![Page 1: Dust: Data and Sources Dr Richard Washington University of Oxford Dr Martin Todd University College London Prof Andrew Goudie University of Oxford Dr Mike](https://reader033.vdocument.in/reader033/viewer/2022061618/56649cfa5503460f949cba57/html5/thumbnails/1.jpg)
Dust: Data and Sources
Dr Richard Washington University of Oxford
Dr Martin ToddUniversity College London
Prof Andrew GoudieUniversity of Oxford
Dr Mike BithellUniversity of Cambridge
![Page 2: Dust: Data and Sources Dr Richard Washington University of Oxford Dr Martin Todd University College London Prof Andrew Goudie University of Oxford Dr Mike](https://reader033.vdocument.in/reader033/viewer/2022061618/56649cfa5503460f949cba57/html5/thumbnails/2.jpg)
Outline• Dust Data
– Surface based synops (from GCOS, 117 stations, 3hrly 1980-2000)– Surface based synops (from local Met Agencies)– TOMS AI data– IDDI– Shuttle Photographs, NOAA images etc
• Climate Data and Trajectory modelling– Reanalysis Data (NCEP and ERA-15) 3D winds– 25 point forward trajectory clusters– every 6 hours for 10days, 1979-1998– Determine regional transport corridors– Re-circulation – Interannual variability
![Page 3: Dust: Data and Sources Dr Richard Washington University of Oxford Dr Martin Todd University College London Prof Andrew Goudie University of Oxford Dr Mike](https://reader033.vdocument.in/reader033/viewer/2022061618/56649cfa5503460f949cba57/html5/thumbnails/3.jpg)
Zouerat
Atar
N ouakchott
D akar
K iff a
O uarzazate
BecharE l O ued
SirteE l G olea
I n SalahAdrar SebhaO bari
Tam anrasset
D j ibouti
KhargaD akhla
Kufrah Asw an
Agadez
N ’djam ena
Abeche
Faya-LargeauB ilm a
El FasherEl O beid
Khartoum
Potiskum M aiduguri
Sokoto
Tom buktuG ao
N guigm i
M aine-SoroaZinder
N iam eyO uagadougou
Bobo-D iou lasso
R iyadh
Kuw ait
D eir Zzor
Abu Kam al
Palm yra
AqabaElat
G hor El Safi
M a’anSafaw i
H am adan
Nr Missing Months 1980-2000
![Page 4: Dust: Data and Sources Dr Richard Washington University of Oxford Dr Martin Todd University College London Prof Andrew Goudie University of Oxford Dr Mike](https://reader033.vdocument.in/reader033/viewer/2022061618/56649cfa5503460f949cba57/html5/thumbnails/4.jpg)
Kuw ait
D ohaD ahran Bahrain
H am adan
Kandahar
Kunduz
J ask
Q uetta
J iw an iB ikaner
D al BandinG anganagar
J odhpur
Ashabad
N ukusLeninskC im baj
Karakalpakia
J aslykKzyl-O rda
I rgiz TaupAralsk
Zam iin U de
Choibalsan
M inq in
U rum qiTurpan
Lanzhou
D ongsheng
Nr Missing Months 1980-2000
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M ex ico C ity
Torreon Airport (M X)
D odge C ity (KS)
Lubbock (TX)
M idland (TX)
Nr Missing Months 1980-2000
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OodnadattaMarla
OnslowLearmonth
Alice Springs
Birdsville
Mildura
Nr Missing Months 1980-2000
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Nouakchott duststorm activity 1980-86.
