Regional Carbon Fluxes in WI: Moving towards synthesis Cheas IX, June 2006 Ankur R. Desai Pennsylvania State University, Dept. of Meteorology National Center for Atmospheric Research, Advanced Study Program University of Wisconsin, Atmospheric & Oceanic Sciences Dept.

What is the regional carbon flux? Do we have to study its ursprache? Question One of several overarching ChEAS questions is: What is the regional carbon flux? Do we have to study its ursprache?

Pardon? WHAT -> define? quantify? explain? IS -> present? past? future? THE -> only one answer? REGIONAL -> scale? CARBON -> CO2, CH4, VOC? FLUX? -> Vertical, horizontal, NBP?

Approaches Biometric / FIA Ecophysiological Tall tower + footprint models Stand scale eddy covariance towers Tall tower ABL budgets Multi-tower mesoscale inversion Remote sensing (MODIS, LiDAR) Modeling (ED, SiB, Biome-BGC)

A Bit About ED Ensemble-average canopy gap model (Moorcroft et al., 2001; Albani et al., in press; Desai et al, submitted) Conditioned on stand age and plant height (modifies light environment) Multiple competing plants Disturbance, mortality, harvest, reproduction control dynamics Traditional soil/leaf biogeochemistry

A Bit About ED For ChEAS: 40 km radius of WLEF Forcing: Pre-European settlement vegetation Ecophysiological and allometric growth/respiration parameters Long-term climate data Forest harvest statistics FIA to tune forest structure and params. 3 “grid cells” / subregions

Mesic Upland / N. Hardwoods Xeric Upland / Mixed conifer ED MODEL PFTS Mesic Upland / N. Hardwoods GR Grass AS Aspen BI Birch SM Sugar maple/basswood HE Hemlock/Spruce Xeric Upland / Mixed conifer Shrub/Pine Barren JP Jack Pine RP Red Pine WP White Pine/Fir RM Red maple/Oak/Ash Lowland / Wetland Meadow grass AW Alder/Willow shrub TM Tamarack CE Cedar BS Black spruce

What Have We Learned When you’re up you’re up When you’re down you’re down And when you’re only halfway up, you’re neither up nor down Puzzling results when comparing up-scaled estimates from one approach to another at a larger scale You’re asking for trouble if you try to measure something more than once or in more than one way

What Have We Learned Stand age and species matter Within site IAV < Across-site variability

What Have We Learned Climate explains much of interannual variability of CO2 flux We’re doing a better job at modeling it

What Have We Learned But it’s harder to model indiv. stands

What Have We Learned Over the long term, forest dynamics matter

What Have We Learned Scale matters

What Have We Learned Tree biophysics matter

What Have We Learned Animals and pests matter

What Have We Learned People matter

What Have We Learned There’s a lot of things to worry about when answering “What is the regional carbon flux?” We’re making good progress in spite of that Starting to put together some of our top-down and bottom-up flux estimates Need your help

Some Numbers NEE, several methods (gC m-2 yr-1) better in Jun-Aug than all year   LEF tall tower Decomp. Multi-site ED Bakwin, 2004 Helliker, Year 2003 2000 1997 Jun-Aug -76 -149 -124 -258 -298 -177 -140 -174 Annual 80 95 44 -119 N/A -143 77 -40

Some Numbers NPP (gC m-2 yr-1): FIA 553 (1996-2004 biomass increment) – litter (~100) MODIS NPP (MOD17) 2002: ~600 Ahl et al, RSOE, 05 (ATLAS 15 m): 403 ED model: 423

Moving Toward Synthesis? Maybe More observations, more models, more processes Will it help? When is it enough? What’s the next step? Working on paper this summer at PSU on regional synthesis

Moving Toward Cuteness!