Non-Parametric Time Between Events and Amplitude Methods for Monitoring Drought Characteristics

TL;DR

This paper introduces non-parametric control charts based on Time Between Events and Amplitude for monitoring drought characteristics, demonstrating their effectiveness through simulations and real-data assessments to aid climate resilience.

Contribution

It proposes novel non-parametric control chart methods for drought monitoring using TBEA metrics, validated through simulations and application to climate data.

Findings

Proposed methods effectively detect changes in drought characteristics.

Simulation results show good statistical performance of the control charts.

Methods are useful for climate resilience planning and water management.

Abstract

Drought is a significant natural phenomenon with profound environmental, economic, and societal impacts. Effective monitoring of drought characteristics -- such as intensity, magnitude, and duration -- is crucial for resilience and mitigation strategies. This study proposes the use of non-parametric Time Between Events and Amplitude (TBEA) control charts for detecting changes in drought characteristics, specifically applying them to the Standardized Precipitation and Evapotranspiration Index. Aware of being non-exhaustive, we considered two non-parametric change-point control charts based on the Mann-Whitney and Kolmogorov-Smirnov statistics, respectively. We studied the in-control statistical performances of the change-point control charts in the time between events and amplitude framework through a simulation study. Furthermore, we assessed the coherence of the results obtained with a distribution-free upper sided Exponentially Weighted Moving Average control chart specifically designed for monitoring TBEA data. The findings suggest that the proposed methods may serve as valuable tools for climate resilience planning and water resource management.