Sri Lanka Atomic Energy Board

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Isotope Database in Rain Water

Stable Isotope Database in Rain Water across the Country

Isotope composition (d18O and dD) in precipitation is widely used worldwide for a multitude of hydrological, ecological and climate studies. The variability of monsoon rains has a significant impact on regional livelihoods and ecosystems. Understanding the rain process is therefore important in view of predicting local and regional climatic conditions affecting the livelihoods and ecosystems. Also the knowledge on isotope variation in precipitation over the country will be useful to understand the groundwater recharge mechanism, groundwater origin, aquifer interconnections and groundwater age etc… for proper groundwater management activities.  

International Atomic Energy Agency (IAEA) in collaboration with World Meteorological Organization (WMO) is measuring d18O and dD of precipitation at over 300 stations all over the world, under the program of Global Network for Isotopes in Precipitation (GNIP). There are three active GNIP stations in Sri Lanka; one in Colombo (West coast) which is being operated since 2008 and other two are being operated since 2014 at Katugastota (Central Highlands) and at Jaffna (North coast) (Figure 1). These three stations continuously provide data to the GNIP program.  

Isotope Hydrology Section-SLAEB has also launched a program to collect rain water for few years in other areas in the country to establish baseline data. Under that, rainwater was collected in 20 selected locations in the dry zone areas in north-central, central and eastern provinces from 2012-2015 as phase-1 of the study (Figure1). During phase-2, 26 rain stations have been established in 2017 in selected locations in wet and semi-arid zones in north-western, western, sabaragamuwa, central and uwa provinces (Figure 2). Phase -2 will be continued until 2019 in these stations.  

The overall objectives of this study are to construct a map with rain isotope data across the country and establish Local Meteoric Water Lines (LMWLs) for each geographical region in the country as baseline information of isotopes in rain.

The published data can be accessed through:         



  Figure 1: GNIP and Dry Zone areas rain collecting stations (Edirisinghe et al., 2017)



    Figure 2. Rain collecting stations in wet and semi-arid zones


Project Team     

1.Mr. Viraj Edirisinghe-  Director (Radiation Technology Applications / Industrial Application Division)

2.Ms. Nadeesha Thilakarathna- Scientific Officer

3.Ms. Shakila Priyadarshanee- Scientific Officer

4.Ms. Chathurangi Gunasekara- Scientific Officer  

5.Mr.  Mahesh Maduwantha- Lab Assitant











Last Updated on Thursday, 18 January 2018 15:32  

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