基于NDVI的石羊河流域植被演变特征及其对沙尘暴的影响分析

利用石羊河流域2000-2016年卫星遥感数据和7个气象站1961-2020年逐日沙尘暴资料,使用一元回归趋势法、线性倾向率、相关系数等方法,分析该流域植被覆盖与沙尘暴频次、持续时间、强度的多尺度变化特征及关系,探讨其对沙尘暴发生发展的影响程度.结果表明:流域植被轻微增大,NDVI以每年0.000 9的速度增大,200...

Analysis on Characteristics of Vegetation Evolution and Its Impact on Sandstorm in Shiyang River Basin Based on NDVI

Based on the satellite remote sensing data from 2000 to 2020 and the daily sandstorm data of seven meteorological stations from 1961 to 2020 in the Shiyang River Basin, we analyzed the multi-scale variation characteristics and relationship between watershed vegetation coverage and sandstorm frequency, duration and intensity, and explored its influence on the occurrence and development of sandstorm by using the methods of univariate regression trend method, linear tendency rate and correlation coefficient. The results showed that the watershed vegetation coverage increased slightly, and NDVI increased at the rate of 0.000 9 per year. The NDVI began to recover in 2007. Recovery was more obvious after 2010, and the recovery rates in the upper and middle reaches were faster than that in the lower reaches. The sandstorm frequency decreased significantly, and the interannual trend rate was -2.8 d/10 a. It decreased the most significantly in the past 10 years, which was 14.5 days less than that in the 1970s. The rate of reduction was slower in the middle reaches and that was faster in the lower reaches. The rate of reduction in four seasons followed the order of spring>summer>winter>autumn. The sandstorm duration was significantly shortened, the interannual trend rate was -12.2 m/10 a. The duration in the last 10 years was the shortest, which was 60.9 min shorter than that in the 1970s. The shorting time in the middle reaches was slower and that was faster in the lower reaches. The sandstorm intensity had no obvious change, and the minimum visibility was around 0.496 km. The frequency and duration of sandstorm were negatively correlated with full-basin NDVI, NDVI >0.3 area, NDVI of upper, middle and lower reaches in the current year and the previous year. The sandstorm intensity had a weak negative correlation with full-basin NDVI, NDVI >0.3 area, NDVI of upper, middle and lower reaches, and a weak positive correlation with NDVI of the previous year. The improvement of vegetation cover in the watershed had obvious restraining effect on sandstorm.