1. Liang and Yung, Isotopic Constraints on the Global Budget and Trend of Atmospheric Nitrous Oxide Isotopic Constraints on the Global Budget and Trend of Atmospheric Nitrous Oxide Mao-Chang Liang Research Center for Environmental Changes, Academia Sinica Y. L. Yung Divisions of Geological and Planetary Sciences, California Institute of Technology European Geosciences Union General Assembly 2009, Vienna, Austria, 19 – 24 April 2009 EGU 2009

2. Liang and Yung, Isotopic Constraints on the Global Budget and Trend of Atmospheric Nitrous OxideEGU 2009

3. Liang and Yung, Isotopic Constraints on the Global Budget and Trend of Atmospheric Nitrous OxideEGU 2009

4. Courtesy of SJ Kao Liang and Yung, Isotopic Constraints on the Global Budget and Trend of Atmospheric Nitrous OxideEGU 2009

5. ISI 200Liang and Yung, Isotopic Constraints on the Global Budget and Trend of Atmospheric Nitrous OxideEGU 2009

6. 14 N 14 N 16 O (446) _ 14 N 15 N 16 O (456) -- N  15 N 14 N 16 O (546) -- N  14 N 14 N 18 O (448) -- 18 O (δ 15 N = ½ [δN  + δN  ]) # Source: natural -- land -- ocean anthropogenic -- agriculture, fossil fuels & industry, biomass burning,… # Sink : (stratosphere) -- photolysis and chemistry (~160-220 nm) N 2 O continues to increase in the atmosphere. However, contribution of each source is not well-quantified. Liang and Yung, Isotopic Constraints on the Global Budget and Trend of Atmospheric Nitrous Oxide EGU 2009

7. Kim and Craig 1993 Liang and Yung, Isotopic Constraints on the Global Budget and Trend of Atmospheric Nitrous OxideEGU 2009

8. Liang and Yung 2007 Liang and Yung, Isotopic Constraints on the Global Budget and Trend of Atmospheric Nitrous OxideEGU 2009

9. Liang and Yung, Isotopic Constraints on the Global Budget and Trend of Atmospheric Nitrous Oxide

10. (1) Ocean source = prescribed isotopic composition. (2) The isotopic composition of anthropogenic source = land source (3) Solve the mean isotopic composition of land for PRE. (4) Magnitude of the natural and anthropogenic sources are deduced. (5) The strength of STE does not vary. (6) The lifetimes do not vary with time. Troposphere F_oceanF_landF_anthro. F_sink Liang and Yung, Isotopic Constraints on the Global Budget and Trend of Atmospheric Nitrous Oxide Available measurements: 1. N 2 O trend 2.  18 O 3.  15 N (  and  ) EGU 2009

11. (1) Ocean source = prescribed isotopic composition. (2) The isotopic composition of anthropogenic source = land source (3) Solve the mean isotopic composition of land for PRE. (4) Magnitude of the natural and anthropogenic sources are deduced. (5) The strength of STE does not vary. (6) The lifetimes do not vary with time. Troposphere F_oceanF_landF_anthro. F_sink Liang and Yung, Isotopic Constraints on the Global Budget and Trend of Atmospheric Nitrous Oxide Available measurements: 1. N 2 O trend 2.  18 O 3.  15 N (  and  ) EGU 2009

12. x: Machida et al. [1995] +: Bernard et al. [2006] Liang and Yung, Isotopic Constraints on the Global Budget and Trend of Atmospheric Nitrous OxideEGU 2009

13. x: R o ckmann and Levin [2005] x: Park et al. [2009] Time evolution of δ 18 O(N 2 O) and δ 15 N (N 2 O) Liang and Yung, Isotopic Constraints on the Global Budget and Trend of Atmospheric Nitrous OxideEGU 2009

14. Sources and sinks OC -- ocean LD -- land AN -- anthropogenic Total = OC+LD+AN SK -- sink TD -- trend Liang and Yung, Isotopic Constraints on the Global Budget and Trend of Atmospheric Nitrous OxideEGU 2009

15. 150 GtC (Broecker 2007)

16. Models Liang and Yung, Isotopic Constraints on the Global Budget and Trend of Atmospheric Nitrous OxideEGU 2009

17. Use the Caltech/JPL 2-D and MOZART/CAM- CHEM 3-D models for better estimates.  Better measurements are needed as present data have large errors. Liang and Yung, Isotopic Constraints on the Global Budget and Trend of Atmospheric Nitrous OxideEGU 2009