Spatiotemporal Variation Of Drought Research Articles

Correction to: Evaluating the Influence of El Nino–Southern Oscillation (ENSO) Patterns on the Spatio-Temporal Variations of Drought over Southern Peninsular Indian Region

Correction to: Evaluating the Influence of El Nino–Southern Oscillation (ENSO) Patterns on the Spatio-Temporal Variations of Drought over Southern Peninsular Indian Region

Spatiotemporal variations of drought and driving factors based on multiple remote sensing drought indices: A case study in karst areas of southwest China

Spatiotemporal variations of drought and driving factors based on multiple remote sensing drought indices: A case study in karst areas of southwest China

Spatiotemporal variation of drought in the Western Sichuan Plateau based on standardized precipitation evapotranspiration index.

Drought is a destructive natural disaster in the Western Sichuan Plateau. Understanding its spatiotemporal variations has important practical significance for drought prevention, ensuring agricultural production safety, and maintaining ecosystem health in the region. Based on the daily meteorological data from 48 meteorological stations in the Western Sichuan Plateau from 1980 to 2020, we used the Penman-Monteith model to calculate potential evapotranspiration and standardized precipitation evapotranspiration index (SPEI). The temporal and spatial variations of drought in the Western Sichuan Plateau were analyzed using linear trend analysis and drought characteristics analysis methods. The results showed that the annual and spring SPEI of the Western Sichuan Plateau showed a weak wetting trend from 1980 to 2020, while summer, autumn, and winter showed a drought trend. The southwest mountains and northeast grasslands in the study region were prone to drought. The range of interannual drought impact in the study area was weakly increasing, with a decreasing trend in spring and an increasing trend in summer, autumn, and winter. The overall drought frequency in the whole region was relatively high. The areas drought of low-frequency were mainly located in parts of west and northeast of the Western Sichuan Plateau, while the rest were high frequency areas.

Spatio-Temporal Analysis of Drought in the North-Eastern Coastal Region of Vietnam Using the Standardized Precipitation Index (SPI)

Spatio-temporal analysis of drought provides valuable information for drought management and damage mitigation. In this study, the Standardized Precipitation Index at the time scale of 6 months (SPI-6) is selected to reflect drought conditions in the North-Eastern coastal region of Vietnam. The drought events and their characteristics from 1981 to 2019 are detected at 9 meteorological stations and 10 Chirps rainfall stations. The spatio-temporal variation of drought in the study region is analyzed on the basis of the number, duration, severity, intensity, and peak of the detected drought events at the 19 stations. The results show that from 1981 to 2019 the drought events mainly occurred with 1-season duration and moderate intensity and peak. The number, duration, severity, and peak of the drought events were the greatest in the period 2001-2010 and were the smallest in the period 2011-2019. Among the 19 stations, the drought duration tends to decrease at 11 stations, increase at 7 stations, and has a slight variant at 1 station; the drought severity tends to decrease at 14 stations, increase at 4 stations, and has not a significant trend at 1 station; the drought intensity tends to decrease at 17 stations, increase at 1 station, and has a slight variant at 1 station; and the drought peak tends to decrease at 18 stations and increase at 1 station.

Spatiotemporal variation of drought in Iraq for shared socioeconomic pathways

Spatiotemporal variation of drought in Iraq for shared socioeconomic pathways

Intensity and spatiotemporal variations of drought in Tumakuru district, India using drought indices

Depletion of water resources and soil moisture leading to drought is a global concern and the effective assessment and monitoring using a drought model has become essential. A detailed account of frequency, run length and temporal trend of the drought events are presented in the study from 1981 to 2019 at the 1-, 3-, 6-, 9-, 12- and 24-month timescale using the Standardized Precipitation Index and Standardized Precipitation Evapotranspiration Index. SPI recorded more drought months in the extreme category with 14 months at Gubbi station for example, while SPEI showed only 5 months. SPEI showed longer drought length in moderate and severe categories for agricultural and hydrological drought. At a 1-month timescale, both the indices reported extreme drought events where Tiptur station in May 2016 (–4.75) and Chikkanayakanahalli station in March 1992 (–2.76) were the worst-case scenarios. The study aims at providing practical results to facilitate decision-makers for drought risk management.

