title: Current and future carbon budget at Takayama site, Japan, evaluated by a regional climate model and a process-based terrestrial ecosystem model.
abstract: Accurate projection of carbon budget in forest ecosystems under future climate and atmospheric carbon dioxide (CO2) concentration is important to evaluate the function of terrestrial ecosystems, which serve as a major sink of atmospheric CO2. In this study, we examined the effects of spatial resolution of meteorological data on the accuracies of ecosystem model simulation for canopy phenology and carbon budget such as gross primary production (GPP), ecosystem respiration (ER), and net ecosystem production (NEP) of a deciduous forest in Japan. Then, we simulated the future (around 2085) changes in canopy phenology and carbon budget of the forest by incorporating high-resolution meteorological data downscaled by a regional climate model. The ecosystem model overestimated GPP and ER when we inputted low-resolution data, which have warming biases over mountainous landscape. But, it reproduced canopy phenology and carbon budget well, when we inputted high-resolution data. Under the future climate, earlier leaf expansion and delayed leaf fall by about 10 days compared with the present state was simulated, and also, GPP, ER and NEP were estimated to increase by 25.2%, 23.7% and 35.4%, respectively. Sensitivity analysis showed that the increase of NEP in June and October would be mainly caused by rising temperature, whereas that in July and August would be largely attributable to CO2fertilization. This study suggests that the downscaling of future climate data enable us to project more reliable carbon budget of forest ecosystem in mountainous landscape than the low-resolution simulation due to the better predictions of leaf expansion and shedding.
authors.affiliation: Nagano Environmental Conservation Research Institute, 2054-120 Kitago, Nagano, 381-0075, Japan. kuribayashi-masatoshi-r@pref.nagano.lg.jp.
authors.forename: Masatoshi
authors.identifier: http://orcid.org/0000-0001-7709-1287
authors.initials: M
authors.lastname: Kuribayashi
authors.affiliation: River Basin Research Center, Gifu University, 1-1 Yanagido, Gifu, 501-1193, Japan.|School of Forest Resources and Environmental Science, Michigan Technological University, G026, UJ Noblet Forestry Building 1400 Townsend Drive, Houghton, MI, 49931-1295, USA.
authors.forename: Nam-Jin
authors.initials: NJ
authors.lastname: Noh
authors.affiliation: River Basin Research Center, Gifu University, 1-1 Yanagido, Gifu, 501-1193, Japan.
authors.forename: Taku M
authors.initials: TM
authors.lastname: Saitoh
authors.affiliation: Center for Global Environmental Research, National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, 305-8506, Japan.
authors.forename: Akihiko
authors.initials: A
authors.lastname: Ito
authors.affiliation: College of Science, Ibaraki University, 2-1-1 Bunkyo, Mito, 310-8512, Japan.
authors.forename: Yasutaka
authors.initials: Y
authors.lastname: Wakazuki
authors.affiliation: River Basin Research Center, Gifu University, 1-1 Yanagido, Gifu, 501-1193, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Muraoka
mesh_terms: D002244:Carbon / Q000032:analysis*; D002245:Carbon Dioxide / Q000032:analysis; D002980:Climate; D065928:Forests; D007564:Japan; D008962:Models, Theoretical; D018515:Plant Leaves / Q000254:growth & development; D012621:Seasons; D014197:Trees / Q000254:growth & development; D014887:Weather
chemical_list: D002245:Carbon Dioxide; D002244:Carbon
keywords: carbon budget; dynamical downscaling; future projection; mountainous terrain; terrestrial ecosystem model