Standardized Precipitation Index Method Research Articles

Drought Analysis and Forecast Using Landsat-8 Sattelite Imagery, Standardized Precipitation Index and Time Series

A drought is a phenomenon of shortages in water supply in an area for a long time. Drought usually occurs in areas that have little rain for a long time or in areas with low precipitation. Drought have negative impacts on many sectors such as agriculture, plantations, water resources and environment. This paper describes the results of a research that aims to analyze data to get the level of drought during four yearly periods, and predict the likelihood of drought to occur in the future. The level of drought was analyzed using the Inverse Distance Weighted (IDW) method and the Standardized Precipitation Index (SPI). Least square time series was utilized to forecast the level of drought in the near future. Data consists of drought data collected from electronic news, rainfall data from BMKG, and anual Landsat-8 satellite imagery. All data are for Western Southeast Mallucas in the range of 2015-2018. Analysis using IDW and SPI methods produce similar interpretation for year 2015, i.e. mild dryness, and fro year 2018, i.e. no drought. However, the two methods show discrepancy in analysis of data for 2016 and 2017. The use of least square time series to forecast drought in 2019 gives SPI value of 0.03 which intepretes as normal weather (no drought) that is consistent with the result of field observation.

Precipitación acumulada en las tierras altas entre las secciones Tilarán y Central, Costa Rica

Se analiza el total acumulado de la precipitación cada cinco año, utilizando tres estaciones meteorológicas: Zarcero, Piedades Sur y Montes de Oro en Costa Rica. Estas localidades fueron seleccionadas, ya que cada una se ubica en sectores con distintos niveles de precipitación. De esta manera es posible tener una idea del comportamiento de la precipitación a lo largo de veinte años. Esto debido a que, por ser estaciones ubicadas en sectores muy rurales, solo una de ellas, la primera tiene datos superiores a los cincuenta años, pero para homogenizar los registros se tuvo que considerar solo veinte años. Los periodos históricos cada cinco años secos o húmedos se identifican mediante el método de índice de precipitación estandarizado y sus tendencias se analizan para evaluar la posible relación con el evento ENOS. Todas las estaciones evidencian cierta igualdad en la distribución quinquenal en la precipitación en el transcurso del período de estudio (1994-2013). La tendencia en cada estación es la siguiente, Zarcero, muestran niveles altos en el periodo 2004-2008. En Montes de Oro los niveles de precipitación son muy regulares, aunque con un ligero incremento entre el 2004-2008, pero en realidad es muy leve el incremento. En el caso de Piedades Sur se muestra un fuerte incremento en la lluvia en el quinquenio de 2004-2008. Esto refleja la existencia de una relación entre la precipitación del área en estudio con respecto a evento del ENOS, así como la influencia de la irregularidad en el relieve montañoso.

Analysis of Drought in the Northern Region of Bangladesh Using Standardized Precipitation Index (SPI)

Drought is an extended period when a region notes a deficiency in its water supply. The Standardized Precipitation Index (SPI) method was used in this study to analyze drought. Northern region of Bangladesh was the area of study. Monthly rainfall data of northern region of Bangladesh was obtained from the Meteorological Department of Bangladesh. Obtained rainfall data was from 1991 to 2011 and values from 2012 to 2026 were generated using Markov model. Then SPI values from 1991 to 2026 were calculated by using SPI formula for analyzing drought. Analysis with SPI method showed that droughts in northern region of Bangladesh varied from moderately dry to severely dry conditions and it may vary from moderately dry to severely dry conditions normally in future but in some cases extreme drought may also take place. From the study, it is observed that the northern region of Bangladesh has already experienced severe drought in 1991, 1992, 1994, 1995, 1997, 1998, 2000, 2003, 2005, 2007, 2009 and 2010. The region may experience severe drought in 2012, 2015, 2016, 2018, 2019, 2021, 2022, 2023, 2024, 2025 and 2026 and extreme drought in 2012, 2014, 2016, 2023 and 2024.
 J. Environ. Sci. & Natural Resources, 11(1-2): 199-216 2018

