HR: 17:05h
AN: B24A-03 INVITED     [Abstracts]
TI: Evaluating Self Initialization
AU: * Pietsch, S A
EM: Stephan.Pietsch@boku.ac.at
AF: Univ. of Natural Resources and Appl. Life Sciences, Peter-Jordan-Str. 82, Vienna, A-1190, Austria
AU: Hasenauer, H
EM: hubert.hasenauer@boku.ac.at
AB: In large scale ecosystem models self-initialization routines are used to generate ‘steady state' starting values needed to model transient behaviour. The steady state reached at the end of self initialization is interpreted as the "temporally averaged state of an undisturbed ecosystem for a region large enough to encompass all its natural development stages". We evaluate this assumption for biological realism by comparing model predictions with observations from the central European virgin forest reserve Rothwald, a category I IUCN wilderness area. Results indicate that standard self-initialization towards a steady state using constant biomass mortality rates produces biased and inconsistent predictions resulting in systematically overestimated C and N pools vs. observations. We improved the self-initialization routine by developing a dynamic mortality model which addresses natural forest dynamics with higher mortality during senescence and regeneration vs. lower mortality during the period of optimum forest growth between regeneration and senescence. Running self-initialization with this new dynamic mortality routine resulted in consistent and unbiased model predictions compared with field observations.
DE: 0414 Biogeochemical cycles, processes, and modeling (0412, 0793, 1615, 4805, 4912)
DE: 0428 Carbon cycling (4806)
DE: 0495 Water/energy interactions (1878)
DE: 1630 Impacts of global change (1225)
DE: 1631 Land/atmosphere interactions (1218, 1843, 3322)
SC: Biogeosciences [B]
MN: 2007 Joint Assembly