Remember, remember the fifth of November: was that thunder I heard or not? Article Published Version Creative Commons: Attribution 4.0 (CC-BY) Open Access Owens, M.J. (2016) Remember, remember the fifth of November: was that thunder I heard or not? Weather, 71 (6). pp. 134-137. ISSN 0043-1656 doi: https://doi.org/10.1002/wea.2725 Available at http://centaur.reading.ac.uk/63950/ It is advisable to refer to the publisher's version if you intend to cite from the work. To link to this article DOI: http://dx.doi.org/10.1002/wea.2725 Publisher: Wiley All outputs in CentAUR are protected by Intellectual Property Rights law, including copyright law. Copyright and IPR is retained by the creators or other copyright holders. Terms and conditions for use of this material are defined in the End User Agreement . www.reading.ac.uk/centaur CentAUR Central Archive at the University of Reading Reading's research outputs online 1842 it was in dissolving embryo: but it facilitating the development of systematic Middleton WEK. 1964. The History of the is true, as General Sabine has said, that it regional- and global-scale meteorology Barometer. Johns Hopkins: Baltimore, MD. would not have flourished but for my exer- have been underrepresented in science Ronalds F. 1845–1852. Annual report tions. I maintained it against the strong history. concerning the observatory of the British opposition of many influential members Association at Kew. Reports of the British of the British Association (& particularly Association for the Advancement of of one…). The system now pursued at Acknowledgements Sci ence. Kew is precisely that which I long since The author thanks staff at the Institution Ronalds F. 1847. Experiment made at the of Engineering and Technology Archives; Kew Observ atory on a new kite-apparatus in a document, received by a commit- for meteorological observations, or other tee, strenuously advocated. For the con- National Meteorological Library and Archive; purposes. Philos. Mag. Ser. 3 XXXI: stantly kind… & powerfull [sic] support British Science Association; UCL Special 191–192; reprinted 1896: The use of the of Sir John Herschell [sic] Bar t and several Collections; Royal Society; Cambridge kite in meteorology. Monthly Weather Sir Francis Ronalds and the Kew ObservatorySir Ronalds and the Kew Francis other gentlemen I shall ever feel grateful University Library – Royal Greenwich Review 24: 416–417. (Ronalds, 1860). Observatory Archive; the Science Museum Ronalds F. 1855. Descriptions de in South Kensington; and the Museum of the Quelques Instruments Météorologiques et Magnétiques. Printed privately. Working always in an honorary capacity, History of Science at the University of Oxford, Ronalds F. 1860. Autobiographical Letter, Ronalds set up the observatory, in part with for their kind assistance in this research. his own funds and equipment, and moulded UCL Special Collections, Ronalds Papers, GB 0103 MS ADD 206. its successful mission. His belief in Kew remained steady when others were wavering Ronalds BF. 2016. Sir Francis Ronalds: References Father of the Electric Telegraph. Imperial or, worse, undermining his efforts. Critically, Colleg e Press: London, UK. Athenæum. 1845. p 639. it was the excellence of his instruments Scott RH. 1885. The history of the Kew and observations that brought numerous BAAS. 1843–1872. Reports of the British Observatory. Proc. R. Soc. London 39: supporters to the institution, and they later Association for the Advancement of 37–86. Weather – June 2016, Vol. 71, No. 6 71, No. Vol. – June 2016, Weather Science. http://www.biodiversitylibrary. used their influence to promote its aims and org/bibliography/2276#/summary fight the necessary political battles. Today’s (accessed 1 December 2015). hindsight confirms that Ronalds deserves Collen H. 1846. On the application of the considerable credit for Kew’s early survival photographic camera to meteorological Correspondence to: Beverley F. Ronalds and later evolution into one of the most registration. Philos. Mag. Ser. 3 XXVIII: 73–75. [email protected] important meteorological and geomagnetic observatories in the world. His contributions Galvin JFP. 2003. Kew Observatory. © 2016 Royal Meteorological Society Weather 58: 478–484. in establishing Kew’s reputation and in doi:10.1002/wea.2739 Remember, remember the fifth of November: Was that thunder I heard or not? M. J. Owens or even changes in the space environment the NCAS British Atmospheric Data Centre (Stringfellow, 1974; Owens et al., 2014). (http://badc.nerc.ac.uk). The measurement Space and Atmospheric Electricity Group, Thunder day observations are potentially is a simple one: Met Office observers sim- Department of Meteorology, University susceptible to false positives, such as vehicle ply record a thunder day on any day they of Reading, UK noise or natural/anthropogenic explosions hear thunder (Lewis, 1991). There