Drought characteristics and propagation from meteorological to hydrological drought via agricultural drought in the semi-arid River Basin of Peninsular India

Código

I-EBHE0016

Autores

Ajay Gupta, Manoj Kumar Jain, Rajendra Prasad Pandey

Tema

WG 2.1: Drought in the Anthropocene

Resumo

Understanding drought propagation from one form to another has emerged as one of the most crucial aspects of research in recent decades. The majority of research has employed a correlation-based strategy to examine drought propagation; however, application of these techniques is limited in India due to very strong seasonality in precipitation. Also, only a few researchers have used an event-based approach to analyse drought propagation. Furthermore, only a few studies have examined drought propagation in the intensity domain. The present work aims to analyse the propagation of drought from meteorological to hydrological drought through agricultural drought using an event-based approach in the Krishna River Basin of India. The Standardised Precipitation Evapotranspiration Index (SPEI), Standardised Soil Moisture Index (SSMI), and Standardised Streamflow Index (SSI) representing meteorological, agricultural, and hydrological drought, respectively, were estimated at 3 and 9-month timescales at sub-basin scale. Two different cases of drought propagation are analysed: meteorological-to-agricultural (SPEI-to-SSMI) drought and agricultural-to-hydrological (SSMI-to-SSI) drought. Propagation of drought is quantified using three-time matrices, namely the time difference between initiation-to-initiation (??t?_i2i), peak-to-peak (??t?_p2p), and termination-to-termination (??t?_t2t) at 3 and 9-month timescales using different drought threshold values of 0 and -1, respectively. The different threshold values will help us understand the drought propagation change from mild to extreme drought conditions in detail. The results indicate that the propagation time from SPEI-to-SSMI drought at 3 and 9-month timescales in the case of ??t?_i2i, ??t?_p2p and ??t?_t2t decreased for all the tributaries of the Krishna River for a threshold of -1 when compared with a threshold of 0, whereas it increased significantly for the SSMI-to-SSI drought. The propagation of drought changes with respect to time as well as magnitude (intensity and severity). The propagation factor (PF), defined as the ratio of the average drought characteristics value of a succeeding drought to the preceding drought, has also been studied. The drought characteristics, such as duration PF, severity PF, and intensity PF, are analysed. The duration PF decreased for all the tributaries from the SPEI-to-SSMI drought with an increase in timescale from 3 to 9 months using a threshold value of 0, whereas it increased from the SSMI-to-SSI drought. The severity PF increased for all the tributaries from SPEI-to-SSMI drought at a 3- and 9-month timescale. Also, the intensity PF increased for all the tributaries from SPEI-to-SSMI drought using a threshold value of 0 at a 3-month timescale and decreased using a threshold value of -1 at a 3- and 9-month timescale. Thus, the proposed study provides valuable insights into drought propagation dynamics, aiding in managing and mitigating droughts in the semi-arid River Basin of India and elsewhere.