图尔盖—阿克苏河谷近数百年冰川作用和气候变化研究

Research on Glaciers and Climate Fluctuation in Turgen-Asu Valley, Terskey Ata-Too Range

根据树木年轮和对冰碛物系列的地衣测年资料恢复了图尔盖-阿克苏河谷近380年的气候变化曲线。在利用树木年轮资料和地农测年资料重建曲线时,既考虑了生物本身生长规律和气候因子的影响作用,又参考了冰碛物系列的特征。把重建曲线与现代气象台站的实际观测资料进行了对比并对重建曲线进行了较正。研究表明,近几百年来降水存在着明显的波动,峰值在1670,1720,1750,1770—1790和1830年左右,从19世纪60年代至今,降水量直线减少,冰川面积总的趋势在缩小。

Reconstruction of Turgen-Aksu valley glacial history and precipitation regime is made using methods of moraine lichenometry and dendroindication. Cores of Picea Shrenkiniana were sampled at the upper forests line at the height about 2 900 m. After the correlation analysis of ring-width indices and meteoparametrs obtained on meteostation Krasny Oktiabr we decided the precipitation to be the limiting factor of Picea growth. Equations of line regression for year and cold period precipitation and row of ring-width indices (mean for 5 trees) were calculated using 5-year smoothing of data. Then the year amounts of precipitation for the period 1600-1983 were calculated according to the equation. Coefficient of correlation between row of ring-width indices and observational data on meteostation Krasny Oktiabr 0.83. Another part of this paper is devoted to the moraine age indication. The following forms of licheons were used for evaluation of the moraine age of three glaciers in Turgen-Aksu value Caloplaca elegans, Placonlecanora muralis, Aspicilia sp., Rhizocarpon geographicum. All the moranies were formed in the XIX-XX centuries, the previous didn't survive. According to the reconstruction, the most moist period of recent 380 years was from the end of XVII to the end of XVIII century. The maximums precipitation occurred in the decades of 1670-th, 1720-th, 1750-th, 1770-1990-th, and 1830-th. One of the strongest glacier's advance which occurred in the latest of these periods had left its traces in the moraine. Periods of high precipitation in the XX century also coincide with periods of glaciers advance. That's why we make a proposal that advances of glaciers in this region were occurring during all of the main maximums of reconstructed precipitations, even in the case we don't find moraine as their trace.