摘要
2005年使用花杆法在小冬克玛底冰川上进行了两轮积雪融化观测,结果显示:6月中、下旬,冰川区积雪消融基本与气温同步变化,但到7月上旬积雪消融发生了变化:其融化时间提前了2 h,在12:00融化量就达到一定高度;融化量大,日平均融化量较6月中下旬大0.71 mm水当量;最大积雪融化量出现时间滞后于气温最高时间约2 h,于18:00达到最大值.雪坑雪层剖面真实记录了积雪积累与融化过程中的雪层变化.积雪融化除受温度影响之外,还与风速等其它因素有密切关系.温度越高,融化量越大;风速与积雪融化量的关系相对复杂.积雪融化量只与1.5 m高度风速有关.在2h尺度上,近地面风速大,积雪融化量也大;在日尺度上,风速与积雪融化量的关系较好,但在两个观测时段表现出不同的相关关系.研究区积雪量很少,受昼夜气温变化与下垫面状况的影响,积雪融水几乎不产生径流,对河川径流的影响程度极小.
Snowmelt was observed in the Xiao Dongkemadi Glacier in the source region of the Yangtze River using flag rod from June 18 to 30 and from July 5 to 9, 2005. The results show that snowmelt coincided basically with air temperature variation on the glacier basin from June 18 to 30. Features of snowmelt from July 5 to 9 was that the initial time of snowmelt moved up two hours, from 14.00 （from June 18 to 30） to 12.00, that daily average snowmelt amount was about 0.71 mm water equivalent more than that from June 18 to 30, and that the time of maximal snowmelt, appearing at 18：00, was about two hours later than that of maximal air temperature. The profiles of snow pits recorded truly the processes of snow accumulation and ablation. Besides, temperature, snowmelt has close relations to radiation, wind, and other factors. The high the temperature is, the large the snowinelt is. The relation between snowmelt and wind speed is relatively complicated. The amount of snowmelt has correlation only with wind speed at 1.5 m height above land surface. On two-hour time scale, snowmelt was great when wind speed near surface is high. On daily time scale, the correlation of snowmelt and wind speed was good. However, the correlation was reverse from June 18 to 30 and from July 5 to 9. Snow cover is few in the Dongkemadi River basin. Snowmelt water almost cannot generate runoff and then has little impact on the streamflow of Dongkemadi River. This is due to the daily air temperature variation and the alpine meadow vegetation.
出处
《冰川冻土》
CSCD
北大核心
2007年第2期258-264,共7页
Journal of Glaciology and Geocryology
基金
国家自然科学基金项目(403010104037102640401012)
中国科学院知识创新工程重要方向性项目(KZCX3-SW-345)资助
关键词
长江源区
冬克玛底冰川
积雪融化
响应
the source region of the Yangtze River
Dongkemadi Glacier
snowmelt
response
