Temporal and spatial distribution of isotopes in river water in Central Europe: 50 years experience with the Austrian network of isotopes in rivers

The Austrian network of isotopes in rivers comprises about 15 sampling locations and has been operated since 1976. The Danube isotope time series goes back to 1963. The isotopic composition of river water in Central Europe is mainly governed by the isotopic composition of precipitation in the catchment area; evaporation effects play only a minor role. Short-term and long-term isotope signals in precipitation are thus transmitted through the whole catchment. The influence of climatic changes has become observable in the long-term stable isotope time series of precipitation and surface waters. Environmental ³H values were around 8 TU in 2015, short-term ³H pulses up to about 80 TU in the rivers Danube and March were a consequence of releases from nuclear power plants. The complete isotope data series of this network will be included in the Global Network of Isotopes in Rivers database of the International Atomic Energy Agency (IAEA) in 2017. This article comprises a review of 50 years isotope monitoring on rivers and is also intended to provide base information on the (isotope-)hydrological conditions in Central Europe specifically for the end-users of these data, e.g. for modelling hydrological processes. Furthermore, this paper includes the 2006–2015 supplement adding to the Danube isotope set published earlier.

奥地利河流同位素网络（Austrian network of isotopes in rivers）共设约15个采样点位，自1976年起投入运行。多瑙河同位素时间序列的观测历史可追溯至1963年。中欧河流水体的同位素组成主要受流域降水的同位素组成控制，蒸发作用的影响相对微弱。因此，降水中的短期与长期同位素信号可传递至整个流域。气候变化的影响已在降水与地表水体的长期稳定同位素时间序列中得以显现。2015年，环境中氚（³H）的活度浓度约为8氚单位（Tritium Unit，TU）；多瑙河与马奇河中出现的最高达约80 TU的短期氚浓度脉冲，源自核电站的排放。该网络的完整同位素数据集将于2017年被收录至国际原子能机构（International Atomic Energy Agency，IAEA）的全球河流同位素网络数据库（Global Network of Isotopes in Rivers）中。本文对50年来的河流同位素监测工作进行了综述，同时旨在为该数据集的终端用户（如水文过程模拟从业者）提供中欧地区（同位素）水文条件的基础参考信息。此外，本文还补充了2006—2015年的观测数据，作为此前已发表的多瑙河同位素数据集的增补内容。