Key Laboratory of Disaster Monitoring and Mechanism Simulating in Shaanxi Province, College of Geography and Environment, Baoji University of Arts and Sciences, Baoji 721013, China.
Institute of Water Resources and Hydro-electric Engineering, Xi'an University of Technology, Xi'an 710048, China.
Int J Environ Res Public Health. 2022 Feb 27;19(5):2771. doi: 10.3390/ijerph19052771.
Historical environmental evidence has been characterized by time accuracy, high spatial resolution and rich information, which may be widely used in the reconstruction of historical data series. Taking the upper reaches of the Weihe River as an example in Western China, the grades and index sequences of the drought and flood disasters from 1800 to 2016 were reconstructed based on various historical environmental information and standardized precipitation indicator (SPI). Moreover, the characteristics of droughts and floods were analyzed using statistical diagnostic methods, and the mechanisms affecting centennial-scale droughts and floods were discussed. The validity of reconstruction sequence of droughts/floods was verified, which showed that the reconstruction sequence may reasonably indicate the status of drought and flood. The reconstruction indicated the following periods of drought/flood: a period of extreme and big droughts in 1835s-1893s, 1924s-1943s and 1984s-2008s, a period of extreme and big floods in 1903s-1923s, and a period of extreme and big droughts/floods in 1944s-1983s. Moreover, the droughts were more serious in the western part of this region and the floods were relatively severe in the east of this region, while the droughts and floods have long-term period of about 100 years and mutation. The influence mechanism of external environmental forcing factors driving floods/droughts were revealed. The results showed that the cycle of El Niño Southern Oscillation (ENSO) and sunspot activities were closely related to the variations of drought/flood, meanwhile, ENSO has a significant lag time scale cumulative influence on droughts and floods, especially the 15-year sliding effect was the most obvious. In the peak year of sunspots, the probability of heavy drought/extreme floods was large, and the 102-year sunspot cycle has a more significant effect on drought and flood disasters. The mutation of droughts and floods occurred in the context of the drastic changes in the ground environment, and transformation of precipitation and land use structure. These results will enhance the understandings of historical environmental climate characteristics and mechanisms over the hundred years, and be useful for the future regional water resources and assessment, and ecological environment management.
历史环境证据具有时间精度高、空间分辨率高和信息丰富的特点，可广泛应用于历史数据序列的重建。以中国西部渭河流域上游为例，基于各种历史环境信息和标准化降水指标（SPI），重建了 1800 年至 2016 年的干旱和洪涝灾害等级和指数序列。此外，还使用统计诊断方法分析了干旱和洪水的特征，并讨论了影响百年尺度干旱和洪水的机制。验证了干旱/洪水重建序列的有效性，结果表明重建序列可以合理地指示干旱和洪水的状况。重建表明存在以下旱涝时期：1835 年至 1893 年、1924 年至 1943 年和 1984 年至 2008 年的特大干旱期、1903 年至 1923 年的特大洪灾期以及 1944 年至 1983 年的特大旱涝期。此外，该地区西部的干旱更为严重，东部的洪水相对严重，而旱涝具有约 100 年的长期周期和突变。揭示了外部环境强迫因素驱动旱涝的影响机制。结果表明，厄尔尼诺南方涛动（ENSO）和太阳黑子活动周期与旱涝变化密切相关，同时 ENSO 对旱涝具有显著的滞后时间尺度累积影响，尤其是 15 年滑动效应最为明显。在太阳黑子活动高峰期，重旱/特大洪水的概率较大，102 年太阳黑子周期对旱涝灾害的影响更为显著。旱涝的突变发生在地面环境剧烈变化、降水和土地利用结构转变的背景下。这些结果将增强对百年历史环境气候特征和机制的认识，有助于未来区域水资源和评估以及生态环境管理。