Spatiotemporal Variations of Drought and the Related Mitigation Effects of Artificial Precipitation Enhancement in Hengyang-Shaoyang Drought Corridor, Hunan Province, China

It is important to reveal the spatial and temporal variations of drought and evaluate the alleviating effects of artificial precipitation on drought severity, as it will contribute immensely to the formulation of drought prevention and mitigation measures and the provision of guidance to artificial precipitation enhancement operation. Based on the monthly precipitation data of 28 meteorological stations in Hengyang-Shaoyang Drought Corridor (HSDC) from 1960 to 2019, the standardized precipitation index (SPI) at multiple time scales were calculated to estimate drought frequency, drought station ratio, and drought intensity. Then the spatiotemporal variations of drought in the study area were unveiled, and the effects of artificial precipitation enhancement were evaluated in line with the relevant data from 2005 to 2019. The results show that at the annual scale, drought occurred in 3/4 of past sixty years in the study area, where almost 1/3 of such years experienced area-wide droughts. Drought coverage in HSDC exhibited a decreasing trend, but drought intensity, as well as the number of area-wide droughts and regional droughts showed an increasing one. Mild and moderate droughts occurred in an extensive part of the HSDC, whereas severe and extreme droughts were mainly found in a few stations. At the seasonal scale, winter drought occurred most frequently, followed by summer and autumn droughts, while spring drought events had the lowest frequency. Overall, drought is more serious in spring, autumn, and winter, but less severe in summer; although drought intensity decreased slightly in summer, both its intensity and coverage showed an increasing trend in other seasons. At the monthly scale, the ratio of positive to negative SPI values in HSDC was basically balanced in the past six decades, exhibiting no distinct variation characteristics. In addition, artificial precipitation enhancement effectively eased monthly and even seasonal drought in HSDC. These findings, which fully reflect the characteristics of drought in the study area, can also raise awareness of the contribution that artificial precipitation could make to drought mitigation, which in turn will contribute to the formulation of appropriate strategies for climate change mitigation and adaptation.

Evaluating the Influence of El Nino–Southern Oscillation (ENSO) Patterns on the Spatio-Temporal Variations of Drought over Southern Peninsular Indian Region

Evaluating the Influence of El Nino–Southern Oscillation (ENSO) Patterns on the Spatio-Temporal Variations of Drought over Southern Peninsular Indian Region

Spatiotemporal Variation of Drought and Its Correlation With Plant Species of Yunnan Province, China

Drought is the main natural disaster in Yunnan Province, China. In the present paper monthly precipitation observation data from Yunnan Province durign the period of 1966 - 2015 were used. From the data, the selected percentage of precipitation anomalies was used as drought index. By applying the ArcGIS inverse distance interpolation method and Mann Kendall non parametric trend test method the spatiotemporal variation characteristics of drought in Yunnan province were analyzed. Results show that the drought in Yunnan Province has a slightly upward trend. In spring and winter, there is a tendency to become wet but in summer and autumn, the tendency is shown by dry condition. It was observed that the studied area is prone to a severe drought in winter, and there will be more droughts in the east part, the northwest part, and the southwest part of Yunnan province when it is autumn. In other periods, severe doughts usually attack the middle part of Yunnan province, which can be proved by the characteristics of vegetation distribution. Bangladesh J. Bot. 50(4): 1133-1142, 2021 (December)

Spatio-Temporal Variation of Drought within the Vegetation Growing Season in North Hemisphere (1982–2015)