0
5
10
15
20
25
30
Day
s/m
on
th
GCOS Data Compared with locally Obtained Data
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Annual cycle of visibility 1980-2000 for station 606300 (In Salah, Algeria)
8000
9000
10000
11000
12000
13000
14000
15000
J F M A M J J A S O N D
Vis
ibil
ity
(m)
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Annual cycle of visibility 1980-2000 for station 610240 (Agadez South, Niger)
8000
9000
10000
11000
12000
13000
14000
J F M A M J J A S O N D
Vis
ibil
ity
(m)
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Annual cycle of visibility 1980-2000 for station 612020 ((Tessalit, Mali)
6000
8000
10000
12000
14000
16000
18000
20000
22000
J F M A M J J A S O N D
Vis
ibil
ity
(m)
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Annual cycle of visibility 1980-2000 for station 655010 (Dori, Burkina Faso)
8000
10000
12000
14000
16000
18000
20000
J F M A M J J A S O N D
Vis
ibil
ity
(m)
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In Salah visibility 80-00
Monthly mean visibility for station 606300 (In Salah, Algeria)
5000
7000
9000
11000
13000
15000
17000
19000
1980
1982
1984
1986
1988
1990
1992
1994
1996
1998
2000
Vis
ibilit
y (
m)
12 per.Mov. Avg.
![Page 13: Dust: Data and Sources Dr Richard Washington University of Oxford Dr Martin Todd University College London Prof Andrew Goudie University of Oxford Dr Mike](https://reader033.vdocument.in/reader033/viewer/2022061618/56649cfa5503460f949cba57/html5/thumbnails/13.jpg)
Outline• Dust Data
– Surface based synops (from GCOS, 117 stations)– Surface based synops (from local Met Agencies)
Niger, Chad, Algeria, Mali, Mari– TOMS AI data– IDDI– Shuttle Photographs, NOAA images etc
• Climate Data and Trajectory modelling– Reanalysis Data (NCEP and ERA-15) 3D winds– 25 point forward trajectory clusters– every 6 hours for 10days, 1979-1998– Determine regional transport corridors– Re-circulation
![Page 14: Dust: Data and Sources Dr Richard Washington University of Oxford Dr Martin Todd University College London Prof Andrew Goudie University of Oxford Dr Mike](https://reader033.vdocument.in/reader033/viewer/2022061618/56649cfa5503460f949cba57/html5/thumbnails/14.jpg)
Niger visibility 70-00
Days of bad visibility/year for four stations in Niger 1970-2000.
0
20
40
60
80
100
120
140
160
180
Year
Day
s of
bad
vis
ibili
ty/y
r.
Zinder
Agadez
Bilma
Tahoua
Linear (Zinder)
Linear (Agadez)
![Page 15: Dust: Data and Sources Dr Richard Washington University of Oxford Dr Martin Todd University College London Prof Andrew Goudie University of Oxford Dr Mike](https://reader033.vdocument.in/reader033/viewer/2022061618/56649cfa5503460f949cba57/html5/thumbnails/15.jpg)
N’Djamena, Chad: Haze Vs Obs RainfallBy season
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Bilma, Niger: sandstorms Vs TOMSby season
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North AfricanSurfaceDust stormsCorrelationTOMS1980-2000
![Page 18: Dust: Data and Sources Dr Richard Washington University of Oxford Dr Martin Todd University College London Prof Andrew Goudie University of Oxford Dr Mike](https://reader033.vdocument.in/reader033/viewer/2022061618/56649cfa5503460f949cba57/html5/thumbnails/18.jpg)
Bilma surface visibility Vs TOMS (march 1980-2000)
![Page 19: Dust: Data and Sources Dr Richard Washington University of Oxford Dr Martin Todd University College London Prof Andrew Goudie University of Oxford Dr Mike](https://reader033.vdocument.in/reader033/viewer/2022061618/56649cfa5503460f949cba57/html5/thumbnails/19.jpg)
