Comprehensive stochastic assessment of meteorological drought indices

Abstract

Drought indices are among the most important tools used to monitor and detect drought around the world. Most of these indices have been experientially developed using data extracted from specific geographic locations and climatic conditions. Regarding the inherent complexity of drought phenomenon itself as well as local climatic conditions, there have been great uncertainties when using such indices to provide accurate and logical assessments of drought in different regions. Few stochastic assessment studies, if any, have been published to evaluate and compare the inherent performance and capability of drought indices. Drought monitoring studies are usually based on a historical data record with relatively short length, e.g. 20-50 years, and have also focused on some particular aspects. In this study, seven meteorological drought indices and Monte-Carlo simulation method have been used to monitor drought characteristics in 12 diverse parts of the world endowed with various climatic conditions. Theoretical features of the indices as well as their inherent performance have been considered in the course of drought monitoring assessments. Accordingly, 50-year historical rainfall data of 12 stations in diverse parts of the world have been employed to generate synthetic rainfall time series of 1000 sequences in terms of monitoring drought characteristics and quantifying the inherent aspects of drought indices. The results confirmed the comparative advantage of the standardized precipitation index (SPI) as an accurate and realistic analysis. Similarly, Nitzche Index introduced itself as the best candidate for initial analyses. Meanwhile, other indices indicated significant deviations from the expected occurrence of normalized natural processes and their results could not be rationally and sufficiently applied to predict drought events.

Seasonal Hydrological Drought Indicator for Tropical Drought Identification

“…It has been frequently used on time series of irregular hydrologic events to identify drought components and investigate their statistical properties [21], [22]. A -run‖ is defined as a portion of time series of the variable that is less than the chosen threshold [23], [24]. Following Nalbantis and Tsakiris [18], the drought event in this study is defined as the period where SDI values are less than the threshold value of zero.…”

Meteorological Drought Monitoring in Northeastern China Using Multiple Indices

“…This was consistent with previous studies [17,43,44], which indicated that considering more than one DI for drought studies can help investigate how well they cohere with each other and examine the sensitivity and accuracy of DIs. Montaseri and Amirataee [45] used seven meteorological drought indices to monitor drought characteristics in 12 diverse parts of the world endowed with various climatic conditions and found that the application of SPI can result in higher relative advantages to undertake a comprehensive and accurate analysis. Our study agrees with this study and also found SPI was the most reliable drought indicator among the DIs.…”

Yukarı Gediz Havzası Yağışlarının Meteorolojik Kuraklık Analizleri

“…Bu indekslerden, meteorolojik kuraklığı tanımlamada sadece yağış değerlerini kullanan standartlaştırılmış yağış indeksi (SYİ) yöntemi dünyada sıklıkla kullanılır hale gelmiştir [6][7][8][9]. Dünya genelinde farklı kıtalardaki 10 ülkede bulunan toplam 12 bölgede gözlenmiş yağışla , farklı meteorolojik kuraklık indekslerini karşılaştırılmış ve bunlardan SYİ yönteminin diğer yöntemlere kıyasla meteorolojik kuraklığı tanılamakta daha tutarlı olduğu gösterilmiştir [7]. Polonya'da 2005 yılından itibaren, kuraklık izleme sistemlerinde 1, 2, 3, 6, 12, 24, 36 ve 48 aylık dönemlerdeki meteorolojik kuraklıklarının belirlenmesinde SYİ yönteminin etkin bir biçimde kullanıldığı belirlenmiştir [10].…”