scholarly journals Temporal-Spatial Characteristics of Drought in Guizhou Province, China, Based on Multiple Drought Indices and Historical Disaster Records

2018 ◽  
Vol 2018 ◽  
pp. 1-22 ◽  
Author(s):  
Qingping Cheng ◽  
Lu Gao ◽  
Ying Chen ◽  
Meibing Liu ◽  
Haijun Deng ◽  
...  
Keyword(s):  
Drought Index ◽  
Meteorological Drought ◽  
Guizhou Province ◽  
Drought Indices ◽  
Drought Severity ◽  
Severe Drought ◽  
Drought Event ◽  
Drought Duration ◽  
Increasing Trend ◽  
Western Guizhou

Guizhou Province, China, experienced several severe drought events over the period from 1960 to 2013, causing great economic loss and intractable conflicts over water. In this study, the spatial and temporal characteristics of droughts are analyzed with the standard precipitation index (SPI), comprehensive meteorological drought index (CI), and reconnaissance drought index (RDI). Meanwhile, historical drought records are used to test the performance of each index at identifying droughts. All three indices show decreasing annual and autumn trends, with the latter particularly prominent. 29, 30, and 32 drought events were identified during 1960–2013 by the SPI, CI, and RDI, respectively. Continuous drought is more frequent in winter–spring and summer–autumn. There is a significant increasing trend in drought event frequency, peak, and strength since the start of the 21st century. Drought duration indicated by CI shows longer durations in the higher-elevation region of central and western Guizhou. The corresponding drought severity is high in these regions. SPI and RDI indicate longer drought durations in the lower elevation central and eastern regions of Guizhou Province, where the corresponding drought severity is also very strong. SPI shows an increasing trend in drought duration and drought severity across most of the regions of Guizhou. In general, SPI and RDI show an increasing trend in the western Guizhou Province and a decreasing trend in central and eastern Guizhou. Comparing these three drought indices with historical records, the RDI is found to be more objective and reliable than the SPI and CI when identifying the periods of drought in Guizhou.

scholarly journals Elucidating Diverse Drought Characteristics from Two Meteorological Drought Indices (SPI and SPEI) in China

2020 ◽  
Vol 21 (7) ◽  
pp. 1513-1530 ◽  
Author(s):  
Lingcheng Li ◽  
Dunxian She ◽  
Hui Zheng ◽  
Peirong Lin ◽  
Zong-Liang Yang
Keyword(s):  
Clustering Algorithm ◽  
Potential Evapotranspiration ◽  
Standardized Precipitation Index ◽  
Three Dimensional ◽  
Meteorological Drought ◽  
Drought Indices ◽  
Drought Severity ◽  
Severe Drought ◽  
Small Areas ◽  
Drought Characteristics

AbstractThis study elucidates drought characteristics in China during 1980–2015 using two commonly used meteorological drought indices: standardized precipitation index (SPI) and standardized precipitation–evapotranspiration index (SPEI). The results show that SPEI characterizes an overall increase in drought severity, area, and frequency during 1998–2015 compared with those during 1980–97, mainly due to the increasing potential evapotranspiration. By contrast, SPI does not reveal this phenomenon since precipitation does not exhibit a significant change overall. We further identify individual drought events using the three-dimensional (i.e., longitude, latitude, and time) clustering algorithm and apply the severity–area–duration (SAD) method to examine the drought spatiotemporal dynamics. Compared to SPI, SPEI identifies a lower drought frequency but with larger total drought areas overall. Additionally, SPEI identifies a greater number of severe drought events but a smaller number of slight drought events than the SPI. Approximately 30% of SPI-detected drought grids are not identified as drought by SPEI, and 40% of SPEI-detected drought grids are not recognized as drought by SPI. Both indices can roughly capture the major drought events, but SPEI-detected drought events are overall more severe than SPI. From the SAD analysis, SPI tends to identify drought as more severe over small areas within 1 million km2 and short durations less than 2 months, whereas SPEI tends to delineate drought as more severe across expansive areas larger than 3 million km2 and periods longer than 3 months. Given the fact that potential evapotranspiration increases in a warming climate, this study suggests SPEI may be more suitable than SPI in monitoring droughts under climate change.

