Hydrological Drought Characteristics Research Articles

Assessment of Hydrological and Meteorological Composite Drought Characteristics Based on Baseflow and Precipitation

Traditional univariate drought indices may not be sufficient to reflect comprehensive information on drought. Therefore, this paper proposes a new composite drought index that can comprehensively characterize meteorological and hydrological drought. In this study, the new drought index was established by combining the standardized precipitation index (SPI) and the standardized baseflow index (SBI) for the Jiaojiang River Basin (JRB) using the copula function. The prediction model was established by training random forests on past data, and the driving force behind the combined drought index was explored through the LIME algorithm. The results show that the established composite drought index combines the advantages of SPI and SBI in drought forecasting. The monthly and annual droughts in the JRB showed an increasing trend from 1991 to 2020, but the temporal characteristics of the changes in each subregion were different. The accuracies of the trained random forest model for heavy drought in Baizhiao (BZA) and Shaduan (SD) stations were 83% and 88%, respectively. Furthermore, the Local Interpretable Model-Agnostic Explanations (LIME) interpretation identified the essential precipitation, baseflow, and evapotranspiration features that affect drought. This study provides reliable and valid multivariate indicators for drought monitoring and can be applied to drought prediction in other regions.

Correction: Abu Arra, A.; Şişman, E. Characteristics of Hydrological and Meteorological Drought Based on Intensity-Duration-Frequency (IDF) Curves. Water 2023, 15, 3142

In the original publication [...]

Future projections of meteorological, agricultural and hydrological droughts in China using the emergent constraint

Study regionChina. Study focusIn the context of global warming, droughts occur more frequently and have caused great losses to human society. Therefore, understanding the potential changes in future droughts under climate change is of great scientific significance for disaster prevention and mitigation. In this paper, combining with climate models from CMIP6, the emergent constraint and the skill scoring methods are used to analyze the characteristics of meteorological, agricultural and hydrological droughts in China under four socioeconomic scenarios in the mid and late 21st century. New hydrological insights for the regionIn the mid-21st century, there are more frequent meteorological, agricultural and hydrological droughts in northern China. In the late 21st century, sustained and more intense droughts are more likely to occur in China than in the mid-21st century. Additionally, the relationship between meteorological drought and agricultural/hydrological drought is strengthened to varying degrees in the future. From the perspective of extreme drought events, the probabilities of extreme drought events with long duration and high severity increase significantly in Northwest and Central China under each scenarios. In a higher socioeconomic scenario, drought is suppressed in the mid 21st century, but is intensified in the late 21st century. These findings are of great significance for drought monitoring under climate change and can provide a basis for developing measures to respond to drought.

Spatiotemporal heterogeneity in meteorological and hydrological drought patterns and propagations influenced by climatic variability, LULC change, and human regulations

This study aims to quantify meteorological–hydrological drought propagations and examine the potential impacts by climatic variability, LULC change (LULC), and human regulations. An integrated observation-modeling framework quantifies drought propagation intervals and assesses mechanisms influencing hydrological droughts. Meteorological droughts are characterized using the Standardized Precipitation Evapotranspiration Index (SPEI), and hydrological droughts are assessed through the Standardized Streamflow Index (SSI) across diverse climatic zones. Cross-correlation analysis between SPEI and SSI time series identifies the lag time associated with the highest correlation as the drought propagation interval. Mechanisms are investigated via a coupled empirical-process modeling framework incorporating the Soil and Water Assessment Tool (SWAT). Discrepancies between simulated and observed SSI time series help quantify the extent of human regulation impacts on hydrological drought characteristics and propagation. The Yellow River Basin (YRB), divided into six subzones based on climate characteristics, is selected as the case study. Key findings include: (1) Meteorological droughts were extremely severe across most YRB during the 1990s, while the 2000s showed some mitigation primarily due to precipitation increases. (2) Hydrological droughts and propagation times from meteorology to hydrology demonstrated substantial spatiotemporal variability. In general, summer propagation times were shorter than other seasons. (3) Propagation times were shorter in arid regions with cropland or built-up land cover versus grassland and woodland, while the reverse held for humid regions. (4) Human regulations prolonged propagation times, likely due to reservoir regulations designed to overcome water deficits. While the YRB is the focus of this paper, the methodologies and findings are applicable to other regions worldwide to enhance drought forecasting and water resource management. In various hydrological and climatic contexts worldwide.

