Skip to main content Accessibility help
×
Home

Contents:

Information:

  • Access
  • Cited by 5

Actions:

      • Send article to Kindle

        To send this article to your Kindle, first ensure no-reply@cambridge.org is added to your Approved Personal Document E-mail List under your Personal Document Settings on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part of your Kindle email address below. Find out more about sending to your Kindle. Find out more about sending to your Kindle.

        Note you can select to send to either the @free.kindle.com or @kindle.com variations. ‘@free.kindle.com’ emails are free but can only be sent to your device when it is connected to wi-fi. ‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.

        Find out more about the Kindle Personal Document Service.

        Recent accelerated shrinkage of Ürümqi glacier No. 1, Tien Shan, China
        Available formats
        ×

        Send article to Dropbox

        To send this article to your Dropbox account, please select one or more formats and confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your <service> account. Find out more about sending content to Dropbox.

        Recent accelerated shrinkage of Ürümqi glacier No. 1, Tien Shan, China
        Available formats
        ×

        Send article to Google Drive

        To send this article to your Google Drive account, please select one or more formats and confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your <service> account. Find out more about sending content to Google Drive.

        Recent accelerated shrinkage of Ürümqi glacier No. 1, Tien Shan, China
        Available formats
        ×
Export citation

The Editor,

Journal of Glaciology

Sir,

Glacier melting contributes to sea-level rise that could submerge highly populated coastal lowlands, and also has climatological and hydrological implications for the populations who depend on the meltwater, hence the importance of glacier monitoring. At present, continuous conventional measurements spanning more than 20 years exist for only about 40 glaciers worldwide (Dyurgerov and Meier, 1997). The only such glacier in China is Urumqi glacier No. 1 (UG1; 43°05 N, 86°49 E) at the source of the Uriimqi river, Tien Shan. Continuous and systematic measurements of mass balance, terminus position and areal extent commenced on UG1 in 1979. In addition, a hydrometeorological station (G1HS) (43º06′ N, 87º15′ E; 3693ma.s.l.) was established just 200 m from the glacier tongue. Temperature and precipitation observations at G1HS allow us to analyze the impact of climate change on this glacier. We report observations on this glacier, and analyze the causes of its recent behavior.

UG1 has shortened by about 90 m since 1980. Figure 1 presents the observed yearly terminus retreat rates over the past two decades. The retreat rate is clearly increasing. Linear regression through the data indicates a retreat acceleration of 0.073 m a-2 over the period 1980-2002. The cumulative retreat of the glacier reflects the trend in cumulative mass balance (Fig. 2) which is calculated based on more than 60 stake measurements extrapolated to the whole glacier area and updated every few years. This suggests the mass-balance variations are responsible for the accelerated retreat. The cumulative mass balance was -8747.5 mmw.e., equivalent to an ice volume loss of 1.73 × 107 m3 over the period 1979/80 to 2001/02. About 65% of the total ice- volume loss occurred during 1990/91 to 2001/02, ~51 % in the last 6 years (1996/97 to 2001/02).

Fig. 1. Yearly variations in the terminus of UG1at the source of the Urumqi river during the past two decades.

Fig. 2. Comparison between the variations of cumulative mass balance (filled circles) and the cumulative length change (open circles) of UG1 during the past two decades.

Maps of UG1 have been made at different times over the past two decades (You, 1988; Chen and others, 1996; personal communication from Chen Jianming and others, 2004). These maps are useful for investigating the changes in glacier area. Figure 3 shows glacier area as a function of time, indicating UG1 lost 0.149 km2 over the period 1980−2001, a decrease of ~8%, with rapid shrinkage during 1992−94. The average shrinkage rate after 1992, -0.014 km2 a, is about seven times greater than before 1992, ~0.002 km2 a-1.

Fig. 3. Changes in area of UG1 during the past two decades. The line with filled circles is the glacier area; the step line is the area change.

The critical link between glaciers and climate is glacier mass balance (Meier, 1965). Mass balance in a balance year is predominantly controlled by climatic conditions. We therefore examine climatic factors (temperature and precipitation) observed at G1HS and the mass-balance values measured on UG1 to determine the major causes of the glacier variations. Table 1 shows correlation coefficients (CC) between annual mass balance and precipitation within different periods of the balance year. There is no significant correlation, which implies that precipitation is not a major influence on the behavior of UG1. However, the annual mass balance is correlated (significant at 1%) with summer mean air temperature (see Table 2), suggesting summer temperatures are a major cause of the variation in mass balance. Although precipitation increased, the mass balance of UG1 has become more negative with summer warming during the past two decades (Fig. 4). The summer warming trend is 0.48°C (10 a)-1 at G1HS, but only 0.37°C (10 a)-1 at Ürümqi station (43°47′ N, 87°37′ E; 919ma.s.l.) over the period 1980−2000. Many studies have shown that the magnitude of change in temperature increases with elevation (Beniston and Rebetez, 1996; Aizen and others, 1997; Wang and others, 1999; Liu and Chen, 2000). Enhanced warming at high elevations impacts on the behavior of UG1 and other mountain glaciers.

