PP11B-2243
Understanding the variability of water isotopologues in near-surface atmospheric moisture observed over a rice paddy in Tsukuba, Japan
Monday, 14 December 2015
Poster Hall (Moscone South)
Zhongwang Wei1, Kei Yoshimura1, Atsushi Okazaki1, Chun-Ta Lai2, Keisuke Ono3, Wonsik Kim3 and Masaharu Yokoi4, (1)Atmosphere and Ocean Research Institute University of Tokyo, Tokyo, Japan, (2)San Diego State University, San Diego, CA, United States, (3)NIAES National Institute for Agro-Environmental Sciences, Tsukuba, Japan, (4)SANYO TRADING CO., LTD., Tokyo, Japan
Abstract:
In this study, stable isotopes in precipitation and atmospheric water vapor were observed over a paddy field near Tsukuba, Japan, from June 2013 to May 2014. We used observed isotope ratios, in combination with an isotope-enabled GCM (IsoGSM) to improve our understanding of the impacts of moisture source and its transport on the variability of water vapor isotopes. The isotopic measurements of water vapor and precipitation suggested that vapor isotopes in the study area were controlled not only by air-rain isotopic exchange but also kinetic effects associated with vegetation activity at the seasonal time scale. The contribution of land evapotranspiration to local water vapor content (FET) was approximately 14.8±12.8% on an annual average with a summer maximum of 23.2±13.8%. Our results show that large scale atmospheric circulation is the primary control on the variability of the near surface water vapor δD. An IsoGSM tagging simulation experiment demonstrated advection and mixing of moisture from different oceanic source regions can explain the large temporal variation of surface water vapor isotope at this site.
