Impact of Changing Atmospheric Dynamics on d excess in Precipitation in the Great Lakes Region of the United States
Abstract
The use of stable isotopes has long been rooted in hydrology, providing insight to source identification, mixing systems, and water cycling. As of late, the use of stable isotopes to better understand atmospheric dynamics has become increasingly common, in particular the deuterium excess parameter, or d excess, has been used. The d excess parameter is defined [1] as d = δ2H - 8δ18O, derived from the Global Meteoric Water Line (GMWL), where δ2H = 8δ18O + 10 [2]. This parameter can be used to look at secondary processes such as evaporation or secondary source contribution to vapor masses. The study area, Kalamazoo, MI, is a prime candidate in using d excess as the region receives a significant amount of what is known as "Lake Effect" precipitation. A previous study provides baseline data on stable isotopes in precipitation and they calculated lake contribution for precipitation during the summer of 1992 [3]. Since then a more detailed study has been carried out [4]. This study focuses on the temporal variation (1992-1995 and 2014-2018) in summer (rain) and winter (snow) d excess. The extensive data generated shows discernible variations that will be investigated in the light of recent climate changes and associated impact on secondary moisture sources and air mass movement in the region.
[1] Dansgaard, W. Stable isotopes in precipitation. Tellus A 16: 436-468 (1964). [2] Craig, H. Standard for Reporting Concentrations of Deuterium and Oxygen-18 in Natural Waters. Science 133, 1833-1834 (1961). [3] Machavaram, M. &, Krishnamurthy, R.V. Earth surface evaporative process: a case study from the Great Lakes region of the United States based on deuterium excess in precipitation. Geochim. et Cosmochem. Acta 59, 4279-4283 (1995). [4] Hurst, S. and Krishnamurthy, R.V. Book Chapter "Stable Isotopes in Precipitation: a Review". Encyclopedia of Water: Science, Technology, and Society. Ed. Cassie Strickland. John Wiley (2018).- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFMPP21F1486H
- Keywords:
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- 3344 Paleoclimatology;
- ATMOSPHERIC PROCESSESDE: 1041 Stable isotope geochemistry;
- GEOCHEMISTRYDE: 1655 Water cycles;
- GLOBAL CHANGEDE: 1833 Hydroclimatology;
- HYDROLOGY