MAPPING OF RAINFALL CHEMISTRY IN IRELAND 1972-94

This payer presents an analysis of data collected from rainfall-monito ring networks operating in Ireland over the period 1972-94. In particu lar, mean rainfall chemistry over the periods 1972-4, 1982-4, 1986-8, 1988-91 and 1992-4 is discussed, with greatest emphasis placed on quan tifying sources of acidity in Irish precipitation. Along with rainfall amounts, species analysed include Na+, Cl-, SO42--S, NO3--N, NH4+-N, Ca2+, Mg2+, K+, various P fractions, H+ and total acidity. With the ai d of a geographic information system, distribution maps of rainfall co ncentration levels and deposition loads have been produced for each of these species (except P) for each of the five periods, but only those for 1992-4 are reproduced in this paper. The significance of sea-spra y is discussed, along with trends in the deposition of acidity, sulphu r and nitrogen in Ireland. The interpolated maps indicate the broad re gional variations across Ireland and complement these available for th e UK. The maps should prove useful to researchers requiring best-avail able estimates of inputs of nutrients or major ions from precipitation to major river or lake catchments in Ireland, and may help to define areas susceptible to acidification under present and Future emission s cenarios.