Standardized Precipitation Index Results Research Articles

Introducing modified total storage deficit index (MTSDI) for drought monitoring using GRACE observations

Although total storage deficit index (TSDI) is a well-known GRACE-based drought index, it is not efficient for the basins with high consumption because water harvesting in these areas affect GRACE signal. To overcome this limitation, the modified total storage deficit index (MTSDI) is introduced in this paper. To develop MTSDI, residuals of the signal were used instead of total signal. The proposed approach was applied to monitor drought in the Markazi Basin, Iran, during 2002–2016. Based on the obtained results, TSDI detected a moderate drought event in 2012 and a long-term severe drought from 2013 to 2016, which is not compatible with the recorded results of standardized precipitation index (SPI), Standardized Precipitation Evapotranspiration Index (SPEI). Meanwhile MTSDI identified two drought events in 2008–09 and 2010–11 that coincided with droughts detected using SPI and SPEI. Results revealed that MTSDI is highly correlated with SPI and SPEI at a 12 month-scale, showing a correlation coefficient of 0.75 and 0.62, respectively. On the other hand, the coefficient of correlation between TSDI and SPI12 was 0.42 and between TSDI and SPEI12 was 0.26. A pixel-by-pixel analysis showed MTSDI and SPI/SPEI had a significant correlation in most areas of the basin. Further, the investigation of droughts in Markazi Basin revealed that dry years coincide with the occurrence of strong La Niña events. Overall, the results indicated a good potential of GRACE observations for developing a drought monitoring system, which its performance can be enhanced with respect to large-scale climate signals.

QUANTITATIVE METHODS OF PEDOLOGICAL DROUGHT ANALYSIS IN THE NORTHEASTERN PART OF ROMANIA (1961 – 2006)

In the context of desertification and climate changes, under the pressure of a growing need for food all over the world, the increasing frequency and severity of droughts becomes an intensely debated subject by a great number of stakeholders, scientists, planners and decision makers. The aims of this study are to establish a good correlation between the atmospheric and soil pedological within the northeastern part of Romania, by modeling the role of different soil properties on drought propagation. Here, the authors present the results of Standardized Precipitation Index, Palfai Aridity Index and Palmer Drought Severity Index, indices that were computed using data of temperature and precipitation from four meteorological stations, evenly spread within the study area. Significant correlations were found between the above mentioned indices, hence the Palmer Drought Severity Index was modified by replacing the standard soil available water content with the real value obtained from 7 soil profiles (Chernozem, Phaeozem, Luvisol, Preluvisol, Vertisol and Gleysol) situated within the study area. Finally, based on a diagram between the water content and the wilting point the results of the study led to the identification of the most susceptible soil to drought, as an important preliminary step to drought risk management.