BAe-146

GV

Global Hawk

CAST flight planning and analysis using NAME- Jan-Feb 2013

Neil Harris, Michal Filus, Matt Ashfold, Alistair Manning and John PyleBoulder, Oct 2013

Thanks to WAS team

Goals

1. Designing science flights whose measurements can be jointly used to study the transport of trace gases in convection (inflow and outflow).

2. Use ATTREX 2013 as a trial run.

3. Analyse tracer measurements from ATTREX 2013, esp. WAS.

Joint flight plans - Jan-Feb 2014

Target area Source coordinates

Source altitude

/km

Source dimensions / deg.deg.km

Density / particles/layer

NAME runs /day

Met Office forecast

days

1. EAST PACIFIC GH

10oS-30oN 130-170 oW

14-16 16-18 40 x 40 x 2 (2) 80,000 12 back 1, 2, 3, 4, 5

2. SOUTH PACIFIC '146'

20oS-10oN 160oE-170oW 0-5 30 x 30 x 5 225,000 2-5

forward 0, 1, 2, 3

3. WEST PACIFIC '146'

5oS-25oN 130-160oE 0-5 30 x 30 x 5 225,000 2-5

forward 0, 1, 2, 3

Linking GH and ‘146’

•Data representation: – Distribution studies: fractions crossed 5km– Air history maps– *Altitude vs time plots: qualitative assessment of air mass convection– *Meteorological maps showing weather conditions –

Density of particles below 5 km.12 day back trajectories run using forecast and analysis data. Back-traj started in solid boxes

Linking GH and 146

15%51%

10%12%

Met Office forecasts and analyses

NAME traj dispersion

12 days back

Start at 14-16 km in East Pacific

Run daily

25/1/13

27/1/13

29/1/13

31/1/13

2/2/13

4/2/13

6/2/13

8/2/13

10/2/13

12/2/13

14/2/13

16/2/13

18/2/13

20/2/13

22/2/13

24/2/13

26/2/13

28/2/13

2/3/13

4/3/13

6/3/13

8/3/13

10/3/13

12/3/13

14/3/13

16/3/13

18/3/13

20/3/13

22/3/13

24/3/13

26/3/13

28/3/13

30/3/13

1/4/13

0.0

10.0

20.0

30.0

40.0

50.0

60.0

day1 15

NAME traj date

Mas

s fr

actio

n be

low

5 k

m /

%

Fraction of air at 14-16 km coming from BL

25 Jan – 29 Mar 2013

Variation over time

Consistency between forecasts

Linking GH and 146

GH East Pacific NAME runs: altitude changes25

60

SW box above 16 km

SW box 14-16 km

WAS CHBr3 - 2013

-175 -170 -165 -160 -155 -150 -145 -1400

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1CHBr3

16 > z > 14 km

-175 -170 -165 -160 -155 -150 -145 -1400

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1CHBr3

Z > 16 km

Mean of easterly values

Mean of easterly values

WAS CHBr3 - 2013

-175 -170 -165 -160 -155 -150 -145 -1400

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1CHBr3

16 > z > 14 km

-175 -170 -165 -160 -155 -150 -145 -1400

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1CHBr3

Z > 16 km

LZRH mean (WMO, 2011)Upper TTL mean (WMO, 2011)

Upper TTL mean (WMO, 2011)Tropical tropop (WMO, 2011)

Mean of easterly values

Mean of easterly values

Excess caused by recent convection?

Simple model:• Two sources of air: TTL and inflow region

Depends on• Time since boundary layer• Fraction from in boundary layer

• Can make more complicated assumptions about trajectories which did not enter low troposphere (in-mixing)

[T]MBL = ~2 ppt for CHBr3

= 0.2 ppt for CHBr3[T]TTL

100%0%Fraction of air from MBL

[T]MBL

[T]TTL

Ongoing analysis of WAS CHBr3 - 2013

• Tracer analysis: Density distribution over the boxes• Calculate concentrations of tracers based on WMO climatology and fixed half-life• Compare modelled results with ATTREX measurements• What resolution is feasible?

Back trajectories fromFeb 26 2013 which cross 5 km (left) &

1 km (right)

Ongoing analysis of WAS CHBr3 - 2013

Met Office forecasts and analyses

NAME traj dispersion

12 days back

Start at 14-16 km in East Pacific

Run daily

25/1/13

27/1/13

29/1/13

31/1/13

2/2/13

4/2/13

6/2/13

8/2/13

10/2/13

12/2/13

14/2/13

16/2/13

18/2/13

20/2/13

22/2/13

24/2/13

26/2/13

28/2/13

2/3/13

4/3/13

6/3/13

8/3/13

10/3/13

12/3/13

14/3/13

16/3/13

18/3/13

20/3/13

22/3/13

24/3/13

26/3/13

28/3/13

30/3/13

1/4/13

0.0

10.0

20.0

30.0

40.0

50.0

60.0

day1 15

NAME traj date

Mas

s fr

actio

n be

low

5 k

m /

%

Fraction of air at 14-16 km coming from BL

25 Jan – 29 Mar 2013

Variation over time

Consistency between forecasts

Variability – select dates, areas

Forward calculations from West Pacific below 5 km

Met Office forecasts

NAME traj dispersion

+5 days ahead

Start in region of 146

Run daily

Anticyclone clear

Much in range of GV

Based on Ashfold et al., 2012

> 13 km

> 10 km

Met Office forecasts

NAME traj dispersion

+5 days ahead

Start in region of 146

Run daily

Variation over time

Fraction of air in BL reaching 10 km

1 Jan – 31 Mar 2013

0

0.3

Forward calculations from West Pacific below 5 km

Forward calculations from West Pacific below 5 km

Consider 4 regions

Forward calculations from West Pacific below 5 km

Variability in allWithin 5 days of forecasts, most which have got up there are still within 20°

Forward calculations from West Pacific below 5 km

16 km

13 km

10 km

0.02

0.14

0.30

Less transport to higher altitudesMore geographic spread if it gets there

Implication for flight planning: also need 12 day back-trajectories

Thank you

Thank youSurface and sonde measurements

Certainly use trajectories – others?