分类： 地球科学 >> 地球科学其他学科 提交时间： 2024-02-21 合作期刊: 《干旱区科学》
摘要： Severe soil erosion and drought are the two main factors affecting the ecological security of the Loess Plateau, China. Investigating the influence of drought on soil conservation service is of great importance to regional environmental protection and sustainable development. However, there is little research on the coupling relationship between them. In this study, focusing on the Jinghe River Basin, China as a case study, we conducted a quantitative evaluation on meteorological, hydrological, and agricultural droughts (represented by the Standardized Precipitation Index (SPI), Standardized Runoff Index (SRI), and Standardized Soil Moisture Index (SSMI), respectively) using the Variable Infiltration Capacity (VIC) model, and quantified the soil conservation service using the Revised Universal Soil Loss Equation (RUSLE) in the historical period (2000–2019) and future period (2026–2060) under two Representative Concentration Pathways (RCPs) (RCP4.5 and RCP8.5). We further examined the influence of the three types of drought on soil conservation service at annual and seasonal scales. The NASA Earth Exchange Global Daily Downscaled Projections (NEX-GDDP) dataset was used to predict and model the hydrometeorological elements in the future period under the RCP4.5 and RCP8.5 scenarios. The results showed that in the historical period, annual-scale meteorological drought exhibited the highest intensity, while seasonal-scale drought was generally weakest in autumn and most severe in summer. Drought intensity of all three types of drought will increase over the next 40 years, with a greater increase under the RCP4.5 scenario than under the RCP8.5 scenario. Furthermore, the intra-annual variation in the drought intensity of the three types of drought becomes smaller under the two future scenarios relative to the historical period (2000–2019). Soil conservation service exhibits a distribution pattern characterized by high levels in the southwest and southeast and lower levels in the north, and this pattern has remained consistent both in the historical and future periods. Over the past 20 years, the intra-annual variation indicated peak soil conservation service in summer and lowest level in winter; the total soil conservation of the Jinghe River Basin displayed an upward trend, with the total soil conservation in 2019 being 1.14 times higher than that in 2000. The most substantial impact on soil conservation service arises from annual-scale meteorological drought, which remains consistent both in the historical and future periods. Additionally, at the seasonal scale, meteorological drought exerts the highest influence on soil conservation service in winter and autumn, particularly under the RCP4.5 and RCP8.5 scenarios. Compared to the historical period, the soil conservation service in the Jinghe River Basin will be significantly more affected by drought in the future period in terms of both the affected area and the magnitude of impact. This study conducted beneficial attempts to evaluate and predict the dynamic characteristics of watershed drought and soil conservation service, as well as the response of soil conservation service to different types of drought. Clarifying the interrelationship between the two is the foundation for achieving sustainable development in a relatively arid and severely eroded area such as the Jinghe River Basin.
分类： 地球科学 >> 大气科学 提交时间： 2023-05-11 合作期刊: 《干旱区科学》
摘要：In the context of global warming, drought events occur frequently. In order to better understanding the process and mechanism of drought occurrence and evolution, scholars have dedicated much attention on drought propagation, mainly focusing on drought propagation time and propagation probability. However, there are relatively few studies on the sensitivities of drought propagation to seasons and drought levels. Therefore, we took the Heihe River Basin (HRB) of Northwest China as the case study area to quantify the propagation time and propagation probability from meteorological drought to agricultural drought during the period of 1981–2020, and subsequently explore their sensitivities to seasons (irrigation and non-irrigation seasons) and drought levels. The correlation coefficient method and Copula-based interval conditional probability model were employed to determine the drought propagation time and propagation probability. The results determined the average drought propagation time as 8 months in the whole basin, which was reduced by 2 months (i.e., 6 months) on average during the irrigation season and prolonged by 2 months (i.e., 10 months) during the non-irrigation season. Propagation probability was sensitive to both seasons and drought levels, and the sensitivities had noticeable spatial differences in the whole basin. The propagation probability of agricultural drought at different levels generally increased with the meteorological drought levels for the upstream, midstream, and southern downstream regions of the HRB. Lesser agricultural droughts were more likely to be triggered during the irrigation season, while severer agricultural droughts were occurred mostly during the non-irrigation season. The research results are helpful to understand the characteristics of drought propagation and provide a scientific basis for the prevention and control of droughts. This study is of great significance for the rational planning of local water resources and maintaining good ecological environment in the HRB.
点击量
通过
点击量
下载量
评论
