Satellite measurements of nitric monoxide (NO) in the mesosphere and lower thermosphere

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1 Satellite measurements of nitric monoxide (NO) in the mesosphere and lower thermosphere S. Bender 1, M. Sinnhuber 1, T. von Clarmann 1, G. Stiller 1, B. Funke 2, M. López-Puertas 2, K. Pérot 3, J. Urban 3, K. Walker 4, J. P. Burrows 1 KIT / 2 IAA-CSIC / 3 Chalmers University / 4 University of Toronto / University of Bremen 1 KIT 1-6 University of the Stefan StateBender: of Baden-Wuerttemberg Satellite MLT NOand measurements KIT National Laboratory of the Helmholtz Association

2 Solar variability and climate Climate variability (natural and anthropogenic) Solar activity: solar cycle, solar storms, CMEs Geomagnetic activity: aurora, SPEs Solar activity impact on Earth s atmosphere and climate Solar particle forcing in climate models Solar particles and X-rays: NO in mesosphere and lower thermosphere (MLT, 1 km) Satellite NO measurements in MLT Envisat (ESA mission): MIPAS, SCIAMACHY Odin (ESA third party mission): SMR SCISAT-1 (ESA third party mission): ACE-FTS Stefan Bender: Satellite MLT NO measurements KIT

3 Solar influences on the atmosphere Figure: Gray et al., Stefan Bender: Satellite MLT NO measurements KIT

4 Solar influences on the atmosphere Figure: Gray et al., Stefan Bender: Satellite MLT NO measurements KIT

5 Solar influences on the atmosphere Figure: Gray et al., Stefan Bender: Satellite MLT NO measurements KIT

6 Mesospheric Thermospheric NO by-product of N 2 (strong bond) dissociation: main reactions: N + O 2, NO + hν energy source: auroral and fast secondary electrons, soft solar X-rays coupling to the atmosphere below (polar winter, SSW) Altitude [km] Oct 8 1 Nov Dec 8 NOx vmr - 9N 1 Jan Stefan Bender: Satellite MLT NO measurements KIT.1 1 Feb 9 K 3 K 1 Mar 9 K K 1 Apr ppbv CO vmr - 9N ppmv Figure: NOx descent 8/9, data courtesy of the MIPAS collaboration Altitude [km]. 1.. K 3 K K K

7 Mesospheric Thermospheric NO by-product of N 2 (strong bond) dissociation: main reactions: N + O 2, NO + hν energy source: auroral and fast secondary electrons, soft solar X-rays coupling to the atmosphere below (polar winter, SSW) Altitude [km] Oct 8??? NOx vmr - 9N??? 1 Nov Dec 8 1 Jan Stefan Bender: Satellite MLT NO measurements KIT.1 1 Feb 9 K 3 K 1 Mar 9 K K 1 Apr ppbv CO vmr - 9N ppmv Figure: NOx descent 8/9, data courtesy of the MIPAS collaboration Altitude [km]. 1.. K 3 K K K

8 Satellite NO MLT measurements Daily zonal mean data scans in the MLT region ( km to 1 km) ACE-FTS: IR, solar occultation, 1941 days 4 1 MIPAS: IR, limb sounding, upper atmosphere (UA) mode, 199 days 12 SCIAMACHY: UV, limb sounding, MLT mode, 78 days 8 12 (only daytime data) SMR: radio, limb sounding, 31 days 3 present Analysis time series at selected altitudes and latitudes multi-linear regression analysis superposed epoch analysis 1-6 Stefan Bender: Satellite MLT NO measurements KIT

9 Time series Morphological overview at 8 km latitude [deg N] latitude [deg N] ACE-FTS daily mean NO number density, 8 km SCIAMACHY. 1.daily 1. mean 2. NO number density, km latitude [deg N] latitude [deg N] MIPAS daily mean NO number density, 8 km SMR. daily 1. mean 1. NO 2. number 2. density, km Stefan Bender: Satellite MLT NO measurements KIT

10 Time series Morphological overview at 1 km latitude [deg N] latitude [deg N] ACE-FTS daily mean NO number density, 1 km SCIAMACHY. 1. daily 1. mean 2. NO number density, km latitude [deg N] latitude [deg N] MIPAS daily mean NO number density, 1 km SMR. daily 1.mean 1.NO 2. number 2.density, km Stefan Bender: Satellite MLT NO measurements KIT

