scholarly journals Drought or Wet Assessment of Daily Rainfall Pattern of the Budhi Gandaki River Basin, Nepal: Standardized Precipitation Index Approach using Probabilistic Model

2020 ◽  
Vol 4 ◽  
pp. 57-72
Author(s):  
Rajendra Man Shrestha
Keyword(s):  
River Basin ◽  
Goodness Of Fit ◽  
Standardized Precipitation Index ◽  
Daily Rainfall ◽  
Precipitation Index ◽  
Cumulative Distribution ◽  
Rainfall Pattern ◽  
Natural Phenomenon ◽  
Severe Drought ◽  
Chi Square

Background: Rainfall is a natural phenomenon. Dramatic changes in the rainfall pattern lead to extreme climatic or hydrological events like flash floods, or floods, landslides or severe drought events at any parts of the world. Objective: The objective of this study aims to perform analysis of drought/ wet for fifteen meteorological /hydrological stations distributed over the Budhi Gandaki River Basin, Nepal. Materials and Methods: The Kolmogorov-Simonov test, Anderson-Darling test and Chi-square test are used for testing of the hypothesis of goodness of fit supported by the q-q plot (or p-p plot), cumulative distribution function plot and probability density function plot. The standardized precipitation index is a widely used to develop the index to monitor the dryness/wetness in a given day. Results: Johnson SB distribution and Weibull distribution were fitted to the daily rainfall across the fifteen stations. Conclusion: There were some episodes of moderate drought events across six stations. Similarly, there were a moderate type of wetness across five stations. The rest of the stations had a majority of near normal days out of 13514 days. Supplementary Material avialable here https://doi.org/10.3126/njs.v4i0.33499

scholarly journals Application of Markov chains to Standardized Precipitation Index (SPI) in São Francisco River Basin

2019 ◽  
Vol 14 (3) ◽  
pp. 1
Author(s):  
Esdras Adriano Barbosa dos Santos ◽  
Tatijana Stosic ◽  
Ikaro Daniel de Carvalho Barreto ◽  
Laélia Campos ◽  
Antonio Samuel Alves da Silva
Keyword(s):  
Markov Chains ◽  
River Basin ◽  
Arid Region ◽  
Standardized Precipitation Index ◽  
Precipitation Index ◽  
Severe Drought ◽  
Sao Francisco River ◽  
São Francisco River ◽  
Semi Arid Region ◽  
Semi Arid

This work evaluated dry and rainy conditions in the subregions of the São Francisco River Basin (BHSF) using the Standardized Precipitation Index (SPI) and Markov chains. Each subregion of the BHSF has specific physical and climatic characteristics. The data was obtained from the National Water Agency (ANA), collected by four pluviometric stations (representative of each subregion), covering 46 years of data, from 1970 to 2015. The SPI was calculated for the time scales of six and twelve months and transition probabilities were obtained using the Markov chain. Transition matrices showed that, at both scales, if the climate conditions were severe drought or rainy, switching to another class would be unlikely in the short term.  Correlating this information with the probabilities of the stationary distribution, it was possible to find the regions that are most likely to be under rainy or dry weather in the future. The recurrence times calculated for the stations that belong to the semi-arid region were smaller when compared to the value of the return period of the representative station of Upper São Francisco that has higher levels of precipitation, confirming the predisposition of the semi-arid region to present greater chances of future periods of drought.

scholarly journals Computation of the Standardized Precipitation Index (SPI) and Its Use to Assess Drought Occurrences in Cameroon over Recent Decades

2014 ◽  
Vol 53 (10) ◽  
pp. 2310-2324 ◽  
Author(s):  
Guy Merlin Guenang ◽  
F. Mkankam Kamga
Keyword(s):  
Time Scales ◽  
Goodness Of Fit ◽  
Standardized Precipitation Index ◽  
Research Unit ◽  
Distribution Functions ◽  
Precipitation Index ◽  
Severe Drought ◽  
East Anglia ◽  
The Standardized Precipitation Index ◽  
Short Time

