• Rainfall characteristics and thresholds for periglacial debris flows in the Parlung Zangbo Basin, southeast Tibetan Plateau

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      https://www.ias.ac.in/article/fulltext/jess/127/01/0011

    • Keywords

       

      Rainfall characteristics; runoff generated; threshold; debris flows; southeast Tibetan Plateau.

    • Abstract

       

      The Parlung Zangbo Basin in the southeastern Tibet Plateau is affected by the summer monsoon from the Indian Ocean, which produces large rainfall gradients in the basin. Rainfall data during 2012–2015 from five new meteorological stations are used to analyse the rainfall characteristics. The daily rainfall, rainfallduration, mean rainfall intensity, and peak rainfall intensity are consistent, but sometimes contrasting. For example, these values decrease with increasing altitude, and the gradient is large downstream and small upstream, respectively. Moreover, the rainfall intensity peaks between 01:00 and 06:00 and increasesduring the afternoon. Based on the analysis of 14 debris flow cases in the basin, differences in the rainfall threshold differ depending on the location as sediment varieties. The sediment in the middle portions of the basin is wet and well structured; thus, long-duration, high-intensity rainfall is required to generatedebris flows. Ravels in the upstream area are arid and not well structured, and short-duration rainfall is required to trigger debris flows. Between the above two locations, either long-duration, low-intensity rainfall or short-duration, high-intensity rainfall could provoke debris flows. Clearly, differences in rainfall characteristics and rainfall thresholds that are associated with the location must be considered in debris flow monitoring and warnings.

    • Author Affiliations

       

      Mingfeng Deng1 Ningsheng Chen1 Haitao Ding1

      1. Key Laboratory of Mountain Hazards and Surface Processes, Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, No. 9, Section 4, Renminnanlu Road, Chengdu 610041, Sichuan, People's Republic of China
    • Dates

       
  • Journal of Earth System Science | News

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