广西北部湾入海流域径流演变特征及其对气候变化和人类活动的响应

Variation Characteristics of Runoff in Basin Entering the Sea in the Beibu Gulf of Guangxi and Its Response to Climate Change and Human Activities

关键词:  径流  入海流域  人类活动  气候变化  演变特征

Key words:  runoff  basin entering the sea  human activity  climate change  variation characteristics

摘要:

为探讨入海流域径流的演变特征，定量分析气候变化和人类活动对入海流域径流的影响，本文基于气象数据和径流数据，采用彭曼公式、滑动t检验、Hurst指数和小波分析等方法对比分析广西北部湾入海流域径流深的时空演变特征和未来趋势，并采用累积量斜率变化率比较法定量评估气候变化和人类活动对广西北部湾入海流域径流深变化的贡献率。结果表明：广西北部湾入海流域径流深空间分布格局分异较大，北仑河流域和防城江流域多年平均径流深较大，分别为2 115.58 mm和2 105.56 mm；径流深较小的是钦江流域和南流江流域，多年平均径流深分别为719.33 mm和744.50 mm。仅钦江流域径流深呈不显著上升趋势，其余流域均为下降趋势。广西北部湾入海流域各流域径流深的突变年份呈现一致性，均在1992年和2003年附近。在演变周期上，钦江流域、南流江流域、大风江流域、防城江流域、北仑河流域的历年年均径流深演化过程中存在2-6 a、7-15 a和16-24 a 3种时间尺度的周期变化规律，丰、枯交替变化比较明显；茅岭江流域径流深的周期震荡变化稍有不同，存在7-24 a和25 a以上两种时间尺度的周期变化规律。T2时期相对于T1时期，降水是广西北部湾入海径流变化的主导因素，人类活动次之，蒸散发对径流的影响极小；但随着时间推移，T3时期相对于T2时期，人类活动对径流的影响作用增强，蒸散发对径流的影响也相对增强。

Abstract:

In order to explore the evolution characteristics of runoff into the sea basin and quantitatively analyze the impact of climate change and human activities on runoff into the sea basin,based on meteorological data and runoff data,the spatial and temporal evolution characteristics and future trends of runoff depth in the Beibu Gulf of Guangxi into the sea basin were compared and analyzed by Penman formula,sliding t test,Hurst index and wavelet analysis et al.The cumulative slope change rate comparison method was used to quantitatively evaluate the contribution rate of climate change and human activities to the change of runoff depth in the Beibu Gulf of Guangxi into the sea basin.The results showed that the spatial distribution pattern of runoff depth in the Beibu Gulf of Guangxi has a large spatial difference.The multi-year average runoff depth of Beilun River Basin and Fangcheng River Basin was 2 115.58 mm and 2 105.56 mm,respectively.The smaller runoff depths were in the Qinjiang River Basin and the Nanliu River Basin,the multi-year average runoff depth was 719.33 mm and 744.50 mm,respectively.Only the runoff depth of Qinjiang River Basin showed no significant upward trend,while the rest of the basin showed a downward trend.The mutation years of runoff depth in each basin of the Beibu Gulf in Guangxi were consistent,which were around 1992 and 2003.In the evolution cycle,there were 3 periodic variation rules in the evolution process of annual average runoff depth in Qinjiang River Basin,Nanliu River Basin,Dafeng River Basin,Fangcheng River Basin and Beilun River Basin.The time scales were 2-6 a,7-15 a and 16-24 a,respectively.And the alternating changes of abundance and depletion were more obvious.The periodic oscillation variation of runoff depth in Maoling River Basin was slightly different,and there were 2 kinds of periodic variation laws of 7-24 a and more than 25 a.Compared with the T1 period,precipitation was the dominant factor in the change of runoff into the sea in the Beibu Gulf of Guangxi,followed by human activities,and evapotranspiration had little effect on runoff.But with the passage of time,compared with T2,the impact of human activities on runoff increased in T3,and the impact of evapotranspiration on runoff also relatively increased.