Study on the UV-A and UV-B Changes and Their Correlations with Meteorological Factors in the Haibei Alpine Meadow in the Qilian Mountains

Abstract

Based on the one-year data observed in the Haibei alpine meadow in the Qilian Mountains located in northeast of the Qinghai-Tibetan Plateau,in this study the UV-A and UV-B changes and their correlations with meteorological factors are analyzed,and the UV-A and UV-B are modeled using the data of some meteorological factors.The results reveal that the UV-A and UV-B changes are significant,their maximum and minimum values occur in June and December,and their accumulative sums are 138.11 MJ/m2 and 35.14 MJ/m2,respectively.There are also the significant daily and annual changes of the ratios of UV-A and UV-B in DR(direct radiation).In daily change,their ratios are the highest at noon and decrease to their minimum values in early morning and at night.In annual change,their maximum and minimum values occur in summer and winter,and their annual mean values are 2.17% and 0.54%,respectively.There are the significant correlations between the UV-A and UV-B and many meteorological factors,but it can not be considered that these factors affect directly the UV-A and UV-B.According to the factors affecting DR,soil temperature at 5 cm in depth can be regarded as a prediction factor to develop the ten-day correlative simulation equation affecting UV-A and UV-B,which is very significant at the level of dual linear regression.