Slovenian Network of Isotopes in Precipitation (SLONIP) – a review of activities in the period 1981–2015

Polona Vreča,Neža Malenšek

doi:10.5474/geologija.2016.004

Abstract

The first investigations of oxygen and hydrogen isotope composition (δ18O and δ2H) and the tritium activity (3H) in precipitation over Slovenia were performed in the frame of tracer experiments conducted in the period 1972-1975 in the Ljubljanica River drainage basin. The first regular and systematic monitoring of isotope composition of precipitation only began in 1981 in Ljubljana but has been extended during the last 35 years to 30 different locations countrywide. Herein, we present a review of research performed during the period 1981-2015. We collected information about sampling, analytical methods, available data and their evaluation including calculations of local meteoric water lines. Based on the data, we identify gaps in the research and make recommendations for future monitoring in the frame of the Slovenian Network of Isotopes in Precipitation (SLONIP).

Highlights

The importance of systematically collecting data on the water isotope composition of precipitation, i.e. stable isotopes of oxygen and hydrogen and the radioactive hydrogen isotope tritium (3H), in the frame of the Global Network of Isotopes in Precipitation (GNIP) has been steadily increasing since it was initiated by the International Atomic Energy Agency (IAEA) and the World Meteorological Organisation (WMO) in 1958 (Internet 1)
In the early 1980s, isotope ratio mass spectrometer (IRMS) techniques for determining stable oxygen and hydrogen isotope composition in water samples were implemented for the first time in Slovenia at the Jožef Stefan Institute (JSI).The first systematic monitoring of isotopes in precipitation started in 1981 at the synoptic station Ljubljana–Bežigrad located at the Hydrometeorological Survey of Slovenia
The stable isotope composition of monthly precipitation samples was determined at the JSI and tritium activity was measured at the Ruđer Bošković Institute (RBI) in Zagreb, Croatia (Krajcar Bronič et al, 1998; Pezdič, 1999; Vreča et al, 2008)

Summary

Introduction

The importance of systematically collecting data on the water isotope composition of precipitation, i.e. stable isotopes of oxygen (expressed as δ18O) and hydrogen (expressed as δ2H) and the radioactive hydrogen isotope tritium (3H), in the frame of the Global Network of Isotopes in Precipitation (GNIP) has been steadily increasing since it was initiated by the International Atomic Energy Agency (IAEA) and the World Meteorological Organisation (WMO) in 1958 (Internet 1). In the last decade has the demand for accurate spatial and temporal predictions of point, regional, and continental-scale δ18O and δ2H values in precipitation been increasing (Terzer et al, 2013). This is especially the case for those regions where little or no GNIP data exist. The network is still not a part of a national monitoring programme, such as that operating in European countries, for example, in Switzerland (Schürch et al, 2003) and Germany (Stumpp et al, 2014)

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