Assessment of Groundwater Drought in the Mangyeong River Basin, Korea

When groundwater drought occurs, baseflow discharges to surface-water bodies will be reduced and then domestic and agricultural water usage becomes at risk of insufficient supply. Thus, in this study, several methods for groundwater drought assessment were tested with long-term monitoring water-level data in the study area to preserve groundwater sustainability from drought, principally caused by reduced precipitation and propagated through agricultural drought and groundwater drought. Because of the Monsoon climate on the Korean Peninsula, the groundwater storage (or water-level) is secured until the end of summer, then falls by natural discharge during the dry seasons of autumn, winter and the following spring. Thus, the rainfall in the wet season seems to mainly influence groundwater storage until the spring of the following year. As the groundwater level (GWL) declines due to natural drainage and the use of agricultural water increases by the end of the dry season (October–May), the GWL will become lowered below the critical level. Below this level, sufficient water supply is not secured. Using the Standardized Precipitation Index (SPI), threshold method and 95% probability occurrence method, drought detection and the frequency of drought are compared. Groundwater drought using the threshold method results in more frequent occurrence than using the SPI method. The 95% occurrence method responds to severe drought but it also has weakness in missing the man-induced GWL decline in every spring season. For groundwater drought assessment, an appropriate drought index should be utilized according to climatic conditions and catchment characteristics. In the study area, variations of the both natural and anthropogenic effects are mixed and the threshold method is more suitable as a measure for preventing water resources shortage.

Pemetaan Indek Kekeringan dan Sebaran Titik Hotspot Daerah Potensi Kebakaran Hutan dan Lahan di Propinsi Riau

Riau is one of the most vulnerable provinces to forest and land fires in Indonesia. The potency for forest and land fires is inseparable from the presence of peatlands and exacerbated by drought. The purpose of this research is to know the characteristics of meteorological drought using SPI (Standardized Precipitation Index) method and its relation with forest and peatland fire as one of disaster management effort in Riau Province. The data used in this research are monthly rainfall data from meteorology station and rainfall posts of BMKG, hotspot data from NOAA satellite, map of Forest Use Agreement (TGHK), peat land map and land use map. Analysis of drought characteristics was done by calculating monthly SPI-1 then determining the maximum duration, intensity, severity and drought exposure. Determination of the severity of the drought by weighting and suspension method was based on duration and intensity while drought exposure was done by overlaying the map of the severity of the drought with the land use map. Meanwhile, to know the potential of forest and land fires began with the selection of hotspots on peatlands and forest areas every month then created a graph of the relationship of meteorological drought with the number of hotspots. Then, to see the relationship of drought distribution to the distribution of hotspots in dry season (MK) and wet season (MH) of 2015 was done by overlaying cover the drought distribution with hotspot distribution. The result shows that drought characteristic in the most of Riau province has maximum duration around 4-6 months, dry category of intensity, high category of severity with exposure area in paddy field, field, habitation, and plantation. Then, negative SPI Index (dry condition) has potential to increase the number of hotspots otherwise positive SPI index (wet condition) leads to low occurrence of hotspot. The drought distribution in the dry season (July, August, September) of 2015 triggers the number of hotspots during drought conditions, while in wet season (April, November, December) of 2015 are dominated by normal conditions, some areas are dry and wet, resulting in lower hotspots distribution compared to the dry season.

Meteorological drought analysis based on rainfall data of temperate region of Kashmir

Drought monitoring is an important aspect for water budgeting, planning and management. The present study was conducted to analysis drought of Srinagar area of Jammu and Kashmir using Standardized Precipitation Index (SPI) approach which is based on probability concept. The SPI method has several important characteristics over previous indices, including its simplicity, temporal flexibility and minimal data requirement. Monthly precipitation data from 1985 to 2014 for Srinagar were used to compute SPI values. The SPI series was plotted for short, intermediate as well as for long time scales. The SPI results shown that the drought occurred in years 1999, 2000, 2001, 2007 during 1985 to 2014. The extreme severe drought results were found in the year of 1999 when the rainfall deficit was 43.85%. The results showed that for kharif season, moderate drought occurred in the years 1989, 2002, 2004, 2010 and 2012; severe drought occurred in the years 2000, 2001 and 2008; whereas extreme drought occurred only in the year 1999. For rabi season, moderate drought occurred in the years 1989, 2002, 2004, 2010 and 2012; severe drought occurred in the years 2000, 2001 and 2008; whereas extreme drought occurred in the years 1999 and 2001. For zaid season, moderate droughts occurred in the years 1987, 1990, 1993 and 2004; severe drought occurred in the years 1997, 1998, 2000, 2001, 2003 and 2008; whereas extreme drought occurred in years 1989 and 1999. Thus, the most critical drought year was found in 1999. The results of the study are also relevant to climate change studies to understand the historic patterns and build future scenarios of drought.

