Dynamical perspective on the middle

atmosphere research in Sweden

2010-03-24, SRS-Meeting, Stockholm

Heiner Körnich, MISUheiner@misu.su.se

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Overview

• The middle atmosphere• Impact direction?• Research areas• Outlook• Summary

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By Mark R. Schoeberl

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Middle atmosphere

Climatesystem +

Troposphere

Dynamical influence goesBottom-up Top-down

Planetary, gravity and tidal wavesLocal instability

“Downward propagation”?4

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Downward propagation of the zonal wind at 60ºNP

ress

ure

(hP

a)

NCEP reanalysis

60

50

40

30

20

10

0

-10

-20

m/s

6

Downward propagation of the zonal wind at 60ºNP

ress

ure

(hP

a)

NCEP reanalysis

60

50

40

30

20

10

0

-10

-20

m/sdrag

7

Downward propagation of the zonal wind at 60ºNP

ress

ure

(hP

a)

NCEP reanalysis

60

50

40

30

20

10

0

-10

-20

m/s

drag

8

Downward propagation of the zonal wind at 60ºNP

ress

ure

(hP

a)

NCEP reanalysis

60

50

40

30

20

10

0

-10

-20

m/s

drag

By

Mar

k R

. S

choe

berl

Noctilucent clouds are very sensitive

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Photo by Nathan Wilhelm

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Photo by Nathan Wilhelm

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Photo by Nathan Wilhelm

• Sweden, France, Finland, Canada

• launched on February 20, 2001

• 250 kg

• sun-synchronous near-polar orbit at ~600 km altitude

• 2 instruments:

- Sub-mm / mm Radiometer (SMR)

- Optical Spectrograph and InfraRed Imaging System (OSIRIS)

NLC properties observed by Odin

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NLC radii from Odin

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Polar winter stratosphere temperature as planetary

wave activity proxy

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Polar winter stratosphere temperature as planetary

wave activity proxyVS.NLC radii from Odin

Signals are on the opposite side of globe!

After Karlsson et al. (GRL 2007)

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Interhemispheric coupling – The essential modelTemperature response (shaded) and control mean (contours)

-20 -10 -5 -2 -1 1 2 5 10 20

Kör

nich

and

Bec

ker

(AS

R 2

010)

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NLC ∝- ΔT

Interhemispheric coupling – The essential modelTemperature response (shaded) and control mean (contours)

-20 -10 -5 -2 -1 1 2 5 10 20

Kör

nich

and

Bec

ker

(AS

R 2

010)

Planetary waves in winter tropo-stratosphere.

Change in the mean flow

Feedbackbetween

mean flowand

gravity waves

Change in circulation and

NLC

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-20 -10 -5 -2 -1 1 2 5 10 20

Kör

nich

and

Bec

ker

(AS

R 2

010)

No interhemispheric coupling- because no gravity waves in the Summer hemisphere

Planetary waves in winter tropo-stratosphere.

Change in the mean flow

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Northern and southern winter stratosphere as seen by Odin

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(c) Chalmers

Height of the summer mesopauseKirkwood et al. (GRL 2008)

Polar mesosphere summer echos (PMSE) is a proxy for the mesopause height

On southern hemishpere more variable

Southern hemisphere summer mesopause 2007/2008 unusually high

Interhemispheric coupling helps to explain these observations.

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Annual cycle in H2O observed by Odin

Lossow et al. (JGR 2009)

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Annual cycle in H2O observed by Odin

Difference in transport circulation

through interhemispheric coupling

Lossow et al. (JGR 2009)

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By

Mar

k R

. S

choe

berl

Probing the stratospheric transport

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Stratospheric Age of Air

Stratospheric age: time from entry in the tropics to any point

New method: Using water isotopologues observed by Odin combined with a transport model

Sanchez et al. (to be submitted to ACP 2010)

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Descent observed by OdinUrban et al. (ACP 2009), Orsolini et al. (ACP 2009)

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Pot

entia

l tem

pera

ture

Tracer-tracer correlations by OdinKhosrawi et al. (ACP 2009)

Includes both transport and chemistryDiabatic descent in Ozone and N2OImportant benchmark for chemical climate models 28

By

Mar

k R

. S

choe

berl

Mesospheric instability

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Summer mesospheric 2 and 5-day wave

Belova et al. (AG 2008)

30Belova et al. (AG 2008)

Belova et al. (AG 2008)

Local instability

could yieldTop-downinfluence?

Summer mesospheric 2 and 5-day wave

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By Mark R. Schoeberl

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By

Mar

k R

. S

choe

berl

Measuring winds in the stratosphere

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Atmospheric Dynamics Mission

ADM - Aeolus

By Mark R. Schoeberl

PREMIER: Process Exploration through Measurements of Infrared and Millimetre-wave Emitted Radiation

Tropopause as key region - Research with PREMIER

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Summary Wag the tail:

Interhemispheric coupling

Stratospheric transport Wag the dog:

2 and 5-day waves?

Combining observational data with dynamical models yields a more complete picture of the atmospheric circulation.

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