scholarly journals A Probabilistic Approach for Assessment of Future Drought in Bagmati River Basin, Nepal

2018 ◽  
Vol 2 ◽  
pp. 75-88
Author(s):  
Rajendra Man Shrestha ◽  
Azaya Bikram Sthapit ◽  
Srijan Lal Shrestha
Keyword(s):  
River Basin ◽  
Probabilistic Approach ◽  
Standardized Precipitation Index ◽  
Severe Drought ◽  
Summer Drought ◽  
The Future ◽  
Moderate Drought ◽  
Extreme Distribution ◽  
Bagmati River

Background: The Bagmati River is the rain-fed river in the basin of Nepal. The climate change in rainfall patterns may lead to drought or flashflood in this basin. Drought is a silent and pervasive hazard due to the deficit of water availability. It may have adverse impact on society leading to impact on environment, culture, political and other functions of the region.Objective: This study aims to assess the future drought in the Bagmati River Basin, Nepal.Materials and Methods: Providing Regional Climates for Impact Studies precipitation data was obtained from Department of Hydrology and Meteorology, Kathmandu. The Generalized Extreme Distribution was fitted to respective total precipitations in 3 time-scales using EasyFit software. Standardized Precipitation Index (SPI) method was used to derive SPI for winter drought, SPI for summer drought and SPI for long-term (annual) drought.Results: The results of data analysis showed that winter moderate drought episodes may occur in years 2035, 2042, 2048, 2049, 2051 and 2053. Likewise, summer severe drought episode may occur in 2046. The year 2046 also indicated long-term extreme drought. Moreover, 2030, 2031, 2035, 3040 and 2053 may be long-term moderate drought episodes years in future.Conclusion: There may be winter moderate drought, summer severe drought and a long-term extreme as well as moderate drought during the future period 2030-2060.Nepalese Journal of Statistics, Vol. 2, 75-88

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.

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.

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>

scholarly journals EVALUATION OF POSSIBLE CHANGES IN THE RIVER LINE OF THE OKA BASIN FOR THE COMING PERIOD OF THE FIRST HALF OF THE XXI CENTURY

2020 ◽  
Vol 1 (5) ◽  
pp. 71-75
Author(s):  
G. Kh. Ismaiylov ◽  
◽  
N.V. Muraschenkova ◽  
Keyword(s):  
River Basin ◽  
21St Century ◽  
River Runoff ◽  
River Flow ◽  
Climatic Conditions ◽  
Global Changes ◽  
The Future ◽  
Seasonal Runoff ◽  
The City

A retrospective analysis and assessment of long-term changes in the annual and seasonal runoff of the Oka River basin over a long 131-year observation period (1881 / 1882–2011/2012) was performed. The changes in the annual distribution of the Oka river runoff over the seasons of the year (spring flood, summer-autumn and winter low water) from its annual value for the selected time periods (before and after 1976/1977) are considered. It has been noted that over the past decades, river runoff has been formed in new climatic conditions associated with global changes and, as a result, regional climate. The assessment of possible changes in the annual and seasonal runoff of the Oka River basin (to the final alignment – the city of Kaluga, with a basin area of 54,900 km2 ) in the first half of the 21st century is carried out. In assessing changes in the river flow of the Oka basin for the future period, the method of trends (trends) is used, based on the identification of cycles in fluctuations in hydrological characteristics and unidirectional trends (trends) inherent in individual phases (ups and downs) of these cycles, as well as to the establishment of functional (correlation) relationships between environmental factors (climatic, anthropogenic) and the nature of the response (river flow). In this case, the trend model serves as an alternative to the homogeneity hypothesis of long-term fluctuations in river flow. The change in the future values of the river flow of the Oka basin was estimated using averaged data of 30-year periods of time characterized by relative stationarity of climatic and hydrological conditions. The dynamics of the average 30-year values of the annual runoff in the upper reaches of the Oka River (the closure target is the city of Kaluga for the period 1881/1882–2011/2012) is considered. Possible forecasted mean annual values of the annual flow of the Oka River for the first half of the 21st century are obtained

scholarly journals Spatiotemporal Variation of the Meteorological and Groundwater Droughts in Central Taiwan