Analysis on Precipitation Behaviors and Droughts & Floods Over the Past 51 Years in the Yangtze River Delta

To learn about the changing trend of water resources quantity in the Yangtze River Delta, make rational allocation of water resources, and prevent regional drought & flood risks, the spatial and temporal distribution characteristics of precipitation and drought & flood in the Yangtze River Delta were investigated. Sliding average method, standardized precipitation index method (SPI), and inverse distance weighted interpolation method (IDW) etc. were used to analyze the hydrologic characteristics of YRD based on the daily precipitation data from 15 national meteorological stations in the Yangtze River Delta during the period from 1960 to 2010. According to the result: (1) The Yangtze Delta exhibited a gradually increasing trend of annual precipitation, while the flood frequency has been higher than drought frequency over the past 51 years; (2) At the Yangtze Delta, the maximum mean precipitation was normally observed in June, the minimum mean precipitation in December, the highest flood frequency in April and July, and the highest drought frequency in March; (3) The precipitation gradually increased from north to south at the Yangtze Delta, spatially, the precipitation was more evenly distributed in the north than in the south; the flood prone area was larger than drought prone area at the Yangtze Delta with West Hangzhou, East Shaoxing and West Ningbo susceptible to both drought and flood.1

Use of Drought Index and Crop Modelling for Drought Impacts Analysis on Maize (Zea mays L.) Yield Loss in Bandung District

Drought impacts on crop yield loss depend on drought magnitude and duration and on plant genotype at every plant growth stages when droughts occur. This research aims to assess the difference calculation results of 2 drought index methods and to study the maize yield loss variability impacted by drought magnitude and duration during maize growth stages in Bandung district, province of West Java, Indonesia. Droughts were quantified by the Standardized Precipitation Index (SPI) and the Standardized Precipitation Evapotranspiration Index (SPEI) at 1- to 3-month lags for the January1986-December 2015 period data. Maize yield responses to droughts were simulated by AquaCrop for the January 1986-May 2016 period of growing season. The analysis showed that the SPI and SPEI methods provided similar results in quantifying drought event. Droughts during maize reproductive stages caused the highest maize yield loss.

Spatial and temporal analysis of the drought vulnerability and risks over eight decades in a semi-arid region (Tensift basin: Morocco)

In the last few decades, drought has become a chronic phenomenon in Morocco. It began at the end of the 1970s and continued to the late 2000s. In the present study, hydrometeorological data sets, Standardized Precipitation Index method, and non-parametric tests were used to recognize the frequency and the severity of drought events during the period between 1929 and 2010. The Standardized Precipitation Index showed significant inter-annual fluctuation and evolution of rainfall amounts representing wet cycles (i.e., before 1975) followed by a long period of drought between 1975 and 2004. The inter-annual variability of rainfall is accompanied by shifts of stationarity in the rainfall series. The statistical test of Pettitt, Bayesian method of Lee and Heghinian, Buishand procedure, and Hubert test revealed shifts around the mid 70s. After this period, a deficit of rainfall (with a maximum value of −30 %) was registered. The probabilities of monthly Standardized Precipitation Index values were normal to below normal during the last 40 years. In fact, the increase of drought risk may be resulted from the increase of frequency and severity of meteorological drought. The proposed Standardized Precipitation Index method and non-parametric tests yielded reasonable and satisfactory results for Morocco. Therefore, this approach could be successfully applied to other semi-arid, dry, sub-humid, or semi-humid regions worldwide, where rainfall series are showing high seasonality and year-to-year variability.

