The stable isotope composition of hoarfrost

ABSTRACT

Atmospherically deposited hoarfrost is probably the least important quantitative component of the hydrosphere, yet in places acts as an important source of water. Although countless studies have investigated the stable isotope composition of virtually all other components of the global hydrosphere, little is known on its stable isotope composition. We addressed this gap in knowledge by investigating the stable isotope composition of hoarfrost and precipitation in the Southern Carpathian Mountains (East-Central Europe) in relation with the local and regional meteorological parameters and hoarfrost characteristics. Hoarfrost and precipitation were collected at the Țarcu Peak Weather Station (2180 m a.s.l.) between December 2018 and February 2019. The main sources of moisture (as indicated by high deuterium excess values) were the Black (and possibly Caspian) Sea as well as the terrestrial sources in Eastern Europe and Western Asia. Hoarfrost was deposited during periods of intense wind, with δ¹⁸O and δ²H being strongly correlated with air temperature. No correlation has been found between the intensity of hoarfrost deposition and its stable isotope characteristics. Our data indicates that the δ¹⁸O values of hoarfrost deposits faithfully record air temperature variability during deposition, while the d-excess parameter records conditions at the moisture sources.

KEYWORDS:

• Atmospheric circulation
• Carpathian Mountains
• deuterium excess
• hoarfrost
• hydrogen-2
• isotope hydrology
• oxygen-18
• precipitation

Acknowledgments

The meteorological data were used with the agreement of the ‘Banat-Crișana’ Regional Meteorological Centre, Timișoara, Romania. Eddie van Halen provided the musical background during the final writing of this article.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

The IAEA partly supported the stable isotope collection and analysis in the framework of CRP F33025 (Isotope Techniques for the Evaluation of Water Sources in Irrigation Systems, contract 22895) and CRP F31006 (Isotope variability of rain for assessing climate change impacts, contract 23550) research contracts awarded to AP. UEFISCDI Romania partly supported stable isotope analyses through grants PN-III-P1-1.1-TE-2016-2210 and PN-II-RU-TE-2011-3-0235 awarded to AP.AP was further supported by grants PN-III-P4-ID-PCCF-2016-0016 and EEA 4/2019.