Chloride concentration in rain

The file Imre_1992-2005.xls contains the data provided by Dutch National Institute for Public Health and the Environment (RIVM)
The concentrations used in the study are plotted on Chloride_concentrations_in_precipitation.png

The chemical composition of rain water has been extensively monitored in the Netherlands in the framework of the 
Dutch National Precipitation Chemistry Monitoring Network [van der Swaluw et al., 2010]. 
Time series of rain chloride concentrations have been registered for a number of monitoring locations by the 
Dutch National Institute for Public Health and the Environment (RIVM) between 1993 and 2008. 
An interpolation of the mean concentrations shows a strong decreasing concentration gradient from the coast inland, 
with concentrations close to 7 mg/l on the coast to 1.5 mg/l in the most continental parts of the country. 
The data collected within this monitoring framework have been used in the chloride balance of this study. 
The rain chloride concentrations of the three closest rain monitoring stations from the field site are 
shown in the figure available on the file 'Plotted_data.docx', together with the 1 year moving averages. 
The large chloride concentration variations reflect the continental or marine origin of the rain [Stuyfzand, 1991].
The ridge of Salland is situated between these three rain monitoring stations, at distance varying from 30 to 50km. 
Interpolation of the mean chloride concentration of the 1 year moving average of the chloride concentrations 
results to an estimate of the chloride concentration on the ridge of Salland of 1.9mg/l. 
The interpolated standard deviation of the 1 year moving average, which can be considered a reasonable estimate of the 
variation in chloride concentration in rain water feeding the aquifer, amounts 0.3 mg/l.
