Snow-Cover Area and Runoff Variation under Climate Change in the West Kunlun Mountains

Abstract

In recent years, the climate in the arid region of Northwest China has become warmer and wetter; however, glaciers in the north slope of the West Kunlun Mountains (NSWKM) show no obvious recession, and river flow is decreasing or stable. This contrasts with the prevalent response of glaciers to climate change, which is recession and initial increase in glacier discharge followed by decline as retreat continues. We comparatively analyzed multi-timescale variation in temperature–precipitation–snow cover-runoff in the Yarkant River Basin (YRK), Karakax River Basin (KRK), Yurungkax River Basin (YUK), and Keriya River Basin (KRY) in the NSWKM. The Mann–Kendall trend and the mutation–detection method were applied to data obtained from an observation station over the last 60 years (1957–2017) and MODIS snow data (2001–2016). NSWKM temperature and precipitation have continued to increase for nearly 60 years at a mean rate of 0.26 °C/decade and 5.50 mm/decade, respectively, with the most obvious trend (R2 > 0.82) attributed to the KRK and YUK. Regarding changes in the average snow-cover fraction (SCF): YUK (SCF = 44.14%) > YRK (SCF = 38.73%) > KRY (SCF = 33.42%) > KRK (SCF = 33.40%). Between them, the YRK and YUK had decreasing SCA values (slope < −15.39), while the KRK and KRY had increasing SCA values (slope > 1.87). In seasonal variation, the SCF of the three of the basins reaches the maximum value in spring, with the most significant performance in YUK (SCF = 26.4%), except for YRK where SCF in spring was lower than that in winter (−2.6%). The runoff depth of all river basins presented an increasing trend, with the greatest value appearing in the YRK (5.78 mm/decade), and the least value in the YUK (1.58 mm/decade). With the runoff response to climate change, temperature was the main influencing factor of annual and monthly (summer) runoff variations in the YRK, which is consistent with the runoff-generation rule of rivers in arid areas, which mainly rely on ice and snow melt for water supply. However, this rule was not consistent for the YUK and KRK, as it was disturbed by other factors (e.g., slope and slope direction) during runoff generation, resulting in disruptions of their relationship with runoff. This research promotes the study of the response of cold and arid alpine regions to global change and thus better serve regional water resources management.

Possible Causes of Anomalous Glacier Mass Balance in the Western Kunlun Mountains

“…Guliya adjoins the upstream of the Keriya River, whose water is mainly derived from glacier meltwater from the eastern part of the WKM and precipitation in the Keriya River basin (Ma et al., 2019). Therefore, annual precipitation and glacier meltwater at Guliya are likely to be related to the runoff of the Keriya River.…”

“… (a) The measured and modeled annual glacier‐wide mass balances and modeled seasonal glacier‐wide mass balances for Guliya; (b) seasonal glacier‐wide snowfall on Guliya and ablation‐season air temperature at AWS2 site; (c) modeled glacier‐wide meltwater for Guliya in this work and measured runoff depth at Keriya Hydrological Station obtained from Ma et al. (2019); and (d) modeled and geodetic mean glacier‐wide mass balance for different periods for Guliya, expect for Zhou et al. (2018)'s result.…”

Spatio-Temporal Variation Characteristics of Snow Depth and Snow Cover Days over the Tibetan Plateau

“…As glaciers shrink, permanent snow cover decreases and lake water levels rise [89]. Therefore, monitoring the dynamic changes of snow cover over TP is helpful to provide an important scientific basis for regional water resources management and disaster prevention and control [90].…”

Cryosphere Water Resources Simulation and Service Function Evaluation in the Shiyang River Basin of Northwest China

“…Snow cover has shown a small increase trend in the WCRC between 1951 and 1997 [7]. These changes will definitely affect the water cycle and yearly runoff variation in the cold alpine watershed [8][9][10][11][12]. An increase or decrease in river basin runoff will have an important impact on river basin water resources planning, management, and sustainable use.…”