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Title
Mapping without the sun
Author
Zhang, Jixian

174
LAND COVER CHANGE AND CLIMATIC VICISSITUDE RESEARCH IN
HEADSTREAM REGIONOF YELLOW RIVER IN THE NINETIES OF THE
TWENTIETH CENTURY
DAI Ji-guang a ’ *, YANG Tai-bao b , REN Jia-qiang a ,
a School of Geomatics, Liaoning Technical University, Fuxin 123000, P.R.China-daijg03@163.com
b School of Resources and Environment, Lanzhou University, Lanzhou 730000, P R China,yangtb@lzu.edu.cn
KEY WORDS: headstream region of the Yellow River, land cover, climatic vicissitude
ABSTRACT:
The objective of this study was to monitor land cover change process and patem between 1990 and 2000 in Headstream Region of
yellow river based on NOAA-AVHRR date BY using the Back-Propagation(BP) neural network , and the course of climate change
in the study area was analyzed. The results indicate, the types of land cover in the headstream region of the Yellow River
dramatically changed within 11 years, namely from 1990 through 2000. The changes are characterized by large-area degradation of
grassland, shapely decrease of the average regional vegetation cover rate, dramatically increase of the barren land’s area.
Simultaneously, Both the annually average temperature and the annually maximum temperature have risen sharply. Annually
minimum temperature has also slowly increased. Nevertheless, the annually average precipitation has decreased with the trend of
fluctuation; Through analysis on land cover and climate change, we get to know that: land cover types area have different connection
with weather genes. In conclusion, climates change is an important driving force of the impact on land cover change.
1. GEOGRAPHY SURVEY OF THE STUDY AREA
Headstream Region of Yellow River is distributed mainly in
the northeast of Tibet plateau which is called Sanjiangyuan
with the headwaters region of the Yangtze River and the
Lantsang River. Known as Chinese water tower, Sanjiangyuan
is a main water source in the east and middle part of china(Wu
yu-hu et al,2003; Wang Gen-Xu et al,2002). The eco-
environment of headstream region of Yellow River are
extremely terrible. The desert , gobi , grassland , lake and
swamp are the main cover types. In recent years, influenced by
global warming and human over-exploitation of natural
Fig. 1 Study Area of Headstream Region
of Chinese Yellow River (UTM47N)
resources, soil erosion and degradation, plant destruction, land
saline-alkalization, land desertification, grassland degeneration,
natural hazard seriously effect the economic development of
the headstream region of Yellow River. Consequently, it is
necessary to study the processes and the mechanism of the
change of land cover.
The research region includes the area from the Longyangxia
Reservoir to the catchment area of headwater region of Yellow
River in Qumalai County which occupied 272km 2 ,ranged from
E95°48'—E103°18' to N32° 12'—N36°33'(Fig.l),the annual
average temperature and precipitation is -2.4°C and 470mm
separately under a typical alpine continental climate with the
average elevation of 4,100 m.
2. RESEARCH METHODS
NOAA-AVHRR satellite data is characterized by wide
observation range, short time period in control system and
satisfactory performance on temporal continuity(WANG Jiang-
shan et al,2005; Gao Li-min et al,2007). And its resolution
(1.1km) attends to the need of middle scale geographical
research. This paper selected continuous AVHRR High
Resolution Picture Transmission (HRPT) 1KM Level IB and
Local Area Coverage (LAC) 1KM Level IB data offered by
Comprehensive Large Array-data Stewarship System
(CLASS) with a two-year step size and studies the process
and pattern of the land cover change in Headwater Region of
Yellow River. Simultaneously, the data of Climate Change
during this period is also studied and finally the relationship
between land cover change and climate change is analyzed.
3. DISPOSAL AND ANALYSES OF WEATHER DATA
Temperature and precipitation are two climatic factors used in
climatic analysis commonly(Huang Jia-hong et al,2006).69
meteorological data from headstream Yellow River region and
* Corresponding author :E-mail:daijg@163.com