Bomb-tritium input function calculated from the details of the nuclear atmospheric bomb tests released by the UNSCEAR [2000]

• Main Authors: Cauquoin, Alexandre, Jean-Baptiste, Philippe, Risi, Camille, Fourré, Elise, Landais, Amaelle
• Format: Dataset
• Language: English
• Published: PANGAEA 2016
• Subjects: AERO; Aerological investigations; Africa; Algeria; Astrachan; Australia; Australia1; Australia2; Bikini_Atoll; Bikini Atoll; China; Cloud base height; Cloud top height; COMBINISO; DATE/TIME; Enewetak_Atoll; Enewetak Atoll; Event label; Hiroshima_J; Japan; Johnston_Atoll; Johnston Atoll; Kasachstan; Kiribati; Latitude of event; Longitude of event; Malden_Is; Malden Island; Montebello_Is; Nagasaki_J; NE_Kasachstan; Nevada; United States of America; Novaya_Zemlya; Novaya Zemlya; Orenburg; Pacific_Ocean1; Pacific_Ocean2; Pacific Ocean; Quantitative picture of interactions between climate; hydrological cycle and stratospheric inputs in Antarctica over the last 100 years via the combined use of all water isotopes; Reggan; Russia; Trinity_site; Trinity site; New Mexico; Tritium release; Tuamotu1; Tuamotu2; Pacific; Antarc*; Antarctica
• Online Access: https://doi.pangaea.de/10.1594/PANGAEA.864909; https://doi.org/10.1594/PANGAEA.864909

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 (HTO) is an extremely valuable tracer, because its content in the different reservoirs involved in the water cycle (stratosphere, troposphere, ocean) varies by order of magnitude. Previous work incorporated natural tritium into LMDZ-iso, a version of the LMDZ general circulation model enhanced by water isotope diagnostics. 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 the model; 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. LMDZ-iso satisfactorily reproduces the general shape of the temporal evolution of tritium. However, LMDZ-iso simulates too high a bomb-tritium peak followed by too strong a decrease of tritium in precipitation. The too diffusive vertical advection in AGCMs crucially affects the residence time of tritium in the stratosphere. 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, complementing water stable isotope modeling.