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?