Naslov
Quantification of the impact of moisture source regions on the oxygen isotope composition of precipitation: case study from Eagle cave, central Spain

Autori
Krklec, Kristina ; Domínguez-Villar, David

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
KR7 Climate Change: The Karst Record. Scientific Programme and Abstracts / Drysdale, R. ; Hellstrom, J. ; Woodhead, J. - Melbourne : Melbourne University Press, 2014, 109-110

Skup
Climate Change: The Karst Record 7th International Conference KR7 "Down Under"

Mjesto i datum
Melbourne, Australija, 29.09.2014. - 03.10.2014

Vrsta sudjelovanja
Predavanje

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
Back trajectory ; Moisture source ; Oxygen isotopes ; Paleoclimate

Sažetak
Quantification of the impact of moisture source regions on the oxygen isotope composition of precipitation: case study from eagle cave, central spain Domínguez-Villar2The ratio of oxygen isotopes 18-O and 16-O is among the most used proxies in reputed archives of past climate such as ice and ocean cores or speleothems. Its variability in continental records depends to a great extent on the variability of the isotope composition of the precipitation. The variables affecting the oxygen isotope ratios in precipitation are relatively well known and include several controls or effects, some of them having a direct empirical link to climate, like the temperature or the amount of precipitation. Although often difficult to compute, there are other controls also affecting the stable isotope variability like changes in seasonality, the ice volume effect or the modification of the moisture sources. The moisture source is an important component of the hydrological cycle that controls, in part, the isotope composition of precipitation. Thus, moisture sources affect the recharge water variability over caves where paleoclimate studies based on oxygen isotope records are studied. Although moisture sources have been proved to be important controls of isotope variability in records like polar ice cores, their study in the continental mid and low latitudes is still scarce. Despite the importance of constraining the source of moisture variability to improve the interpretation of oxygen stable isotope paleorecords, these studies are scarce due to the complexity of the traditionally used general circulation models that enables the computation of oxygen isotopes. Here, we present 5-days reconstruction of air mass history for the days with precipitation at Eagle Cave (central Spain). Together with the calculation of the moisture uptake locations along the back trajectories, we identify the moisture sources of precipitation for this site from the years 2009 to 2011. During this 3-year period, around 30% of the precipitation at Eagle Cave was originated from moisture recycled within the Iberian Peninsula (IP), with the Proximal Atlantic being also a main source region of moisture, whereas the Mediterranean Sea and the Distal Atlantic have large variability during the studied period and other source regions are minor precipitation contributors. The comparison of monthly oxygen isotope composition of precipitation at Eagle Cave with the monthly percentage of precipitation originated in source regions shows a significant negative correlation for the IP region. Thus, the moisture recycling process in the IP region explains 12% of the variability of the monthly oxygen isotope composition of precipitation (p-value <0.1). However, when temperature, amount of precipitation and all source regions are considered, 74% of the variability of the monthly oxygen isotope composition of precipitation is explained (p-value <0.05). Therefore, although for Eagle Cave amount of precipitation and temperature are main contributors of the precipitation oxygen isotope variability (r2=0.54 ; p-value <0.001), the moisture uptake distribution among source regions is a substantial control and should be considered when interpreting oxygen isotope speleothem records from this cave. This research highlights the importance of moisture sources in controlling the oxygen isotope composition of precipitation in mid-latitudes, and the need of the quantification of this effect in order to improve the interpretation of oxygen isotope paleorecords that depend on the isotope composition of precipitation.

Izvorni jezik
Engleski

Znanstvena područja
Geologija

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