Observation and estimation of daily actual evapotranspiration and evaporation on a glacierized watershed at the headwater of the Urumqi River, Tianshan, China

✍ Scribed by Zhang Wanchang; Zhang Yinsheng; Katsuro Ogawa; Yasushi Yamaguchi

• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: English
• Weight: 222 KB
• Volume: 13
• Category: Article
• ISSN: 0885-6087
• DOI: 10.1002/(sici)1099-1085(19990815)13:11<1589::aid-hyp829>3.0.co;2-8

✦ Synopsis

In order to develop an eective approach to estimate evaporation and evapotranspiration (ET) in the glacierized watershed for hydrological process studies, the meteorological and energy budget data obtained in 1986 from a small watershed at the headwater of Urumqi River Basin, Tianshan, China were utilized. The ®eld observation of ET and surface soil water content was brie¯y described. The performance of several existing approaches in estimating the daily actual ET and evaporation for the two kinds of predominant ground surface in the basin (i.e. the alpine tundra and glacier surface) was examined. The estimated daily ET from the alpine tundra for the summer season by Morton's equation correlates fairly well with the lysimeter-observed data, and the proposed wetness index by means of the principle of Morton's complementary relationship, provided reliable information of the surface soil wetness condition for the same period. For the other seasons, Kojima's equation was adopted for estimation of daily evaporation on both alpine tundra and the glacier surface when most parts of the watershed were snow covered. The daily evaporation on the glacier surface for the melting season was ultimately estimated by Ohno's equation for the non-melting season. The monthly mean evaporation estimated for the glacier surface was close to the ®eld observation data obtained in 1987±1988. The annual evaporation obtained on both sites by this approach was in good agreement with that estimated with the water balance method for the same sites by Zhang et al.