Standardized precipitation index formula. , Citation 2014; Ljungqvist et al.

The Standardized Precipitation Index (SPI) was developed by McKee et al (1993) [1] as a monthly indicator for meteorological drought, and has since become one of the most widely used drought indicators. The SPEI is designed to take into account both precipitation and potential evapotranspiration (PET) in determining drought. 1 from CRAN May 30, 2022 · Drought prediction is the most effective way to mitigate drought impacts. Typical SCI are the Standardized Precipitation Index (SPI), the Standardized Runoff Index (SRI) or the Standardized Precipitation Evapotranspiration Index (SPEI). Apr 1, 2012 · The Standardized Precipitation Index (SPI) is widely used as drought meteorological index, to identify the duration and/or severity of a drought. Standardized Precipitation Index (SPI) expresses the actual rainfall as standardized departure from rainfall probability distribution function and, hence, this index The Standard Precipitation Index (SPI) is a relatively new drought index based only on precipitation. Jan 1, 2012 · The Standardized Precipitation Index (SPI) is a drought index that solely uses precipitation, while the Standardized Precipitation Evapotranspiration Index (SPEI) uses the difference between Droughts are the world's costliest natural disasters, causing an estimated $6-$8 billion in global damages annually and affecting more people than any other form of natural disaster. It's an index based on the probability of precipitation for any time scale. Nov 29, 2022 · Hi, I have calculate the SPI using monthly CHIRPS CHG - Data (1981 - present). Apr 1, 2010 · Abstract The authors propose a new climatic drought index: the standardized precipitation evapotranspiration index (SPEI). A data. spi: Standardized Precipitation Index (SPI) in spi: Compute SPI index May 16, 2018 · The widely used meteorological drought index, the Standardized Precipitation Index (SPI), basically assumes stationarity, but recent changes in the climate have led to a need to review this hypothesis. Calculated for different time scales: meteorological, agricultural-economic and hydrological. The SPEI combines the sensitivity of PDSI to changes in evaporation demand (caused by temperature fluctuations and trends) with the simplicity of calculation and the multi-temporal nature of the SPI. •fitted: time series with the values of the Standardized Precipitation-Evapotranspiration Index (SPEI) or the Standardized Precipitation Index (SPI). Some processes are rapidly affected by atmospheric behavior, such as dry land agriculture, and the relevant time scale is a month or two. Jan 14, 2021 · The standardized precipitation index (SPI) and standardized precipitation evapotranspiration index (SPEI) can effectively reflect the changes in drought characteristics of different Nov 3, 2000 · The index is a standardized measure for precipitation in different climatic regions and for seasonal differences. Description Usage Arguments Details Value Author(s) References Examples. View source: R/SPIFromParameters. If you h The SPEI uses the basis of the standardized precipitation index (SPI), which permits to identify the deviation of precipitation values from a long-term average. , Citation 2005). , 2006; Wilhite, 2000). The results •fitted: time series with the values of the Standardized Precipitation-Evapotranspiration Index (SPEI) or the Standardized Precipitation Index (SPI). Meteorological drought assessments are widely evaluated by the concept of standardized precipitation index (SPI), which provides drought classification. Apr 22, 2002 · The standardized precipitation index function returns infinite values (np. patreon. Value. A new variation of SPI - the Standardized Precipitation and Evapotranspiration Index (SPEI) - has been developed (Vicente-Serrano et al. Given the consequences and pervasiveness of droughts, it is important to assess the specialized indices that are used to assess drought severity. In this work, the possibility to calculate SPI by fitting to the precipitation data the normal and the log-normal probability distributions Mar 8, 2022 · The Weighted Anomaly Standardized Precipitation (WASP) Index is used to summarize the weighted standardized monthly rainfall, and the main advantage of the WASP - Index is the use of the weighting factor, which also captures the variability of small rainfall at the beginning or end of the dry season (Lyon and Barnston Citation 2005). What is wrong with my dataset? I have a data frame with 225 columns; each containing the water Jan 1, 2015 · The standardized precipitation index (SPI) has several characteristics that are an upgrading over other indices, with its simplicity and flexibility. 