黔中地区近60年潜在蒸散量时空变化特征及主导因素识别

(贵州师范大学 地理与环境科学学院, 贵阳 550025)

潜在蒸散量; Penman-Monteith模型; 气象因素; 时空变化; 黔中地区

Spatiotemporal Variation Characteristics of Potential Evapotranspiration and Identification of Leading Factors in Central Guizhou in Recent 60 Years
XIAO Yang, ZHOU Xu, LUO Xue, LI Hongguang, LIANG Rengang, YANG Dafang

(School of Geographic and Environmental Sciences, Guizhou Normal University, Guiyang 500025, China)

potential evapotranspiration; Penman-Monteith model; meteorological factors; spatial and temporal variations; central Guizhou

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潜在蒸散量是水文循环和全球能量平衡的组成部分,其长期变化在气候变化研究中备受关注,研究其变化对区域的水资源配置、农业发展、生态环境保护等具有重要意义。基于1960—2019年黔中地区11个气象站点逐日气象数据,利用Penman-Monteith模型计算潜在蒸散量,采用Theil-Sen median趋势分析与Mann-Kendall检验、小波分析等方法分析了年均及四季潜在蒸散量时空变化特征与周期变化特征; 结合相关分析法对影响潜在蒸散量的主要气象要素进行研究。结果表明:(1)1960—2019年黔中地区潜在蒸散量呈显著下降趋势,变化率约为-6.00 mm/10 a,且在年际、年代际与季节尺度变化中存在明显差异性。(2)春夏秋冬四季潜在蒸散量整体呈减小趋势,变化率分别为-2.10 mm/10 a,-3.01 mm/10 a,-0.17 mm/10 a,-0.62 mm/10 a,夏春两季潜在蒸散量占全年的65.91%,是影响年潜在蒸散量下降的主要原因。(3)潜在蒸散量空间分布特征呈自南向北递减趋势,其变化趋势在地区中部(东南—西北走向)呈下降趋势、在地区的南北部呈现增加趋势。(4)潜在蒸散量在1969年左右发生一次明显的突变,并存在21 a的主周期和3 a次周期。(5)研究区存在“蒸发悖论”现象,日照时数是影响潜在蒸散量变化的主导气象因素,其次是风速,且各气象因素在季节上对潜在蒸散量影响存在差异性。研究可为变化环境下的黔中地区水资源合理配置和农业生产提供一定的科学依据。
Potential evapotranspiration is a component of the hydrological cycle and global energy balance. Its long-term changes have attracted much attention in climate change research. Research on its changes is of great significance to regional water resources allocation, agricultural development, and ecological environment protection. Based on the daily meteorological data of 11 meteorological stations in central Guizhou from 1960 to 2019, the Penman-Monteith model was used to calculate the potential evapotranspiration, and the temporal and spatial variation characteristics and periodic variation characteristics of annual average and four seasonal potential evapotranspiration were analyzed by using Theil-Sen median trend analysis, Mann-Kendall test, and wavelet analysis. Correlation analysis method was use to study the main meteorological elements that affected potential evapotranspiration. The results show that:(1)the potential evapotranspiration in central Guizhou showed a significant downward trend from 1960 to 2019, with a change rate of about -6.00 mm/decade, and there were obvious differences in the interannual, interdecadal and seasonal scales;(2)the overall potential evapotranspiration in the four seasons showed a decreasing trend, with the rate of change being -2.10 mm/decade, -3.01 mm/decade, -0.17 mm/decade, and -0.62 mm/decade; that the potential evapotranspiration in summer and spring accounted for the 65.91% of the total aunual potential evapotranspiration was the main reason for the decline in annual potential evapotranspiration;(3)the spatial distribution of potential evapotranspiration was decreasing from south to north, and its change trend was decreasing in the middle(southeast northwest)and increasing in the north and south parts of the region;(4)the potential evapotranspiration had an obvious sudden change in 1969, and there was 21-year main cycle and a 3-year secondary cycle;(5)there was a ‘evaporation paradox' phenomenon in the study area; Sunshine hours were the main meteorological factors affecting the variation of potential evapotranspiration, followed by wind speed, and the influence of various meteorological factors on the potential evapotranspiration varied seasonally. This research can provide a certain scientific basis for the rational allocation of water resources and agricultural production in central Guizhou under the changing environment.