Application of copulas for regional bivariate frequency analysis of meteorological droughts in Turkey

The main objective of this study was to model the joint probability distributions of meteorological droughts of Turkey using copulas. Monthly rainfall data covering of period 1966–2006 from 173 gauge stations uniformly distributed across Turkey is considered for this aim. The principal component analysis is used to identify homogenous rainfall regions of Turkey. For meteorological drought analysis of the monthly rainfall series, standardized precipitation index method is used and the crucial drought characteristics, namely drought duration and severity, are determined. Marginal probability distributions of these characteristics are identified by fitting Weibull, two-parameter Lognormal, generalized Pareto, Gamma, Normal, Logistic, log-Logistic, generalized Extreme Value and Exponential distributions. Based on the Chi-square (χ2) goodness-of-fit test, the two-parameter Lognormal distribution is indicated as the best suitable for the duration series, whereas the Gamma, Weibull and generalized Pareto distributions show better fit for the severity series. As these drought characteristics are highly correlated and follow different probability distributions, copula functions are used to construct the joint distribution function of drought duration and severity series. Four types of bivariate copulas (i.e., Frank, Clayton, Gumbel–Hougaard and Ali–Mikhail–Haq) are evaluated for modeling and the best-fit copula for each homogenous region is then employed to estimate conditional probability properties and joint return periods of the drought characteristics. The drought properties of each region are hereby comprehensively explained and the results indicated here can be helpful in the assessment of the adequacies of water supply systems under drought conditions in all regions.

Drought analysis of the Seyhan Basin by using standardized precipitation ındex (spı) and l-moments

The aim of this study is to monitor drought in the Seyhan Basin by using Standardized Precipitation Index (SPI) based on a long term monthly precipitation of 11 meteorological stations and secondly, to also carry out regional frequency analysis using the index flood procedure coupled with the L-moments method based on recorded precipitation data of the most drought month for each year acquired from Standardized Precipitation Index method for each station. The SPI values of each station for 3, 6, 9 and 12-month time scales were calculated. According to the results, all stations are on the boundary of drought. Research results show that the wettest station is Ulukisla and the most drought station is Karaisali with respect to the average SPI values. According to the drought frequency values, however, the station having the highest drought occurrence frequency is the Karaisali station, whereas the station having the lowest drought frequency is the Tufanbeyli station. Results show that the Seyhan Basin is on the boundary of drought and mildly wet. Drought occurrence frequency is 47.7%. L-moments method was used to define homogenous regions. Homogenous regions for 3 and 6-month time scales minimum precipitation series couldn’t be obtained while homogenous regions for 9-month time scale minimum precipitation series were obtained only by dividing the whole basin into two parts. The whole basin is homogenous for the 12-month time scale minimum precipitation series. The Pearson Type 3 distribution is found to be most suitable for two homogenous sub-basins regarding 9-month time scale minimum precipitation series, whereas the Generalized Normal distribution is found to be most suitable for the whole basin with respect to 12-month time scale minimum precipitation series.

Drought Index Computation Using Standardized Precipitation Index (SPI) Method For Surat District, Gujarat

By definition drought is a long period of unusually low rainfall, especially one that badly affects growing or living conditions. Rainfall is to be believed as a normal, wet and dry condition of the climate. It is one of the most important water associated hazards. It has great impact on agricultural, hydrological, economic, environmental and social systems. Understanding these impacts is crucial for drought planning, mitigation, and response. It also helps decision makers identify and reduce vulnerability to drought. A drought index value is a single number, far more valuable than raw numbers for result making. The standardized precipitation index (SPI) has several characteristics that are an upgrading over other indices, with its simplicity and flexibility. The standardized precipitation index (SPI) method is used for observing and describing drought based on forty (40) year precipitation data of Surat district. Finding drought index with twelve month time scale basis and compare with the actual drought of the station. Positive SPI values point to normal condition to wet condition and negative values indicate normal condition to dry condition. SPI method resulted in showing as 50% variation of normal to wet and normal to dry condition respectively.