8. Oct 1, 2023 · The Standardized Precipitation Evaporation Index (SPEI) was proposed by Vicente-Serrano et al. The SPI is used as it highlights the difference to the mean precipitation during a given time and therefore provides information about drought-like conditions. In this case it is known as the Standardized Precipitation Index (SPI). Download. . Calculation of the Standardized Precipitation-Evapotranspiration Index Description A set of functions for computing potential evapotranspiration and several widely used drought indices including the Standardized Precipitation-Evapotranspiration Index (SPEI). The input data (dataset_pr. [1] Jan 30, 2022 · The evaluation of the meteorological drought is fundamental for the management of the water resource. Description: Standardized Precipitation Index - Package Function performed: download Abstract: The Standardized Precipitation Index (SPI) was generated for certain Environment Canada long-term climate stations in Ontario. Here's the step: 1. Dec 7, 2020 · Further, rainfall is statistically not equally categorized, therefore, the records of long-term rainfall is then matched into a standard normal distribution function using gamma probability distribution, with a mean of zero and variance of one (Sönmez et al. (1993), and described in detail by Edwards and McKee (1997), measures precipitation anomalies at a given location, based on a comparison of observed total precipitation amounts for an The aim of this step-by-step procedure is to create a standardized precipitation index (SPI) timeline based on daily CHIRPS data. The index is based on a specified non‐ exceedance Mar 30, 2022 · The standardized precipitation index (SPI), one of the most commonly used drought indicators, is widely used in the research areas of drought analysis and drought prediction in different fields Jun 4, 2019 · An index developed by McKee et al. (1993) to quantify precipitation deficit at a given location for multiple timescales. Drought classification based on SPI indicates dry and wet spell Therefore, rainfall deviations across space and time need to be interpreted with due care. The SPEI is based on precipitation and temperature data, and it has the advantage of combining multiscalar character with the capacity to include the effects of temperature variability on drought assessment. 0 from the model and observations were considered as the drought years, probabilistic rainfall predictions were made for different categories of SPEI using a cumulative distribution function. Gridded Standardized Precipitation Index (SPI) captures how observed precipitation deviates from the climatological average (using the base period 1895–2014) over a given time period. The May 2, 2019 · In SPIGA: Compute SPI Index using the Methods Genetic Algorithm and Maximum Likelihood. It was intended to retrospectively look at wet and dry conditions using water balance techniques. BOTTOM LINE: All of the above steps makes the SPI independent of both the location and the range of values so that different seasons and climate areas are represented on an equal basis. This overview covers the interval 1993-2012, it focuses mainly on the publications in international journals, and Oct 1, 2022 · 2. spi) containing the following variables: year is the year. The Standardized Precipitation Index (SPI; McKee 1993) is the number of standard deviations that observed cumulative precipitation deviates from the climatological average. Standardized precipitation is the difference of precipitation from the mean for a specified time divided by the standard deviation, where the mean and standard deviation are determined from the climatological record. If data consists of several columns the function will treat each column as independent data, and the result will be a multivariate time series. S. The analysis uses gridded rainfall data from the India Meteorological Department (IMD), which has a spatial resolution of 0. Eea Climateadapt Mapgraphdataset Created 07 May 2012Modified 10 Sept 2022. Feb 12, 2018 · In this video, I have briefly explained how to characterize historically occurred droughts in a station level using the most commonly used index Standard Pre Feb 1, 2019 · The choice of the timescale depends on the intended purpose of gathering information about the drought events. (2010), which builds upon the Standardized Precipitation Index (SPI). Tree rings are one of the main proxies indicating past climate changes. To reduce biases in the presence of many zero (precipitation) events, the