11 High latitudes Northern polar region (67. N) daily mean NO number density, 67. N 1. ACE-FTS SCIAMACHY 8 km MIPAS SMR daily mean NO number density, 67. N ACE-FTS SCIAMACHY 9 km 8. MIPAS SMR daily mean NO number density, 67. N 12. ACE-FTS SCIAMACHY 1 km 1. MIPAS SMR Southern polar region (67. S) daily mean NO number density, 67. S 12. ACE-FTS SCIAMACHY 8 km 1. MIPAS SMR daily mean NO number density, 67. S 12. ACE-FTS SCIAMACHY 9 km 1. MIPAS SMR daily mean NO number density, 67. S 12. ACE-FTS SCIAMACHY 1 km 1. MIPAS SMR Stefan Bender: Satellite MLT NO measurements KIT

12 Multi-linear regression regression model annual and semi-annual harmonics linear in Lyman-α and Kp offset ϱ model NO (φ, z, t) = a(φ, z) + b(φ, z) Lyα(t) + c(φ, z) Kp(t) 2 + [d n (φ, z) cos(nωt) + e n (φ, z) sin(nωt)] n= Stefan Bender: Satellite MLT NO measurements KIT

13 Multi-linear regression fit results Northern polar region (67. N) daily mean NO number density, 67. N ACE-FTS MIPAS SCIAMACHY SMR composite fit 8 km 8 6 daily mean NO number density, 67. N ACE-FTS MIPAS SCIAMACHY SMR composite fit 1 km Residuals Residuals Stefan Bender: Satellite MLT NO measurements KIT

14 Multi-linear regression coefficients Annual cycle (cosine part) 1 ACE-FTS 1 MIPAS SCIAMACHY NO number density / cos(annual) [1 8 cm -3 ] NO number density / cos(annual) [1 8 cm -3 ] SMR NO number density / cos(annual) [1 8 cm -3 ] NO number density / cos(annual) [1 8 cm -3 ] Stefan Bender: Satellite MLT NO measurements KIT

15 Multi-linear regression coefficients Lyman-α 1 ACE-FTS 1 MIPAS SCIAMACHY NO number density / Lyman- [1 7 cm -3 /(1 11 ph cm -2 s -1 )] NO number density / Lyman- [1 7 cm -3 /(1 11 ph cm -2 s -1 )] SMR NO number density / Lyman- [1 7 cm -3 /(1 11 ph cm -2 s -1 )] NO number density / Lyman- [1 7 cm -3 /(1 11 ph cm -2 s -1 )] Stefan Bender: Satellite MLT NO measurements KIT

16 Multi-linear regression coefficients Kp 1 ACE-FTS 1 MIPAS SCIAMACHY NO number density / Kp [1 7 cm -3 ] NO number density / Kp [1 7 cm -3 ] SMR NO number density / Kp [1 7 cm -3 ] NO number density / Kp [1 7 cm -3 ] Stefan Bender: Satellite MLT NO measurements KIT

17 Kp vertical profile Polar region regression coefficients solar (particle) influence NO number density / Kp simple model for NO in MLT 1-D chemistry model ionisation rates SCIAMACHY 6 N nominal MLT NO density / Kp [1 7 cm -3 ] Stefan Bender: Satellite MLT NO measurements KIT

18 Kp vertical profile Polar region regression coefficients solar (particle) influence NO number density / Kp simple model for NO in MLT 1-D chemistry model ionisation rates preliminary Figure: 2 3,. < Kp < Stefan Bender: Satellite MLT NO measurements KIT

19 Conclusions MLT NO important proxy for solar activity best suited: UV and IR limb sounders (daily global coverage possible) consistent MLT NO measurements: ACE-FTS, MIPAS, SCIAMACHY, SMR MIPAS and SCIAMACHY lost in April 12 Other instruments OSIRIS: only from 8 km to km SABER: only above km SOFIE: solar occultation (limited global coverage) Outlook refine statistical analysis methods reliable solar forcing parameters for (chemistry) climate models future missions? Stefan Bender: Satellite MLT NO measurements KIT