Data files associated with the Jones and Lister Ascension Island paper
Climatic Research Unit : Data

Data files associated with the Jones and Lister Ascension Island paper

Data files associated with the Jones and Lister (2021) Ascension Island paper Jones, P.D. and Lister, D.H., 2021: The development of long temperature and precipitation series for Ascension Island, International Journal of Climatology, DOI: 10.1002/joc.7314 (Final Submitted copy here)

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 ). The primary sources referred to in the paper and some additional precipitation series are listed under temperature and precipitation below:


1. Data from the GHCN v4 archive (

2. Data from the UKMO Midas database (for example, see

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 ("> ). Series of weather observations from Ascension Island were also collected by Ian Mathieson and made available for the Ascension study.


1. Data held by the Ascension Island government (provided for this work in the form of an Excel workbook – some observations being from US military sources). Similarly, more recent data were provided on request by the Ascension Island Government via their requests to the Meteorological Office staff on Ascension. The former data are all in monthly format and the latter in daily format.

2. Data collected by Ian Mathieson (as in 4. above).

Temperature files – some also in Word as well as .dat (txt)

Data File Units Missing Code Description
°C *10 -999 The series for Widawake – as extracted/processed from UKMO Midas
°C *10 -999 The 09hrs series as adjusted by the values in Table 2 of the paper
Ascension_9hrs.dat °C *10 -999 The series extracted from the US hourly file using 09hrs observations
°C *10 -999 the final composite Ascension Tg series (Wideawake/Airfield)
Ascension_GHCNv4.dat °C *10 -999 This is the Georgetown Tmean file extracted from the GHCNv4 database
Ascension_US_hourly.txt °C -99.9 A subset (selected columns) from the large US hourly file (below)
SHI0000FHAW.mff °C (empty field) The full hourly US file supplied by NCEI (opens in Excel)
°C *10 -999 The latest version of St. Helena Tg series – used for comparison (see Feistel et al, 2003)

Precipitation files – some also in Word as well as .dat (txt)

Data File Units Missing Code Description
Airhead_mth_prec.dat mm *10 -10 This series came from the Ascension Government
Ascension_Airhead_dly-2020.txt mm n/a The daily precip. file (2011-20) from the Ascension met office
mm *10 -10 The final composite precip. series for Airhead/Wideawake
mm *10 -10 The Georgetown precipitation file from the Ascension Government
GreenM.txt mm -1 The precipitation series (ann + monthly) from Ian Mathieson (tab delimited)
mm *10 -10 The Pan Am site precipitation file from the Ascension Government
mm *10 -999 The St. Helena file used for a comparison (from Feistel et al, 2003)
TravHill.txt mm -1.0 The precip. (tabs) series from Travellers Hill – supplied by Ascension Government
TwoBoats.txt mm -1.0 This series (tabs) has the same antecedents as TravHill - Ascension Government

Monthly observations from St Helena are regularly updated here:

Last updated: September 2021, Ian Harris

These datasets are made available under the Open Database License.
Any rights in individual contents of the datasets are licensed under the
Database Contents License under the conditions of Attribution and Share-Alike.
Please use the attribution Climatic Research Unit, University of East Anglia