Direct effects of particle precipitation and ion chemistry
in the middle atmosphere
P. T. Verronen
Finnish Meteorological Institute, Earth Observation
Helsinki, Finland
Contents of presentation
1. Middle atmospheric effects of energetic particle precipitation (EPP)
2. Sodankylä Ion and Neutral Chemistry Model (SIC)
– Analysis of the ion chemistry scheme
– Parameterization of EPP-related changes in HOx and NOy
3. SIC model versus MLS/Aura observations:
– SPEs of January 2005 and December 2006
– Production of HNO3 and OH
4. Summary
ISSI Georgieva, Bern, 24–28 March 2014
2
Energetic particle precipitation
Earth’s magnetic field directs charged particles into polar regions
EPP affects both ionosphere and middle atmosphere
ISSI Georgieva, Bern, 24–28 March 2014
3
Different types of particle precipitation
From a presentation by Randall et al., 2008
ISSI Georgieva, Bern, 24–28 March 2014
4
SPE: example of geomagnetic cutoff
Rodger et al., Journal of Geophysical Research (2006)
ISSI Georgieva, Bern, 24–28 March 2014
5
Effects of energetic particle precipitation (EPP)
energetic particles precipitate into atmosphere
2
N( D)
N2 +
O2 +
O+
O 4+
O2+(H2O)
HO3+(H2O)n
NOx
HOx
Ozone
loss
Ozone connects to temperature and dynamics
ISSI Georgieva, Bern, 24–28 March 2014
6
Sodankylä Ion and Neutral Chemistry (SIC)
ISSI Georgieva, Bern, 24–28 March 2014
7
SIC: D-region ion chemistry
36 positive ions, 29 negative ions, 400 reactions
ISSI Georgieva, Bern, 24–28 March 2014
8
Changes in hydrogen and nitrogen species
Particles precipitate into middle atmosphere
↓↓↓↓↓
– Positive ion chemistry dissociates N2 and H2O
– Negative ion chemistry redistributes NOy (inside the blue box)
– From Verronen and Lehmann, Ann. Geophys., 2013.
ISSI Georgieva, Bern, 24–28 March 2014
9
SIC: example of HOx production paths
−
N2 + p (E)
+
→
N2 + e + p (E − ∆E)
N 2 + O2
+
→
O2 + N2
O2 + O2 + M
→
O4 + M
→
O2 (H2O) + O2
→
H3O (OH)H2O + O2
→
H (H2O)3 + OH
H (H2O)3 + H2O + M
→
H (H2O)4 + M
−
→
H + 4H2O
+
+
O4 + H2O
+
+
+
+
+
...
+
O2 (H2O)2 + H2O
+
H3O (OH)H2O + H2O
+
+
H (H2O)4 + e
−−−
Net : H2O
ISSI Georgieva, Bern, 24–28 March 2014
+
+
+
−−−
→
OH + H
10
SIC: example of HNO3 production paths
+
−
+
+
N2 + p (E)
→
N2 + e + p (E − ∆E)
−
→
O2 + O2
O2 + O3
→
O3 + O2
−
→
CO3 + O2
CO3 + NO2
−
→
NO3 + CO2
NO3 + H2O + M
→
NO3 (H2O) + M
→
NO3 (HNO3) + H2O
→
HNO3 + HNO3 + 4H2O
O2 + O2 + e
−
O3 + CO2
−
−
NO3 (H2O) + HNO3
−
+
NO3 (HNO3) + H (H2O)4
−−−
Net : H2O + O3 + NO2
ISSI Georgieva, Bern, 24–28 March 2014
−
−
−
−
−
−
−−−
→
OH + HNO3 + O2
11
P/Q: relative production/loss rates from SIC
P/Q = (ionic production - ionic loss) / ionization rate
– H2O becomes the limiting factor at upper altitudes
– At night: more negative ions, more HNO3 production
ISSI Georgieva, Bern, 24–28 March 2014
12
P/Q: relative production/loss rates from SIC
P/Q = (ionic production - ionic loss) / ionization rate
– Note: Zero net change of NOy (incl. HNO3) by negative ion chemistry
– Net production of NOx is by positive ion chemistry
ISSI Georgieva, Bern, 24–28 March 2014
13
Outstanding issue: nitric acid in CCMs
– From Jackman et al., Atmos. Chem. Phys., 2008
ISSI Georgieva, Bern, 24–28 March 2014
14
MLS/Aura observations
–
–
–
–
Microwave Limb Sounder, measures emissions at mm and sub-mm wavelengths
Launched in July 2004 into a near-polar orbit, observations cover latitudes between
82◦S – 82◦N, day and night
Can be used to monitor temperature and more than 15 trace gases,
including O3, OH, and HNO3
First satellite instrument providing continuous observations of
mesospheric OH and HO2
ISSI Georgieva, Bern, 24–28 March 2014
15
Nitric acid: comparisons
Modeling: Sodankylä Ion and Neutral Chemistry
–
–
–
Uses MLS temperatures, neutral density, and water vapor.