probability of these events (p This Factsheet provides a detailed technical description of the indicator Standardized Precipitation Index (SPI), produced by the Copernicus European Drought Observatory (EDO), which is used for detecting and characterizing meteorological drought. Calculate rainfall average and standard deviation by month (I used 1981 - 2014 as a base period), you can used Cell Statistics tool in the Spatial Analyst toolbox, and choose MEAN and STD to calculate the average and standard deviation for JAN, FEB, , DEC 1981 - 2014. chelliah@noaa. frame (precintcon. The objective of this article is to describe computing options that provide flexible and robust use of the SPEI. By adding a temperature component, the SPEI accounts for the effect of temperature on the development of drought conditions – high temperatures have been empirically shown to Apr 22, 2024 · The Standardized Precipitation Evapotranspiration Index (SPEI) is an extension of the widely used Standardized Precipitation Index (SPI). 1 Standardized Precipitation Index (SPI) SPI was devised by McKee and others (1993). The standardized precipitation index (SPI) method is used for observing and describing drought based on forty (40) year precipitation data of Surat district. Precipitation positively affected tree growth Sep 21, 2020 · Abstract. This study illuminates that long-standing dispute and proposes a solution that ensures the normality of the index for all common accumulation periods in a Standardized Climate Index (SCI). Mar 14, 2024 · Hence, this work considers analyzing 15-day Standardized Precipitation Index (SPI) trends and drought characteristics using conventional methods and Innovative Trend Analysis (ITA) techniques. 1. The development of a drought is a gradual process with a long duration and large range of influence, with major impacts on agriculture and social economy (Fang et al. The above command will compute SPI (standardized precipitation index, both gamma and Pearson Type III distributions) from an input precipitation dataset (in this case, IMERG precipitation dataset). Jan 28, 2019 · I tried to calculate a SPEI (aggregation over two months) for my 225 sites but spei only returns NA's. Feb 2, 2021 · The Standard Precipitation Index (SPI) is a widely used statistical technique for the characterization of droughts. Since SPEI values less than −1. The Standardized Precipitation Index (SPI) is a widely accepted drought index. R. About. Jul 27, 2023 · The Standardized Precipitation Evapotranspiration Index (SPEI) is calculated using a similar methodology to the Standardized Precipitation Index (SPI). , 2010), which includes precipitation and temperature, in order to identify increases in drought severity linked with higher water demand by evapotranspiration. A suite of notes that attempt to explain or clarify complex climate phenomena, Climate Monitoring products and methodologies, and climate system insights Jun 10, 2012 · The formula for the Standardized Precipitation Index (SPI) is as follows: SPI = (x - μ) / σ where x is the amount of precipitation recorded in a given period, μ is the mean precipitation over the same period, and σ is the standard deviation of the precipitation over the same period. ) that were collected in the Taihe Mountains on the western Loess Plateau, China, were used to analyze the effects of climate and drought on radial growth and to reconstruct the mean April-June Standardized Precipitation Evapotranspiration Index (SPEI) during the period 1730–2012 AD. However, the SPI only considers the precipitation factor, whereas the SPEI is a drought index that considers both precipitation and evapotranspiration. com/roelvandepaarWith th The standardized anomaly is then computed with results having an average of zero and a standard deviation of one. Description. Its calculation algorithm normalizes the index via a distribution function. gov) Nov 21, 2022 · #Drought Tools in AgriMetSoft:https://agrimetsoft. It seams that the function can not deal with some precipitation thresholds (maximum and minimum). published the article "The Relation of Drought Frequency and Duration to Time Scales" in which they introduced the "Standardized Precipitation Index" (SPI) as a proxi for precipitation related droughts. inf) for some time periods in which the precipitation is maximum or minimum (see Figure). , 2019; Huang et al. 1993 ). transformSCIapplies the standardisation. Standardized Precipitation Index (SPI) expresses the actual rainfall as a standardized departure with respect to rainfall probability distribution function and hence the index has Mar 7, 2023 · fitted: