Abstract:  The “pulsereserve” conceptual model was one of the most-cited paradigms to study the eco-process triggered by precipitation pulse in water-controlled ecosystem in the past decades, giving people a new scope to understand the relationship between precipitation and structure and function of desert ecosystem in arid area. In this paper, different sizes of precipitation pulse events contributing to annual precipitation and its frequency as well as its change in the marginal zone of the Junggar Basin, China were analyzed based on the daily precipitation data observed at 6 meteorological stations in the study area. The results showed that the proportion of low precipitation pulse event size (lower than or equal to 5 mm) was as high as 87.5%, while that of high one (higher than 10 mm) was only 4.3% of the total annual precipitation pulse frequency. However, the contribution rates of low and high precipitation pulse event sizes to annual precipitation were 47.5% and 26.6% respectively. In the past 50 years, annual precipitation was increased significantly, but the change of annual precipitation frequency was not significant. It could be explained that the low precipitation pulse event size was in a decrease trend, but the high one was in a significant increase trend. Anyway, the precipitation pulse event sizes in the marginal zone of the Junggar Basin were amplified in the past 50 years.

Key words: climate change, precipitation pulse, arid region, desert ecosystem, Junggar Basin