Construction and testing of a low-cost device for the collection of rainfall samples destined for stable isotope analysis
DOI:
https://doi.org/10.17159/sajs.2023/14914Keywords:
precipitation, oxygen isotopes, hydrogen isotopes, rainfall collector, southern AfricaAbstract
Oxygen- and hydrogen-isotope ratios in rainfall provide important hydroclimatic information, yet despite a global network of rainfall isotope measurements, significant geographical gaps exist in data coverage, with only three long-term stations spanning the southern African region. Project-based, ad hoc collections of rainfall for isotope analysis can improve this coverage. However, all rainfall samples that are destined for stable isotope analysis must be collected in such a way to avoid evaporation and resultant isotope fractionation. While such rainwater collectors are available commercially, both the product and shipping are prohibitively costly. We describe the construction of a simple rainfall collector using a design from the literature and materials that are readily available in South African hardware stores. Our rainwater collector can be constructed for the much lower cost of just under ZAR820 in comparison with the cost of ZAR9300 inclusive of shipping from commercial outlets (2022 prices). Our design modifications have the added advantage of portability, with the rainwater collector housed in a bucket with a handle. The device was tested by comparing its performance, in terms of evaporative water loss and isotopic fractionation, with that of an open bottle, using tap water in both cases. Testing confirmed that the collector prevented evaporation over a one-week period, indicating that it is suitable for weekly or more frequent sampling of rainfall. Although the design described was based on materials procured in South Africa, it could easily be adapted for construction elsewhere.
Significance:
- Hydrogen and oxygen isotope composition of rainfall provides valuable climatic information.
- Rainwater collectors for stable isotope samples must prevent evaporation, as evaporation will alter the isotopic signature.
- We describe the construction and testing of a bespoke, low-cost and portable device that can be used to collect rainfall samples destined for oxygen- and hydrogen-isotope analysis without significant evaporation.
Published
Issue
Section
License
All articles are published under a Creative Commons Attribution 4.0 International Licence
Copyright is retained by the authors. Readers are welcome to reproduce, share and adapt the content without permission provided the source is attributed.
Disclaimer: The publisher and editors accept no responsibility for statements made by the authors
How to Cite
- Abstract 303
- PDF 439
- EPUB 72
- XML 164