![Page 20: Dust: Data and Sources Dr Richard Washington University of Oxford Dr Martin Todd University College London Prof Andrew Goudie University of Oxford Dr Mike](https://reader033.vdocument.in/reader033/viewer/2022061618/56649cfa5503460f949cba57/html5/thumbnails/20.jpg)
Outline• Dust Data
– Surface based synops (from GCOS, 117 stations)– Surface based synops (from local Met Agencies)
Niger, Chad, Algeria, Mali, Mari– TOMS AI data– IDDI– Shuttle Photographs, NOAA images etc
• Climate Data and Trajectory modelling– Reanalysis Data (NCEP and ERA-15) 3D winds– 25 point forward trajectory clusters– every 6 hours for 10days, 1979-1998– Determine regional transport corridors– Re-circulation
![Page 21: Dust: Data and Sources Dr Richard Washington University of Oxford Dr Martin Todd University College London Prof Andrew Goudie University of Oxford Dr Mike](https://reader033.vdocument.in/reader033/viewer/2022061618/56649cfa5503460f949cba57/html5/thumbnails/21.jpg)
![Page 22: Dust: Data and Sources Dr Richard Washington University of Oxford Dr Martin Todd University College London Prof Andrew Goudie University of Oxford Dr Mike](https://reader033.vdocument.in/reader033/viewer/2022061618/56649cfa5503460f949cba57/html5/thumbnails/22.jpg)
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REOF2 of TOMS AI monthly anomalies for the period 1980-05/93 and 1997-2000
-800
-600
-400
-200
0
200
400
600
800
1000
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REOF3 of TOMS AI monthly anomalies for the period 1980-05/93 and 1997-2000
-600
-400
-200
0
200
400
600
800
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REOF5 of TOMS AI monthly anomalies for the period 1980-05/93 and 1997-2000
-600
-400
-200
0
200
400
600
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REOF6 of TOMS AI monthly anomalies for the period 1980-05/93 and 1997-2000
![Page 27: Dust: Data and Sources Dr Richard Washington University of Oxford Dr Martin Todd University College London Prof Andrew Goudie University of Oxford Dr Mike](https://reader033.vdocument.in/reader033/viewer/2022061618/56649cfa5503460f949cba57/html5/thumbnails/27.jpg)
REOF7 of TOMS AI monthly anomalies for the period 1980-05/93 and 1997-2000
-300
-200
-100
0
100
200
300
400
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REOF8 of TOMS AI monthly anomalies for the period 1980-05/93 and 1997-2000
![Page 29: Dust: Data and Sources Dr Richard Washington University of Oxford Dr Martin Todd University College London Prof Andrew Goudie University of Oxford Dr Mike](https://reader033.vdocument.in/reader033/viewer/2022061618/56649cfa5503460f949cba57/html5/thumbnails/29.jpg)
Apr Potential Sand Flux overlay TOMS q = 2.61 U3
* pg –1 (1-U*/U*)(1+U*/U*)2
![Page 30: Dust: Data and Sources Dr Richard Washington University of Oxford Dr Martin Todd University College London Prof Andrew Goudie University of Oxford Dr Mike](https://reader033.vdocument.in/reader033/viewer/2022061618/56649cfa5503460f949cba57/html5/thumbnails/30.jpg)
Sahel TOMS (white contours), potential sand flux (black contours), with DEM (colour). LTM for JFM 80-00.
![Page 31: Dust: Data and Sources Dr Richard Washington University of Oxford Dr Martin Todd University College London Prof Andrew Goudie University of Oxford Dr Mike](https://reader033.vdocument.in/reader033/viewer/2022061618/56649cfa5503460f949cba57/html5/thumbnails/31.jpg)
Central Asia TOMS (white contours), potential sand flux (black contours), with DEM (colour). Long term mean for 80-00.
