scholarly journals Spatiotemporal Evolution of Droughts and Their Teleconnections with Large-Scale Climate Indices over Guizhou Province in Southwest China

Water ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 2104
Author(s):  
Liying Xiao ◽  
Xi Chen ◽  
Runrun Zhang ◽  
Zhicai Zhang
Keyword(s):  
Large Scale ◽  
Southwest China ◽  
Standardized Precipitation Index ◽  
Extreme Drought ◽  
Guizhou Province ◽  
Drought Severity ◽  
Climate Indices ◽  
Spatiotemporal Evolution ◽  
Study Region ◽  
Periodicity Analysis

The spatiotemporal evolution of meteorological droughts in Guizhou Province, Southwest China is analyzed based on a new set of the Standardized Precipitation Index series that mainly includes drought events that occurred from 1961 to 2004 at 81 meteorological stations. The cluster analysis shows that the study region can be classified into six homogeneous sub-regions where the drought characteristics and their temporal evolutions are quite different. The trend test and periodicity analysis indicate that Guizhou Province experienced a drier trend, which was most significant in the western parts of the region. It was found that the intensified drought severity was not always coincident with the drier trend but relied on the occurrence of extreme drought events. The trends of drier climate and drought severity were highly coincident with the temporal evolution of the drought periodicities, which were shortened from 1–4 years to less than one year. The shortened drought periodicity was found to be associated principally with a shift of the large-scale dominant climate indices from the North Atlantic Oscillation to the Indian Ocean Dipole after the late 1970s, and variations of the extreme drought events were mostly related to NINO34 in the study region.

Spatio-temporal changes of drought in Romania (1961-2015), according to atmospheric circulation types and teleconnection indices

2020 ◽  
Author(s):  
Radu-Vlad Dobri ◽  
Liviu Apostol ◽  
Lucian Sfîcă ◽  
Simona Țîmpu ◽  
Ion-Andrei Niță
Keyword(s):  
Atmospheric Circulation ◽  
Standardized Precipitation Index ◽  
Atmospheric Precipitation ◽  
Climatic Conditions ◽  
Extreme Drought ◽  
Drought Severity ◽  
Severe Drought ◽  
Circulation Types ◽  
Teleconnection Indices ◽  
Moderate Drought

<p>Drought can be determined by climatic conditions (atmospheric precipitation, water supply from soil accessible to the plant, moisture and air temperature and wind speed) but is also induced by environmental aspects some of them related to anthropogenic influences.</p><p>In order to monitor the drought and its impact for Romania, four indices were analyzed in the present study (SPI (Standardized Precipitation Index), PNI (Percent of Normal Index), DI (Deciles index), and ZSI (Z-score Index)), through Meteorological Drought Monitoring software, using the total daily amount of precipitation for 27 weather stations in Romania, of which 22 stations for the period 1961-2015, 4 stations for the period 1961-2000 and one station for the period 1964-2015.</p><p>Preliminary analyzes resulting from the use of these indices were correlated with 18 GWT (Großwettertypen) atmospheric circulation types of daily mean sea level pressure (SLP). This was done using COST733 class software to evaluate the influence of large-scale mechanisms of atmospheric circulation. Also, four teleconnection indices were used, more exactly AO (Arctic Oscillation), NAO (North Atlantic Oscillation), PNA (Pacific-North American Pattern) and AAO (Antarctic Oscillation) that are recognized for their effect on climatic conditions at European scale,  <br>provided by National Oceanic and Atmospheric Administration (NOAA) – Climate Prediction Center.</p><p>Therefore, according to the types of circulation, the amount of precipitation produced in certain areas and implicitly the degree of drought severity is influenced. The types of anticyclonal circulation 13, 16 or 18, for example, which occur on average in 46 (12.7%), 14 (3.9%) , respectively 20 (5.4%) days a year, cause less precipitation as known, compared to the types of cyclonal circulation 1, 2 or 17 for example with an average of 12 (3.2%), 12 (3.2%), respectively 19 (4.3%) days a year.</p><p>In terms of drought analysis indices, according to SPI, the entire analysis interval for Iasi, located in the northeast region of Romania, was 6 years of "moderately dry", 5 years of "severely dry", and one year of "extremely dry", unlike Cluj, located in the central western region, with two years of "moderately dry", 3 years of "severely dry" and two years of "extremely dry". In Bucharest, located in the southern region of Romania there were 4 "moderately dry" years and 5 "severely dry" years. In Iasi, according to the ZSI index with the same classifications as the SPI index, there were 3 "moderately drought" years, 7 "severely drought" years and 7 "extreme drought" years, while in Cluj there were 9, 3 and respectively 6 years and in Bucharest 7, 5 and respectively 6 years with the above classification.</p><p>According to the PNI index, there were 5 "moderate drought" years in Iasi and Cluj and 6 "moderate drought" years in Bucharest. Also, there were 9 "weak drought" years in Iasi, 3 in Cluj and 5 in Bucharest.</p><p>And last but not least, according to the DI index, at all 3 stations there were 5 "extreme drought" years, 6 "severe drought" years and 5 "moderate drought" years.</p>