scholarly journals ASSESSING DROUGHT CHARACTERISTICS OF MELAKA BASIN USING JOINT METEOROLOGICAL AND STREAMFLOW INDICES

2020 ◽  
Vol 80 (1) ◽  
Author(s):  
Kee An Hong ◽  
Jer Lang Hong ◽  
Izihan Ibrahim
Keyword(s):  
Drought Index ◽  
Meteorological Drought ◽  
Hydrological Drought ◽  
Drought Indices ◽  
Severe Drought ◽  
Frequency Of Occurrence ◽  
Streamflow Data ◽  
Hydrological Droughts ◽  
Drought Occurrence ◽  
Meteorological Droughts

In this study, drought occurrence in the Melaka basin has been assessed using the meteorological and hydrological drought indices. A continuous rainfall and streamflow data of 40 years were used for drought analysis. Results show that in terms of meteorological drought index, the severe drought occurred in 1986-1988. The streamflow drought index indicates that the extreme drought occurred in 1982-1984. Further analysis based on seasonal precipitation and streamflow data shows that there is no drought for 79% of the time for the period 1960-2000 where there are hydrological records. For most of the dry and wet seasons, it is more likely that the frequency of occurrence of hydrological droughts only is higher than the frequency of occurrence of meteorological and hydrological droughts simultaneously or only meteorological droughts.

scholarly journals Drought Frequency Analysis Based on the Development of a Two-Variate Standardized Index (Rainfall-Runoff)

Water ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 2599 ◽  
Author(s):  
Gholamreza Nikravesh ◽  
Mohammad Aghababaei ◽  
Mohammad Nazari-Sharabian ◽  
Moses Karakouzian
Keyword(s):  
Standardized Precipitation Index ◽  
Drought Indices ◽  
Flow Index ◽  
Severe Drought ◽  
Drought Event ◽  
Rainfall Runoff ◽  
Drought Duration ◽  
Novel Approach ◽  
Standardized Index ◽  
The Standardized Precipitation Index

Drought is one of the most drastic events, which has imposed irreparable damages on human societies and may occur in any climate regime. To define drought, given its properties of multidimensionality and randomity, one cannot rely on a single variable/index (e.g., precipitation, soil moisture, and runoff). Accordingly, implementing a novel approach, this study investigated drought events in two basins with different climatic regimes, using multivariate frequency analyses of drought duration, severity, and severity peak, based on developing a Two-variate Standardized Index (TSI). The index was developed based on the concept of copula, by applying rainfall-runoff data (1974–2019) and comparing them with two popular drought indices, the Standardized Precipitation Index (SPI) and Standardized Stream Flow Index (SSFI), in terms of derived drought characteristics. The results show that TSI determined more severe drought conditions with fewer return periods than SPI and SSFI in a specific drought event. This implies that the disadvantages of SPI and SSFI might not be found in TSI. The developed index can be employed by policymakers and planners to protect water resources from drought.

scholarly journals Comparative evaluation of precipitation-temperature based drought indices (DIs): A case study of Moroccan Lower Sebou basin

2021 ◽  
Author(s):  
Oualid HAKAM ◽  
◽  
Abdennasser BAALI ◽  
Touria EL KAMEL ◽  
Ahouach Youssra ◽  
...  
Keyword(s):  
Drought Index ◽  
River Flow ◽  
Potential Evapotranspiration ◽  
Standardized Precipitation Index ◽  
Data Availability ◽  
Drought Indices ◽  
Drought Severity ◽  
Drought Event ◽  
Precipitation Temperature ◽  
Drought Conditions

