Trend Analysis of Ground-Level Ozone Exposure and Ozone Uptake of Oaks in Eastern Austria for the Period

Transcription

1 Umwelttoxikologie Pflanzliche Bioindikation Trend Analysis of Ground-Level Ozone Exposure and Ozone Uptake of Oaks in Eastern Austria for the Period Gerhard SOJA AIT Austrian Institute of Technology GmbH, Health and Environment Department, Tulln, Austria Elisabeth Scheicher Provincial Government for Lower Austria, Dept. Environmental Technics, St. Pölten, Austria Stephan Pietsch University for Natural Resources and Life Sciences Vienna, Institute for Silviculture. Contact: 1

2 Umwelttoxikologie Pflanzliche Bioindikation Introduction Methodology Results I: Climate parameters Results II: Ozone parameters Ozone monitoring in Austria AOT40-values May July, mean of study area Source: 2

3 Introduction Methodology Results I: Climate parameters Umwelttoxikologie Pflanzliche Bioindikation Austria: distribution of oaks forests Results II: Ozone parameters 3

4 Umwelttoxikologie Pflanzliche Bioindikation Introduction Methodology Results I: Climate parameters Results II: Ozone parameters Formulation of hypotheses as raison d être for this study Fixed study period ( ) and fixed location (North-East Austria) Hypothesis 1: Rising ozone concentrations over the years cause increasing ozone exposure doses Hypothesis 2: Ozone uptake increases less than ozone exposure (because of climate-change-associated changes in meteorological parameters which affect stomatal conductance) 4

5 Umwelttoxikologie Pflanzliche Bioindikation Introduction Methodology Results I: Climate parameters Results II: Ozone parameters Methodology 1. Combine ozone concentrations with the corresponding meteorological parameters in one file per year (1-hour or 30- minutes values) 2. Check the data for plausibility and completeness 3. Calculate the accumulated ozone exposure and ozone uptake doses for each year during the observation period ( ) g sto = g max * f phen * f light *max {f min, (f temp * f VPD * f SWP } No local parameterisation but functions derived from literature data for temperate oak species 4. Perform trend analysis tests for meteorological and ozone impact parameters to check for significant time trends 5

6 Derivation of results: Trend analyses for each month for 7 months per year Statistical tests: Linear regression Neumann Cox and Stuart 2 sites (Wolkersdorf, d f Mistelbach) 3 irradiation intensities (sun, shade and intermediate leaves) Ozone indices: Seven hour-mean (9-16 h) Proportion of values above 80 ppb Exposure dose AOT40 CUO 1,6 (cumulative uptake dose for ozone with threshold 1,6 nmol.m -2.s -1 ) Meteorological parameters: Temperature, VPD, precipitation, p global radiation, wind speed 6

7 Minor increase in precipitation p Annual precipitation sum Vienna y = ,349*year p = 0,08 mm m Whole year linear regression 95% Conf.Int. Mittel = 680 mm Mittel = 607 mm

8 Minor increase in precipitation p contd Summer precipitation sum (04-09) Vienna y = ,345*year p = 0, Summer half year mm linear regression 95% Conf.Int. Mittel = 403 mm Mittel = 352 mm

9 Minor increase in precipitation p contd. II 400 Summer precipitation sum (06-08) Vienna summer months mm linear regression 95% Conf.Int. Mean = 220 mm Mean = 196 mm y = ,753*year p = 0,

10 Marginal increase in air humidity Vapour pressure deficit (VPD) (Apr.01 - Oct.31) (Wolkersdorf) y = 11,376-0,00540*year p = 010 0,10 kpa) VPD (in VPD ( ) linear regression VPD 95 % confidence interval mean = 0,570kPa Year 10

11 Umwelttoxikologie Pflanzliche Bioindikation Introduction Methodology Results I: Climate parameters Results II: Ozone parameters Sunnier conditions Global radiation (Apr.01 - Oct. 31) (Mistelbach) 150 y = ,511*year 140 p = 0, lobal radia ation relative g global radiation ( ) 80 linear regression global radiation 95 % confidence interval 100 % = 198 W/m² Year 11

12 Marginally windier conditions Wind speed (Apr.01 - Oct.31) (Mistelbach) y = -41,05+0,0223*year p = 0,10 relat tive wind speed wind speed ( ) linear regression wind speed 95 % confidence interval 100 % = 3,51 m/s Year 12

13 Slightly warmer conditions Temperature mean (Apr.01 - Oct. 31) (Mistelbach) y = -72,2+0,0438*year p = 0,06 16 ( C) tem mperature temperature mean ( ) linear regression temperature 95 % confidence interval 100 % = 15,3 C Year 13

14 No change in proportion of ozone concentrations ti >80 ppb Ozone concentrations >80 ppb (Apr.01 - Oct. 31) (Mistelbach) ozone >80 ppb hours with t (%) ortion of h ng daylight Propo durin proportion >80 ppb ( ) linear regression proportion >80 95 % confidence interval Mean = 0,69 % p = 0, Year 14

15 Average ozone concentrations marginally increased ozone 7-h-mean (9 a.m. - 4 p.m.) (Apr.01 - Oct.31) (Mistelbach) relative ozone 7-h- --mean (p pb) 120 y = -766,6+0,433*year p = 0, ozone 7-h-mean ( ) linear regression ozone 7 h-mean 95 % confidence interval 100 % = 42,9 ppb Year 15

16 Average ozone exposure (AOT40) did not increase ozone AOT40 (Apr.01 - Oct.31) (Mistelbach) y = ,846*year p = 0,37 relativ ve ozone AOT ozone AOT40 ( ) linear regression ozone uptake 95 % confidence interval 100 % = ppb.h Year 16

17 Ozone uptake (CUO 1,6 / POD 1,6 ) increased relative ozone upta ake (in %) 130 ) ozone uptake (Mistelbach) sun leaves of oak y = ,535*year p = 0, ozone uptake ( ) linear regression ozone uptake % confidence interval 100 % = 15,1 mmol/m² Year 17

18 Monitoring of forest damages in Austria: reduction in national monitoring after 2002 Oak average of tree species Oak was more damaged than other tree species Source:

19 ICP-Forest monitoring data show more severe defoliation in oak species (except Holm oak) than in other tree species Source:

20 Umwelttoxikologie Pflanzliche Bioindikation Conclusions Ozone cumulative ozone uptake increased Caused mainly by meteorological conditions favouring ozone uptake but only to a minor degree by increasing ozone concentrations Hypothesis 1 confirmed (ozone is slightly increasing) Hypothesis 2 rejected (ozone uptake does not increase less than ozone exposure) Ozone continues to be a contributing stress factor to oaks in Eastern Austria 20

21 Umwelttoxikologie Pflanzliche Bioindikation Acknowledgements Verband der Land- und Forstwirte for financing the basic study Lisa Emberson (SEI York) for help in the parameterisation of the uptake model 21