Urbanization Effects on GHCN Temperature Trends, Part III: Using Population Density, 1880-2015
March 17th, 2023 by Roy W. Spencer, Ph. D.
This is the third in my (never-ending, it appears) series on measuring the effect of Urban Heat Islands (UHI) on land surface temperature trends.
In Parts I and II I emphasized the Landsat-based “built-up” structure dataset as a proxy for urbanization, which I’m sure we will continue to examine as part of our Department of Energy grant to examine (mostly) satellite-based methods and datasets for testing climate models and their predictions of global warming.
Much of the original research on the UHI effect (e.g. T.R. Oke, 1973 and later) related warming to the total population of towns and cities. Since population datasets extend back in time much further than the satellite period, they can provide information on the UHI effect going back well before 1900. In the last few weeks I’ve taken a detour from using the Landsat-based diagnoses of human settlement built-up structures as a proxy for urbanization, to population density (PD). Along the way I’ve had to investigate issues related to low correlations, and linear regression (specifically, regression dilution). I decided not to cover that here because it’s a little too technical.
The deeper I dig into this project, the more I learn.
Urbanization Effects from 1880 to 2015
https://www.drroyspencer.com/2023/03/urbanization-effects-on-ghcn-temperature-trends-part-iii-using-population-density-1880-2015/