AbstractThe standardized precipitation index (SPI) is computed and analyzed using 55 years of precipitation data recorded in 24 observation stations in Cameroon along with University of East Anglia Climate Research Unit (CRU) spatialized data. Four statistical distribution functions (gamma, exponential, Weibull, and lognormal) are first fitted to data accumulated for various time scales, and the appropriate functions are selected on the basis of the Anderson–Darling goodness-of-fit statistic. For short time scales (up to 6 months) and for stations above 10°N, the gamma distribution is the most frequent choice; below this belt, the Weibull distribution predominates. For longer than 6-month time scales, there are no consistent patterns of fitted distributions. After calculating the SPI in the usual way, operational drought thresholds that are based on an objective method are determined at each station. These thresholds are useful in drought-response decision making. From SPI time series, episodes of severe and extreme droughts are identified at many stations during the study period. Moderate/severe drought occurrences are intra-annual in short time scales and interannual for long time scales (greater than 9 months), usually spanning many years. The SPI calculated from CRU gridded precipitation shows similar results, with some discrepancies at longer scales. Thus, the spatialized dataset can be used to extend such studies to a larger region—especially data-scarce areas.

scholarly journals Severity, Duration, and Magnitude Regionalization of Standardized Precipitation Index Over Iran During 1993-2016

2021 ◽  
Author(s):  
Farshad Fathian ◽  
Zohreh Dehghan ◽  
Babak Vaheddoost
Keyword(s):  
Water Use ◽  
Standardized Precipitation Index ◽  
Precipitation Index ◽  
Regional Frequency Analysis ◽  
Natural Phenomenon ◽  
Severe Drought ◽  
Agricultural Water ◽  
Drought Characteristics ◽  
Agricultural Water Use ◽  
Pearson Type

Abstract Drought is a natural phenomenon that has environmental and socio-economical drawbacks. Especially in arid and semi-arid regions, human activities are closely linked to the water supply and agricultural water use. Although the consequences of drought are prolonged, immediate actions are needed in practice which urges the continuous need for drought monitoring. The present study addresses a regional frequency analysis (RFA) for extreme drought events including severity, duration, and magnitude over Iran. Standardized precipitation index (SPI) time series with 1, 3, 6, 9, and 12 moving averages are determined from 106 meteorological stations for the period 1993-2016. Using Ward’s clustering analysis, the drought characteristics are grouped into different clusters and their homogeneity is confirmed by the heterogeneity measure test based on the L-moment approach. The results of RFA indicate that both generalized Pareto (GP) and Pearson type 3 (PE3) distribution functions are the best-fitted regional models to the most identified homogenous clusters of all three drought characteristics, by which the quantiles of each drought characteristic related to different return periods, T = 2, 5, 10, 25, 50, 75, and 100 years, are estimated. The spatial pattern of the drought characteristics for all SPI time scales shows that extreme droughts in terms of severity, duration, and magnitude may occur everywhere in the country regardless of local climate conditions. As such, even humid and rainy regions including northern, northwestern, and western parts of Iran that receive high annual precipitation would encounter extreme and severe drought characteristics. It is concluded that the drought risks in the region are mostly the outcome of mismanagement, water resource allocation, and agricultural water use but could be exacerbated due to climatic events.

scholarly journals Drought assessment using a multivariate drought index in the Huaihe River basin of Eastern China

2015 ◽  
Vol 369 ◽  
pp. 61-67
Author(s):  
Q. Li ◽  
M. Zeng ◽  
H. Wang ◽  
P. Li ◽  
K. Wang ◽  
...  
Keyword(s):  
River Basin ◽  
Drought Index ◽  
Eastern China ◽  
Standardized Precipitation Index ◽  
Cumulative Distribution ◽  
Huaihe River Basin ◽  
Huaihe River ◽  
Drought Assessment ◽  
The Huaihe River ◽  
Multivariate Drought Index

Abstract. The Huaihe River Basin having China's highest population density (662 persons per km2) lies in a transition zone between the climates of North and South China, and is thus prone to drought. Therefore, the paper aims to develop an appropriate drought assessment approach for drought assessment in the Huaihe River basin, China. Based on the Principal Component Analysis of precipitation, evapotranspiration, soil moisture and runoff, the three latter variables of which were obtained by use of the Xin'anjiang model, a new multivariate drought index (MDI) was formulated, and its thresholds were determined by use of cumulative distribution function. The MDI, the Standardized Precipitation Index (SPI) and the self-calibrating Palmer Drought Severity Index (sc-PDSI) time series on a monthly scale were computed and compared during 1988, 1999/2000 and 2001 drought events. The results show that the MDI exhibited certain advantages over the sc-PDSI and the SPI in monitoring drought evolution. The MDI formulated by this paper could provide a scientific basis for drought mitigation and management, and references for drought assessment elsewhere in China.

