约束线方法改进的ITVDI在荆州市干旱评估中的应用

Application of ITVDI Improved by Constraint Line Method to Drought Assessment in Jingzhou City

干旱是影响农业生产和区域可持续发展的重要因素。监测和分析干旱的时空变化特征及其驱动因素对于制定有效的应对措施具有重要意义。基于约束线方法对温度植被干旱指数(ITVDI)进行了改进,利用2001—2020年MODIS NDVI和LST数据对荆州市的干旱进行了监测和分析。结果表明,荆州市的干旱强度呈现出波动变化,2015年后有所减轻。空间上,荆州市的干旱特征存在较大的异质性,西部和东部地区的干旱显著增加,而市中心的干旱显著减少。进一步识别和量化了人类活动(人口、GDP、土地利用类型)、气候变化(降水、温度)和地形(海拔、坡度)等因素对荆州市干旱强度的约束影响。结果显示,这些因素对干旱强度存在8种约束效应类型,包括U型曲线、正线性、负线性、对数型、负凸型、正凸型、指数型和驼峰型。降水和温度是影响干旱强度最直接的因素,其对干旱强度的上下边界都有约束效应。海拔、坡度、GDP和人口对干旱强度的约束效应在尺度上稳定。值得注意的是,土地利用类型对干旱强度的约束效应呈U型,且最小值阈值出现在林地和水域覆盖区域。该研究为缓解区域干旱和促进区域可持续发展提供了科学决策支持,最后展望了未来的研究方向和需求。

Drought is an important factor affecting agricultural production and regional sustainable development.Monitoring and analyzing the temporal and spatial characteristics of drought and its driving factors were of great significance for formulating effective response measures.The temperature vegetation drought index(ITVDI)was improved based on the constraint line method,and the MODIS NDVI and LST data from^(2)001 to 2020 were used to monitor and analyze the drought in Jingzhou City.The results showed that the drought intensity in Jingzhou City had fluctuated and decreased after 2015.Spatial heterogeneity existed in the drought characteristics of Jingzhou City.The drought in the western and eastern areas increased significantly,while the drought in the downtown area decreased significantly.We further identified and quantified the constrained effects of human activities(population,GDP,land use type),climate change(precipitation,temperature)and topography(elevation,slope)on drought intensity in Jingzhou City.It was found that these factors had eight constraint effects on drought intensity,including U-shaped curve,positive linear,negative linear,logarithmic,negative convex,positive convex,exponential and hump type.Precipitation and temperature were the most direct factors affecting drought intensity,and they had a constraint effect on the upper and lower boundaries of drought intensity.The constraint effected of altitude,slope,GDP and population on drought intensity were stable in scale.It was worth noting that the constraint effect of land use type on drought intensity was U-shaped,and the minimum threshold value appeared in the area covered by forest land and water.We provided scientific decision support for alleviating regional drought and promoting regional sustainable development,so as to look forward to future research directions and needs.