Application of several data-driven techniques to predict a standardized precipitation index

Atmósfera ◽  
2016 ◽  
Vol 29 (2) ◽  
pp. 121 ◽  
Author(s):  
Bahram Choubin ◽  
Arash Malekian ◽  
Mohammad Gloshan
Keyword(s):  
Large Scale ◽  
Fuzzy Inference ◽  
Standardized Precipitation Index ◽  
Precipitation Index ◽  
Climate Indices ◽  
Inference System ◽  
Model Tree ◽  
Climate Signals ◽  
M5p Model Tree ◽  
Semi Arid

Climate modeling and prediction is important in water resources management, especially in arid and semi-arid regions that frequently suffer further from water shortages. The Maharlu-Bakhtegan basin, with an area of 31 000 km2 is a semi-arid and arid region located in southwestern Iran. Therefore, precipitation and water shortage in this area have many problems. This study presents a drought index modeling approach based on large-scale climate indices by using the adaptive neuro-fuzzy inference system (ANFIS), the M5P model tree and the multilayer perceptron (MLP). First, most of the climate signals were determined from 25 climate signals using factor analysis, and subsequently, the standardized precipitation index (SPI) was predicted one to 12 months in advance with ANFIS, the M5P model tree and MLP. The evaluation of the models performance by error parameters and Taylor diagrams demonstrated that performance of the MLP is better than the other models. The results also revealed that the accuracy of prediction increased considerably by using climate indices of the previous month (t – 1) (RMSE = 0.802, ME = –0.002 and PBIAS = –0.47).

scholarly journals Spatiotemporal Variation of Drought Characteristics Based on Standardized Precipitation Index in Central Java over 1990-2010

2021 ◽  
Vol 893 (1) ◽  
pp. 012022
Author(s):  
Misnawati ◽  
R Boer ◽  
F Ramdhani
Keyword(s):  
Standardized Precipitation Index ◽  
Rain Gauge ◽  
Precipitation Index ◽  
Extreme Drought ◽  
Drought Severity ◽  
Severe Drought ◽  
Drought Event ◽  
Drought Characteristics ◽  
Central Java ◽  
Moderate Drought

Abstract Drought is a natural hazard that results from a deficiency of precipitation, leading to low soil moisture and river flows, reduced storage in reservoirs, and less groundwater recharge. This study investigates the spatial variations of drought characteristics (drought event frequency, duration, severity, and intensity). This study using the Standardized Precipitation Index (SPI) to analyse the drought characteristics in Central Java during 1990-2010. The rain gauge station data and CHIRPS rainfall data over Central Java is used to calculate the SPI index. The SPI was calculated at multiple timescales (1-, 3-, 6-, 12-, 24- and 48-month), the run theory was used for identification and characterization of drought events. Analysis of drought characteristics by SPI from 1990 to 2010 shows the longest drought event is four months, the maximum drought severity is 6.06, and the maximum drought intensity is 2.02. El Nino year probability drought occurrence reached 100% in August for moderate drought, severe drought, and extreme drought category, whereas the probability drought occurrences in the Normal and La Nina year range 0-70% for moderate drought, 0-50% for severe drought category and 0-40% for extreme drought category. The results of this study may help inform researchers and local policymakers to develop strategies for managing drought.

scholarly journals Analysis of Drought Investigation Using Standard Precipitation Index (SPI) of Historical Rainfall Data (1979-2013) Under Temperate Conditions Over Anand, Gujarat (India)

2021 ◽  
pp. 117-124
Author(s):  
G. J. Kamani ◽  
N. K. Pampania ◽  
S. S. Chinchorkar
Keyword(s):  
Standardized Precipitation Index ◽  
Extended Period ◽  
Precipitation Index ◽  
Extreme Drought ◽  
Reference Level ◽  
Drought Severity ◽  
Monthly Precipitation ◽  
The World ◽  
Intermediate Time ◽  
Drought Occurrence