Spatio-temporal Drought Analysis in Arid and Semi-arid Regions: A Case Study from Palestine

Arid and semi-arid regions are generally characterized by water scarcity and low per capita water allocation. This situation is further exacerbated when such areas are agriculturally dominated with high-density residential areas. Faria catchment (320 km2), located in the northeastern part of the West Bank, Palestine, is one of these arid to semi-arid catchments where recently, the prolonged drought periods in the catchment and the increasing water demand have made the existing obtainable water resources vulnerable. Catchment drought analysis provides useful information for a sustainable water resources management. In this study, spatial and temporal dimensions of meteorological drought vulnerability in Faria catchment have been investigated using the Standardized Precipitation Index (SPI) as a measure for drought severity. The SPI method was used to detail geographical variations in the drought vulnerability based on frequency and severity of drought events at 1-year time step. This study is applied to rainfall records (1960–2003) for 6 rainfall stations located within the Faria catchment. Magnitude–duration curves are plotted to depict the relationships between drought duration and magnitude. Critical (threshold) drought values were derived spatially to determine the least amount of rainfall required to avoid from drought initiation. Once drought duration and magnitude have been found objectively, it is possible to use this when manage resources for bridging the supply-demand gap to drought affected areas either from alternative water resources or from water stored during wet periods.

Copula-based risk evaluation of droughts across the Pearl River basin, China

Daily precipitation data for the period of 1960–2005 from 42 precipitation gauging stations in the Pearl River basin were analyzed using the Mann–Kendall trend test and copula functions. The standardized precipitation index method was used to define drought episodes. Primary and secondary return periods were also analyzed to evaluate drought risks in the Pearl River basin as a whole. Results indicated that: (1) in general, the drought tendency was not significant at a 95 % confidence level. However, significant drought trends could be found in November, December, and January and significant wetting trends in June and July. The drought severity and drought durations were not significant at most of the precipitation stations across the Pearl River basin; (2) in terms of drought risk, higher drought risk could be observed in the lower Pearl River basin and lower drought risk in the upper Pearl River basin. Higher risk of droughts of longer durations was always corresponding to the higher risk of droughts with higher drought severity, which poses an increasing challenge for drought management and water resources management. When drought episodes with higher drought severity occurred in the Pearl River basin, the regions covered by higher risk of drought events were larger, which may challenge the water supply in the lower Pearl River basin. As for secondary return periods, results of this study indicated that secondary return periods might provide a more robust evaluation of drought risk. This study should be of merit for water resources management in the Pearl River basin, particularly the lower Pearl River basin, and can also act as a case study for determining regional response to drought changes as a result of global climate changes.

Drought classification in Northern Serbia based on SPI and statistical pattern recognition

AbstractThis paper proposes a procedure for decision‐making regarding the extent to which a certain geographical region is affected by drought. Professional circles generally recognize the Standardized Precipitation Index (SPI) as a good indicator of a drought event. However, as a result of varying precipitation levels due to various local geographical, climatic, vegetational and other factors, this indicator is determined based on precipitation measurements and different meteorological centres within the same administrative region often generate different SPI values, even when the geographical distance between them is small. During a dry period, various local authorities, ministries of agriculture or governments have to make important decisions about, for example, declaring disasters, subsidizing farmers for certain crops, or providing financial aid to agricultural producers, based on voluminous and diverse data about local precipitation, the yield of various crops, or the condition of the soil. This paper proposes an automated methodology for such decision‐making, which can be used as a support tool by decision‐makers. The methodology is based on the SPI and statistical pattern recognition methods (dimension reduction and classifier design based on the desired output). The entire procedure is illustrated using Vojvodina, a region in Serbia in the southern portion of the Pannonian Plain, as a case study. The proposed algorithm is not subject to any constraints with regard to geographical locations of regions, their surface areas, or inter‐relationships. Copyright © 2010 Royal Meteorological Society

Use of the standardized precipitation index (SPI) and a modified SPI for shaping the drought probabilities over Turkey

