A 250 year drought catalogue for the island of Ireland (1765-2015)

This work created a 250 year historic drought catalogue by applying the Standardised Precipitation Index (SPI) to the Island of Ireland Precipitation (IIP) network (1850-2015) and a reconstructed precipitation series from 1765. Documentary sources from newspaper archives spanning the last 250 years, together with other historical sources are used to (i) add confidence to the quantitative detection of drought episodes and (ii) gain insight to the socio-economic impacts of historic droughts. The results show that Ireland is drought prone but recent decades are unrepresentative of the longer-term drought climatology. A large decline in 30-year accumulated SPI-12 values is evident from around the 1990s onwards. During the years 1850-2015 seven major drought rich periods were identified with an island-wide fingerprint in 1854-1860, 1884-1896, 1904-1912, 1921-1923, 1932-1935, 1952-1954 and 1969-1977. These events exhibit substantial diversity in terms of drought development, severity and spatial occurrence. Two exceptionally long events are found in the record: the continuous drought of 1854-1860 and the drought of 1800-1809 (in fact a series of three droughts with brief interludes). Over the last 250 years droughts have resulted in agricultural hardship, water resource crises and failures and preceded some of the major famines of the 18th and 19th centuries. This work shows that newspaper archives can be used to trace the progression of drought events and impacts and we thus advocate their wider use in corroborating quantitative assessments. The resulting catalogue challenges prevailing perceptions about drought in Ireland whilst strengthening the evidence base for future drought and water resource planning across the island

From Boatyard to Museum: 3D laser scanning and digital modelling of the Qatar Museums watercraft collection, Doha, Qatar

This is the final version of the article. Available from Wiley via the DOI in this record.This article presents the results of a project to 3D laser scan and digitally model 14 watercraft from the Qatar Museums collection, comprising a range of regional vessels: most had not been surveyed previously. The project used the resulting point clouds generated 2D naval lines and orthographic records of the vessels in their current condition, and photorealistic 3D digital models for gallery display. This case study provides illustrative examples of the intermediate stages and final outputs. It assesses the pros and cons of 3D laser scanning as a survey technology for nautical scholars in terms of the time, cost, and skillset, as well as logistical considerations. It also compares the accuracy of traditional hand survey methods.We wish to thank QM for enabling and funding this research (Grant number SL-05894)

Rate-induced tipping in heterogeneous reaction-diffusion systems: an invariant manifold framework and geographically shifting ecosystems

We propose a framework to study tipping points in reaction-diffusion equations (RDEs) in one spatial dimension, where the reaction term decays in space (asymptotically homogeneous) and varies linearly with time (nonautonomous) due to an external input. A compactification of the moving-frame coordinate together with Lin’s method to construct heteroclinic orbits along intersections of stable and unstable invariant manifolds allows us to (i) obtain multiple coexisting pulse and front solutions for the RDE by computing heteroclinic orbits connecting equilibria at negative and positive infinity in the compactified moving-frame ordinary differential equation, (ii) detect tipping points as dangerous bifurcations of such heteroclinic orbits, and (iii) obtain tipping diagrams by numerical continuation of such bifurcations. We apply our framework to an illustrative model of a habitat patch that features an Allee effect in population growth and is geographically shrinking or shifting due to human activity or climate change. Thus, we identify two classes of tipping points to extinction: bifurcation-induced tipping (B-tipping) when the shrinking habitat falls below some critical length and rate-induced tipping (R-tipping) when the shifting habitat exceeds some critical speed. We explore two-parameter R-tipping diagrams to understand how the critical speed depends on the size of the habitat patch and the dispersal rate of the population, uncover parameter regions where the shifting population survives, and relate these regions to the invasion speed in an infinite homogeneous habitat. Furthermore, we contrast the tipping instabilities with gradual transitions to extinction found for logistic population growth without the Allee effect

Irish orthography: what do teachers and learners need to know about it, and why?

Irish has significant State support, but lacks a research base to support the teaching of Irish reading. Current approaches to teaching Irish reading are presented, and outcomes summarised. Issues of consistency and complexity in Irish orthography are discussed in light of an analysis of a corpus of early reader texts, and the formulation of rules for discriminating between words which are regular by letter-sound and grapheme-sound rules is outlined. While the most frequent words show a high level of regularity, underlying rules are very complex. The need to target decoding skills early is discussed. Recommendations regarding the teaching of aspects of Irish orthography are presented.Author has checked copyrightAM