Remotely Sensed Nightlights to Map Societal Exposure to Hydrometeorological Hazards

Agnes Gómez,Giuliano Di Baldassarre,Allan Rodhe,Veijo Pohjola

doi:10.3390/rs70912380

Abstract

This study used remotely sensed maps of nightlights to investigate the etiology of increasing disaster losses from hydrometeorological hazards in a data-scarce area. We explored trends in the probability of occurrence of hazardous events (extreme rainfall) and exposure of the local population as components of risk. The temporal variation of the spatial distribution of exposure to hydrometeorological hazards was studied using nightlight satellite imagery as a proxy. Temporal (yearly) and spatial (1 km) resolution make them more useful than official census data. Additionally, satellite nightlights can track informal (unofficial) human settlements. The study focused on the Samala River catchment in Guatemala. The analyses of disasters, using DesInventar Disaster Information Management System data, showed that fatalities caused by hydrometeorological events have increased. Such an increase in disaster losses can be explained by trends in both: (i) catchment conditions that tend to lead to more frequent hydrometeorological extremes (more frequent occurrence of days with wet conditions); and (ii) increasing human exposure to hazardous events (as observed by amount and intensity of nightlights in areas close to rivers). Our study shows the value of remote sensing data and provides a framework to explore the dynamics of disaster risk when ground data are spatially and temporally limited.

Highlights

Floods, droughts, earthquakes and volcano eruptions are natural events that potentially can lead to disasters if they coincide with vulnerable societies (e.g., [1,2,3])
The goal of this work is, to explore the etiology of trends in disasters caused by natural events
(“natural disasters” on) in Guatemala, those caused by hydrometeorological hazards

Summary

Introduction

Droughts, earthquakes and volcano eruptions are natural (extreme) events that potentially can lead to disasters if they coincide with vulnerable societies (e.g., [1,2,3]). Natural hazards have significantly affected the development of societies over history. While being impacted by natural hazards, societies have responded to them placing structural and non-structural measures to manage and mitigate risk [3]. Disaster risk is often formalized as a combination of two components: a natural component, which is the probability of natural extreme events (i.e., hazard), and a social component, which is the potential adverse consequences (i.e., vulnerability, which is highly related and analyzed in terms of exposure) [1,4]. Property damage and the number of people affected have significantly increased. The number of people killed by each event has decreased in the recent years

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