Due to the lack of studies on drought in the Lower Sebou basin (LSB), the complexity of drought event and the difference in climate conditions. The identification of the most appropriate drought indices (DIs) to assess drought conditions has become a priority. Therefore, assessing the performance of different drought indices was considered in order to identify the universal drought indices that are well adapted to the LSB. Based on data availability, five DIs were used: Standardized Precipitation Index (SPI), Standardized Precipitation and Evapotranspiration Index (SPEI), Reconnaissance Drought Index (RDI), self-calibrated Palmer Drought Severity Index (sc-PDSI) and Streamflow Drought Index (SDI). The DIs were calculated on an annual scale using monthly time series of precipitation, temperature and river flow from 1984-2016. Thornthwaite's method was used to calculate potential evapotranspiration (PET). Pearson's correlation (r) were analyzed. Furthermore, five decision criteria namely robustness, traceability, transparency, sophistication and scalability were used to evaluate the performance of these indices. The results proved the fact that SPI is suitable to detect the drought duration and intensity compared to other indices with high correlation coefficients especially in sub humid regions, knowing that it tends to give more results that are humid in stations with semi-arid climates. SPI, SPEI and RDI follow the same trend during the period studied. However, sc-PDSI appears to be the most sensitive to temperature and precipitation by overestimating the drought conditions. Eventually, the results of the performance evaluation criteria revealed that SPEI classified first (total score = 137) among other meteorological drought indices, followed by SPI, RDI and sc-PDSI.

scholarly journals Mediterranean-Scale Drought: Regional Datasets for Exceptional Meteorological Drought Events during 1975–2019

Atmosphere ◽  
2021 ◽  
Vol 12 (8) ◽  
pp. 941
Author(s):  
Shifa Mathbout ◽  
Joan Albert Lopez-Bustins ◽  
Dominic Royé ◽  
Javier Martin-Vide
Keyword(s):  
Drought Index ◽  
Standardized Precipitation Index ◽  
Principal Component ◽  
Meteorological Drought ◽  
Western Mediterranean ◽  
Drought Indices ◽  
Drought Event ◽  
Evaporative Demand ◽  
Atmospheric Circulation Patterns ◽  
Dry Conditions

Drought is one of the most complex climate-related phenomena and is expected to progressively affect our lives by causing very serious environmental and socioeconomic damage by the end of the 21st century. In this study, we have extracted a dataset of exceptional meteorological drought events between 1975 and 2019 at the country and subregional scales. Each drought event was described by its start and end date, intensity, severity, duration, areal extent, peak month and peak area. To define such drought events and their characteristics, separate analyses based on three drought indices were performed at 12-month timescale: the Standardized Precipitation Index (SPI), the Standardized Precipitation Evapotranspiration Index (SPEI), and the Reconnaissance Drought Index (RDI). A multivariate combined drought index (DXI) was developed by merging the previous three indices for more understanding of droughts’ features at the country and subregional levels. Principal component analysis (PCA) was used to identify five different drought subregions based on DXI-12 values for 312 Mediterranean stations and a new special score was defined to classify the multi-subregional exceptional drought events across the Mediterranean Basin (MED). The results indicated that extensive drought events occurred more frequently since the late 1990s, showing several drought hotspots in the last decades in the southeastern Mediterranean and northwest Africa. In addition, the results showed that the most severe events were more detected when more than single drought index was used. The highest percentage area under drought was also observed through combining the variations of three drought indices. Furthermore, the drought area in both dry and humid areas in the MED has also experienced a remarkable increase since the late 1990s. Based on a comparison of the drought events during the two periods—1975–1996 and 1997–2019—we find that the current dry conditions in the MED are more severe, intense, and frequent than the earlier period; moreover, the strongest dry conditions occurred in last two decades. The SPEI-12 and RDI-12 have a higher capacity in providing a more comprehensive description of the dry conditions because of the inclusion of temperature or atmospheric evaporative demand in their scheme. A complex range of atmospheric circulation patterns, particularly the Western Mediterranean Oscillation (WeMO) and East Atlantic/West Russia (EATL/WRUS), appear to play an important role in severe, intense and region-wide droughts, including the two most severe droughts, 1999–2001 and 2007–2012, with lesser influence of the NAO, ULMO and SCAND.

scholarly journals Drought Risk Assessment in Central Asia Using a Probabilistic Copula Function Approach

Water ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 421 ◽  
Author(s):  
Leyuan Zhang ◽  
Yi Wang ◽  
Yaning Chen ◽  
Yifei Bai ◽  
Qifei Zhang
Keyword(s):  
Central Asia ◽  
Three Dimensional ◽  
Joint Probability ◽  
Copula Function ◽  
Drought Severity ◽  
Drought Risk ◽  
Severe Drought ◽  
Drought Event ◽  
Drought Duration ◽  
Climate Conditions

