Evaluation of dryness conditions in Babylon governorate Using the Standardized Precipitation Index (SPI) and the Normalized Difference Water Index (NDWI)

Abstract

Drought is an anomaly from normal climatic conditions, which affects most of the climatic zones worldwide. Drought monitoring is a very crucial step to detect drought vulnerable zones and to raise awareness about the future of development. The present study aimed to investigate the efficiency of drought monitoring indicators: the standardized precipitation index (SPI) and the Normalized Difference Water Index (NDWI) to spatially description of drought conditions of Babylon governorate for the period 1980-2016. On the basis of SPI values, the season 1995-1996 was classified as a rainy season with the highest positive SPI value of 1.83 among 17 wet seasons represented by the positive values of the SPI. The season 2010-2011 was classified as a very drought season with the highest negative SPI value of -2.25 among 14 dry seasons with negative values of the SPI. The results of NDWI showed that the year 2000 was classified as a dry with the highest negative deviation from the average of the period from 2000 to 2016, while 2014 was classified as a wet with the highest positive deviation from the average of the mentioned period. The results confirmed that the use of plant indices was supportive of the meteorological indices in detecting and monitoring the intensity and severity of the effect of the drought. The study established that the intensity and impact of the drought could be extended to the years after the dry year. That confirms the necessity of adopting the condition of moisture in the plant as a sensitive and effective indicator to assess the severity of drought and the extent of negative effects. The integration of satellite and rainfall derived indices has contributed to provide an effective representation of drought conditions in the study area.