气象干旱-水文干旱传播过程特征及其影响因素--以贵州黔中水利工程区为例

Characteristics of Meteorological Drought-Hydrological Drought Propagation Process and Its Influencing Factors-Taking Guizhou Qianzhong Water Conservancy Project Area as An Example

为探究喀斯特区域气象干旱向水文干旱传播过程特征,使用SPI与SRI标准化指数识别区域干旱,采用交叉小波、小波相干、状态转移概率等方法探讨传播强度、响应率等干旱传播特征。结果表明:(1)上世纪60 s和70 s气象干旱、水文干旱的干旱持续时间较短,而80 s与21世纪初期区域干旱持续时间较长;SPI与SRI间呈显著的正相关关系,气象干旱向水文干旱传播的过程需要1.5个月。(2)喀斯特区域的干旱传播强度DPI>1,且响应率偏高,水文干旱对气象干旱的发生极为敏感,尤其是在地表切割深度较浅、岩溶发育较为强烈的区域。(3)传播过程主要受地表切割深度的影响较大,各下垫面条件对干旱传播过程的影响程度依次为地表切割深度>岩溶发育强度>高程>地形地貌,其中,干旱传播特征与地表切割深度呈显著的负相关,与岩溶发育强度、高程、地形地貌呈正相关;在浅切割、中等切割或海拔较低、岩溶发育强烈的区域,各等级间的DPI、Rr的转移较为活跃,整体上传播特征在57年间呈增强的趋势。研究结果旨在为区域干旱防治与监测提供理论依据,尤其是为喀斯特生态环境脆弱区的可持续发展规划提供理论参考。

In order to explore the characteristics of the propagation process of meteorological drought to hydrological drought in karst region,the SPI and SRI standardization indexes were used to identify regional drought,and methods of cross wavelet,wavelet coherence and state transition probability were used to explore the drought propagation characteristics such as propagation intensity and response rate.The results showed that:(1)The duration of meteorological drought and hydrological drought in the 60 s and 70 s of the last century was shorter,while the regional droughts in the 80 s of the last century and the early 21st century lasted longer.There was a significant positive correlation between SPI and SRI,and the process of meteorological drought tended to hydrological drought took 1.5 months.(2)The transmission intensity of drought DPI in the karst area was greater than 1 and the response rate was relatively high.Hydrological drought was extremely sensitive to the occurrence of meteorological drought,especially in areas where the cutting depth of the surface was relatively shallow and the karst development was relatively strong.(3)The propagation process was mainly affected by the cutting depth of the surface.The influence degree of each underlying surface condition to the drought propagation process was sequenced as surface cutting depth>karst development intensity>elevation>topography and landforms,among them the characteristics of drought propagation was significantly negatively correlated with the depth of surface cutting,and positively correlated with the intensity of karst development,elevation,and topography.In the areas with shallow cut,medium cut,or low altitude and strong karst development,the transfer of DPI and Rr between each grade was more active.On the whole,the propagation characteristics showed an increasing trend in 57 years.The results could provide a theoretical basis for drought prevention and monitoring in karst areas,especially for the sustainable development planning of ecologically fragile areas.