Studies on satellite snow cover monitoring and snowmelt
runoff forecast in the upper reaches of The Yellow River
Zeng Qunzhu, Fen Xuezhi, chen Xianzhang, Lan Yongchao
Wang Jain, Jin Dehong
Lanzhou Institute of Glaciology and Geocryology
Chinese Academy of Sciences
Liu Yujie
Satellite Meteorology Center, State Meteorological Administration
Beijing, China
Song Qiang
Geography Deparment of Huazhong Teachers University,
Wuhan, China
Abstract
The formation and spatial and temporal variation feature of winter-spring snow cover in the upper reaches of the Yellow River and the effects on hydrologic situation made by snowmelt runoff were studied in this paper systematically by using NOAA, Land sat MSS, Tm images and ground truth data. The spring runoff Forecast Model was developed based on the Ridge regression and gray system theory employing satellite snow cover data and hydrometer logical data. The inflow forecast for each ten-day to longyang Gorge Reservoir from the first ten days of April to the first ten days of June has been carried out successfully for 3 years (1987, 1989, and 1990) The result shows that the forecast precision is within the permitted error range and can meet the need of user perfectly.
General situation of the basin and research content
- General situation of the basin.
The upper reaches of the Yellow River is situated in the northeast of the Qinghai-Xiezang Plateau. To the southwest of the basin there is the Bayanhar MT. as a watershed between the Yangtse River and the Yellow River. And the Anyemaqen MT. lies passing through the basin from the northwest to the southeast. The highest peaks are over 3200m and 6262m a.m.l. respectively (fig 1) The study area was selected from the source of Yellow River to Tangnaihai hydrological station with 1172 km2 in length and an area of 121972 km2 Because of the abundant precipitation (300-750 mm/yr) the low annual mean temperature (-4,0-1 1 0C ) and the weak evaporation of the ground surface the runoff modules reaches 6.51dm3/s.km2 in this area which is about three times as high the mean value of the whole Yellow River basin , so the study area is one of the main runoff producing areas. In addition, the snow and glaciers are disTributed widely (fig 2) and 57 glaciers developed around Maqengangri peak with an area of 120.75 km2 The comparison of topographic man and Land sat MSS shows that the terminal of Halongglacier No.1 the largest glacier in this area has advanced by 720mm in recent ten years by 200m and 430m for the Halong glacier N0 2 and Walema glacier respectively. The melt water from glaciers and snow is one of the main supply sources of ring runoff in the upper reaches of the Yellow River and accounts for about 72.6% of the surface runoff in the same period.
- The Research Content
The dynamic monitoring of winter-spring snow cover in the area and the operational forecast of spring runoff (fig 3 ) have been carried out under the support of Ice and snow Water Resources Information System (ISWRIS ) using snow cover information extracted from NOAA-9 10 , 11 AVHRR data Landsat TM MSS , image or CCT data and the ground data such as field in vestigation data experimental data and hydro metrological data the research results can provide a scientific basis for the management of large reservoirs in the upper reaches of the Yellow River and are very beneficial to their operational run.
