| Abstract | Modifications to the surface albedo through the deployment of cool roofs and pavements
(reflective materials) and photovoltaic arrays (low reflection) have the potential to change
radiative forcing, surface temperatures, and regional weather patterns. In this work we
investigate the regional climate and radiative effects of modifying surface albedo to mimic
massive deployment of cool surfaces (roofs and pavements) and, separately, photovoltaic arrays
across the United States. We use a fully coupled regional climate model, the Weather Research
and Forecasting (WRF) model, to investigate feedbacks between surface albedo changes,
surface temperature, precipitation and average cloud cover. With the adoption of cool roofs and
pavements, domain-wide annual average outgoing radiation increased by 0.16 ± 0.03 W m−2
(mean ± 95% C.I.) and afternoon summertime temperature in urban locations was reduced by
0.11–0.53 "C, although some urban areas showed no statistically significant temperature
changes. In response to increased urban albedo, some rural locations showed summer afternoon
temperature increases of up to +0.27 "C and these regions were correlated with less cloud cover
and lower precipitation. The emissions offset obtained by this increase in outgoing radiation is
calculated to be 3.3 ± 0.5 Gt CO2 (mean ± 95% C.I.). The hypothetical solar arrays were
designed to be able to produce one terawatt of peak energy and were located in the Mojave
Desert of California. To simulate the arrays, the desert surface albedo was darkened, causing
local afternoon temperature increases of up to +0.4 "C. Due to the solar arrays, local and
regional wind patterns within a 300 km radius were affected. Statistically significant but lower
magnitude changes to temperature and radiation could be seen across the domain due to the
introduction of the solar arrays. The addition of photovoltaic arrays caused no significant
change to summertime outgoing radiation when averaged over the full domain, as interannual
variation across the continent obscured more consistent local forcing. |