The aim of this research is to adopt the Standardized Precipitation Evapotranspiration Index (SPEI) with three-month timescale (SPEI-3) to analyze drought risk in Central Asia. Based on SPEI-3, a drought event is defined through Run Theory. The multidimensional Copula function based on drought risk is then comprehensively assessed through the multivariable joint probability of drought duration, drought severity, and drought peak. Results indicate as follows: (1) the climate conditions were relatively stable from 1961–1974 and 1979–1995, while they varied from 1974 to 1979 and from 1995 to 2017, during which the study areas experienced recurrent drought. (2) The drought characteristics show noticeable spatial variability, and the severity of drought is larger in the west than in the east in Central Asia; the duration of drought contrasts with the severity of drought spatially. (3) The drought risk in the three-dimensional joint distribution is similar to the analysis using the two-dimensional distributions, and the study area has gone through the process from moderate to slight and then to severe drought risk from 1961 to 2017; the return period studied in this paper was calculated to be 80% probability in about two years.

scholarly journals High-spatial resolution probability maps of drought duration and magnitude across Spain

2018 ◽  
Author(s):  
Fernando Domínguez-Castro ◽  
Sergio M. Vicente-Serrano ◽  
Miquel Tomás-Burguera ◽  
Marina Peña-Gallardo ◽  
Santiago Beguería ◽  
...  
Keyword(s):  
Standardized Precipitation Index ◽  
Generalized Pareto Distribution ◽  
Value Theory ◽  
Mitigation Measures ◽  
Drought Indices ◽  
Drought Severity ◽  
Drought Event ◽  
Drought Duration ◽  
Drought Assessment ◽  
Peak Over Threshold

Abstract. We mapped – for the first time – the probability of occurrence of drought over Spain, with the overriding aim of improving current drought assessment, management and mitigation measures and strategies across the region. We employed two well-established drought indices: the Standardized Precipitation Index (SPI) and the Standardized Precipitation Evapotranspiration Index (SPEI). Drought characteristics (i.e. duration and severity) were characterised at 1-, 3-, 6- and 12-month, implying that drought event is attained only when the index values are lower than zero. We applied the extreme value theory to map drought hazard probability. Following this procedure, we tested different thresholds to generate the peak-over-threshold drought severity and magnitude series, besides evaluating different three-parametric distributions and thresholds to fit these series. Our results demonstrate that the Generalized Pareto distribution performs well in estimating the frequencies of drought magnitude and duration, with good agreement between the observed and modelled data when using upper percentiles to generate the peak-over-threshold series. Spatially, our estimations suggest a higher probability of extreme drought events in southern and central areas of Spain, compared to northern and eastern regions. Nevertheless, there are strong differences in drought probability estimations between drought indices (i.e. SPI and SPEI), as well as among drought timescales.

scholarly journals Characterizing Spatiotemporal Patterns of Drought among the Pastoralists of Southern Ethiopia, Eastern Africa

2021 ◽  
Author(s):  
Mekuria Guye ◽  
Abiyot Legesse ◽  
Yimer Mohammed
Keyword(s):  
Drought Index ◽  
Meteorological Drought ◽  
Spatiotemporal Patterns ◽  
Eastern Africa ◽  
Southern Ethiopia ◽  
Drought Severity ◽  
Gradual Decline ◽  
Increasing Trend ◽  
Slope Estimator ◽  
Spatially Varying

Abstract This paper is an inquiry of investigating trends and spatiotemporal patterns of meteorological drought in semi-arid pastoral areas in southern Ethiopia. Monthly gridded rainfall and temperature data for thirty years between 1986 to 2016 were obtained d from Ethiopian Meteorological Agency. Nonparametric Mann Kendall’s test (MK) along with Sen’s slope estimator was employed to see trends of drought. In addition, Reconnaissance Drought Index (RDI) was used to characterize the drought patterns. The result indicates that under all time scale, drought events tend to show an increasing trend with varying magnitude and intensity. The highest drought severity category for major and small rainy months was identified during May 2000 with RDI= -2.28 and September 2000 with RDI= -2.55 . The drought magnitudes of the small rainy months range from -11.15 in November to -11.76 in September, while it ranges from -10.08 in April to -11.38 in March for the major rainy months. There are some variations of drought magnitude among the seasons while rainfall tend to show gradual decline as a manifestation of spatially varying drought severity, frequency and intensity in the watershed.

