Bremen 2017 – wissenschaftliches Programm
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UP: Fachverband Umweltphysik
UP 15: Klimamodellierung
UP 15.2: Vortrag
Donnerstag, 16. März 2017, 16:30–16:45, GW2 B3009
Modeling the global bomb tritium transient signal with the AGCM LMDZ-iso: A method to evaluate aspects of the hydrological cycle — •Alexandre Cauquoin1,2, Philippe Jean-Baptiste2, Camille Risi1, Élise Fourré2, and Amaelle Landais2 — 1Laboratoire de Météorologie Dynamique (LMD), Paris, France — 2Laboratoire des Sciences du Climat et de l'Environnement (LSCE), Gif-sur-Yvette, France
Improving the representation of the hydrological cycle in atmospheric general circulation models (AGCMs) is one of the main challenges in modeling the Earth's climate system. One way to evaluate model performance is to simulate the transport of water isotopes. Among those available, tritium is an extremely valuable tracer, because its content in the different reservoirs involved in the water cycle (stratosphere, troposphere, and ocean) varies by order of magnitude. Here for the first time, the anthropogenic tritium injected by each of the atmospheric nuclear bomb tests between 1945 and 1980 has been first estimated and further implemented in LMDZ-iso, a version of the LMDZ general circulation model enhanced by water isotope diagnostics; it creates an opportunity to evaluate certain aspects of LDMZ over several decades by following the bomb tritium transient signal through the hydrological cycle. Simulations of tritium in water vapor and precipitation for the period 1950-2008, with both natural and anthropogenic components, are presented in this study. This insight into model performance demonstrates that the implementation of tritium in an AGCM provides a new and valuable test of the modeled atmospheric transport.