Integrated Water Systems and Governance

The spatiotemporal monitoring of droughts is a complex task. In the past decades, drought monitoring has been increasingly developed, while the consideration of its spatio-temporal dynamics is still a challenge. This study proposes a method to build the spatial tracks and paths of drought, which can enhance its monitoring. The steps for the drought tracks calculation are (1) identification of spatial units (areas), (2) centroids localisation, and (3) centroids linkage. The spatio-temporal analysis performed here to extract the areas and centroids builds upon the Contiguous Drought Area (CDA) analysis. The potential of the proposed methodology is illustrated using grid data from the Standardized Precipitation Evaporation Index (SPEI) Global Drought Monitor over India (1901-2013), as an example. The method to calculate the drought tracks allows for identification of drought paths delineated by an onset and an end in space and time. Tracks, severity and duration of the drought are identified, as well as localisation (onset and end position), and rotation. The response of the drought tracking method to different combinations of parameters is also analysed. Further research is in progress to set up a model to predict the drought tracks for particular regions across the world, including India (https://www.researchgate.net/project/STAND-Spatio-Temporal-ANalysis-of-Drought).

Lately, drought is more intense and much more severe around the globe, causing more deaths than other hazards in the past century. Drought can be characterized quantitatively for its spatial extent, intensity and duration by using drought indicators. Several indicators have been developed in order to characterize drought, being the most widespread the Standardized Precipitation Index (SPI). Nevertheless, due to its known limitations, other indicators have been proposed. In this paper, evaporation and runoff simulations of a basin were used to evaluate the variation and performance of different meteorological and hydrological drought indicators in identifying drought. Daily simulations of evaporation and runoff were computed by using a distributed hydrological model of a catchment located in the southeast of Mexico. After calibration of the hydrological model, we calculated at different time steps the drought indicators: Standardized Precipitation Index (SPI), Standardized Precipitation Evaporation Index (SPEI), Evapotranspiration Deficit Index (ETDI), Standardized Evapotranspiration Deficit Index (SEDI) and Standardized Runoff Index (SRI). Furthermore, the so-called Non-Contiguous Drought Analysis (NCDA) was carried out to compare the skill of each indicator to identify drought. Results show that meteorological drought indicators do not identify all drought events for the time steps of 1 and 3 months. For 3-, 6-and 9-month time steps, meteorological drought indicators tend to identify the onset with a lag. For long-time steps of 12 and 24, the use of agricultural and hydrological droughts indicators is recommended, since these indicators can identify prolonged drought periods. The results suggest that for a better monitoring of drought in a catchment, it is important the joint evaluation and the use 739 Vitali Diaz Mercado et al. / Procedia Engineering 154 (2016) 738 – 744 of not only meteorological drought indicators but also hydrological and agricultural ones, in order to identify drought events and their spatio-temporal evolution.