西藏纳木错水深分布及现代湖沼学特征初步分析  

Bathymetric survey and modern limnological parameters of Nam Co,central Tibet

作　　者：王君波[1] 朱立平[1] Gerhard Daut 鞠建廷 林晓[1,4] 汪勇[1] 甄晓林[1] 

机构地区：[1]中国科学院青藏高原研究所,北京100085 [2]Institut fur Geographie, Friedrich-Schiller-Universitat, Jena, Germany [3]中国科学杂志社,北京100717 [4]中国地质大学,武汉430074

出　　处：《湖泊科学》2009年第1期128-134,共7页Journal of Lake Sciences

基　　金：国家自然科学基金项目(40701194);国家重点基础研究发展计划项目(2005CB422002);中国科学院青藏高原研究所青年人才领域前沿专项经费联合资助

摘　　要：2005-2007年对西藏最大的湖泊——纳木错进行了三次综合考察,获得了大量的基础数据和研究材料.本文简要报道纳木错水深测量及其现代湖沼学特征的初步结果等深线图显示纳木错是一个高海拔的深水湖,湖盆中部是一个水深超过90m底部较为平坦的盆地.考察中发现湖泊西北部出现了两个小岛,而1970s考察时仍为半岛,因而水深数据提供了近30年来纳木错湖面上升的有力证据.现场水质测量在16个站点进行,覆盖了除东部湖区以外的大部分湖面范围,结果显示表层水的温度、pH、溶解氧、电导率和环境光的平均值分别为11 63℃、9.13、7 93mg/L、1839μS/cm、2582μmol/(s·m^2).根据湖水特征的垂直变化,较深水域的湖水显示了明显的分层特征:上层湖水从表层到约18-20m,水质参数均一,温度较高,光照充足;中间层范围约为20-60m,是一个明显的温跃层;底层水性质也很稳定,水温很低几乎没有光线到达,形成了寒冷黑暗的深水区.Comprehensive field investigations had been conducted for three times on Nam Co, central Tibet during 2005-2007, Here we presented the preliminary results focusing on bathymetric survey and water quality measurements. Isobathic map showed that Nam Co is a high altitude deep lake where a fiat and large basin lies in the central part with more than 90m water depth. Data on water depth in northwestern bank areas of Nam Co provided unquestionable evidence for water level rising in the recent three decades due to the formation of two small islands which were peninsulas in 1970s. Water quality at 16 stations covering more than half of the whole lake showed that temperature, pH, dissolved oxygen, conductivity and photosynthetically active radiation （PAR） of surface water was averagely 11.63℃, 9.13, 7.93mg/L, 1839μS/cm and 2582μmol/（s·m^2）, respectively. According to the vertical variations of water quality parameters, water column in relatively deep lake areas of Nam Co could be divided into three layers with distinctly various features. The first layer was from surface to about 18-20m depth in which parameters was stable with higher temperature and abundant sunlight; the second layer ranged about 20m to 60m where thermocline developed; and the bottommost layer was characterized as also very stable with low temperature and no light, forming a cold and dark underwater world.

关 键 词：水深测量 湖面上升 湖沼学特征 温跃层 纳木错 青藏高原 

分 类 号：P343.3[天文地球—水文科学]