Affiliations 

  • 1 Centre for Advanced Modelling and Geospatial Information Systems (CAMGIS), University of Technology Sydney, NSW, 2007, Australia. Electronic address: abhirup.dikshit@student.uts.edu.au
  • 2 Centre for Advanced Modelling and Geospatial Information Systems (CAMGIS), University of Technology Sydney, NSW, 2007, Australia; Department of Energy and Mineral Resources Engineering, Sejong University, Choongmu-gwan, 209 Neungdong-ro, Gwangjin-gu, Seoul, 05006, South Korea; Center of Excellence for Climate Change Research, King Abdulaziz University, P. O. Box 80234, Jeddah, 21589, Saudi Arabia; Earth Observation Center, Institute of Climate Change, Universiti Kebangsaan Malaysia, 43600, UKM, Bangi, Selangor, Malaysia. Electronic address: biswajeet.pradhan@uts.edu.au
  • 3 Centre for Advanced Modelling and Geospatial Information Systems (CAMGIS), University of Technology Sydney, NSW, 2007, Australia; School of Life Sciences, Faculty of Science, University of Technology Sydney, Sydney, NSW, 2007, Australia. Electronic address: alfredo.huete@uts.edu.au
J Environ Manage, 2021 Apr 01;283:111979.
PMID: 33482453 DOI: 10.1016/j.jenvman.2021.111979

Abstract

Droughts are slow-moving natural hazards that gradually spread over large areas and capable of extending to continental scales, leading to severe socio-economic damage. A key challenge is developing accurate drought forecast model and understanding a models' capability to examine different drought characteristics. Traditionally, forecasting techniques have used various time-series approaches and machine learning models. However, the use of deep learning methods have not been tested extensively despite its potential to improve our understanding of drought characteristics. The present study uses a deep learning approach, specifically the Long Short-Term Memory (LSTM) to predict a commonly used drought measure, the Standard Precipitation Evaporation Index (SPEI) at two different time scales (SPEI 1, SPEI 3). The model was compared with other common machine learning method, Random Forests, Artificial Neural Networks and applied over the New South Wales (NSW) region of Australia, using hydro-meteorological variables as predictors. The drought index and predictor data were collected from the Climatic Research Unit (CRU) dataset spanning from 1901 to 2018. We analysed the LSTM forecasted results in terms of several drought characteristics (drought intensity, drought category, or spatial variation) to better understand how drought forecasting was improved. Evaluation of the drought intensity forecasting capabilities of the model were based on three different statistical metrics, Coefficient of Determination (R2), Root Mean Square Error (RMSE), and Mean Absolute Error (MAE). The model achieved R2 value of more than 0.99 for both SPEI 1 and SPEI 3 cases. The variation in drought category forecasted results were studied using a multi-class Receiver Operating Characteristic based Area under Curves (ROC-AUC) approach. The analysis revealed an AUC value of 0.83 and 0.82 for SPEI 1 and SPEI 3 respectively. The spatial variation between observed and forecasted values were analysed for the summer months of 2016-2018. The findings from the study show an improvement relative to machine learning models for a lead time of 1 month in terms of different drought characteristics. The results from this work can be used for drought mitigation purposes and different models need to be tested to further enhance our capabilities.

* Title and MeSH Headings from MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.