scholarly journals Modeling, prediction and trend assessment of drought in Iran using standardized precipitation index

2018 ◽  
Vol 10 (1) ◽  
pp. 181-196 ◽  
Author(s):  
Mehdi Bahrami ◽  
Samira Bazrkar ◽  
Abdol Rassoul Zarei
Keyword(s):  
Time Series ◽  
Moving Average ◽  
Standardized Precipitation Index ◽  
Precipitation Index ◽  
Occurrence Frequency ◽  
Natural Phenomenon ◽  
Drought Severity ◽  
Data Series ◽  
Climate Data ◽  
Seasonal Drought

Abstract Drought as an exigent natural phenomenon, with high frequency in arid and semi-arid regions, leads to enormous damage to agriculture, economy, and environment. In this study, the seasonal Standardized Precipitation Index (SPI) drought index and time series models were employed to model and predict seasonal drought using climate data of 38 Iranian synoptic stations during 1967–2014. In order to model and predict seasonal drought ITSM (Interactive Time Series Modeling) statistical software was used. According to the calculated seasonal SPI, within the study area, drought severity classes 4 and 3 had the greatest occurrence frequency, while classes 6 and 7 had the least occurrence frequency. Results indicated that the best fitted models were Moving-Average or MA (5) Innovations and MA (5) Hannan-Rissenen, with 60.53 and 15.79 percentage, respectively. On the other hand, results of the prediction as well, indicated that drought class 4 with the highest percentages, was the most abundant class over the study area and drought class 7 was the least frequent class. According to results of trend analysis, without attention to significance of them, observed seasonal SPI data series (1967–2014), in 84.21% of synoptic stations had a negative trend, but this percentage changes to 86.84% when studying the combination of observed and predicted simultaneously (1967–2019).

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

2019 ◽  
Vol 11 (1-2) ◽  
pp. 199-216
Author(s):  
R Afrin ◽  
F Hossain ◽  
SA Mamun
Keyword(s):  
Standardized Precipitation Index ◽  
Extended Period ◽  
Northern Region ◽  
Precipitation Index ◽  
Rainfall Data ◽  
Extreme Drought ◽  
Severe Drought ◽  
Drought Analysis ◽  
Dry Conditions ◽  
The Standardized Precipitation Index

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

scholarly journals Evaluation of temporal drought variation and projection in a tropical river basin of Kerala

2020 ◽  
Vol 11 (S1) ◽  
pp. 115-132 ◽  
Author(s):  
M. A. Jincy Rose ◽  
N. R. Chithra
Keyword(s):  
River Basin ◽  
Standardized Precipitation Index ◽  
Drought Severity ◽  
Climate Projections ◽  
Severe Drought ◽  
Tropical River ◽  
The Past ◽  
Drought Conditions ◽  
The Future ◽  
The Standardized Precipitation Index

Abstract Temperature is an indispensable parameter of climate that triggers evapotranspiration and has vital importance in aggravating drought severity. This paper analyses the existence and persistence of drought conditions which are said to prevail in a tropical river basin which was once perennial. Past observed data and future climate projections of precipitation and temperature were used for this purpose. The assessment and projection of this study employ the Standardized Precipitation Evapotranspiration Index (SPEI) compared with that of the Standardized Precipitation Index (SPI). The results indicate the existence of drought in the past and the drought conditions that may persist in the future according to RCP 4.5 and 8.5 scenarios. The past drought years identified in the study were compared with the drought declared years in the state and were found to be matching. The evaluation of the future scenarios unveils the occurrence of drought in the basin ranging from mild to extreme conditions. It has been noted that the number of moderate and severe drought months has increased based on SPEI compared to SPI, indicating the importance of temperature in drought studies. The study can be considered as a plausible scientific remark helpful in risk management and application decisions.

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