scholarly journals Indices-Based Evaluation of Spatiotemporal Distribution of Drought Within Derbendkhan Dam Watershed

2021 ◽  
Vol 39 (6) ◽  
pp. 893-914
Author(s):  
Mahmoud S. Al- Khafaji ◽  
Rusul A.H. Al- Ameri
Keyword(s):  
Drought Index ◽  
Standardized Precipitation Index ◽  
Temporal Variations ◽  
Weather Data ◽  
Drought Indices ◽  
Drought Severity ◽  
Environmental Damage ◽  
Eastern Region ◽  
Strong Impact ◽  
Drought Duration

Drought is one of the most significant natural disasters in Iraq. It has a strong impact on the water resources in Iraq. Consequently, it causes massive environmental damage, economic deficiency, and social problems to the country. Therefore, more considerations towards the study and management of drought has become of vital importance in recent decades. In this paper, three drought indices (DIs) were computed for evaluation of the spatiotemporal of drought within Derbendikhan Dam Watershed (DDW) in the Diyala River Basin, Iraq. Based on the monthly weather data for the period (1984 – 2013) downloaded from the Climate Forecast System Reanalysis (CFSR) for eight stations located within DDW. The Reconnaissance Drought Index (RDI), standardized precipitation index (SPI) and Streamflow Drought Index (SDI) at 12-month time scale were computed to assess droughts in the DDW. For each index, the temporal variations of the drought severity and Drought Frequency Patterns (DFPs) for the period (1984 – 2013) were computed and analyzed. In addition, spatial distributions of the drought severity for each index were mapped and investigated. Accordingly, the DFPs were compared to specify the dominant and/or more frequent DFPs. The results show that the performances of different DIs are strongly correlated with the dominant factors of droughts and drought duration. Also, the SPI and SDI are less accurate than the RDI when both precipitation and evaporation are the main factors controlling the drought events. However, the SPI and SDI indices are identical in the same proportions of the dry years which are less than the ratio of dry years to an RDI, but the severity of the drought from the SDI results is higher than the severity of the drought relative to the SPIand RDI. The three indices indicate that the Eastern region is drier than the Western region, which is somewhat wet.

scholarly journals Evaluation of Different Rainfall-based Drought Indices Detection of Meteorological Drought Events in Imo State, Nigeria

2020 ◽  
Vol 24 (4) ◽  
pp. 713-717
Author(s):  
C.S. Ekwezuo ◽  
J.C. Madu
Keyword(s):  
Standardized Precipitation Index ◽  
Meteorological Drought ◽  
Drought Indices ◽  
Severe Drought ◽  
Drought Event ◽  
Technological Advancement ◽  
Drought Assessment ◽  
Imo State ◽  
Humid Environment

Drought Indices are extensively adopted as a drought detection and monitoring tool in all climatic regions. This study assesses and compares the performance of four rainfall based drought indices, Deciles index (DI), Percent of Normal Index (PNI), Standardized Precipitation Index (SPI) and Z-score Index (ZSI) in detection and classification of drought events in Imo state , a humid environment of Nigeria from (1982 to 2016). The resultshows that droughts do occur in humid climatic region of Nigeria. The various indices differ in their detection and classification of drought events in the study area. However, they classified 2007 and 2008 as the year with the most severe drought event in the state. There is high correlation (r > 0.70) among the four indices, with ZSI and PNI showing the highest relationship to SPI (r= 0.97). The differences observed among the drought indices in detecting drought events in the study area can be reduced by using multiple drought indices in addition to the use of SPI in drought assessments especially in Nigeria since technological advancement in drought monitoring software’s has made it easier. Also it is worthwhile to research on why drought detection varies with indices. Keywords: Drought assessment, Rainfall-based drought indices, humid environment, Imo state, Nigeria.

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