Estimating Naples' urban heat island effects using the March 20, 2015 partial solar eclipse

During the partial (~50%) solar eclipse occurred on March 20, 2015, we monitored the time evolution of air temperature and of incoming solar radiation above the historical center of Naples and of Casamicciola town, on the island of Ischia. These measurements were useful to determine the radiative emissivity ε of the two different locations. The experimental conditions were optimal because of the clear sky situation over Italy. The eclipse lasted about 2 hours between 9:25:06 (UT+1, local Italian time) and 11:43:09 (UT+1, local Italian time). We obtained an emissivity of ε=0.86 for the historical center of Naples and ε=0.96 for Casamicciola town. We used these emissivity estimates, the surface air temperature and solar radiance records to characterize the urban heat island of Naples as due to an additional source of heat of about W/m2 at maximum in respect to Casamicciola.