supraglacial and proglacial lakes that have characterized the region in the last decades. 9 Published version https //www.scopus.com/record/display.uri eid=2 s2.0 84935035490 origin=resultslist 28/05/2015 Weak precipitation, warm winters and springs impact glaciers of south slopes of Mt. Everest central Himalaya in the last two decades 1994 2013 Studies on recent climate trends from the Himalayan range are limited, and even completely absent at high elevation >5000ma.s.l. . This study specifically explores the southern slopes of Mt. Everest, analyzing the time series of temperature and precipitation reconstructed from seven stations located between 2660 and 5600ma.s.l. during 1994 2013 salerno et al 2015.PDF Articolo in rivista Copernicus Publ. 1994 0424 The cryosphere Online The cryosphere Online Cryosphere Online The cryosphere. Online TC Gottingen. Online Online franco.salerno SALERNO FRANCO emanuele.romano ROMANO EMANUELE nicolasdominique.guyennon GUYENNON NICOLAS DOMINIQUE gaetano.viviano VIVIANO GAETANO gianni.tartari TARTARI GIANNI TA.P02.031.001 Impatto dei cambiamenti climatici sulla gestione delle risorse idriche |