Drought is a naturally occurring event caused due to deficiency in precipitation over an extended period of time. It is a slow-onset, creeping natural hazard that affects continuously all parts of the world. It occurs in all climatic zones such as high as well as low precipitation areas and causes high economic and social losses around the world. Droughts are generally measured in terms of deficiency in the rainfalls or streams flows below a predefined reference level. The magnitude of departure from the reference level during a drought spell is known as the severity of drought. Droughts are occurring in different regions of the world with increased frequency and severity. In this study, temporal pattern of droughts was analyzed in the Anand Station using SPI approach. Monthly precipitation data from 1979 to 2013 were used to compute Standardized Precipitation Index (SPI) values. The computation of SPI series was done for short as well as intermediate time scales. Analysis of SPI values were done to study the temporal patterns of drought occurrence. The drought severity and duration were also estimated. From the analysis, it was observed that in the years 1980, 1984,1985,1986,1987, 1989, 1991,1992,1993,1995, 1999,2000,2001,2002 and 2009 drought occurred in the area in Anand station. Extreme drought occurred in the year 1987 when the SPI value was -2.27. Also, SPI in the severe and extreme drought years indicate only moderate dryness instead of extreme dryness.

scholarly journals Drought in South Asia: A Review of Drought Assessment and Prediction in South Asian Countries

Atmosphere ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 369
Author(s):  
Sewwandhi S.K. Chandrasekara ◽  
Hyun-Han Kwon ◽  
Meththika Vithanage ◽  
Jayantha Obeysekera ◽  
Tae-Woong Kim
Keyword(s):  
South Asia ◽  
South Asian ◽  
Large Scale ◽  
Standardized Precipitation Index ◽  
Drought Severity ◽  
Asian Countries ◽  
The South ◽  
Individual Country ◽  
Drought Assessment ◽  
Drought Prediction

South Asian countries have been experiencing frequent drought incidents recently, and due to this reason, many scientific studies have been carried out to explore drought in South Asia. In this context, we review scientific studies related to drought in South Asia. The study initially identifies the importance of drought-related studies and discusses drought types for South Asian regions. The representative examples of drought events, severity, frequency, and duration in South Asian countries are identified. The Standardized Precipitation Index (SPI) was mostly adopted in South Asian countries to quantify and monitor droughts. Nevertheless, the absence of drought quantification studies in Bhutan and the Maldives is of great concern. Future studies to generate a combined drought severity map for the South Asian region are required. Moreover, the drought prediction and projection in the regions is rarely studied. Furthermore, the teleconnection between drought and large-scale atmospheric circulations in the South Asia has not been discussed in detail in most of the scientific literature. Therefore, as a take-home message, there is an urgent need for scientific studies related to drought quantification for some regions in South Asia, prediction and projection of drought for an individual country (or as a region), and drought teleconnection to atmospheric circulation.

scholarly journals Comparison of the Entropy- and Copula-based Precipitation-Streamflow Drought Indices for Assessing Agricultural Drought in Arid and Semi-arid Coastal Areas of Southern Iran

2021 ◽  
Author(s):  
Javad Bazrafshan ◽  
Zahra Azhdari
Keyword(s):  
Drought Index ◽  
Standardized Precipitation Index ◽  
Agricultural Drought ◽  
Drought Indices ◽  
Drought Severity ◽  
Study Region ◽  
Southern Iran ◽  
Hydrological Droughts ◽  
Semi Arid ◽  
Meteorological Droughts

Abstract In arid and semi-arid regions, precipitation and seasonal streamflow are the two major sources of water for vegetation. The scarcity of these water sources has a detrimental effect on vegetation cover degradation. The purpose of this research is to study the effect of meteorological and hydrological droughts, and also their combined effects, on vegetation changes in seven coastal sub-basins in southern Iran (part of the Bandar-Sedij and Kol-Mehran catchment). To track meteorological and hydrological droughts, the Standardized Precipitation Index (SPI) and the Streamflow Drought Index (SDI) were used. The copula function and the entropy approach (which is developed in this research) were used to blend individual meteorological and hydrological drought indices, yielding hybrid indices called the Copula-based Drought Index and the Entropy-based Drought Index (EnDI). The single (i.e., SPI and SDI) and hybrid drought indices (CoDI and EnDI) were compared in terms of temporal behavior, drought severity and duration characteristics, drought frequency, and a bivariate analysis of the drought severity-duration return period. The results indicated that the rank correlation (\({r}_{s}\)) between SPI and SDI ranged between 0.327 and 0.726 in the studied sub-basins. However, the two hybrid indices CoDI and EnDI had extremely high correlations (\({r}_{s}\ge 0.9\)). Despite the fact that meteorological droughts benefited both hybrid drought indices more than hydrological droughts, the contribution of meteorological droughts to EnDI was greater than that of CoDI. Over the study region, CoDI reported droughts that were both longer and more severe than those recorded by EnDI. EnDI showed stronger associations with the Normalized Vegetation Difference Index (NDVI) in nearly all the sub-basins, possibly because precipitation has a greater effect on EnDI than it does on CoDI. EnDI was therefore recommended as a superior index for estimating vegetation droughts throughout the research region.