80◦N/December–January, no diurnal variations.
Results reduced to MLS altitude resolution using averaging kernels.
Observations: data version 3.30, SZA > 100◦ (night-time)
–
–
–
–
Data are daily means, uncertainty is standard error of the mean.
Useful range up to 1.5 hPa (≈50 km) in normal conditions, but can be extended into
mesosphere when high amounts are observed.
Mesospheric HNO3 data have not been validated.
Comparison is made with the highest amount of HNO3 observed after the peak of
SPE forcing, assuming that it is least affected by dynamics.
ISSI Georgieva, Bern, 24–28 March 2014
16
SIC vs. MLS: nitric acid, December 2006 SPE
Before (left), during (middle), and after (right) the SPE forcing
06−Dec−2006
09−Dec−2006
85
85
85
80
80
75
75
75
70
70
70
SIC
MLS
80
Altitude (km)
11−Dec−2006
−− 0.005
−− 0.010
−− 0.022
−− 0.046
65
65
65
60
60
60
55
55
55
50
50
50
45
45
45
40
−2
0
2
Mixing ratio (ppbv)
4
40
−2
0
2
Mixing ratio (ppbv)
4
40
−2
−− 0.100
−− 0.147
−− 0.215
−− 0.316
−− 0.464
−− 0.681
−− 1.000
hPa
0
2
Mixing ratio (ppbv)
4
– The model overestimates the HNO3 increase on Dec 9 at 60–65 km.
– Below 50 km the agreement is OK.
– For more details, see Verronen et al., J. Geophys. Res., 2011.
ISSI Georgieva, Bern, 24–28 March 2014
17
MLS: HNO3 (top) and CO (bottom)
Daily avarages at approx. 60 km (2500 K)
ISSI Georgieva, Bern, 24–28 March 2014
18
Odd hydrogen: comparisons
Modeling: Sodankylä Ion and Neutral Chemistry
–
–
Uses MLS temperatures, neutral density, and water vapor.
Latitudes >60◦N, solar proton events of January 2005 and December 2006.
OH observations: data version 3.30
–
–
–
Useful range up to 0.0032 hPa (≈90 km).
Mesospheric data have been validated by Pickett et al., JGR, 2008.
Data are averaged at 65–75◦N, for day and night separately.
MLS was the first instrument that provided continuous and
global observations of mesospheric HOx.
ISSI Georgieva, Bern, 24–28 March 2014
19
SIC vs. MLS: hydroxyl, January 2005
OH at 66 km
6
OH (1/cm3)
8
x 10
MLS
SIC with SPE
SIC without SPE
6
4
2
0
−2
15
16
17
18
OH (1/cm3)
20
21
22
23
24
Difference: SIC − MLS
6
3
19
x 10
Night
Daytime
2
1
0
−1
−2
15
16
17
ISSI Georgieva, Bern, 24–28 March 2014
18
19
20
Day in 2005/01
21
22
23
24
20
SIC vs. MLS: OH
Case I : January 18, 12:10 LT
Case I : January 18, 21:20 LT
90
90
MLS/Aura
SIC model
GOMOS/Envisat
SIC model
80
80
O3
OH
70
Altitude (km)
Altitude (km)
70
60
60
50
50
40
40
30
0
1
Latitudes 69N − 70N
Latitudes 71N − 72N
Longitudes 49W − 27E
Longitudes 35W − 41E
2
3
4
5
−3
OH concentration (cm )
30
6
6
x 10
−90
−60
−30
0
30
60
Relative change of ozone (%)
90
– From Verronen et al., Geophys. Res. Lett., 2006
ISSI Georgieva, Bern, 24–28 March 2014
21
Ion chemistry and its effects in models
• Although there are uncertainties, the understanding of ion chemistry seems
reasonably good for particle effect modelling.
• Our full knowledge is not used when parameterizing ion chemistry in 3-D
atmospheric models, typically:
– HOx and NOx production is included,
– HNO3 and HNO2 production is not included,
– Chlorine activation is not included
(Winkler et al., Geophys. Res. Lett., 2009).
• Two ways to include ion chemistry:
– Parameterization. Simple and good in all situations?
– Full ion chemistry. Computationally too expensive?
ISSI Georgieva, Bern, 24–28 March 2014
22