Precipitation characteristics and its impact on vegetation restoration in Minqin County, Gansu Province, northwest China

Annual, seasonal, monthly and daily precipitation records of Minqin County over 1953-2007 were analysed. In addition, the effects of changing precipitation patterns on vegetative restoration in this area were examined. Annual average precipitation in this area showed a non-significant (p > 0.05) increasing trend, and 76.9% of the rainfall occurred from June to September. Light rain events accounted for a large percentage of the total rainfall event frequency and total annual precipitation. Rainy days have increased by 5.2 days over the past 55 years, with rainfall events of 0-5 and 5-10 mm showing an increasing trend. The 0-5-mm rainfall events contributed 82.3% of the annual precipitation events from 1953 to 2007. These events occurred consistently across different years and gradually became the dominant precipitation type in the study region. Other higher precipitation size classes did not show any apparent trend across the months or years studied, occurring 0-2 times per year. Precipitation in the spring, autumn and winter showed an increasing trend, while a decreasing trend was observed in the summer. The number of 1- and 2-day and longer than 2-day rainfall events showed an increasing trend, with the 1- and 2-day events being more frequent. In addition, the number of short and long drought periods also increased, with the number of long droughts showing an increasing trend. Precipitation variation patterns had a great impact on vegetative succession in this area. Species that mainly use topsoil water may be more adaptive future light precipitation patterns. Thus, plants with shallow roots, especially with adventitious roots, and resistant to sand burial should be used for future ecological restoration in this area. Copyright. (C) 2010 Royal Meteorological Society