The Rain Forest Canopy Reduction Effect on NO Emission from Soils * * results shown here are from the "EUropean Studies on Trace Gases and Atmospheric CHemistry"-project to the "Large-Scale Biosphere-Atmosphere Experiment in Amazonia" Franz X. Meixner (1), Christof Ammann (2), Udo Rummel (1), Urs Andreas Gut (3), and Meinrat O. Andreae (1) 10 th Scientific Conference of the International Association of Meteorology of Atmospheric Sciences (IAMAS) Commission for Atmospheric Chemistry and Global Pollution (CACGP) and 7 th Scientific Conference of the International Global Atmospheric Chemistry Project (IGAC) Creta Maris, Hersonissos, Crete, Greece,18-25 September 2002 (1) Max-Planck-Institut für Chemie, Abteilung Biogeochemie, Postfach 3060, D Mainz, Germany (2) Eidgenössische Forschungsanstalt für Agrarökologie und Landbau, CH Zürich, Switzerland (3) Bundesamt für Energie (BFE), Monbijoustrasse 72, CH-3003 Bern, Switzerland

background remote regions (USA) urban (USA) maritime (Pacific) tropical rainforest wet season ambient mixing ratio (NO+NO 2 ) in ppb VOC as propylene (normalized by reactivity) in ppb isolines = ozone production rate in ppb/h Chameides et al., JGR, 97: , ABLE campaigns end of the 80's tropical NO x sources anthropogenic (traffic) biomass burning (deforestation) biogenic emission from soils

background (tropical) NO soil emission inventories based on chamber measurements there are only a few NO, NO 2 (NO x, NO y ) flux measurements over tall vegetation (forests) at all ( global) atmospheric chemistry models need reliable NO x fluxes as a lower boundary condition mostly a constant or LAI parameterized NO x canopy reduction factor (CRF) is used (e.g. Yienger & Levy, 1995) very recently (!) : Ganzeveld et al. (JGR, September 2002) multilayer trace gas exchange sub-model (in a chemistry general circulation model) to explicitly calculate NO x emissions from forests

biogenic NO emssion from soils (Brazil) Bakwin et al. (1990) Neill et al. (1995, 1997) ? Bakwin et al. (1990) 1 : 10 F NOx, out = 0.25 F NOsoil Jacob & Wofsy (1990) Neill et al. (1999) Verchot et al. (1999) Garcia-Montiel et al. (2001) van Dijk et al. (2002) Gut et al. (2002) Kirkman et al. (2002) ng NO-N m -2 s -1 < 1 ng NO-N m -2 s -1 

3 NO, NO, O, VOC 2 VOC VOC emission from leaves NO + O 3  NO 2 + O 2 NO 2 + O 2  NO + O 3 hv ’RO’ 2 + NO  RO + NO 2 2 O 3 deposition to leaf surface O 3 (and NO ) 2 NO 2 O 3 O 3 and NO 2 deposition to stomata NO emission from soil NO O 3 NO + O 3  NO 2 + O 2 2 NO 2 chemistry vs. biology vs. transport time scales ?

LBA-EUSTACH, Reserva Biologica Jarú, Rondônia/Brazil "missing " fluxes : NO 2, NOy conductance conductance : NO 2 vertical profile (8 levels) NO, NO 2, O 3, CO 2, H 2 O, VOC, aerosols, Rn (  K bulk ) T, j(NO 2 ), R net, glob rad conductance / emission O 3, CO 2, H 2 O, VOC emission / deposition soil profile NO, NO 2, O 3, CO 2, Rn eddy covariance fluxes NO, O 3, CO 2, H 2 O, sensible heat (H), momentum ( u*,  w )

F(NO) in ng N m -2 s -1 eddy covariance (4 days) range (min - max) dynamic chambers (4) average (21 days) 11 m in-canopy m above canopy m "forest floor" 00:00 04:0008:0012:0016:0020:0024:

canopy top LBA-EUSTACH, Reserva Biologica Jarú, dry  wet season transition canopy top (average of 43 days Sept/Oct 1999)

characteristic chemical time scale NO 2 + h  NO + O 3, k' = j NO2 NO + O 3  NO 2 + O 2, k = 2  10 –12 exp(–1400/T air ) characteristic turbulent time scale determination of chemical & turbulent characteristic time scales  chem = 2 /{ j NO2 2 + k 2 ( [O 3 ] – [NO] ) j NO2 k ( [O 3 ] + [NO] + 2[NO 2 ] ) } 0.5 (Lenschow, 1982) trunk space : "ramp patterns" in high frequency scalar time series  coherent structures  surface renewal model  wavelet analysis  "turbulent residence time" Paw U et al., 1995; above canopy :  turb = k (z ref + z 0 ) (  w 2 /u * ) -1 ( Villá-Guerrau & Duynkerke, 1992; 0 – 1m : Rn and CO 2 flux / gradient approach (K bulk ) Gut et al., 2002)

