Monitoring of atmospheric composition using the thermal infrared IASI/MetOp sounder

Transcription

1 Monitoring of atmospheric composition using the thermal infrared IASI/MetOp sounder Cathy Clerbaux, Solène Turquety, Juliette Hadji-Lazaro, Maya George, Anne Boynard Matthieu Pommier Service d'aéronomie / CNRS, IPSL, Université Paris 6 Paris, France Pierre-François Coheur, Daniel Hurtmans Catherine Wespes, Ariane Razavi, Hervé Herbin Spectroscopie de l Atmosphère, Chimie Quantique et Photophysique, Université Libre de Bruxelles, Belgique + 2 oral presentations + 6 posters

2 Outline What is the added value of IASI for tropospheric chemistry? Trace gas retrievals from level 1C radiance spectra - Near-real time global distributions of O 3 and CO - Profile retrievals for chemistry species : O 3, CO, SO 2 Conclusions and perspectives

3 What is the added value of IASI for tropospheric chemistry? (1/3) + IASI provides global Earth coverage twice daily, day AND NIGHT IMG/ADEOS 24h coverage IASI/MetOp 24h coverage # spectra 1.2M 1.M 8.k

4 What is the added value of IASI for tropospheric chemistry? (2/3) + Broad spectral coverage ( cm -1 without gaps) simultaneous sounding of many trace gases SA/CNRS ULB Radiance (W / cm 2 sr cm -1 ) 1.4x x1-5 1.x1-5 8.x1-6 6.x1-6 4.x1-6 2.x1-6 CO 2 HNO 3 CFC11, CFC12 O CO 3 CO 2, N 2 O Ts=275 K N 2 O, CH 4 H 16 2 O, HOD HOD H 16 2 O CH 4 H 18 2 O Wavenumber (cm -1 ) + Thermal + reflected solar radiation during daytime possible improvements on the retrieval performances for CH 4 and HDO

5 What is the added value of IASI for tropospheric chemistry? (3/3) 1.x1-5 IMG Radiance (W / cm 2 sr cm -1 ) 1.2x1-5 1.x1-5 8.x1-6 6.x1-6 4.x1-6 2.x1-6. IMG 9.5x1-6 9.x x1-6 IASI Wavenumber (cm -1 ) IASI IASI spectral resolution (.5 cm -1 apodised) is coarser than IMG or TES (~.1cm -1 ) + IASI radiometric noise performances are above expectations

6 A long story IMG/ADEOS MOPITT/TERRA ACE/SCISAT TES/AURA IASI/MetOp Retrieval algorithm Data assimilation

7 2 complementary tools Near real-time (SA-NN) Columns CO, CH 4, O 3 Research (Atmosphit) profiles of any (IR absorbing) species errors averaging kernels Neural network based techniques Constrained retrieval: Optimal Estimation theory inputs y ˆ b Parameters adjustment outputs ˆx x 6 measurement radiance (W /cm 2 sr cm -1 ) 1.x1-5 O 3 8.x1-6 6.x1-6 4.x1-6 2.x wavenumber (cm -1 ) altitude (km) a priori information O3 vmr (ppm) xˆ = Ax + (I A)xa + Gε [Hadji-Lazaro et al., 1999; Clerbaux et al., 21; Turquety et al., 22, 24] See poster [Coheur et al., 25; Barret et al., 25; Wespes et al., 27; Herbin et al., 27]

8 O 3 CH 4 CO Implemented in the Eumetsat ground segment [Turquety et al, JGR 24]

9 OZONE Complementary information provided by the NRT and offline processing total columns from SA-NN SA/CNRS ULB May 25, 27 Vertical profiles from Atmosphit 45 Validation Radiance (W / cm 2 sr cm -1 ) 8x1-6 6x1-6 4x1-6 2x1-7 observed residual best fit Tsurf = 288 K Tskin = 284 K Altitude (km) a priori retrieved [O3] =399 DU -2x x1 12 2x1 12 3x1 12 4x1 12 Wavenumber (cm -1 ) [O 3 ] (molecules cm -2 ) See poster

10 OZONE Radiance (W / cm 2 sr cm -1 ) 8.x1-6 7.x1-6 6.x1-6 5.x1-6 4.x1-6 3.x1-6 2.x1-6 1.x x1-7 Altitude (km) observed best fit IASI observed-calculated BT = 288 K ΔT = -4 K [O3]~4 DU km Retrieval characterization; comparison between IASI and IMG km km Wavenumber (cm -1 ) DOFS= km -6 km IMG observed BT = 288 K ΔT = -3 K [O3]~35 DU best fit observed-calculated km km km 6-12 km -6 km Averaging kernel DOFS=4.4 Altitude (km) Layers Total error IASI Total error IMG Total error 6 km km km km km 4 17 Retrieval error (%) A priori variability a priori variability (Mozart) similar performances IMG-IASI < 1 % error on the tropospheric column

