Bridging Historical Climatology and Microclimate Modelling: Integrating Early Instrumental Data from the Medici Network (1654–1670)

Historical climatology uses human-produced records (e.g., weather descriptions from written evidence) and early instrumental evidence predating modern national weather networks to reconstruct past climates. As a multidisciplinary field, it enables not only the reconstruction of climatic signals in pre-industrial decades, but also the assessment of societal vulnerability to climate extremes and the study of the history of meteorological observations.

In this context, the earliest coordinated meteorological observation system worldwide - characterized by standardized instruments (i.e., the Little Florentine thermometer) and observational protocols - is the Medici Network (1654 - 1670), funded by the Medici family. It comprised eleven observation stations, seven located in Italian cities and four in Paris (France), Warsaw (Poland), Innsbruck (Austria), Osnabrück (Germany). Previous research has validated the instruments and methods and analyzed north-facing Little Florentine thermometer data, providing a robust basis for assessing measurement reliability.

However, despite their potential, data collected from south-facing Little Florentine thermometers remain largely underutilized and unpublished. A significant research gap lies in the lack of methodologies capable of integrating early instrumental series into physically based microclimate models of the built environments where measurements were taken. Existing literature has mainly focused on climate reconstruction, while the operational use of historical data for comparison with present and future climatic conditions - particularly in relation to building façade microclimates - remains limited.

This study proposes a methodological approach that integrates Medici Network data (i.e., outdoor wall-mounted Little Florentine thermometers) with high-resolution microclimate simulations conducted using ENVI-met, a three-dimensional model that simulates energy exchanges among atmosphere, surfaces, and built structures at the local scale. The methodology involves: (i) selecting and processing historical data series relevant to this preliminary phase, focusing specifically on stations in urban contexts to better capture long-term microclimatic changes, a key issue in urban areas; (ii) transforming these data into model-compatible inputs; (iii) developing comparative scenarios between historical and present-day building façade microclimate conditions. The approach is applied to multiple urban contexts characterized by diverse morphological and building configurations corresponding to the original Medici station locations.

Preliminary findings indicate differences in several meteorological parameters between past and present conditions. Moreover, comparisons across cities suggest the potential to investigate how climate change impacts vary across urban and geographical contexts. These results must be interpreted considering methodological constraints, particularly those related to adapting historical data to model requirements, as some variables are only available as interval-based approximations.

Future work will focus on integrating climate projections to enable comparisons across past, present, and future conditions. Overall, this study represents an initial step toward using early instrumental meteorological series not only for climate reconstruction but also as inputs for building façade simulations, helping bridge historical climatology and contemporary environmental modeling.