|
Journal of Environmental Hydrology
ISSN 1058-3912 |
||
|
Electronic Journal of the International Association for
Environmental Hydrology
JEH Volume 19 (2011), Paper 27 Posted December 28, 2011 ISOTOPIC COMPOSITION OF RAINWATER IN THE SUBTROPICAL ISLAND OF TENERIFE, CANARY ISLANDS
E. Sosa ABSTRACT The results of the most extensive study of stable isotope composition carried out on single precipitation events in a weather station located in La Laguna, Tenerife, Canary Islands are presented. During the year 2007 to 2009, individual precipitation samples have been collected and analyzed for the composition of δ18O and δ2H, within the Global Network of Isotopes in Precipitation (GNIP) project. The data display a wide range of values, from -9.3‰ to -1.4‰ for δ18O and from 6.8‰ to -57.8‰ for δD. The weighted-mean values of all the data are -4.34‰ for δ18O and -18.9‰ for δD. On the basis of 42 precipitation event samples, the local meteoric water line (LMWL) was established as δ2H= 7.6·δ18O+13.7, which coincides with previous work in this region. Precipitation amount effect was investigated, finding a good correlation with mean precipitation intensity (MPI), calculated as the ratio between total precipitation and the total days of event duration. No significant relation between rainfall δ18O and δ2H and surface temperature has been found, according to subtropical island environment. However, the base and the top cloud temperatures, calculated from local atmospheric soundings, show a better correlation due to the fact that the cloud temperature is more likely a better representation of the actual temperature of the precipitation. Finally, the source and pathway of water vapor was analyzed using five-day isentropic back-trajectories. The preliminary results suggest that the δ18O lower values are associated with events derived from the east and after a Sahara invasion event, or with long path trajectories from northwest. The higher values are relative to events derived from the northwest and with short pathways. Reference: Sosa, E., J.C. Guerra, and M.T. Arencibia. 2011. Isotopic composition of rainwater in the subtropical island of Tenerife, Canary Islands. Journal of Environmental Hydrology, Vol. 19, Paper 27. CONTACT: E. Sosa Grupo de Investigación en Hidrometeorología Facultad de Física Universidad de La Laguna Tenerife, Canary Islands, Spain E-mail: estruji@ull.es |
||
|
Return to JEH 2011 Papers
Return to HydroWeb Homepage |
||