LBA-EUSTACH, Reserva Biologica Jarú, m above canopy

LBA-EUSTACH, Reserva Biologica Jarú, MAY m in-canopy

LBA-EUSTACH, Reserva Biologica Jarú, MAY m "forest floor"

j = NO, NO 2, O 3, RO 2 ' F j,plant,7 F j,gas phase,7 F j,turb,6 F j,turb,7 F j,plant,1 F j,gas phase,1 F j,turb,1 F(NO) soil F(NO 2 ) soil F(O 3 ) soil [NO], [NO 2 ], [O 3 ] at 53m R(O 3 ) soil R(NO 2 ) soil F(NO) soil  w /u* j(NO 2 ) R(O 3 ) plant a simple, multilayer diagnostic model

LBA-EUSTACH, Reserva Biologica Jarú, dry  wet season transition

a simple, multilayer diagnostic model : first results F(NO) F(NO 2 ) F(O 3 ) F(NO x ) 0.01 ppb m s -1 = 5.7 ng N m -2 s -1

potential NO x Canopy Reduction Factors F(NO) soil = 6.3 ng N m -2 s -1 = 100 % ; [NO] 53m = [NO 2 ] 53m = 0 ppb [O 3 ] 53m = 40 ppb [O 3 ] 53m = 6 ppb 73 % F(NO x ) out F(NO 2 ) soil F(NO 2 ) plant 14 % 13 % F(NO x ) out 66 % F(NO 2 ) soil F(NO 2 ) plant 21 % 13 %

potential vs. actual NO x Canopy Reduction Factor F(NO) soil = 6.3 ng N m -2 s -1 = 100 % [O 3 ] 53m = 40 ppb [NO] 53m = 0 ppb [NO 2 ] 53m = 0 ppb F(NO x ) out 66 % F(NO 2 ) soil F(NO 2 ) plant 21 % 13 % [O 3 ] 53m = 40 ppb [NO] 53m = 0.06 ppb [NO 2 ] 53m = 0.3 ppb F(NO x ) out F(NO 2 ) soil F(NO 2 ) plant 49 % 22 % 29 %

conclusions rainforest NO x canopy reduction factor of soil emitted NO (daily average): 25 % Jacob & Wofsy (1990) 50 % Yienger & Levy (1995) 43 % this work (actual CRF) 40–50 % Ganzeveld et al. (September 2002) high vegetation canopies are ideal environments for important chemistry–turbulence–biology interactions in the case of NO–NO 2 –O 3 the main controllers are (a) turbulence intensity over the canopy (b) ozone mixing ratio over the canopy (c) biogenic NO emission from soil (d) canopy structure deciduous (Gao et al., 1993), spruce (Duyzer et al., 1995), pine (Joss & Graber, 1996), orchard (Walton et al., 1997); maize (Fehsenfeld & Williams, 2000) future needs – NO 2 conductance / NO 2 canopy compensation mixing ratio – effect of different canopy structures – fluxes / flux divergences of NO 2 and NO y – interactions with radicals (RO 2 ) and reactive VOC's

....vergelt'sgod ! Andreas Gut Christof Ammann Udo Rummel

above-canopy ramp pattern in scalar time-series CO 2 ' H 2 O' O3'O3'O3'O3' T' w'

residence time surface renewal model coherent structures...wavelet analysis ramp patterns.... residence time

biogenic NO emission from forest floor : 5 different techniques 4 dynamic chambers : NO, NO 2, O 3 surface fluxes Gut et al., JGR, 2002b (gas-phase reactions and absorption to walls considered by blank chamber) soil air profile : NO and Radon fluxes Gut et al., JGR, 2002a ("closed cycle" flushing of semi-permeable tubings (3 layers); soil diffusion coefficient by Rn profile and Rn surface flux (static chamber)) "bulk exchange" approach: NO fluxes from concentration gradients of NO ( m, above forest floor) Gut et al., JGR, 2002a (bulk exchange cofficient by Rn and CO 2 gradients & surface flux (static chamber)) eddy covariance : NO fluxes at 1 and 11 m above forest floor Rummel et al., JGR, 2002 laboratory studies on soil samples : NO fluxes from NO production and NO consumption rates van Dijk et al., JGR, 2002

background denitrification (mostly anaerobic) nitrification (mostly aerobic) most important controllers: — soil moisture — soil temperature — soil nutrients (NO 3 –, NH 4 + ) — soil texture in soils, production and consumption of nitric oxide are always simultaneous microbiological processes (Conrad, 1996)  NO-exchange is basically bi-directional  usually NO emission is observed

background remote regions (USA) urban (USA) maritime (Pacific) tropical rainforest wet season ambient mixing ratio (NO+NO 2 ) in ppb VOC as propylene (normalized by reactivity) in ppb isolines = ozone production rate in ppb/h Chameides et al., JGR, 97: , ABLE campaigns end of the 80's