大柴旦矿区生态环境影响要素变化特征

Variation Characteristics of Meteorological Elements Influencing Ecosystem Environment in Da Qaidam Mining Area

气象要素变化对矿区生态环境的影响极为重要,尤其是在我国青藏高原寒旱区,全面系统地了解历史气象要素变化特征对高寒矿区生态环境保护具有指导作用。本研究首先基于青藏高原大柴旦矿区1956-2022年的逐月降水、气温、蒸发数据,采用线性倾向估计法、集合经验模态分解(EEMD)、Morlet小波变换等方法对大柴旦地区的降水、气温、蒸发等气象要素的变化趋势进行了全面分析研究;然后选取三期空间分辨率为30 m的Landsat卫星数据,从卫星图像中计算了归一化差异植被指数(I_(NDV))。结果表明:大柴旦矿区气候呈现暖湿化态势,在此因素驱动下,降水量呈现轻微增加趋势,气温呈现明显增高趋势,蒸发量呈明显减小趋势;降水量和气温序列没有突变点,而蒸发量在1979年存在突变,在1956-1979年蒸发量缓慢增加,在1979-2022年缓慢减小;降水量在2000-2016年具有显著12个月的震荡周期,气温和蒸发量在整个时间尺度上都具有12个月的震荡周期;植被多集中分布在水体附近,研究区内整体呈现覆盖增加、生长活动增强趋势。预测大柴旦矿区未来几年降水量仍处于增加状态,温度处于增高阶段,年蒸发量将处于偏少期,植被生长活动整体呈增强趋势。

Changes in meteorological elements have a highly important impact to the ecological environment of the mining area,especially in the cold and arid region of the Qinghai-Tibet Plateau,China.A comprehensive and systematic understanding of characteristics of historical meteorological changes plays a guiding role in the ecological environment protection for alpine mining areas.In this study,trends of precipitation,air temperature,and evaporation were comprehensively analyzed by linear tendency estimation,the ensemble empirical mode decomposition(EEMD),and Morlet wavelet analysis using monthly data from 1956 to 2022 in the Da Qaidam mining area of the Qinghai-Tibet Plateau.The normalized difference vegetation index(I_(NDV))was extracted from three phases of Landsat satellite images with a spatial resolution of 30 m.Results showed that the climate in the study area developed towards warming and humidification with a slightly increasing trend of precipitation,a significantly trend of temperature,and a markedly decreasing trend of evaporation.No abrupt changes points were detected for precipitation and temperature,but a sudden change in evaporation existed in 1979.Evaporation increased slowly from 1956 to 1979,and decreased slowly from 1979 to 2022.Precipitation had a significant 12-month oscillation period from 2000 to 2016,while temperature and evaporation had a 12-month oscillation period throughout the entire study period.I_(NDV)data indicated that vegetation was mostly concentrated near the water bodies,and the coverage expanded and the growth activity enhanced over time in the entire study area.It is predicted that precipitation and temperature would continuously increase and annual evaporation would be in a relatively small period.The vegetation growth activity would be strengthened for next few years in the Da Qaidam mining area.