Development of multivariate standardized drought index for large lake basins based on the copula function: A case study of Hongze Lake Basin, China

Study regionThe Hongze Lake Basin, China. Study focusA drought index is an essential tool for monitoring and prediction, and the construction of a comprehensive drought index is at the cutting edge of current drought research. Considering the regulation effect of lakes, a new drought index aimed at large lake catchment areas, namely the Multivariate Standardized Drought Index for Lakes Basin (MSDILB), can comprehensively characterise meteorological and hydrological drought. Here, the Standardised Precipitation Evapotranspiration Index (SPEI), Standardised Runoff Index (SRI), and MSDILB drought indices were used to evaluate the evolution of drought in the study area. Moreover, the response and conversion relationships between the basin’s hydro-meteorological elements and the regulation of the lake were explored. New hydrological insights for the RegionThe results indicate that: 1) in a dry year, the spatial-temporal heterogeneous runoff in the basin is redistributed by the storage and regulation of large lakes, thereby reducing the frequency of drought events; 2) the MSDILB drought index merges the characteristics of hydrological drought and meteorological drought indices and can monitor the evolution of drought events in lake basins; 3) the MSDILB drought index can sensitively capture the effects of lake hydrological regime change on drought events in the basin. Thus, it has the advantage of comprehensively characterising the drought conditions in large lake basins.

Attribution analysis of non-stationary hydrological drought using the GAMLSS framework and an improved SWAT model

Climate change and human activities are two key factors that modify the hydrological cycle and drought characteristics of a watershed. Quantifying the effects of climate change and human activities on hydrological drought is of great significance for water resources management. The traditional method of hydrological drought assessment is based on the assumption of stationarity, which is no longer applicable. In this study, using the Hanjiang River basin (HRB) as a study area, the Pettitt test and heuristic segmentation algorithm are first used to identify the change points in the runoff time series. Then, a distributed hydrological model (SWAT) is used to reconstruct the natural runoff series during the impacted period. Finally, the impacts of climate change and human activities on hydrological drought are quantitatively assessed using the non-stationary Standardized Runoff Index (NSRI), developed based on the GAMLSS model. Results show that runoff processes in the basin are non-stationary, and the year 1991 is identified as the change point of the runoff series. Both climate change and human activities exacerbate the hydrological drought by increasing its duration, severity, and peak, with climate change playing a dominant role in the 1990s. Human activities, however, have gradually surpassed the impact of climate change on hydrological drought since the 21st century. In addition, reservoir regulation extends the drought duration and severity but mitigates the peak. These findings provide valuable information for drought management and water resource regulation under changing environments.

Long-term meteorological and hydrological drought characteristics on the lower Tigris-Euphrates basin, Türkiye: relation, impact and trend

Long-term meteorological and hydrological drought characteristics on the lower Tigris-Euphrates basin, Türkiye: relation, impact and trend

Actual Evapotranspiration Dominates Drought in Central Asia

Central Asia is a drought-prone region that is sensitive to global climate change. The increased actual evapotranspiration intensifies the drought impacts in this area. However, little is known about the similarities and differences between various types of drought in Central Asia, as well as the relative importance of water income and consumption processes during drought events. Therefore, this study evaluates the trends and characteristics of meteorological, agricultural, and hydrological droughts in Central Asia using precipitation, soil moisture, and terrestrial water storage as indicators; explores the temporal correlation of and spatial similarity between various types of drought; and quantitatively assesses the contribution of water balance variables to drought intensity. The results indicate that drought has intensified in Central Asia, and the trends of precipitation, soil moisture, and terrestrial water storage in this region were −0.75 mm·yr−1 (p = 0.36), −0.0003 m3·m−3 yr−1 (p < 0.01), and −0.3742 cm·yr−1 (p < 0.001), respectively. Severe droughts are typically short in duration and high in intensity. Three various types of drought have low temporal correlation and spatial similarity. Furthermore, agricultural and hydrological droughts were primarily driven by actual evapotranspiration, accounting for relative contributions of 64.38% and 51.04% to these drought types, respectively. Moreover, the extent of increased actual evapotranspiration expanded to cover 49.88% of the region, exacerbating agricultural and hydrological droughts in 23.88% and 35.14% of the total study area, respectively. The study findings demonstrate that actual evapotranspiration plays a critical role in causing droughts. This study establishes a theoretical foundation to carry out drought assessment, the construction of multivariate drought indices, and water resource management in Central Asia.

