Remotely measuring populations during a crisis by overlaying two data sources.

Area of Science:

• Humanitarian Crises
• Population Dynamics
• Remote Sensing

Background:

• Societal instability and crises precipitate large-scale population movements.
• Understanding and measuring these movements is crucial for effective health interventions and response planning.
• Humanitarian crises, such as the 2010 conflict in Côte d'Ivoire, necessitate accurate population data.

Purpose of the Study:

• To retrospectively analyze population movement patterns during a humanitarian crisis.
• To evaluate the utility of remote sensing data for measuring population dynamics.
• To assess the agreement between different remote data sources for population assessment.

Main Methods:

• Utilized nighttime lights satellite imagery as a remote measure.
• Employed anonymized mobile phone call detail records for population assessment.
• Analyzed data to determine average population sizes and dynamic changes across various scales.

Main Results:

• Demonstrated strong agreement between satellite imagery and mobile phone data for average population sizes.
• Leveraged differing spatiotemporal resolutions of data sources to capture long- and short-term population dynamics.
• Successfully measured population changes throughout the crisis period.

Conclusions:

• Complementary remote data sources show significant promise for monitoring population movements in humanitarian crises.
• Identified challenges associated with remotely measuring population displacement.
• Provided recommendations for future research and methodological advancements in crisis response data collection.