近几十年来我国四季天然径流深度的时空特征分析

Analysis of Spatial and Temporal Characteristics of Natural Runoff Depth in Four Seasons in China in Recent Decades

摘要: 本文利用1961~2018年CN05.1降水数据集资料和中国天然径流深度格点数据集(CNRDv1.0)，通过EOF分析、线性趋势分析、Mann-Kendall检验、小波分析、相对变率分析以及相关分析等统计分析方法，对几十年来我国四季天然径流的时空分布特征进行研究，结果表明：1) 我国径流深度在空间分布上极为不均，总体上呈现出由我国东南至西北减少的特征，夏季天然径流深度占全年最多，而冬季占比最小。2)我国不同季节天然径流深度在过去几十年中发生了显著变化，其中春季、夏季和秋季天然径流深度在20世纪后半期经历了显著的下降趋势，在21世纪初期有所回升，但总体仍低于20世纪初期。冬季径流深度在20世纪后期表现出下降趋势，21世纪初期有所回升。3) 我国大部分地区春季、夏季和秋季径流深度与降水呈现显著的正相关关系，表明降水量的增加通常伴随着径流深度的增加。然而，冬季径流深度与降水量之间的关系较为复杂，我国北方部分地区为负相关关系，表明冬季降水量与径流深度的联系并不一致。

Abstract: Using CN05.1 precipitation dataset from 1961 to 2018 and China natural runoff depth grid dataset (CNRDv1.0), this paper uses statistical analysis methods such as EOF analysis, linear trend analysis, Mann-Kendall test, wavelet analysis, relative variability analysis and correlation analysis. The spatial and temporal distribution characteristics of natural runoff in four seasons in China over the past decades are studied. The results show that: 1) the spatial distribution of runoff depth in China is extremely uneven, and it decreases from southeast to northwest of China. The natural runoff depth in summer accounts for the most of the whole year, while the proportion in winter is the least. 2) The depth of natural runoff in different seasons in China has changed significantly in the past few decades. The depth of natural runoff in spring, summer and autumn experienced a significant decline in the second half of the 20th century, and rebounded in the early 21st century, but the overall depth is still lower than that in the early 20th century. Winter runoff depth showed a downward trend in the late 20th century and a rebound in the early 21st century. 3) There was a significant positive correlation between runoff depth and precipitation in spring, summer and autumn in most areas of China, indicating that the increase of precipitation was usually accompanied by the increase of runoff depth. However, the relationship between runoff depth and precipitation in winter is complicated, and a negative correlation is found in some parts of northern China, indicating that the relationship between precipitation and runoff depth in winter is not consistent.