time series with the values of the Standardized Precipitation-Evapotranspiration Index (SPEI) or the Standardized Precipitation Index (SPI). com May 17, 2001 · The Standardized Precipitation Index (SPI) was developed to detect drought and wet periods at different time scales, an important characteristic that is not accomplished with typical drought indices. In this video, I go through how to analyze rainfall data to determine the standardized precipitation index (SPI). . At twenty years after its launch, the Standardized Precipitation Index (SPI) is intensively used both in fundamental studies and practical applications. Therefore, rainfall deviations across space and time need to be interpreted with due care. The procedure to calculate the index is detailed and involves a In this study, the Standardized Precipitation Evaporation Index (SPEI) was applied to characterize the drought conditions in Southwest China from 1982–2012. , Citation 2020). Usage Apr 3, 2019 · standaRdized is an R package for the calculation of Standardized Index values (SPI, SPEI, SSI,) on a daily basis. One of the most used indices to evaluate the drought is the standardized precipitation index (SPI) due to its practicality and evaluation in a variety of time scales, however, this uses precipitation as the only variable, depending on the deviations in the precipitation values. com/rdithttps://agrimetsoft. calculate the standardized precipitation index, from alpha and beta parameter of the Gamma function. 250-N. Share. Feb 22, 2016 · SPEI is calculated on a monthly basis and for calculation requires monthly precipitation data. different time scales, better comparability in time and space, but Vicente-Serrano et al. Feb 1, 2022 · The standardized precipitation index (SPI) was developed as a stationary method in which the parameters of the distribution used to estimate the cumulative probability of rainfall amounts do not vary over time. May 2, 2019 · The SPI function computes the SPI index (McKee et al. gov) & Li Xu (li. The current study examined the ability of three renowned machine learning models, namely additive regression (AR), random subspace (RSS), and M5P tree, and their hybridized versions (AR-RSS, AR-M5P, RSS-M5P, and AR-RSS-M5P) in predicting the standardized precipitation evapotranspiration index (SPEI) in multiple time scales. This study aims to test data fitability of ten statistical distribution functions (gamma, weibull, exponential, lognormal, gumbel, cauchy, logistic, chi-square, burr Dec 21, 2013 · The standardized precipitation evapotranspiration index (SPEI) was developed in 2010 and has been used in an increasing number of climatology and hydrology studies. Mar 7, 2023 · A set of functions for computing potential evapotranspiration and several widely used drought indices including the Standardized Precipitation-Evapotranspiration Index (SPEI). SPEI: Calculation of the Standardized Precipitation-Evapotranspiration Index version 1. I discuss how to go about analyzing data to Oct 19, 2022 · This function,written by Tayeb Raziei in October 2022, computes the Simplified Standardized Precipitation Index (SSPI) described in Raziei, Tayeb, 2021, "Revisiting the Rainfall Anomaly Index to The Standardized Precipitation Index (SPI) was developed to detect drought and wet periods at different time scales, an important characteristic that is not accomplished with typical drought indices. SCI was originally developed for precipitation. Dec 9, 2019 · As a representative index for monitoring and assessing drought, the Standardized Precipitation Index (SPI) relies on a suitable probability distribution function (PDF) to describe a precipitation series, which allows interregional comparisons following normalization. The SPI is space-independent and has a sound performance when representing precipitation anomaly (Mckee et al. Standardized Precipitation and Evapotranspiration Index (SPEI) The SPEI uses the advantages of the SPI, e. Standardized Precipitation Index (SPI) expresses the actual rainfall as a standardized departure with respect to rainfall probability distribution function and hence the index has Jun 29, 2024 · Global warming and climate change impacts intensify hydrological cycle and consequently unprecedented drought and flood appear in different parts of the world. The script will be executed within Google Earth Engine and will drought affected area as one with rainfall between 26‐ 50% and less than 50% of the normal rainfall respectively. Drought indices of 1-month to 3-month timescale have often been used for agricultural The aim of this step-by-step guide, offered on the UN-SPIDER