Comparative Study of Solid Precipitation Observation in Alpine Mountains

Abstract

Precipitation plays an important role in the process of water cycle and is a main driving force of terrestrial hydrological process.The change of precipitation form is an important part of understanding the evolution of land water cycle under the background of global warming， which is a hot and difficult issue for scholars at home and abroad.In our study， an observation comparison experiment of solid precipitation measurements with a PWS100 laser sensor and a Geonor T-200B at the terminus of Urumqi Glacier No.1， Tianshan Mountains from May 2018 to April 2020 was carried out.Three parts of results are obtained from this study.Firstly， the experiment site was dominated by solid precipitation particles， accounting for 63% of total precipitation particles.The liquid particles accounted for 37% of total precipitation particles.On the monthly scale， the number of particles from June to August was the largest， with 57% of liquid particles and 43% of solid particles.In the other months， the number of solid particles accounted for 96% of the total number of particles.Secondly， based on the proportion of precipitation particles in different temperature ranges， the precipitation types were divided with the temperature 6.5 ℃ as the critical value.The modified total precipitation accumulation of Geonor T-200B was 1202 mm， accounting for 67% of DFIR， which underestimated the precipitation， but the average relative capture rate was about 87%.Thirdly， the daily precipitation recorded PWS100 and Geonor T-200B was strong correlated and the annual amount of precipitation recorded by two instruments differed 71 mm.However， there was a small seasonal difference between two observed data sets.The amount of precipitation from PWS100 was 73 mm higher in June to August and 37 mm lower in September to May in the next year compared with the values recorded by Geonor T-200B.PWS100 observed large precipitation in summer with large precipitation and complex precipitation types， but less precipitation in winter.Moreover， PWS100 was not sensitive to small raindrops， which would lead to insufficient catch quantity.Therefore， it indicated that Geonor T-200B was more efficient than PWS100 in terms of catching solid precipitation.The results provide experimental basis for further research on the seasonal changes of mountainous runoff under the background of climatic warming.

Keywords

• precipitation observation
• geonor t-200b
• pws100
• headwaters of urumqi river
• alpine mountains