Abstract
Surface soil moisture is an important variable which significantly affects the hydrological environment of region. It is necessary to better understand the spatial distribution of surface soil moisture for an accounting of the water and theenergy balances at the land-atmosphere boundary. In this paper, the characteristics of spatial distribution and the time stability of sampling locations for sloping grassland filed were discussed using the field data obtained by 100 cm3 core samplers. As a result, the variability of surface soil moisture decreased with an increase in water contents, and its distribution was led not to show the normal distribution with the decrease of water contents. The area-scale mean water contents at each area indicated that the mean water content at the low area was the highest, and that the surface soil moistures were different according to each area. The coefficient of variation for surface soil moisture at the slope areawas the largest. It was also implied that the sampling location which always exhibited the field-scale mean water content irrespective of a temporal variation existed using the concept of time stability. However, it was clear that a lot of sampling events were needed for the application of the concept.