Drought disasters jeopardize the production of vegetation and are expected to exert impacts on human well-being in the context of global climate change. However, spatiotemporal variations in drought characteristics (including the drought duration, intensity, and frequency), specifically for vegetation areas within a growing season, remain largely unknown. Here, we first constructed a normalized difference vegetation index to estimate the length of the growing season for each pixel (8 km) by four widely used phenology estimation methods; second, we analyzed the temporal and spatial patterns of climate factors and drought characteristics (in terms of the Standardized Precipitation Evapotranspiration Index (SPEI)), within a growing season over vegetation areas of the northern hemisphere before and after the critical time point of 1998, which was marked by the onset of a global warming hiatus. Finally, we extracted the highly drought-vulnerable areas of vegetation by examining the sensitivity of the gross primary production to the SPEI to explore the underlying effects of drought variation on vegetation. The results revealed, first, that significant (p < 0.05) increases in precipitation, temperature, and the SPEI (a wetting trend) occurred from 1982 to 2015. The growing season temperature increased even more statistically significant after 1998 than before. Second, the duration and frequency of droughts changed abruptly and decreased considerably from 1998 to 2015; and this wetting trend was located mainly in high-latitude areas. Third, at the biome level, the wetting areas occurred mainly in the tundra, boreal forest or taiga, and temperate coniferous forest biomes, whereas the highly drought-vulnerable areas were mainly located in the desert and xeric shrubland (43.5%) biomes. Our results highlight the fact that although the drought events within a growing season decreased significantly in the northern hemisphere from 1998 to 2015, the very existence of a mismatch between a reduction in drought areas and an increase in highly drought-vulnerable areas makes the impact of drought on vegetation nonnegligible. This work provides valuable information for designing coping measures to reduce the vegetative drought risk in the Northern Hemisphere.

Spatiotemporal Variations of Drought and Their Teleconnections with Large-Scale Climate Indices over the Poyang Lake Basin, China

The intensity and frequency of droughts in Poyang Lake Basin have been increasing due to global warming. To properly manage water resources and mitigate drought disasters, it is important to understand the long-term characteristics of drought and its possible link with large-scale climate indices. Based on the monthly meteorological data of 41 meteorological stations in Poyang Lake Basin from 1958 to 2017, the spatiotemporal variations of drought were investigated using the standardized precipitation evapotranspiration index (SPEI). Ensemble empirical mode decomposition (EEMD) methods and the modified Mann–Kendall (MMK) trend test were used to explore the spatiotemporal characteristics and trends of drought. Furthermore, to reveal possible links between drought variations and large-scale climate indices in Poyang Lake Basin, the relationships between SPEI and large-scale climate indices, such as North Atlantic Oscillation (NAO), El Niño–Southern Oscillation (ENSO), Arctic Oscillation (AO), Indian Ocean Dipole (IOD) and Pacific Decadal Oscillation (PDO) were examined using cross-wavelet transform. The results showed that the SPEI in Poyang Lake Basin exhibited relatively stable quasi-periodic oscillation, with approximate quasi-3-year and quasi-6-year periods at the inter-annual scale and quasi-15-year and quasi-30-year periods at the inter-decadal scale from 1958 to 2017. Moreover, the Poyang Lake Basin experienced an insignificantly wetter trend as a whole at the annual and seasonal scales during the period of 1958–2017, except for spring, which had a drought trend. The special characteristics of the trend variations were markedly different in the basin. The areas in which drought was most likely to occur were mainly located in the Poyang Lake region, northwest and south of the basin, respectively. Furthermore, relationships between the drought and six climate indices showed that the drought exhibited a significant temporal correlation with five climate indices at restricted intervals, except for IOD. The dominant influences of the large-scale climate indices on the drought evolutions shifted in the Poyang Lake Basin during 1958–2017, from the NAO, Niño 3.4, and the Southern Oscillation Index (SOI) before the late 1960s and early 1970s, to the AO and PDO during the 1980s, then to the NAO, AO and SOI after the early 2000s. The NAO, AO and SOI exerted a significant influence on the drought events in the basin. The results of this study will benefit regional water resource management, agriculture production, and ecosystem protection in the Poyang Lake Basin.

Spatiotemporal variations of drought in the Yunnan-Guizhou Plateau, southwest China, during 1960–2013 and their association with large-scale circulations and historical records