Multiyear Droughts and Pluvials over the Upper Colorado River Basin and Associated Circulations

2017 ◽  
Vol 18 (3) ◽  
pp. 799-818 ◽  
Author(s):  
Abayomi A. Abatan ◽  
William J. Gutowski ◽  
Caspar M. Ammann ◽  
Laurna Kaatz ◽  
Barbara G. Brown ◽  
...  
Keyword(s):  
River Basin ◽  
Large Scale ◽  
Climate Models ◽  
Colorado River ◽  
Standardized Precipitation Index ◽  
Precipitable Water ◽  
Colorado River Basin ◽  
Height Anomaly ◽  
Study Region ◽  
Upper Colorado River Basin

Abstract This study analyzes spatial and temporal characteristics of multiyear droughts and pluvials over the southwestern United States with a focus on the upper Colorado River basin. The study uses two multiscalar moisture indices: standardized precipitation evapotranspiration index (SPEI) and standardized precipitation index (SPI) on a 36-month scale (SPEI36 and SPI36, respectively). The indices are calculated from monthly average precipitation and maximum and minimum temperatures from the Parameter-Elevation Regressions on Independent Slopes Model dataset for the period 1950–2012. The study examines the relationship between individual climate variables as well as large-scale atmospheric circulation features found in reanalysis output during drought and pluvial periods. The results indicate that SPEI36 and SPI36 show similar temporal and spatial patterns, but that the inclusion of temperatures in SPEI36 leads to more extreme magnitudes in SPEI36 than in SPI36. Analysis of large-scale atmospheric fields indicates an interplay between different fields that yields extremes over the study region. Widespread drought (pluvial) events are associated with enhanced positive (negative) 500-hPa geopotential height anomaly linked to subsidence (ascent) and negative (positive) moisture convergence and precipitable water anomalies. Considering the broader context of the conditions responsible for the occurrence of prolonged hydrologic anomalies provides water resource managers and other decision-makers with valuable understanding of these events. This perspective also offers evaluation opportunities for climate models.

scholarly journals Utilizing Objective Drought Severity Thresholds to Improve Drought Monitoring

2020 ◽  
Vol 59 (3) ◽  
pp. 455-475 ◽  
Author(s):  
Zachary T. Leasor ◽  
Steven M. Quiring ◽  
Mark D. Svoboda
Keyword(s):  
Standardized Precipitation Index ◽  
Region Of Interest ◽  
Cumulative Distribution ◽  
Drought Severity ◽  
Study Region ◽  
South Central ◽  
Central United States ◽  
Systematic Biases ◽  
The Standardized Precipitation Index ◽  
Western Portion

AbstractDrought is a prominent climatic hazard in the south-central United States. Drought severity is frequently classified using the categories established by the U.S. Drought Monitor (USDM). This study evaluates whether the thresholds for the standardized precipitation index (SPI) used by the USDM accurately classify drought severity. This study uses the SPI based on PRISM precipitation data from 1900 to 2015 to evaluate drought severity in Texas, Oklahoma, and Kansas. The results show that the fixed SPI thresholds for the USDM drought categories may lead to a systematic underestimation of drought severity in arid regions. To address this issue, objective drought thresholds were developed at each location by fitting a cumulative distribution function at each location to ensure that the observed frequency of drought in each severity category (D0–D4) matched the theoretical expectations of the USDM. This approach reduces the systematic biases in drought severity across the western portion of the study region. Therefore, we recommend developing objective drought thresholds for each location and SPI time scale (e.g., 1, 3, and 6 months). This method can be used to develop objective drought thresholds for any drought index and climate region of interest.

