Ireland's Pre-1940 Daily Rainfall Records

There is an increasing demand for climatological information to support scientific understanding of the impacts of climate change. Accurate and reliable long-term meteorological records are essential for understanding climate trends and variability, evaluating reanalysis products and climate models and climate risk management. Consequently, much work is being carried out internationally to rescue historical climate data and develop long-term climate series.

An article published in Geoscience Data Journal describes recent work undertaken by Met Éireann, in collaboration with Maynooth University, to digitise and transcribe daily rainfall data and metadata for Ireland from historical manuscripts located in Met Éireann’s archives. The main objective of this work was to create a digital archive of the paper records of Ireland’s longest meteorological stations, and from these imaged records to extend the availability of long-term daily rainfall data prior to 1941.

To facilitate the transcription of rainfall observations from paper records, the historical manuscripts were scanned and integrated into Met Éireann’s digital archives. The transcription from digital image to data format was undertaken in collaboration with students at Maynooth University as part of a novel crowdsourcing initiative to integrate data rescue activities into the classroom. In total, 3,616 station years of rainfall data (~1.32 million daily values) were transcribed. The data, which was double keyed, have undergone basic quality assurance to check for transcription errors and the resultant raw data and associated metadata are presented. It is envisaged that by presenting the data in its original state it can be easily integrated into current international data rescue initiatives, for example Copernicus Climate Change Service Global Land and Marine Observations Database, and that future research will have recourse to the raw data. Ongoing work involves the application of further quality assurance and homogenization techniques to develop a long-term, quality assured daily rainfall network for Ireland.

Read the full article here

Sample rainfall register. The annual forms report daily rainfall observations and station metadata for various locations throughout Ireland

Sample rainfall register. The annual forms report daily rainfall observations and station metadata for various locations throughout Ireland

Sample meteorological register. The monthly forms report daily observations for multiple parameters including temperature, pressure, precipitation, sunshine, wind and other parameter

Sample meteorological register. The monthly forms report daily observations for multiple parameters including temperature, pressure, precipitation, sunshine, wind and other parameter

Metis EDS Gamma professional digital scanner used to image historical meteorological registers held in Met Éireann

Metis EDS Gamma professional digital scanner used to image historical meteorological registers held in Met Éireann