knowledge portal, is to create a standardized precipitation index (SPI) timeline based on daily CHIRPS data. For calculation of SPEI - Standardised Precipitation Evapotranspiration Index (Vicente-Serrano, S. This article presents the computation of SPI using 55 years of data from 24 stations in Cameroon and its use to identify drought occurrences and thresholds. It is based on a probabilistic standardization procedure, which converts a Gamma-type probability distribution function (PDF) into a normal (Gaussian) standard series with zero mean and unit standard deviation. SCI is a transformation of (smoothed) climate (or environmental) time series that removes seasonality and forces the data to take values of the standard normal distribution. com/drought%20monitoring%20and%20predictionhttps://agrimetsoft. It was developed by Vicente-Serrano et al. The SPI indicator, which was developed by McKee et al. xu@noaa. 2. Nov 19, 2021 · GIS: Standardized Precipitation Index (SPI) equation using ArcGIS DesktopHelpful? Please support me on Patreon: https://www. spi is the standardized precipitation index. It is implemented operationally in numerous Hydrological and Meteorological Services, being considered a universal drought index. Introduction. The Standardised Precipitation-Evapotranspiration Index The SPEI is a multiscalar drought index based on climatic data. month is the month. The standardized precipitation index (SPI) has several SPI: Standardized Precipitation Index. Oct 1, 2014 · The standardized precipitation index (SPI) is a probability index that quantifies precipitation deficits on various time scales. To this day, the SPI is used world wide to address precipitation information when it comes to drought like conditions. Based on the SPEI, the multi-scale patterns, the trend, and the spatio-temporal extent of drought were evaluated, respectively. The difference between the two indices is that SPEI accounts for both precipitation and potential evapotranspiration, whereas SPI accounts for only precipitation. It is derived from the nClimGrid-Monthly dataset and includes timescales of 1, 2, 3, 6, 9, 12, 24, 36, 48, 60 and 72 months. This global SPI is derived from the NOAA CMORPH dataset, using the Climate Engine tool, and includes timescales of 1, 2, 3, 6, 9 and 12 months. The Standardized Precipitation Index (SPI) is a probability index that was developed to give a better representation of abnormal Jul 14, 2021 · In today's tutorial, we address standardized precipitation indices (SPI) using Python Pandas and self-defined function for a point location's precipitation t Standardized Precipitation-Evapotranspiration Index (SPEI)# The SPEI is an extension of the widely used SPI. , 2016). Author(s) Lucas Venezian Povoa lucasvenez@gmail. 1. 250-E and 0. It can be used for determining the onset, duration and magnitude of drought conditions with respect to normal conditions in a variety of natural and managed systems such as crops, ecosystems, rivers, water resources, etc. , 1993) from a predefined time scale (1 month, 3 months, 24 months, etc. More and more users employ the SPI to monitor droughts. The SPI quantifies the precipitation deficit and surplus for multiple time scales, including: one month three months six Feb 1, 2022 · 1. Apr 28, 2012 · The standardized precipitation index (SPI) is a probability-based indicator that depicts the degree to which the accumulative precipitation of a specific period departs from the average state. Nov 30, 2022 · The goal of this work is to use SPI (standardized precipitation index) and SPEI (standardized precipitation evapotranspiration index) to investigate the differences in drought characteristics Aug 19, 2016 · Standardized Precipitation Index. The Standardized Precipitation Evapotranspiration Index (SPEI) is a multiscalar drought index based on climatic data. Its application is based on the probabilistic standardization procedure, but in the Python implementation for calculating the Standard Precipitation Index (SPI) and Standard Precipitation Evapotranspiration Index (SPEI) - e-baumer/standard_precip Functions for generating Standardized Climate Indices (SCI). In this study, a new non-stationary SPI that considers not only the modified probability distribution parameter but also the return period under the non-stationary process was proposed. com/mdmPlaylist The U. The input dataset is monthly rainfall accumulation data and the calibration period used will be Jun-2000 through Dec-2020. In this study, we considered nine PDFs (exponential (EXP), extreme value (EV), gamma (GAM), generalized Pareto (GP), logistic Overview . Aug 19, 2016 · The