2021 ◽  
Vol 3 ◽  
Author(s):  
Hsin-Fu Yeh
Keyword(s):  
River Basin ◽  
Groundwater Level ◽  
Standardized Precipitation Index ◽  
Extreme Drought ◽  
Water Shortages ◽  
Level Data ◽  
Groundwater Drought ◽  
Central Taiwan ◽  
The Standardized Precipitation Index

In recent years, Taiwan has been facing severe water shortages due to extreme drought. In addition, changes in rainfall patterns have resulted in an increasingly notable drought phenomenon, which affects the management and utilization of water resources. Therefore, this work examines basins in Central Taiwan. Long-term records from 13 rainfall and 17 groundwater stations were selected. The Standardized Precipitation Index (SPI) and Standardized Groundwater Level Index (SGI) were used to analyze the drought characteristics of this region. The rainfall and groundwater level data from basins in Central Taiwan were analyzed in this study. The results show that the year 2015 experienced extreme drought conditions due to a correlation with SPI and SGI signals. In addition, with regard to groundwater drought, more drought events occurred in the Da'an River basin; however, the duration and intensity of these events were relatively low, in contrast to those of the Wu River basin. Finally, the correlation between SPI and SGI was observed to vary in different basins, but a certain degree of correlation was observed in all basins. The results show that drought intensity increases with longer drought durations. Moreover, severe droughts caused by rainfall tend to occur at a greater frequency than those caused by groundwater.

scholarly journals Spatio-Temporal Analysis of Drought Variability Using CWSI in the Koshi River Basin (KRB)

2019 ◽  
Vol 16 (17) ◽  
pp. 3100 ◽  
Author(s):  
Han Wu ◽  
Donghong Xiong ◽  
Bintao Liu ◽  
Su Zhang ◽  
Yong Yuan ◽  
...  
Keyword(s):  
River Basin ◽  
Temporal Analysis ◽  
Water Shortage ◽  
Severe Drought ◽  
Crop Water ◽  
Water Shortages ◽  
Moderate Drought ◽  
Koshi River Basin ◽  
Spatio Temporal ◽  
One Year

Drought is one of the most frequent meteorological disasters, and has exerted significant impacts on the livelihoods and economy of the Koshi River Basin (KRB). In this study, we assessed drought patterns using the Crop Water Shortage Index (CWSI) based on the MOD16 product for the period between 2000 and 2014. The results revealed that the CWSI based on the MOD16 product can be act as an indicator to monitor the characteristics of the drought. Significant spatial heterogeneity of drought was observed in the basin, with higher CWSI values downstream and upstream than in the midstream. The midstream of the KRB was dominated by light drought, moderate drought occurred in the upstream, and the downstream was characterized by severe drought. The monthly CWSI during one year in KRB showed the higher CWSI between March to May (pre-monsoon) and October to December (post-monsoon) rather than June to September (monsoon), and the highest was observed in the month of April, suggesting that precipitation plays the most important role in the mitigation of CWSI. Additionally, the downstream and midstream showed a higher variation of drought compared to the upstream in the basin. This research indicates that the downstream suffered severe drought due to seasonal water shortages, especially during the pre-monsoon, and water-related infrastructure should be implemented to mitigate losses caused by drought.

scholarly journals Dry and Wet Events in Andean Populations of Northern Peru: A Case Study of Chachapoyas, Peru

2021 ◽  
Vol 9 ◽  
Author(s):  
Jesús Rascón ◽  
Wildor Gosgot Angeles ◽  
Lenin Quiñones Huatangari ◽  
Manuel Oliva ◽  
Miguel Ángel Barrena Gurbillón
Keyword(s):  
Anthropogenic Activities ◽  
Standardized Precipitation Index ◽  
Population Increase ◽  
Severe Drought ◽  
Drought Event ◽  
Climatic Data ◽  
Economic Activities ◽  
The North ◽  
Moderate Drought ◽  
The Standardized Precipitation Index