Characteristics of Hydrological and Meteorological Drought Based on Intensity-Duration-Frequency (IDF) Curves

As a catastrophic phenomenon, drought has destructive impacts on water resources, the environment, and the ecosystem. Consequently, drought plays a vital role in risk assessment, water resources management, and drought mitigation plans. The main aim of this research is to obtain critical intensity-duration-frequency (IDF) drought curves and to provide a comprehensive understanding of the drought characteristics by considering the meteorological Standardized Precipitation Index (SPI), Standardized Precipitation Evapotranspiration Index (SPEI), and hydrological Standardized Streamflow Index (SSI). Critical IDF curves for the drought index and return period selection are identified. Also, new terms are defined as the specific drought duration, the maximum drought duration, and the critical intensity based on drought IDF curves. The results show that the SPI3 based on run theory for 500 years return period has higher drought intensity compared with other drought indices. In some IDF curves, the 2-year return period of a 12-month duration timescale is not provided. Regarding the maximum drought duration, the SPEI12 gave a longer duration. With the new concepts in this research, the presented IDF drought methodology has a novel additional practice to identify the critical intensity and maximum drought duration. Using this methodology for any drought index will contribute to converting data with mathematical calculations into IDF curves for design and risk assessment purposes.

Future changes in hydrological drought across the Yangtze River Basin: identification, spatial–temporal characteristics, and concurrent probability

Hydrological droughts have caused greater damage due to climate change and rapid socio-economic development. Exploring future hydrological drought variations is imperative for drought defense and infrastructure construction. This study aims to investigate future changes in hydrological droughts across the Yangtze River Basin during 2025 ∼ 2100. The Distributed Time-Variant Gain Model coupled with the Standard Operation Policy module (DTVGM-SOP) was employed to project future runoff driven by the bias-corrected Coupled Model Intercomparison Project Phase 6 (CMIP6) data. Subsequently, future spatial–temporal changes in the characteristics of hydrological droughts were analyzed based on the Standardized Runoff Index (SRI). Lastly, future changes in the probability of concurrent hydrological droughts were evaluated using the bivariate copula functions. Results show that: (1) The DTVGM-SOP model can satisfactorily simulate monthly streamflow with a high Nash-Sutcliff Efficiency (NSE) of 0.75 ∼ 0.92. Future annual maximum discharge and annual average discharge in the mainstream and the northern tributaries are expected to increase by 3.34%∼58.19% and 3.11%∼32.66% respectively, while annual maximum discharge in the southern tributaries decreases by 0.54%∼20.09%. (2) The future annual and seasonal hydrological drought frequency is expected to decrease in most regions, while the frequency in spring increases in the Qinghai Tibet Plateau. The duration and severity of future hydrological droughts are expected to decrease by 9.52%∼78.69% and 5.13%∼81.36% in the whole basin except the source area and the Yalong River Basin. (3) Future concurrent hydrological droughts will be mitigated with decreasing frequency. The probability of concurrent hydrological droughts is expected to decrease by 46.15%∼96.47%, while future changes in the conditional probability of the mainstream are diverse in different concurrent scenarios with a range of −93.41%∼40.09%. The findings are helpful to improve the understanding of future hydrological drought variations in the Yangtze River Basin and provide essential information for damage reduction.

Insights from CMIP6 SSP scenarios for future characteristics of propagation from meteorological drought to hydrological drought in the Pearl River Basin

Drought is a common and widely distributed natural hazard. Analyzing and predicting drought characteristics and propagation are important for the early warning, prevention, and mitigation of drought disasters. This study used the precipitation and runoff outputs from General Circulation Models (GCMs) of Coupled Model Intercomparison Project Phase 6 (CMIP6) to evaluate the meteorological drought (MD) and hydrological drought (HD) characteristics in the Pearl River Basin (PRB) under two Shared Socioeconomic Pathways (SSPs) (i.e., SSP2-4.5 and SSP5-8.5). The propagation characteristics of external propagation (response between different type of drought) and internal propagation (drought development and recovery stages of a single type of drought) were also comprehensively investigated based on CMIP6. The results revealed that: 1) the percentage of grids within the dry range of MD and HD will decrease from the historical period to the future period under the two scenarios. The PRB is projected to exhibit wetter patterns; 2) Higher emission scenarios (SSP5-8.5) are more likely to weaken dryness conditions; 3) regarding the external propagation, the drought response time from MD to HD would be 2 months, and there would be no significant change under two scenarios; and 4) regarding the internal propagation, during three study periods (1971–2010, 2021–2060 and 2061–2100), the MD (HD) average recovery time changed from 3.90 (3.36) to 3.75 (3.41) and then to 3.95 (3.43) months under the SSP2-4.5 scenario, and changed from 3.93 (3.46) to 3 (3.51) and then to 3.7 (3.25) months under the SSP5-8.5 scenario. These results aid in understanding future drought characteristics and drought propagation under climate change.