integrated drought index is the mean of the ensemble mean soil moisture percentiles and the SRI3 averaged over all models. The Standardized Precipitation Index, or SPI, is a drought index that captures how observed precipitation deviates from the climatological average over a given time period. Reconstructions over the past hundreds to thousands of years based on tree-ring chronologies are essential for revealing global and regional hydroclimatic variations at decade-century scales (Breitenmoser et al. Jun 26, 2023 · The proposed approach, called the Simplified Standardized Precipitation-Evapotranspiration Index (SSPEI), uses the Box-Cox transformation to normalize water balance anomalies (WBA) and subsequently convert the transformed series into the standard normal distribution (SND) using the Z-score formula. ) to a period choosen by users. The concurrence measure is the fraction of indices in the D1 & above categories as the integrated drought index. g. Apr 17, 2009 · Monthly rainfall data from June to October for 39 years were used to compute Standardized Precipitation Index (SPI) values based on two parameter gamma distribution for a low rainfall and a high rainfall districts of Andhra Pradesh state, India. The SPEI was calculated by precipitation and temperature data for various accumulation periods. Contacts: Muthuvel Chelliah (muthuvel. , Citation 2014; Ljungqvist et al. The Standardized Precipitation Index (SPI) is the most commonly used indicator worldwide for detecting and characterizing meteorological droughts. In 1993 McKee et al. Watch carefully to avoid mistakes. M Nov 1, 2021 · The Rainfall Anomaly Index (RAI) is revisited herein as an alternative to the Standardized Precipitation Index (SPI), taking into account different time scales and the probability of zero Aug 1, 2014 · The standardized precipitation evapotranspiration index (SPEI) was developed in 2010 and has been used in an increasing number of climatology and hydrology studies. Therefore a new drought index (the Standardized Precipitation Evapotranspiration Index; SPEI) has been formulated based on precipitation and PET. Aug 30, 2023 · 1. In particular, we present methods for estimating the parameters of the log‐logistic distribution for obtaining Apr 1, 1999 · ABSTRACT: The Palmer Drought Severity Index (PDSI) has been calculated for about 30 years as a means of providing a single measure of meteorological drought severity. This map shows the Standardized Precipitation Index (SPI) for multiple monthly accumulation periods for the globe. Jul 24, 2015 · Tree-ring samples from Chinese Pine (Pinus tabulaeformis Carr. (2010) added evapotranspiration as additional information to account for the sensitivity of droughts to evaporation and temperature. Drought comprises a water shortage due to an imbalance in water supply caused by decreased precipitation (Huang et al. Dec 21, 2023 · The performance of the Standardized Precipitation Index (SPI) is affected by the choice of an incorrect probability distribution function, which can skew the values of the index, exaggerating or minimizing the severity of drought. Which distribution function to use is still disputed within the literature. Contact. Feb 9, 2021 · Scientific Reports - Forecasting standardized precipitation index using data intelligence models: regional investigation of Bangladesh \right)\) is the kernel function based on Mercer Sep 3, 2015 · SDAT can be used to generate nonparametric standardized drought indicators such as: - Standardized Precipitation Index (SPI), - Standardized Soil Moisture Index (SSI), - Standardized Runoff Index (SRI) - Standardized Streamflow Index (SSFI), - Standardized Relative Humidity Index (SRHI), - Standardised Groundwater level Index (SGI), Standardized Precipitation Index. Recent Observations: 24Jul2024 Topo 3-Month SPI 6-Month SPI 12-Month SPI 24-Month SPI Boundaries Standardized Precipitation Index. pr) does not have any nan or fill/missing value. It is implemented operationally in May 3, 2021 · In this video, you'll learn how to calculate Standardized Anomaly Index (SAI) using Excel step by step procedure. (2010) at the Institute Pirenaico de Ecologia in Zaragoza, Spain . Dec 1, 2015 · At twenty years after its launch, the Standardized Precipitation Index (SPI) is intensively used both in fundamental studies and practical applications. The SPI is usually computed by fitting the gamma probability distribution to the observed precipitation data. Feb 18, 2022 · where O t is the observed SPEI, P t is the predicted SPEI, t is the time, and n = number of data points in the testing period. sk pd rd lm ss yp ya la ph je