研究人员认为，基于216年的波河出口河流流量时间序列，2022 年的水文干旱是最严重的事件(比第二严重的事件低 30%，重现期为 6 个世纪)，是严重干旱发生率增加趋势的一部分。夏季河流流量的下降(每年每秒减少 4.14 立方米)比降水量的下降更相关，这归因于降水状况的变化，导致积雪率(每年减少 0.6%)和融雪量(每年每天减少 0.18 毫米)的下降，以及蒸发率(每年增加 0.013立方千米)和灌溉面积(从 1900 年增加 100%)的增长。
研究提出了一个令人信服的案例，气候变化的水文影响因水文季节性和用水的局部变化而加剧。
据介绍，人们对最近的水文干旱的原因及其在气候变化下的未来演化仍知之甚少。
附：英文原文
Title: Why the 2022 Po River drought is the worst in the past two centuries
Author: Alberto Montanari, Hung Nguyen, Sara Rubinetti, Serena Ceola, Stefano Galelli, Angelo Rubino, Davide Zanchettin
Issue&Volume: 2023-08-09
Abstract: The causes of recent hydrological droughts and their future evolution under a changing climate are still poorly understood. Banking on a 216-year river flow time series at the Po River outlet, we show that the 2022 hydrological drought is the worst event (30% lower than the second worst, with a six-century return period), part of an increasing trend in severe drought occurrence. The decline in summer river flows (-4.14 cubic meters per second per year), which is more relevant than the precipitation decline, is attributed to a combination of changes in the precipitation regime, resulting in a decline of snow fraction (-0.6% per year) and snowmelt (-0.18 millimeters per day per year), and to increasing evaporation rate (+0.013 cubic kilometers per year) and irrigated areas (100% increment from 1900). Our study presents a compelling case where the hydrological impact of climate change is exacerbated by local changes in hydrologic seasonality and water use.
DOI: adg8304
Source: https://www.science.org/doi/full/10.1126/sciadv.adg8304