Intensification of drought propagation over the Yangtze River basin under climate warming

AbstractThe propagation from meteorological to hydrological drought is critical for better understanding hydrological drought. However, how climate change would affect the drought propagation has not been well studied, especially over regions mixed with massive human interventions. The study attempts to explore changes in the characteristics of meteorological and hydrological droughts, and the corresponding drought propagation under different climate change scenarios across six watersheds over the Yangtze River basin (YZB). Seasonal meteorological and hydrological droughts were characterized by using standardized precipitation and streamflow index at 3‐month scales (SPI‐3 and SSI‐3), which were calculated using precipitation simulations from 15 Coupled Model Intercomparison Project Phase 6 (CMIP6) climate models and streamflow simulations from PCR‐GLOBWB 2.0 hydrological model driven by CMIP6 outputs. Drought propagation characteristics, including propagation ratio, lag and lengthening, were then determined. Both meteorological and hydrological drought durations would shorten, while their drought severity would increase excluding a downstream watershed. About 40%–50% of meteorological droughts could develop into hydrological droughts, with lag time less than 1.4 months and lengthening time less than 1.8 months, respectively. Under climate warming, the drought propagation ratio would increase over two watersheds, while decrease and then increase over three watersheds. The drought propagation lag time is expected to prolong over the regions above Cuntan under moderate emission scenario, while prolong first and then shorten over most watersheds under high‐emission scenario. The drought propagation lengthening time would shorten over most watersheds excluding a downstream watershed, where drought conditions would further worsen during drought propagation. This study calls for climate mitigation efforts to suppress drought aggravation in the propagation particularly for the downstream YZB.

Roles of reservoirs in regulating basin flood and droughts risks under climate change: Historical assessment and future projection

Study regionNenjiang River Basin (NRB), Northeast China. Study focusWater safety management and sustainable development planning increasingly seek to incorporate the impact of reservoirs on downstream floods and droughts; while the effectiveness of reservoir operation in regulating flood and drought risks under climate change has not been assessed extensively. We focus on discerning whether and to what extent reservoirs can mitigate the risk of hydrologic extremes from the perspective of historical and future climate change. New hydrological insight for the regionWe found that coupling reservoir operations into basin hydrological simulation can efficiently improve model capacity to capture both flood and hydrological drought characteristics. The Nierji Reservoir contributed largely to reducing historical flood and drought risks in the NRB. However, the risk of floods and hydrological droughts will increase under future climate change, and reservoir operations cannot completely eliminate the increasing risks of future floods and hydrological droughts. The annual probability of flooding under different future scenarios will exceed 48%, much higher than the 22.2% for the historical period. The frequency of droughts is anticipated to increase by 139.20% under the Shared Socioeconomic Pathways (SSP) 370 scenario. To mitigate the increase of flood and drought risks caused by future climate change, it is necessary to further optimize reservoir scheduling principles, thereby improving the basin's resilience to hydrological extremes.

A new approach for characterization of meteorological and hydrological droughts: Cumulative standardized drought index (CSDI)

Identifying drought events and their characteristics for a river watershed that provides drinking water for metropolitan centers is crucial to sustaining water resources management. In this study, Cumulative Standardized Drought Index (CSDI) is developed to examine the effect of previous dry or wet periods on the characteristics of the drought event. Meteorological and hydrological droughts of the Gordes and Tahtali watersheds, which provide a significant part of the drinking water of Izmir, Turkey, determined for 1, 3, 6 and 12 month time scale by CSDI. The peak turning points of CSDI according to time show the transition from wet to dry period, whereas the lowest turning points do the transition from dry to wet period. Cumulative sum (CUSUM), Pettitt and means square error (MSE) analyzes are used to determine whether the turning points are significant turning point. As a result of the study, the characteristics of dry events, duration, magnitude and intensity, are determined with CSDI, especially those occurring at short time scales such as 1 and 3 months. In addition, the characteristics of meteorological and hydrological droughts observed at 12 month time scale are determined with the CSDI method and the Run Theory and comparisons were made in the study. As a result of the comparison, it is found that drought events, which seem to be different drought periods, indicate a single period when the effect of the past periods is considered. It is shown that the CSDI method can be used adequately to determine the dry and wet periods and their characteristics of the watersheds.