11 TROPOSPHERIC OZONE See posters O3-SAF: GOME2+IASI

12 CARBON MONOXIDE Complementary information provided by the NRT and offline processing SA/CNRS ULB May 25, East coast of USA latitude: longitude: Altitude (km) a priori retrieved [CO] = molecules cm CO vmr (ppb) Altitude (km) Northern Pacific 5 a priori latitude: +1.6 longitude: retrieved [CO] = molecules cm CO vmr (ppb) 3 Altitude (km) Southern Pacific latitude: longitude: retrieved [CO] = molec. cm -2 a priori CO vmr (ppb) Validation High thermal contrast case DOFS= km 19 km 17 km 15 km 13 km 11 km 9 km 7 km 5 km 3 km 1 km See poster DOFS: 1 to Averaging kernel

13 2/8 24/8 25/8 CARBON MONOXIDE AVHRR UTC (

14 CARBON MONOXIDE Example of fires in Greece, August _ _82 7.x1-7 Radiance (W / cm 2 sr cm -1 ) 6.x1-7 5.x1-7 4.x1-7 3.x1-7 2.x1-7 1.x Ratio.9 Fine scale composition variations within the plume are captured.8 CO enhancement wavenumber (cm -1 )

15 CARBON MONOXIDE 8194_ _82 Example of fires in Greece, August 27 4.x _ _82 2 a priori (MOZART) Radiance (W / cm 2 sr cm -1 ) 3.x1-7 2.x1-7 Best fit Observed Best fit Observed 15 1.x1-8 Residual Residual. Altitude (km) 1 IASI spectrum [CO] = molecules cm -2-1.x Wavenumber (cm -1 ) Wavenumber (cm -1 ) 5 spectrum [CO] = molecules cm IASI conference-- CO mixing ratio November (ppb) 12-16, 27

16 SULFUR DIOXIDE SO 2 NRT detection criteria based on brightness temperature difference (ΔT) in ν 1 ΔT averaged for October 27 Bck@189.5 line@ line@117. 8x1-6 line@ line@ Bck@ Radiance (W / cm 2 sr cm -1 ) 7x1-6 6x1-6 5x1-6 4x1-6 IASI simulation no SO2 with SO2?? Jebel el-tair eruption on October 1 3x Wavenumber (cm -1 )

17 SULFUR DIOXIDE Jebel at-tair eruption, October 1, 27 OMI ~11: UTC IASI ~7:18 UTC AIRS

18 SULFUR DIOXIDE Jebel at-tair eruption, October 1, 27 Radiance (W / cm 2 sr cm -1 ) 1.2x1-5 1.x1-5 8.x1-6 6.x1-6 4.x1-6 2.x s s Ratio / ν 1 SO 2 transmittance spectrum ν Wavenumber (cm -1 )

19 SULFUR DIOXIDE Altitude (km) Tropopause IASI [SO 2 ] = 28 ± 7 7:18 UTC SO2 vmr (ppb) Altitude (km) ~SCIAMACHY 2 12:3 UTC <OMI 35 1:56 UTC Vertical sensitivity.5 km 1.5 km 2.5 km 4. km 6. km 8. km 1. km 12. km 14. km 16. km 18. km 2. km 22. km 24. km Averaging kernel

20 SULFUR DIOXIDE Correlation with other species 3 SO 2 N 2 O CH 4 O 3 CO 2 2 Altitude (km) 1 Tropopause vmr (ppm)

21 Conclusions and perspectives IASI spectra seem of very high quality level 1C received operationally since May 27 (> spectra daily) level 2 (P, T, clouds) received operationally since September 27 NRT processing O 3, CO columns and O 3 partial columns provided in NRT using the SA-Neural Network algorithm Preliminary comparisons with other space-based instruments show good agreement Some problems have been identified and need to be fixed (e.g. emissivity above desert) Current research processing O 3, CO profile with similar accuracy and vertical resolution than other sounders (to be confirmed on larger scale) CH 4 profiles using either ν 4 or ν 4 and ν 3 bands to increase sensitivity to the ground HNO 3 total columns Volcanic SO 2 Water isotopologues Others (CFCs, OCS)

22 Conclusions and perspectives Towards operational applications GMES 26 MetOp (IASI/GOME) 22 Ozone SAF EU FP7 CityZen IPY - Polarcat Volcanic threat