Abstract It is imperative that more powerful drought indicators are used to objectively quantify the characteristics of droughts. A revised reconnaissance drought index (RDI) was used to detect drought in the Yunnan-Guizhou Plateau (YGP), and the impacts of potential evapotranspiration, precipitation, and climate index anomalies were also considered. This will help to further elucidate the causes of meteorological droughts from a climate change perspective, and is of great importance in guiding future drought prediction and control. The non-parametric Mann-Kendall test was applied to identify points of change for meteorological droughts in the YGP during 1960–2013, and a cross wavelet analysis was used to reveal correlations between monthly climate indices and the RDI. The results are as follows: (1) The decreasing RDI trends (annual (−0.066/10a), summer (−0.18/10a), autumn (−0.196/10a), and winter (−0.056/10a)) indicate increasing drought severity, while the increasing trend in spring (0.084/10a) indicates a decreasing drought severity. However, these trends were insignificant, and no mutations occurred in the YGP during 1960–2013. (2) The drought duration was longest in the central, southern, northwestern, and northeastern edge of Yunnan Province (YP) and in the western parts of Guizhou Province (GP), while the drought severity was higher in the southwestern, eastern, and western edge of YP, and throughout GP. For the entire YGP, the duration and severity of droughts in the 1960s, 1980s, and 2000s was generally stronger than in 1970s and 1990s (3) Drought events that were identified by the RDI are consistent with those in historical records, but there are also inconsistencies during individual years. It was found that the RDI accounts for both the influence of precipitation and evaporation on drought: a decreased annual precipitation (84.6%) and an increased evaporation (40.7%) both contributed to decreased RDI (59.3%) for all stations. Therefore, the decrease in precipitation may lead to drought in the YGP. (4) The El Nino Southern Oscillation and the Arctic Oscillation play major roles in meteorological droughts in the YGP and affect the RDI over a relatively short timescale (1–8 years); severe droughts in spring occurred mainly during El Nino events, whereas both El Nino and La Nina events were associated with droughts in summer, autumn, and winter. Overall, severe droughts occurred more frequently during the El Nino event than during the La Nina event.

Correction: Liu, L., et al. Spatiotemporal Variation of Drought and Associated Multi-Scale Response to Climate Change over the Yarlung Zangbo River Basin of Qinghai–Tibet Plateau, China. Remote Sensing 2019, 11, 1596

The authors wish to make the following corrections to this paper [1]: [...]

The Spatiotemporal Variation of Drought in the Beijing-Tianjin-Hebei Metropolitan Region (BTHMR) Based on the Modified TVDI

This study proposes a modified vegetation-dependent temperature-vegetation dryness index (TVDI) model for analyzing regional drought disasters in the Beijing-Tianjin-Hebei Metropolitan Region (BTHMR) of China. First, MODIS monthly normalized difference vegetation index (NDVI), land surface temperature (LST) data and land use/cover data (Land cover type2) were pre-processed as a consistent big dataset. The land use/cover data were modified and integrated into six primary types. Then, these land types were used as the base data layer to calculate the TVDI by parameterizing the relationship between the MODIS NDVI and LST data. By emphasizing different types of land uses, this study was able to compare and analyze the differences of the TVDI indices between the entire study area (no consideration of the land types) and the six classified land uses. The soil moisture data were used to validate the modified TVDI values based on different land uses, which confirmed that the modified model more effectively reflected drought conditions. Finally, the aforementioned model was used to analyze the temporal and spatial variation of drought experienced by vegetation cover from 2000 to 2014. The results of the modified model were validated with the synchronized soil moisture and precipitation data. The case study clearly demonstrated that the modified TVDI model, which is based on different vegetation indexes, could better reflect the drought conditions of the study area.

An improvement of the Ts-NDVI space drought monitoring method and its applications in the Mongolian plateau with MODIS, 2000–2012

Surface soil moisture is a key variable to describe water and energy exchanges at the surface/atm interface and measure drought and aridification. The Ts-NDVI space is an effective method to monitor regional surface soil moisture status. Due to the disturbance of multiple factors, the established dry or wet boundary with monotemporal remote sensing data is unstable. This paper developed a Ts-NDVI triangle space with MODIS NDVI dataset to monitor soil moisture in the Mongolian Plateau in 2000–2012. Based on the temperature vegetation dryness index (TVDI), the spatiotemporal variations of drought were studied. The results indicated that (1) the general Ts-NDVI space method is an effective way to monitor regional soil moisture. However, if the single time space shows perfect structure, there would be no differences between the inverted results of the single time space and the general space. (2) The TVDI calculated in the paper is expected to show the water deficit for the region from low (bare soil) to high (full vegetation cover) NDVI values, and it is found to be in close negative agreement with precipitation and soil moisture; changes in the TVDI are dependent on the water status in the study area. (3) In the Mongolian Plateau, TVDI presented a zonal distribution with changes in Land Use/Land Cover types, vegetation cover, and latitude. Drought was serious in bare land, construction land, and grassland. Drought was widely spread throughout the Mongolian Plateau, and there was aridification in the study period. Vegetation degradation, overgrazing, and climate warming could be considered as the main reasons.