Integrating multiple comparison methods for attributing hydrological drought evolution and drought propagation: The impact of climate change cannot be ignored

Enhancing the comprehension of hydrological drought evolution and drought propagation mechanisms is crucial for effective drought risk management in a changing environment. Previous studies have either inadequately considered the effects of climate change or conflated the impacts of large reservoirs and human activities. This study presents a comprehensive framework that integrates multiple comparison methods to quantify the effects of climate change, large reservoirs, and other human activities. The framework comprises three steps: (1) preparation of four types of streamflow based on critical time, large reservoirs inflow and outflow, and hydrological model; (2) estimation of hydrological drought characteristics, including duration, severity, peak intensity, instantaneous development speed, and instantaneous recovery speed and drought propagation characteristics, such as correlation, transition rate, and three types of the propagation time (PT) based on the start point (PTS), peak point (PTP), and end point (PTE); (3) quantification of the influences of various factors on the characteristic variables. The upper Yellow River Basin, a cold basin with large cascade reservoirs, was selected as the study area to utilize the proposed framework. The results revealed that climate change and large reservoirs reduced the duration and severity of drought events with relative contribution rates ranging from 146.6% to 340.2% and 381% to 707.7%, respectively, while those were increased by human activities with relative contribution rates from 428.0% to 1147.9%. Large reservoirs played the most crucial role in the development and recovery stages, with relative contribution rates of 75% and 85%, respectively. Climate change strengthened the correlation between the two drought indices, while human activities and large reservoirs weakened the correlation. The changes in three PT indicated that climate change shortened drought development and recovery period, while those were prolonged by human activities. Many hydrological droughts occurred before meteorological droughts due to large reservoir regulations. The changes in transition rates are −30.3%, 48.0%, and −28% under the influences of climate change, human activities, and large reservoirs, respectively. The framework and results of this study provide valuable insights into the mechanisms of hydrological drought and drought propagation and serve as a scientific basis for drought mitigation in changing environments.

Characterization and assessment of hydrological droughts using GloFAS streamflow data for the Narmada River Basin, India.

Hydrological droughts severely affect the demand of water for domestic water supply, irrigation, hydropower generation, and several other purposes. The pervasiveness and consequences of hydrological droughts necessitate a thorough investigation of their characteristics, which is hindered due to unavailability of continuous streamflow records at desirable resolutions. This study aims to assess the hydrological drought characteristics and their spatial distribution using high-resolution Global Flood Awareness System (GloFAS) v3.1 streamflow data for the period 1980 to 2020. Streamflow Drought Index (SDI) was used to characterize droughts at 3-, 6-, 9-, and 12-monthly timescales starting from June, i.e., the start of water year in India. GloFAS is found to capture the spatial distribution of streamflow and its seasonal characteristics. The number of hydrological drought years over the basin varied from 5 to 11 during the study duration, implying that the basin is prone to frequent abnormal water deficits. Interestingly, the hydrological droughts are more frequent in the eastern portion of the basin, i.e., the Upper Narmada Basin. The trend analysis of multi-scalar SDI series using non-parametric Spearman's Rho test exhibited increasing drying trends in the easternmost portions. The results were not similar for the middle and western portions of the basin, which may bedue to presence of a large number of reservoirs in these regions and their systematic operations. This study highlights the importance of open-access global products that can be used for monitoring hydrological droughts, especially over ungauged catchments.

Using the Global Navigation Satellite System and Precipitation Data to Establish the Propagation Characteristics of Meteorological and Hydrological Drought in Yunnan, China

AbstractAnalyzing the spatiotemporal characteristics and evolution of meteorological and hydrological droughts can reproduce the process of drought propagation, which helps reduce the impact of droughts and improve water resources management. While emerging studies have attempted to build drought severity index based on the cutting‐edge space geodetic observations, few have focused the propagation characteristics of meteorological to hydrological drought using geodetic data. In this paper, using global navigation satellite systems (GNSS) observations together with precipitation data, we systematically investigated drought propagation in the Yunnan province, Southwest China. We first identified seven meteorological and seven hydrological droughts in Yunnan from January 2011 to May 2021, and the meteorological drought was mainly concentrated in northern Yunnan lasting for 1–11 months. By contrast, hydrological droughts were more severe and larger than meteorological droughts, lasting for 2–16 months. The drought propagation time was 2–7 months, short in the southwest but long in the northeast. Water vapor, precipitation, and water storage demonstrated a spatiotemporal pattern of uneven distribution, with the red river fault (RRF) as the boundary, and their phase difference also presented notable regional differences, indicating that the RRF not only influences spatial variation of water resources but also affects drought propagation.