![Page 32: Dust: Data and Sources Dr Richard Washington University of Oxford Dr Martin Todd University College London Prof Andrew Goudie University of Oxford Dr Mike](https://reader033.vdocument.in/reader033/viewer/2022061618/56649cfa5503460f949cba57/html5/thumbnails/32.jpg)
Correlation of monthly visibility anomalies at Nouakchott (Mauritania) with global NCEP derived potential sand flux for 1980-2000
![Page 33: Dust: Data and Sources Dr Richard Washington University of Oxford Dr Martin Todd University College London Prof Andrew Goudie University of Oxford Dr Mike](https://reader033.vdocument.in/reader033/viewer/2022061618/56649cfa5503460f949cba57/html5/thumbnails/33.jpg)
Correlation of monthly visibility anomalies at Bobo-Dioulasso (Burkina Faso) with global NCEP derived potential sand flux for 1980-2000
![Page 34: Dust: Data and Sources Dr Richard Washington University of Oxford Dr Martin Todd University College London Prof Andrew Goudie University of Oxford Dr Mike](https://reader033.vdocument.in/reader033/viewer/2022061618/56649cfa5503460f949cba57/html5/thumbnails/34.jpg)
Outline• Dust Data
– Surface based synops (from GCOS, 117 stations)– Surface based synops (from local Met Agencies)
Niger, Chad, Algeria, Mali, Mari– TOMS AI data– IDDI– Shuttle Photographs, NOAA images etc
• Climate Data and Trajectory modelling– Reanalysis Data (NCEP and ERA-15) 3D winds– 25 point forward trajectory clusters– every 6 hours for 10days, 1979-1998– Determine regional transport corridors– Re-circulation
![Page 35: Dust: Data and Sources Dr Richard Washington University of Oxford Dr Martin Todd University College London Prof Andrew Goudie University of Oxford Dr Mike](https://reader033.vdocument.in/reader033/viewer/2022061618/56649cfa5503460f949cba57/html5/thumbnails/35.jpg)
Bodele
Djouf region
![Page 36: Dust: Data and Sources Dr Richard Washington University of Oxford Dr Martin Todd University College London Prof Andrew Goudie University of Oxford Dr Mike](https://reader033.vdocument.in/reader033/viewer/2022061618/56649cfa5503460f949cba57/html5/thumbnails/36.jpg)
Parcel trajectory climatology
May (1979-98)
Bodele depression (17.5N, 17E)
54% of trajectories cross the 15W meridian
27% of trajectories remain over N. Africa
21% of trajectories remain over Sahara (> 15N)
![Page 37: Dust: Data and Sources Dr Richard Washington University of Oxford Dr Martin Todd University College London Prof Andrew Goudie University of Oxford Dr Mike](https://reader033.vdocument.in/reader033/viewer/2022061618/56649cfa5503460f949cba57/html5/thumbnails/37.jpg)
![Page 38: Dust: Data and Sources Dr Richard Washington University of Oxford Dr Martin Todd University College London Prof Andrew Goudie University of Oxford Dr Mike](https://reader033.vdocument.in/reader033/viewer/2022061618/56649cfa5503460f949cba57/html5/thumbnails/38.jpg)
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Parcel trajectory climatology
June (1979-98)
Bodele depression (17.5N, 17E)
79% of trajectories cross the 15W meridian
13% of trajectories remain over N Africa
9% of trajectories remain over Sahara (> 15N)
![Page 40: Dust: Data and Sources Dr Richard Washington University of Oxford Dr Martin Todd University College London Prof Andrew Goudie University of Oxford Dr Mike](https://reader033.vdocument.in/reader033/viewer/2022061618/56649cfa5503460f949cba57/html5/thumbnails/40.jpg)
Parcel trajectory climatology
Dec (1979-98)
Bodele depression (17.5N, 17E)
66% of trajectories cross the 15W meridian
23% of trajectories remain over N. Africa
6% of trajectories remain over Sahara (> 15N)
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0
20
40
60
80
100
0
18
36
54
72
90
10
8
12
6
14
4
16
2
18
0
19
8
21
6
23
4
Time (hours)
% t
raje
cto
ries
Dust Recycling potential
May
JuneJuly
Dec
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Parcel trajectory climatology
May (1979-98)
Bodele depression (17.5N, 17E)
Mean 0-15N
![Page 43: Dust: Data and Sources Dr Richard Washington University of Oxford Dr Martin Todd University College London Prof Andrew Goudie University of Oxford Dr Mike](https://reader033.vdocument.in/reader033/viewer/2022061618/56649cfa5503460f949cba57/html5/thumbnails/43.jpg)
Parcel trajectory climatology
Dec (1979-98)
Bodele depression (17.5N, 17E)
Mean 0-15N
![Page 44: Dust: Data and Sources Dr Richard Washington University of Oxford Dr Martin Todd University College London Prof Andrew Goudie University of Oxford Dr Mike](https://reader033.vdocument.in/reader033/viewer/2022061618/56649cfa5503460f949cba57/html5/thumbnails/44.jpg)
TOMS AI over Bodele region (15-17N, 16-18E)
mean
May 1991
May 1989
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Bilma: Dust Storms and Haze
02468
101214161820
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May 1991
Long.