Spatiotemporal Variations of Meteorological Droughts in China During 1961–2014: An Investigation Based on Multi-Threshold Identification

As a major agricultural country, China suffers from severe meteorological drought almost every year. Previous studies have applied a single threshold to identify the onset of drought events, which may cause problems to adequately characterize long-term patterns of droughts. This study analyzes meteorological droughts in China based on a set of daily gridded (0.5° × 0.5°) precipitation data from 1961 to 2014. By using a multi-threshold run theory approach to evaluate the monthly percentage of precipitation anomalies index (Pa), a drought events sequence was identified at each grid cell. The spatiotemporal variations of drought in China were further investigated based on statistics of the frequency, duration, severity, and intensity of all drought events. Analysis of the results show that China has five distinct meteorological drought-prone regions: the Huang-Huai-Hai Plain, Northeast China, Southwest China, South China coastal region, and Northwest China. Seasonal analysis further indicates that there are evident spatial variations in the seasonal contribution to regional drought. But overall, most contribution to annual drought events in China come from the winter. Decadal variation analysis suggests that most of China’s water resource regions have undergone an increase in drought frequency, especially in the Liaohe, Haihe, and Yellow River basins, although drought duration and severity clearly have decreased after the 1960s.

Reconnaissance Drought Index Based Evaluation of Meteorological Drought Characteristics in Bundelkhand

Among all the different types of extreme events drought is considered to be the most hazardous in terms economic losses and number of people being affected by its impacts, mainly due to the various complexities involved. Since it is rather difficult to predict and forecast droughts with a reasonable degree of certainty, the drought management aspects are also very complex and needs to be fine-tuned with the spatial and temporal variation of drought characteristics. It is therefore mandatory to evaluate the drought characteristics effectively for development of operative action oriented drought management plans. Generally there are many techniques available for the measurement of drought characteristics; however the drought indices can be effectively used to identify the characteristics of various types of droughts including the meteorological, hydrological and agricultural droughts. TheReconnaissance Drought Index (RDI) have been applied to evaluate the characteristics of the meteorological drought in Bundelkhand region located in central India. RDI has been used by many researchersfor identifying the drought characteristics as it is more suited to arid and semi-arid areas. The RDI uses precipitation as well as potential evapotranspiration (PET) and can also be used to analyse the climate change impacts on the drought scenario of a region.ThePenman-Monteith method has been used to estimate the PET. The spatio-temporal variation of drought in Bundelkhand has been investigated and it is found that every drought events has its own characteristics in terms of its areal extent, its progression, withdrawal and severity.

Spatio-temporal variation of drought in China during 1961–2012: A climatic perspective

Summary Understanding the spatial and temporal variation of drought is essentially important in drought assessment. In most previous studies, drought event is usually identified in space and time separately, ignoring the nature of the dynamic processes. In order to better understand how drought changes have taken place in China during the past half-century, we carried out a comprehensive analysis of their spatio-temporal variation based on multiple drought indices from a climatic perspective. A 3-dimensional clustering method is developed to identify drought events in China from 1961 to 2012 based on the 0.25° gridded indices of SPI3 (3 months Standardized Precipitation Index), RDI3 (3 months Reconnaissance Drought Index) and SPEI3 (3 months Standardized Precipitation Evapotranspiration Index). Drought events are further characterized by five parameters: duration, affected area, severity, intensity, and centroid. Remotely sensed soil moisture data were used to validate the rationality of identified drought events. The results show that the two most severe drought events in the past half century which occurred in the periods 1962–1963 and 2010–2011 swept more than half of the non-arid regions in China. Large magnitude droughts were usually centered in the region from North China Plain to the downstream of Yangtze River. The western part of North China Plain, Loess Plateau, Sichuan Basin and Yunnan-Guizhou Plateau had a significant drying trend, which is mainly caused by the significant decrease of precipitation. The three drought indices have almost the same performance in the humid regions, while SPI and RDI were found to be more appropriate than SPEI in the arid regions.