DATA FOR ASCENSION ISLAND

Data files associated with the Jones and Lister (2021) Ascension Island paper.

Quick links : Temperature files : Precipitation files

Both temperature and precipitation data came from a variety of sources. Not all series listed/provided below were actually used to produce the final temperature and precipitation series – as documented in the paper. Some series were only partially used. UKMO data archives would normally have been the dominant data source, but it was found that while UKMO recognise the two principal observing locations Georgetown and Wideawake (or Airhead) airfield, some data values (around the transition between the two observing sites) for both locations were identical. This meant that some UKMO data from the transition period had to be disregarded. In addition, only UK observations are normally archived in Midas – we have used US observations where necessary to optimize the completeness of series.

It should be mentioned at this point that some mostly short and relatively recent data series exist from observations made relating to ecological studies. Automatic weather stations have been sited at various points on the island and the data can be obtained from the Ascension Government (for example, see https://www.researchgate.net/figure/Spatial-distribution-of-weather-stations-on-Ascension-Island-installed-November-2007_fig5_324169407 ). The primary sources referred to in the paper and some additional precipitation series are listed under temperature and precipitation below:

Monthly observations from St Helena are regularly updated here: https://www.io-warnemuende.de/en_hix-st-helena-island-climate-index.html.

Temperature

1. Data from the GHCN v4 archive (https://www.ncei.noaa.gov/products/land-based-station/global-historical-climatology-network-monthly).
2. Data from the UKMO Midas database (for example, see https://www.metoffice.gov.uk/research/climate/maps-and-data/data/index).
3. Hourly observations made by US military personnel at Wideawake airfield – relating to US military operations. The hourly file has been provided by NCEI (NOAA).
4. Data collected by Ian Mathieson in the late 1980s (see Mathieson, 1990: Agricultural Climate of St Helena.pdf). A more recent hydrological investigation relating to St. Helena has been reported here (https://www.sainthelena.gov.sh/wp-content/uploads/2019/04/DPLUS051-Project-Report.pdf"> ). Series of weather observations from Ascension Island were also collected by Ian Mathieson and made available for the Ascension study.