A preliminary study of precipitation characteristics in the hinterland of Badain Jaran desert

Based on the positioning observation of precipitation in the hinterland of the Badain Jaran desert and data from four surrounding gauges in the vicinity of the desert, the characteristic of precipitation in the hinterland of the desert is examined.The effect of megadunes on precipitation is primitively analyzed.The difference in precipitation amounts between the margin area and the hinterland of the desert is discussed.Results show that light rain dominates the hinterland and the most common rainfall events are likely to be short in duration less than two hours.Precipitation exhibits a great deal of seasonal variability, and the annual precipitation depends very much on a few rainy days.A good consistency is found in the seasonal distribution of precipitation between the hinterland and the margin area.During the observation, the precipitation amount of the hinterland is lower than that of the southern margin, but is evidently higher than that of the northern, northwestern and southeastern margins.It is possible for the hinterland region to encountering local heavy rainfall events with precipitation greater than 20 mm and the maximum intensity of precipitation exceeding 4 mm/h; however, the occurrence of such events is rather instantaneous and random.It is evident that a megadune can influence precipitation as the annual precipitation and rainy days on the top of the megadune are slightly more than those in the interdune areas, and so do the duration and accumulation of a single precipitation event.During heavy rainfall events, spottiness is likely to occur on an average scale of 16.8 km.The cross-correlation analysis demonstrates that the space correlation decreases significantly with the increase of distances in the summer time of a year.However, the space correlation to 50 km is still high in the winter time of a year due to cold frontal precipitation.