An Investigation of Hydrological Drought Characteristics in Kızılırmak Basin, Türkiye: Impacts and Trends

Drought is a natural disaster that is generally defined as precipitations which are significantly below the precipitation recorded in normal times. Drought has been classified as meteorological, hydrological, agricultural, and socio-economic by many researchers. Hydrological drought takes place when deficiencies in the surface and ground waters occur as a result of the long-term lack of precipitation. In this study, a hydrological drought analysis has been performed for Kızılırmak Basin which is the second biggest basin of Turkey by using streamflow drought index (SDI) and innovative trend analysis (ITA) for the time scales of 1, 3, 6, 9, 12-month. Monthly mean streamflow records of 7 stations are obtained from the General Directorate of State Hydraulic Works (DSİ). Drought severity and drought duration which is two important drought characteristics have been calculated for each time scale with their occurrence term. Results have shown that Mild Drought and Wet (SDI≥0) have the highest percentage of occurrences. Using Run Theory, the longest lasted and highest drought has been noted in the SDI-12-time scale of E15A017 station with 149.72 and 103 months as severity and duration, respectively. From the highest severity and longest lasted droughts, it is seen that starting with 2000, the basin is exposed to the highest occurrence of droughts. ITA results have shown that in most of the SDI series of any time scale a trend is existent and these trends are mostly decreasing trends. Therefore, the results of this have shown that the basin needs to be kept from the potential effects of droughts with effective water resources management plan.

SEBARAN KEKERINGAN HIDROLOGI BERDASARKAN DEBIT ALIRAN DI KABUPATEN BIMA

A phenomenon that often occurs in Indonesia which is also an annual disaster that hit several areas is drought. Drought is a condition in which an area, land, or community experiences a shortage of water so that it cannot meet their needs. Drought can be caused because an area does not experience rain or is dry for a long period of time or the rainfall is below normal, so that the water content in the soil is reduced or even non-existent. The areas to be analyzed are the Hidirasa watershed, the Rontu watershed, and the Jangka watershed in Bima Regency, West Nusa Tenggara. The analysis drought aims to determine the deficit, drought duration, drought criteria based on deficits and surpluses that occur by analogy to Oldeman's criteria, hydrological drought index analysis, and hydrological drought distribution maps. In this study, data were used for the Tawali watershed in the Hidirasa watershed, the Sari watershed for the Jangka and the Kumbe water for the Rontu watershed to determine the Q50 and Q80 thresholds using the method Flow Duration Curve (FDC) to obtain hydrological drought characteristics. In the analysis of hydrological drought in several watersheds in Bima Regency, the results show that the maximum deficit in the Hidirasa, Term and Rontu watersheds was 1.09 m³/s, 0.14 m³/s, 0.49 m³/s which occurred in 2001, 1995, and 2001. From the deficit, it was found that the average drought period occurred 8-9 months from May to December and even some until January which indicated that the drought criteria were in zone 2 according to Oldeman. The largest hydrological drought index is the Hidirasa watershed, the Jangka Watershed and the Rontu watershed, respectively, -0.45, -1.00, -1.00, with a very strong drought category.

Possible Future Climate Change Impacts on the Meteorological and Hydrological Drought Characteristics in the Jinghe River Basin, China

Revealing the impact of future climate change on the characteristics and evolutionary patterns of meteorological and hydrological droughts and exploring the joint distribution characteristics of their drought characteristics are essential for drought early warning in the basin. In this study, we considered the Jinghe River Basin in the Loess Plateau as the research object. The standardized precipitation index (SPI) and standardized runoff index (SRI) series were used to represent meteorological drought and hydrological drought with monthly runoff generated by the SWAT model. In addition, the evolution laws of the JRB in the future based on Copula functions are discussed. The results showed that: (1) the meteorological drought and hydrological drought of the JRB displayed complex periodic change trends of drought and flood succession, and the evolution laws of meteorological drought and hydrological drought under different spatiotemporal scales and different scenario differ significantly. (2) In terms of the spatial range, the JRB meteorological and hydrological drought duration and severity gradually increased along with the increase in the time scale. (3) Based on the joint distribution model of the Copula function, the future meteorological drought situation in the JRB will be alleviated when compared with the historical period on the seasonal scale, but the hydrological drought situation is more serious. The findings can help policy-makers explore the correlation between meteorological drought and hydrological drought in the background of future climate change, as well as the early warning of hydrological drought.