Lat.
Height (hPa)
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May 1989
Height (hPa)
Lat.
Long.
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Djouf region
![Page 50: Dust: Data and Sources Dr Richard Washington University of Oxford Dr Martin Todd University College London Prof Andrew Goudie University of Oxford Dr Mike](https://reader033.vdocument.in/reader033/viewer/2022061618/56649cfa5503460f949cba57/html5/thumbnails/50.jpg)
TOMS AI over Djouf region (17.5-22.5N, 2.5-7.5W)
![Page 51: Dust: Data and Sources Dr Richard Washington University of Oxford Dr Martin Todd University College London Prof Andrew Goudie University of Oxford Dr Mike](https://reader033.vdocument.in/reader033/viewer/2022061618/56649cfa5503460f949cba57/html5/thumbnails/51.jpg)
Parcel trajectory density climatology
July (1979-98)
Djouf region (17.5-22.5N, 2.5-7.5W)
% trajectories remain over Sahara (> 15N < 30N) 69 33 6
% trajectories crossing the 15W meridian 33 66 83
After days 3 5 10
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Annual CMAP precipitation over Djouf region
Annual TOMS AI over Djouf region
![Page 54: Dust: Data and Sources Dr Richard Washington University of Oxford Dr Martin Todd University College London Prof Andrew Goudie University of Oxford Dr Mike](https://reader033.vdocument.in/reader033/viewer/2022061618/56649cfa5503460f949cba57/html5/thumbnails/54.jpg)
Conclusions
• Surface Synops GCOS data: expensive and patchy
• Surface Synops from Met Agencies• Synops-TOMS AI: sensible but weak• Major mineral dust source regions identified
from TOMS AI data: Bodele and Djouf• Trajectory modelling allows definition of dust
transport corridors– Pronounced seasonal cycle and interannual
variability
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500hPa
80W
40E
10S
40N
Parcel trajectory climatology May (1979-98)
Bodele depression (17.5N, 17E)
![Page 56: Dust: Data and Sources Dr Richard Washington University of Oxford Dr Martin Todd University College London Prof Andrew Goudie University of Oxford Dr Mike](https://reader033.vdocument.in/reader033/viewer/2022061618/56649cfa5503460f949cba57/html5/thumbnails/56.jpg)
Parcel trajectory density climatology
July (1979-98)
Djouf region (17.5-22.5N, 2.5-7.5W)
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West of 15W
0
20
40
60
80
100
0
18
36
54
72
90
10
8
12
6
14
4
16
2
18
0
19
8
21
6
23
4
Time (hours)
% t
raje
cto
ries
Over Sahara >15N <30N
Over Atlantic
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Parcel trajectory climatology
May (1979-93)
Bodele depression (17.5N, 17E)
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TOMS mean AI May 1980-93
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Parcel trajectory climatology
July (1979-98)
Bodele depression (17.5N, 17E)
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Parcel trajectory density climatology
July (1979-98)
Djouf region (17.5-22.5N, 2.5-7.5W)
Mean 10-25N
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