is no being wrongly attributed to thunder (e.g. formal training in discriminating between Rampino, 1989). Thus, increasing urbanisa- thunder and false positives, and there is Introduction tion and industrialisation may result in a no stipulation to use any additional instru- The only long-term observations of thun- long-term change in the noise level and mentation for verification (J. Wilkinson, pers. derstorm activity, extending back more hence bias in the data. On shorter time- comm.). In practice, however, on the sus- than 100 years, are ‘thunder days,’ wherein scales, ‘Bonfire Night’ (or ‘Guy Fawkes Night’) pected identification of thunder, observers an observer records 1 or a 0 depending on 5 November in the UK, as well as New may on occasion also consult radar data on whether or not (they think) they have Year’s Eve, are obvious candidates for false- or radio lightning observations (or ‘sferics’) heard thunder that day (e.g. Brooks, 1925; positive thunder identification. if/when available (P. Inness, pers. comm.). Changnon, 1985; Kitagawa, 1989). Despite Conversely, it is not possible for a thunder the low dynamic range (e.g. storms with 1 Data and analysis day to be recorded without the observer or 1000 lightning strokes will both simply Thunder day records produced by pro- having heard thunder, thus distant bright register a 1 in thunder days) and the inher- fessional observers at Met Office mete- fireworks confused with lightning flashes ent subjectivity of such measurements, they orological stations in the UK are available should not result in false positives in the are invaluable for long-term studies of thun- from Met Office Integrated Data Archiving thunder day record. derstorm occurrence, which could vary as a System (MIDAS) land and marine surface Prior to 1950, thunder days were recorded 134 result of global warming (Romps et al., 2014) stations (1853–current), made available by in the climatological returns of manned UK stations, with monthly totals available in the average T (winter), the fractional climato- ning mean is applied to ΔT, yielding ΔT3. Monthly Weather Report. In the MIDAS daily logical deviations, ΔT, are computed (i.e., This may miss some activity in years when in the reporting of thunder days Variations dataset, thunder day records routinely began ΔT = [T – T50]/T50). fireworks celebrations are split between the in 1950, with the number of manned UK Organised firework displays and private weekends before/after 5 November, but this stations making such observations limited firework use may occur on a number of is preferable to over-smoothing the whole to fewer than 10 until 1957 and fewer than days around 5 November, particularly in dataset and removing the possible signal. 100 until 1971. After this date, there were years when it falls during the middle of An annual composite of ΔT3, centred on approximately 400 stations making thunder the week and the celebrations are shifted 5 November so as to allow for leap days, day observations, though it unfortunately either forwards or backwards to the week- is shown for the 1980–2010 period in slowly tapered off after 2000, to fewer than end. If it assumed that fireworks use is Figure 3(b). In this annual composite, there 200 again at the end of 2010 (see also Perry focussed on the Friday or Saturday closest is clearly no evidence for an increase in the and Hollis, 2005 and Figure 1(a)). Due to to 5 November, then on average this will false-positive reporting of thunder due to the difficulty in discriminating between an mean fireworks use is within ±1.3 days of fireworks. In fact, 5 November has the low- observation of no thunder and no thunder fireworks night. To capture this, a 3-day run- est mean ΔT3 value. observations, any station making a single 6 71, No. Vol. – June 2016, Weather observation of thunder in a given year is assumed to be actively observing and is included in the analysis. T, the fraction of UK observing stations which recorded thunder on a given day, is constructed from indi- vidual station data. Multi-shell rockets and slow-burn com- posite fireworks are most likely to be mis- taken for thunder (pyrosociety.org.uk, pers. Number of stations comm.). It is difficult to obtain data on the widespread use of such fireworks in the UK, but anecdotally at least, they appear Year to have been in widespread public use for Bonfire Night celebrations since at least the early 1980s. Thus this study primarily considers the period 1980–2010. Changing the start year for this interval by ±10 years does not qualitatively change the results reported in this study, as discussed later. Figure 1(b) shows daily (black) and annual (red) T values. As expected, there is a very strong seasonal variation in T. There is some evidence of a change in the annual mean T associated with the increase in the num- ber of stations from 1950 through to the early 1970s.