scholarly journals Supplementary Materials: 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 ◽  
Author(s):  
Rajendra Man Shrestha
Keyword(s):  
River Basin ◽  
Probabilistic Model ◽  
Standardized Precipitation Index ◽  
Daily Rainfall ◽  
Precipitation Index ◽  
Rainfall Pattern ◽  
Index Approach ◽  
Supplementary Material

Supplementary material for the article on pages 57-72 https://doi.org/10.3126/njs.v4i0.33497

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 Drought and climate change assessment using Standardized Precipitation Index (SPI) for Sarawak River Basin

2019 ◽  
Vol 11 (4) ◽  
pp. 956-965 ◽  
Author(s):  
C. H. J. Bong ◽  
J. Richard
Keyword(s):  
Climate Change ◽  
River Basin ◽  
Drought Index ◽  
Standardized Precipitation Index ◽  
Recent Decade ◽  
Kendall Test ◽  
Precipitation Index ◽  
Irrigated Agriculture ◽  
Drought Event ◽  
Monthly Precipitation

Abstract Severe droughts in the year 1998 and 2014 in Sarawak due to the strong El Niño has impacted the water supply and irrigated agriculture. In this study, the Standardized Precipitation Index (SPI) was used for drought identification and monitoring in Sarawak River Basin. Using monthly precipitation data between the year 1975 and 2016 for 15 rainfall stations in the basin, the drought index values were obtained for the time scale of three, six and nine months. Rainfall trend for the years in study was also assessed using the Mann–Kendall test and Sen's slope estimator and compared with the drought index. Findings showed that generally there was a decreasing trend for the SPI values for the three time scales, indicating a higher tendency of increased drought event throughout the basin. Furthermore, it was observed that there was an increase in the numbers of dry months in the recent decade for most of the rainfall stations as compared to the previous 30 to 40 years, which could be due to climate change. Findings from this study are valuable for the planning and formulating of drought strategies to reduce and mitigate the adverse effects of drought.

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.

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