Isolated data showers: exploring nineteenth century weather observations by the first Ordnance Survey of Ireland

Abstract

Recent digitisation of major meteorological sources has offered valuable insights into Ireland's past climate. However, more localised historical weather data remain sparse for most of the country. A largely unexplored resource lies in the early nineteenth century Ordnance Survey (OS) statistical reports collected as a component of the first OS of Ireland. This research sets out how a team of researchers applied diverse techniques such as corpus linguistics, Geographic Information Systems, and sentiment analysis to explore the early OS weather records. Weather Journals from 15 parish “memoirs” across seven northern counties were extracted from the text, providing both qualitative observations and quantitative temperature and pressure data. The readings were analysed and visualised, and a sentiment analysis completed on the qualitative weather observations using a bespoke sentiment dictionary. This reveals inconsistencies in weather recording practices, even by the same individual across multiple parishes. These records offer unique applications, including local weather insights from the early nineteenth century, showcasing the possibilities of using a combination of data types in the study of historic weather. They also shed light on the experiences and methods of OS staff, contributing to a deeper understanding of Ireland's meteorological and survey history.