Substructure of a MAP-Streamer

Mark A. Liniger (MeteoSwiss)

Huw C. Davies (IACETH)

QJRMS, 129, 633-651

(MAP special issue)

12 UTC 6 Nov 1999 (MAP IOP-15)

Evolution of PV @ 320 K

18 UTC 5 Nov. 12 UTC 6 Nov. 06 UTC 7 Nov.

Aim

• Are measured meso-scale features detectable in GCM analyzed fields?

• How far are observed structures linked to synoptic scale transport processes?

data sources:• ECMWF analysis fields (T319L60)• Meteosat water vapour (WV)• WV DIAL (DIfferential Absorption Lidar) flown on the

Falcon aircraft of DLR (Deutsches Zentrum für Luft- und Raumfahrt)

Lagrangian Forward Projection

t =

t =

• bases on RDF technique (Sutton et al. 1994)

• 3D – Trajectories backwardsfrom a prespecified domain

• Projection of a geographical marker or conserved (or non-conserved) tracer from an earlier position to the prespecified domain.

horizontal WV reconstruction

Meteosat WV vertically integrated WV of analysis

vertically integrated WV of LFP for 24 hours

white = dry

Interpretation

LFP for 24 hours to the 450 hPa surface

increase in pressure increase in pot. temperature

WV DIAL & analysis

Longitude

water vapour observed by DIAL (DLR)

Hei

ght (

km)

10

6

8

Hei

ght (

km)

0 E 4 E 8 E

0.01 0.02 0.04 0.08 0.12 g/kg

8

6

10

water vapour from ECMWF analysis, interpolated to observation time.

dry humid

WV DIAL & LFP

10

6

8

0 E 4 E 8 E

8

6

10

Longitude

water vapour observed by DIAL (DLR)

Hei

ght (

km)

H

eigh

t (km

)

0.01 0.02 0.04 0.08 0.12 g/kg

water vapour,LFP for 15h, based on ECMWF analyses

dry humid

WV DIAL & long LFP

10

6

8

8

6

10

0 E 4 E 8 E

water vapour,LFP for 39h, based on ECMWF analyses

Longitude

water vapour observed by DIAL (DLR)

Hei

ght (

km)

H

eigh

t (km

)

0.01 0.02 0.04 0.08 0.12 g/kg

dry humid

10

6

8

0 E 4 E 8 E

8

6

10

Longitude

backscatter ratio (aerosols) observed by DIAL (DLR)H

eigh

t (km

)

H

eigh

t (km

)

0.01 0.02 0.04 0.08 0.12 g/kg

water vapour,LFP for 39h, based on ECMWF analyses

backscatter ratio & long LFP

(from Hoinka et al., 2003)

dry humid

Striation: Interpretation

Streamers breakup, 18 hours composite

contours: LFP for 24 hours to the 310 K surface

increase in pressure increase in pot. temperature

composite 12 UTC 06 to 06 UTC 07

PV @ 310 K

Conclusions

Pronounced dry intrusion of stratospheric origin Spiral structure: arms of distinct origins Striation across western flank: sandwiched boundary layer

air mixing by diffusion Breakup over Alps:

persistent diabatic processes north of Alpsand corresponding upper level negative PV anomaly

Large scale advection explains significant portion of mesoscale structures

LFP relates Lagrangian evolution to Eulerian fields

21. May 2003

21. May 2003

21. May 2003

21. May 2003