| 其他摘要 | Soil water is one of the most important components of soil, it plays a very important
role in the process of soil formation, at the same time, the soil water is involved in the
transformation process of many substances in the soil to a large extent. Moreover, soil water
is the main source of crop water, provide water for crop growth, and is one of the most
important parameters for the agriculture, meteorology and hydrology studies. Soil water is a
necessary condition for agricultural production, especially in the arid and semi-arid area, and
has important significance for the rained agriculture and vegetation growth. As the important
agricultural regions in China, in addition to the precipitation recharge, soil water in North
China Plain (NCP) is also largely affected by irrigation, therefore irrigation has become main
limiting factors restricting the growth of the crops. How to monitor and analyze surface soil
moisture, drought and irrigation of a wide range using remote sensing data, has a special
important value. Studies on soil moisture and irrigation information provide better
understanding about the drought.
In this paper, on the basis of active microwave remote sensing inversion data, soil
moisture index (SWI) data in 1992-2002 and 2006-2013, combined with geostatistical
analysis methods, the spatial and temporal variation of surface soil moisture in the NCP was
analyzed. Relationship between SWI, measured soil moisture of farmland and precipitation
within the same period were analyzed by using correlation analysis. Irrigation information
in the main growing season of winter wheat was extracted by the method of spatial overlay
analysis. The main results as follows:
(1) Correlation between SWI and measured soil moisture of farmland was different in
different soil depth. It was significant correlated between SWI and measured soil moisture
in (0~10cm), the correlation decreased with the increase of soil depth. The annual average
SWI of NCP was about 45%~50%; spatial distribution of surface soil moisture in NCP had
heterogeneity, the soil water content was obviously different in different regions, and it
decreased from north to south. (2) The CV of annual SWI in NCP presents the tendency of increasing from southeast
to northwest, differences of soil water content in southeast regions in different years were
small and it were opposite in northwest. The correlation between annual SWI and summer
SWI was the most strong, which meant the variation of summer SWI affected the annual
SWI the most. The CV of monthly SWI in southwest was larger than that in northeast, which
indicated that the differences of SWI between different months in southwest was larger than
that in northeast. The soil water content in spring was obviously different in different years,
but the differences were smaller in summer and autumn.
(3) The SWI increased obviously in most areas in 2013 compared to that in 1992, it
only decreased a little in a small region.
(4) Increasing of yearly precipitation led to the increasing of soil water in southeast to
a large extent, but the effects turned out to be less in northeast. The SWI changes could
reflect precipitation in some extent.
(5) Most areas in NCP in 1999 were irrigated in different degrees in the main growing
season of winter wheat; the irrigation times in the middle part was the least, and there existed
two or three rounds of irrigation in the northern and southern part, which accounted
approximately 65% of the total study area. The irrigation cells was 79.69% same with
extracted result using land use data in 2000, and the study results and methods can provide
references for the agricultural drought monitoring based on remote sensing.
Key words: European Remote Sensing Satellites; soil water index; North China Plain;
Geostatistic analyst; spatial and temporal variation characteristics; irrigation information |
修改评论