基于数值模拟的流域水循环变化时空特征分析方法

Spatial-temporal characteristics analysis method of basin water cycle change based on numerical simulation

摘要

流域水安全问题关系着粮食安全、人民健康以及社会稳定，为探究全球变暖和社会经济发展背景下流域水循环的历史演变规律，建立一套基于数值模拟的流域水循环变化时空特征分析方法，对制定相关政策来适应和缓解未来可能出现的水灾害具有重要意义。以泰国昭披耶河流域为例，综合应用实测气象、水文及下垫面数据，构建了高分辨率的分布式水文模型GBHM,对1985—2014年昭披耶河流域水文过程进行数值模拟，分析了水循环要素和植被的时空演变规律，并基于EOF方法阐明了降雨年内分布的“双峰”特征。结果显示：昭披耶河流域降水空间分布不均，多集中在东北和东南地区；过去30年，全流域及上游滨河、汪河、永河和难河四个子流域面平均年降雨量均呈现显著上升趋势，上升速率分别为1.25 mm/a、1.06 mm/a、1.50 mm/a、2.61 mm/a和0.65 mm/a;流域年内降水分布呈现双峰形态，其中3—5月出现的第一个峰主要受南亚季风影响，7—9月出现的第二个峰主要受西北太平洋季风和热带气旋的影响；过去30年，昭披耶河流域以及上游四个子流域年径流均呈现显著上升趋势，上升速率分别为2.84亿m³/a、0.62亿m³/a、0.29亿m³/a、0.78亿m³/a和1.04亿m³/a。结果表明，南亚季风主导了该流域前期降雨峰值、西北太平洋季风及热带气旋主导了后期降雨峰值；雨季南亚季风和热带气旋显著增强引起暴雨增加，进而导致洪水加剧。通过对流域水循环过程各类要素时空特征变化分析，充分展示了基于数值模拟的流域水循环变化时空特征分析方法在流域水循环要素分析中的独特作用，可为流域水安全政策制定提供分析工具和有益参考。

Abstract

The basin water security is related to food security, people's health, and social stability. To explore the historical evolution law of basin water cycle under the background of global warming and socio-economic development, a set of spatial-temporal characteristic analysis method for basin water cycle changes based on numerical simulation is established, which is of great significance for formulating relevant policies to adapt to and mitigate future possible water disasters. Taking the Chao Phraya River Basin in Thailand as an example, a high-resolution distributed hydrological model GBHM is constructed by comprehensively applying measured meteorological, hydrological and underlying surface data. The hydrological process of the Chao Phraya River Basin from 1985 to 2014 is numerically simulated, the spatial-temporal evolution law of water cycle elements and vegetation is analyzed, and the “double peak” characteristic of annual rainfall distribution is clarified based on the EOF method. The result show that the spatial distribution of precipitation in the Chao Phraya River Basin is uneven, concentrated in the northeast and southeast regions; over the past 30 years, the average annual rainfall in the whole basin and the four sub-basins of the upper reaches, including the Bang River, Wang River, Yong River and Nan River, has shown a significant upward trend, with the increase rates being 1.25 mm/a, 1.06 mm/a, 1.50 mm/a, 2.61 mm/a and 0.65 mm/a respectively; the annual precipitation distribution in the basin shows a double-peak pattern, of which the first peak appearing from March to May is mainly affected by the South Asian monsoon, and the second peak appearing from July to September is mainly affected by the Northwest Pacific monsoon and tropical cyclones; over the past 30 years, the annual runoff of the Chao Phraya River Basin and the four sub-basins in the upper reaches has shown a significant upward trend, with the increase rates being 284 million m³/a, 62 million m³/a, 29 million m³/a, 78 million m³/a and 104 million m³/a respectively. The result indicate that the South Asian monsoon dominates the early rainfall peak in the basin, while the Northwest Pacific monsoon and tropical cyclones dominate the late rainfall peak; the significant enhancement of the South Asian monsoon and tropical cyclones during the rainy season causes an increase in heavy rain, which in turn leads to intensified floods. Through the analysis of the spatial-temporal characteristic changes of various elements in the basin water cycle process, the unique role of the numerical simulation-based spatial-temporal characteristic analysis method in the analysis of basin water cycle elements is fully demonstrated, which can provide analytical tools and useful references for the formulation of basin water security policies.

关键词

东南亚典型热带流域 / 水循环变化 / 分布式水文模型 / EOF方法

Key words

a typical tropical basin in Southeast Asia / water cycle change / a distributed hydrological model / the EOF method

Author summay

杨舒毓(1996—), 男, 工程师, 副总经理, 博士, 主要从事水利、航道工程建设研究。E-mail: [e-mail]

基金资助

国家自然科学基金项目(41661144031)

大芦线航道一体化运行方案研究及应用场景建设(CTKY-ZDZX-2024-011)