Table 1. Correlation coefficients (calculated across the years) between annual mass balance of UG1 and precipitation measurements at G1HS during different months of the balance year (1979/1980 through 2001/2002)

Table 2. Correlation coefficients (calculated across theyears) between annual mass balance of UG1and air temperature measurements at G1HS during different months of the balanceyear (1979/1980 through 2001/2002)

Fig. 4. Comparisons of the variations in air temperature (a) and precipitation (b) measured at G1HS with the variations in mass balance of UG1 (c) during the past two decades. The lines with filled circles are yearly data series; the dashed lines are linear trends. The significance level of the linear trend is 1% for air temperature, 10% for mass balance and >10% for precipitation (i.e. an increasing trend in precipitation is weak).

Recently, mountain glaciers in other regions have also experienced accelerated shrinkage. Qori Kalis, the largest outlet glacier of the Quelccaya ice cap, Peru, retreated at a rate three times greater during the period 1983-91, and five times greater during the period 1993-95, than between 1963 and 1983 (Thompson, 2000). The volume changes of 67 glaciers in Alaska, U.S.A., have been studied using airborne laser altimetry, and it was found that the glacier thinning rate between the mid-1990s and 2000/01 (1.8 m a) was more than twice that between the mid-1950s and the mid-1990s (0.7 m a 1) (Arendt and others, 2002). Hielo Patagonico Norte and Sur (the northern and southern Patagonia ice fields), South America, lost ice at a rate of 16.7 ± 0.9 km3 a during the period 1968/1975−2000, and average ice-loss rates more than doubled to 41.9 ± 4.4 km3 a 1 in 1995-2000 (Rignot and others, 2003). The current worldwide shrinkage of glaciers should be considered a strong indication of global warming.

Acknowledgements

This research work is supported by the Chinese National Science Foundation (40121101), the Centuria Program and Innovation Research Projects (2003107, 2004102) of the CAREERI, Chinese Academy of Sciences, and Tien Shan Glaciological Station Foundation.

7 October 2004

References

Aizen, V. B., Aizen, E. M., Melack, J. M. and Dozier, J.. 1997. Climatic and hydrological change in the Tien Shan, central Asia. J. Climate, 10 (6), 1393-1404.
Arendt, A. A., Echelmeyer, Harrison, W.D., Lingleand, C. S. Valentine, V.B. 2002. Rapid wastage of Alaska glaciers and their contribution to rising sea level. Science, 297(5580), 382—336. (Tables and figures at http:\\www.sciencemag.org/cgi/content/full/297/5580/382/DC1.)
Beniston, M. and Rebetez, M.. 1996. Regional behaviour of minimum temperatures in Switzerland for the period 1979−1993. Theor. Appl. Climatol., 55(3/4), 231244.
Chen, J., Liu, C. and Jin, M. 1996. [Application of the repeated aerialphoto- grammetry to monitoring glacier variation in the drainage area of the Urumqi River] J Glaciol. Geocryol., 18 (4), 331336. [In Chinese with English summary]
Dyurgerov, M. B. and Meier, M. F.. 1997. Mass balance of mountain and subpolar glaciers: a new global assessment for 1961−1990. Arct. Alp. Res., 29(4), 379391.
Liu, X. and Chen, B.. 2000. Climatic warming in the Tibetan Plateau during recent decades. Int J. Climatol., 20(14), 17291742.
Meier, M. F. 1965. Glaciers and climate. In Wright, H. E. Jr and Frey, D. G., eds. The Quaternary of the United States. Princeton, NJ, Princeton University Press, 795805.
Rignot, E., Rivera, A. and Casassa, G. . 2003. Contribution of the Patagonian icefields of South America to sea level rise. Science, 302 (5644), 434437.
Thompson, L. G. 2000. Ice core evidence for climate change in the Tropics: implications for our future. Quat. Sci. Rev., 19(1−5), 1935.
Wang, N. and 6 others. 1999. On the magnitude of temperature decrease in the equatorial regions during the Last Glacial Maximum. Sci. China, Ser. D, 42(Suppl.),8090.
You, G. 1988. [Map of glacier no. 1 and glacier no. 2 at the source of Ürümqi River, Tien Shan] Xi’an Cartographic Publishing House. [In Chinese]