Climate change and population growth have heavily impacted the ecosystem’s water resources, essential for anthropogenic activities. These also apply to the Andean city of Chachapoyas, located in the north of Peru, which has gone through a substantial population increase in recent years, therefore increasing its water demand. This research aimed to assess dry and wet events from 1981 to 2019 that have taken place in Chachapoyas, by applying the Standardized Precipitation Index (SPI), and the Standardized Precipitation Evapotranspiration Index (SPEI). These events were periodically characterized, and the index relationship was determined at different timescales. The SPI and SPEI indices were calculated at the city’s only weather station for timescales of 3, 6, 12, and 24 months using climatic data. The indices showed a remarkably consistent behavior for timescales of 12 and 24 months detecting an extreme drought event in 1993, while for timescales of 3 and 6 months a severe drought event was detected in the same year. Contrastingly, there has been an increase in extreme wet events in the last decade, hence Chachapoyas is categorized between "moderate drought" and “moderate wet”. It should be noted that the indices have a high correlation between them when calculated for the same timescale. The results were statistically significant (p < 0.05). Considering the results obtained related to dry and wet events and their relation with economic activities such as environmental management, we can conclude that the SPI and SPEI indices are useful and valuable tools for local and regional governments.

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 Reliability Assessment of Agricultural Reservoirs for Water Supply under Climate Change

2020 ◽  
Vol 20 (1) ◽  
pp. 53-60
Author(s):  
Dasang Ko ◽  
Yeongcheol Joo ◽  
Taesam Lee
Keyword(s):  
Climate Change ◽  
Standardized Precipitation Index ◽  
Precipitation Index ◽  
Severe Drought ◽  
Water Shortages ◽  
The Future ◽  
Storage Rate ◽  
The Standardized Precipitation Index ◽  
Agricultural Areas

Recently, the frequency of drought occurrence and the resulting damage has increased due to climate change. Frequent severe droughts induce water shortages in agricultural reservoirs. The role of drought monitoring and prediction is critical for mitigating the effects of severe drought in agricultural areas. In this study, a compound standardized storage and precipitation index (CSSPI) was developed that adapted the existing drought index-the standardized precipitation index (SPI)-by adding hydrological data on storage rate. Furthermore, the future storage rate was simulated using autoregressive models (AR) to estimate the future CSSPI. A dataset containing records of reservoirs and precipitation at the three areas of Jungbu, Youngnam, and Honam was applied to estimate the current and future status of the CSSPI. The results indicate that the CSSPIs generated accurately present the past pattern of the observed data and that they can be considered as inputs for predicting future drought conditions.

scholarly journals SPEI-Based Spatiotemporal Analysis of Drought in Haihe River Basin from 1961 to 2010

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Meijian Yang ◽  
Denghua Yan ◽  
Yingdong Yu ◽  
Zhiyong Yang
Keyword(s):  
River Basin ◽  
Temporal Variability ◽  
Break Point ◽  
Spatiotemporal Analysis ◽  
Haihe River Basin ◽  
Severe Drought ◽  
Haihe River ◽  
The North ◽  
Moderate Drought ◽  
Drought Occurrence

Under the background of climate change, the monthly accumulated precipitation and monthly averaged temperature of 47 meteorological stations in and around Haihe River Basin (HRB) were analyzed using Standardized Precipitation Evapotranspiration Indices (SPEI) to obtain the temporal variability and spatial distribution of different drought levels during the last 50 years with the support of GIS. The results show that(1)from 1961 to 2010 the drought frequency and degree in annual and seasonal scale are rising and the affecting areas of all degrees of drought have a temporal variability of increasing trend. The ratios that the influencing area of drought, light drought, moderate drought, severe drought, and extreme drought account for the whole HRB area are increasing with gradients of 0.64%/a, 0.18%/a, 0.31%/a, 0.14%/a, and 0.01%/a, respectively, and(2)there is a climate break point which occurred in 1990; after the comparison of the drought happening probability between 1961 and 1990 and between 1991 and 2010, all degrees of drought occurrence probability have a remarkable rising trend, and the drought concentrating regions moved from the north HRB to the central HRB.

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