Validating satellite-derived land surface temperature with in situ measurements: a public health perspective.
White-Newsome-JL; Brines-SJ; Brown-DG; Dvonch-JT; Gronlund-CJ; Zhang-K; Oswald-EM; O'Neill-MS
Environ Health Perspect 2013 Aug; 121(8):925-931
BACKGROUND: Land surface temperature (LST) and percent surface imperviousness (SI), both derived from satellite imagery, have been used to characterize the urban heat island effect, a phenomenon in which urban areas are warmer than non-urban areas. OBJECTIVES: We aimed to assess the correlations between LSTs and SI images with actual temperature readings from a ground-based network of outdoor monitors. METHODS: We evaluated the relationships among a) LST calculated from a 2009 summertime satellite image of the Detroit metropolitan region, Michigan; b) SI from the 2006 National Land Cover Data Set; and c) ground-based temperature measurements monitored during the same time period at 19 residences throughout the Detroit metropolitan region. Associations between these ground-based temperatures and the average LSTs and SI at different radii around the point of the ground-based temperature measurement were evaluated at different time intervals. Spearman correlation coefficients and corresponding p-values were calculated. RESULTS: Satellite-derived LST and SI values were significantly correlated with 24-hr average and August monthly average ground temperatures at all but two of the radii examined (100 m for LST and 0 m for SI). Correlations were also significant for temperatures measured between 0400 and 0500 hours for SI, except at 0 m, but not LST. Statistically significant correlations ranging from 0.49 to 0.91 were observed between LST and SI. CONCLUSIONS: Both SI and LST could be used to better understand spatial variation in heat exposures over longer time frames but are less useful for estimating shorter-term, actual temperature exposures, which can be useful for public health preparedness during extreme heat events.
Public-health; Temperature-effects; Heat-conduction; Surface-properties; Monitors; Heat-exposure; Exposure-levels;
Author Keywords: epidemiology; ground truthing; heat; Landsat satellite; land surface temperature; remote sensing; surface imperviousness; temperature; urban areas
J.L. White-Newsome, WE ACT for Environmental Justice, 50 F St. NW, 8th Floor, Washington, DC 20001
Environmental Health Perspectives
University of Michigan, Ann Arbor