Analysis of Abrupt Changes in Heat, Water, and Carbon Fluxes over a Larch Forest in Eastern Siberia, After a Period of Wet Damage Due to Increased Precipitation

Eddy covariance flux measurements have been conducted over a larch forest in eastern Siberia since 1998. This area is characterized by low precipitation; mean annual precipitation from 1998 to 2003 was about 250 mm/year (Ohta et al., 2008). However, precipitation from 2005 to 2008 generally exceeded 300 mm/year, with wet damage to larch trees during this period resulting in weakness and death of some trees (Iijima et al., 2013). Since this event, flux characteristics have changed. To analyze this phenomenon, we have adopted a soil-vegetation-atmosphere transfer (SVAT) model (Kumagai et al., 2006, 2013). By using the ecophysiological parameterization for Siberian larch forest from Xue et al. (2011) and the observed meteorological data, eddy fluxes in August 2005 were successfully simulated. However, Xue's parameterization was no longer applicable for eddy fluxes in August 2011, indicating that the ecophysiological characteristics have changed since the wet damage period. In this presentation, we will try to clarify what caused such abrupt changes in eddy flux characteristics after wet damage occurred.