scholarly journals Monthly drought prediction based on ensemble models

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e9853
Author(s):  
Muhammad Haroon Shaukat ◽  
Ijaz Hussain ◽  
Muhammad Faisal ◽  
Ahmad Al-Dousari ◽  
Muhammad Ismail ◽  
...  
Keyword(s):  
Water Resource Management ◽  
Standardized Precipitation Index ◽  
Climate Indices ◽  
Climate Information ◽  
Study Region ◽  
Ensemble Models ◽  
Percentage Occurrence ◽  
Weather Pattern ◽  
Drought Prediction ◽  
The Times

Drought is a natural hazard, which is a result of a prolonged shortage of precipitation, high temperature and change in the weather pattern. Drought harms society, the economy and the natural environment, but it is difficult to identify and characterize. Many areas of Pakistan have suffered severe droughts during the last three decades due to changes in the weather pattern. A drought analysis with the incorporation of climate information has not yet been undertaken in this study region. Here, we propose an ensemble approach for monthly drought prediction and to define and examine wet/dry events. Initially, the drought events were identified by the short term Standardized Precipitation Index (SPI-3). Drought is predicted based on three ensemble models i.e., Equal Ensemble Drought Prediction (EEDP), Weighted Ensemble Drought Prediction (WEDP) and the Conditional Ensemble Drought Prediction (CEDP) model. Besides, two weighting procedures are used for distributing weights in the WEDP model, such as Traditional Weighting (TW) and the Weighted Bootstrap Resampling (WBR) procedure. Four copula families (i.e., Frank, Clayton, Gumbel and Joe) are used to explain the dependency relation between climate indices and precipitation in the CEDP model. Among all four copula families, the Joe copula has been found suitable for most of the times. The CEDP model provides better results in terms of accuracy and uncertainty as compared to other ensemble models for all meteorological stations. The performance of the CEDP model indicates that the climate indices are correlated with a weather pattern of four meteorological stations. Moreover, the percentage occurrence of extreme drought events that have appeared in the Multan, Bahawalpur, Barkhan and Khanpur are 1.44%, 0.57%, 2.59% and 1.71%, respectively, whereas the percentage occurrence of extremely wet events are 2.3%, 1.72%, 0.86% and 2.86%, respectively. The understanding of drought pattern by including climate information can contribute to the knowledge of future agriculture and water resource management.

scholarly journals The extreme drought of 1842 in Europe as described by both documentary data and instrumental measurements

2019 ◽  
Vol 15 (5) ◽  
pp. 1861-1884 ◽  
Author(s):  
Rudolf Brázdil ◽  
Gaston R. Demarée ◽  
Andrea Kiss ◽  
Petr Dobrovolný ◽  
Kateřina Chromá ◽  
...  
Keyword(s):  
Standardized Precipitation Index ◽  
Severity Index ◽  
Extreme Drought ◽  
Drought Indices ◽  
Drought Severity ◽  
Documentary Data ◽  
Annual Variations ◽  
The North ◽  
Societal Impacts ◽  
The North Atlantic Oscillation

Abstract. Extreme droughts are weather phenomena of considerable importance, involving significant environmental and societal impacts. While those that have occurred in the comparatively recent period of instrumental measurement are identified and dated on the basis of systematic, machine-standardized meteorological and hydrological observations, droughts that took place in the pre-instrumental period are usually described only through the medium of documentary evidence. The extreme drought of 1842 in Europe presents a case in which information from documentary data can be combined with systematic instrumental observations. Seasonal, gridded European precipitation totals are used herein to describe general DJF, MAM, and JJA precipitation patterns. Annual variations in monthly temperatures and precipitation at individual stations are expressed with respect to a 1961–1990 reference period, supplemented by calculation of selected drought indices (Standardized Precipitation Index, SPI; Standardized Precipitation Evapotranspiration Index, SPEI; and Palmer Z index). The mean circulation patterns during the driest months are elucidated by means of sea-level pressure (SLP) maps, the North Atlantic Oscillation Index (NAOI), and the Central European Zonal Index (CEZI). Generally drier patterns in 1842 prevailed in January–February and at various intensities between April and August. The driest patterns in 1842 occurred in a broad zonal belt extending from France to eastern central Europe. A range of documentary data is used to describe the peculiarities of agricultural, hydrological, and socio-economic droughts, with particular attention to environmental and societal impacts and human responses to them. Although overall grain yields were not very strongly influenced, a particularly bad hay harvest, no aftermath (hay from a second cut), and low potato yields led to severe problems, especially for those who raised cattle. Finally, the 1842 drought is discussed in terms of long-term drought variability, European tree-ring-based scPDSI (self-calibrated Palmer Drought Severity Index) reconstruction, and the broader context of societal impacts.

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