AbstractThis paper suggests a new methodology for the Standardized Precipitation Index (SPI), for studying different aspects of drought events in Turkey, including intensity, frequency and identifying the spatial and temporal patterns. The classical SPI is locally defined; for instance, for monthly scale or running means, a drought event would begin when the precipitation amount is below its long‐term average. However, the proposed method considers the local‐time means of the precipitation series by fitting an upper and a lower envelope to precipitation data to obtain the SPI values, thus it explicitly assesses a dry (or wet) spell of weather.When we consider the climatological/meteorological features of precipitation and the physical geographical controls of the climate over Turkey, it is found that the proposed method is more capable of estimating the probability of dry or wet conditions for a station's monthly precipitation totals (or running means) than if the SPI values are obtained using the classical method. Comparisons of the probability values calculated for the long‐term series and various time scales have revealed that the proposed method successfully estimates and/or well represents the various precipitation anomalies, particularly the wet and dry extremes. For instance, the probabilities of monthly values obtained by the proposed SPI method being above normal, below normal, near normal (i.e. normal) and extremely dry are more realistic and reasonable than those found by the classical SPI method. In conclusion, one can apply the proposed SPI methodology for determining and monitoring droughts of other semi‐arid, dry sub‐humid and semi‐humid climate regions, where the precipitation series show high seasonality and year‐to‐year variability, such as in the Mediterranean macro‐climate region. Copyright © 2009 Royal Meteorological Society

Detection of change in drought frequency in the Elbe basin: comparison of three methods

A comparison study is presented of three methods for evaluating trends in drought frequency: the standardized precipitation index (SPI), the Palmer drought severity index (PDSI), and a new method for estimation of dry spells (DS), which is based on average daily temperature and precipitation, and takes into account the length of a spell. The methods were applied to climate data from 450 stations in the Elbe River basin for the period 1951–2003, as well as data from several stations with longer observed time series. Statistical methods were used to calculate trend lines and evaluate the significance of detected trends. The dry spells estimated with the new method show significant trends in the whole lowland part of the Elbe basin during the last 53 years, and at the 10% level almost everywhere in the German part of the basin excluding mountains and the area around the river mouth. The SPI and PDSI methods also revealed significant trends, but for smaller areas in the lowland. The new DS method provides a useful supplement to other drought indices for the detection of trends in drought frequency. Furthermore, the DS method was able to detect statistically significant trends in areas where the other two methods failed to find significant trends, e.g. in the loess region in the southwest of the German part of the basin, where small insignificant changes in climate can lead to significant changes in water fluxes. This is important, because the loess region is the area within the basin having the highest crop yields. Therefore, additional research has to be done to investigate possible impacts of detected trends on water resources availability, and possible future trends in drought frequency under climate change.

Drought risk assessment in the western part of Bangladesh

Though drought is a recurrent phenomenon in Bangladesh, very little attention has been so far paid to the mitigation and preparedness of droughts. This article presents a method for spatial assessment of drought risk in Bangladesh. A conceptual framework, which emphasizes the combined role of hazard and vulnerability in defining risk, is used for the study. Standardized precipitation index method in a GIS environment is used to map the spatial extents of drought hazards in different time steps. The key social and physical factors that define drought vulnerability in the context of Bangladesh are identified and corresponding thematic maps in district level are prepared. Composite drought vulnerability map is developed through the integration of those thematic maps. The risk is computed as the product of the hazard and vulnerability. The result shows that droughts pose highest risk to the northern and northwestern districts of Bangladesh.

Spatial and temporal characteristics of droughts in the western part of Bangladesh

AbstractSpatial and temporal characteristics of droughts in the western part of Bangladesh have been analysed. Standardized precipitation index method is used to compute the severity of droughts from the rainfall data recorded in 12 rainfall gauge stations for the period of 1961–1999. An artificial neural network is used to estimate missing rainfall data. Geographic Information System (GIS) is used to map the spatial extent of droughts of different severities in multiple time scales. Critical analysis of rainfall is also carried to find the minimum monsoon and dry months rainfall require in different parts of the study area to avoid rainfall deficit. The study shows that the north and north‐western parts of Bangladesh are most vulnerable to droughts. A significant negative relationship between multiple ENSO index and rainfall is observed in some stations. Analysis of seasonal rainfall distribution, rainfall reliability and long‐term rainfall trend is also conducted to aid prediction of future droughts in the area. Copyright © 2007 John Wiley & Sons, Ltd.