Date post: | 01-Apr-2015 |
Category: |
Documents |
Upload: | lesley-meacham |
View: | 213 times |
Download: | 1 times |
A METHOD FOR MONOTORING GLACIER MASS BALANCE USING REMOTE SENSING
IN THE FRENCH ALPS :
COMPARISON WITH GROUND MEASUREMENTS (1985-2003)
Jean-Pierre DEDIEU, Antoine RABATEL, Christian VINCENT, Alvaro SORUCO
Laboratoire de Glaciologie et de Géophysique de l’EnvironnementCNRS - Grenoble, France.
http://www.lgge.obs.ujf-grenoble.fr
8th Circumpolar Symposium on Remote Sensing of Polar Environments - June 8 -12, 2004 Chamonix, France
Glaciers Monitoring from Space Glaciers Monitoring from Space
InputInput : Additions of trends towards improvement in : Additions of trends towards improvement in : :
* Spatial and spectral resolutionSpatial and spectral resolution
* Frequency of repeat coverageFrequency of repeat coverage
* Radiometric calibrationRadiometric calibration
** Geometric fidelityGeometric fidelity
* Stereo capabilitiesStereo capabilities
OutputOutput : National and International projects : National and International projects
8th Circumpolar Symposium on Remote Sensing of Polar Environments - June 8 -12, 2004 Chamonix, France
GLIMS : Global Land Ice Measurements from Space (http://www.glims.org)
World glaciers database (ASTER satellite images)
Glacier Inventory at regional scale (Optical satellite images)
Mer de Glace 26.09.2000 © Spot Image
8th Circumpolar Symposium on Remote Sensing of Polar Environments - June 8 -12, 2004 Chamonix, France
© Landsat ETM7 – 30.07.2001 Géant
Leschaux
TalèfreChamonix
Swiss Glacier Inventory (http://www.geo.unizh.ch) Landsat satellite images
Evolution 1973-2000 (by Fanck PAUL, Andreas KAAB & al.)
Mischabel mountain range
Aletsch glacier region
8th Circumpolar Symposium on Remote Sensing of Polar Environments - June 8 -12, 2004 Chamonix, France
Objective : Glacier net mass balance
Ablation area
Accumulation area
Photo : M. Caplain
EEquilibriumline
Mass balance = Accumulation + AblationExpressed in meter water equivalent
MB<0
MB>0MB=0
Martin Gerbaux
St.Sorlin Glacier, 28-09-1986 (© Louis Reynaud) St.Sorlin Glacier, 05-10-1986 (© Spot-Image)
dz
dbZ ELAt annual Mass Balance annual Mass Balance
derived from ELA byderived from ELA by
where db/dz = 0.78 m w.e./100 m (1985-2003)
FOCUS: Equilibrium Line Altitude variations
Remote Sensing databaseFrench Glaciers Observatory Service (LGGE-OSUG, Grenoble)
ARGENTIERE N 45°87/ E 6°90 West, 19 km2
GEBROULAZ N 45°19/ E 6°40 North, 3.2 km2
St. SORLIN N45°10/ E 6°10 North-East, 3 km2
1. Satellite data : 1985-20031985-2003
Remote Sensing processing (optical and SAR data)
© SPOT-Image 26/08/2000 SPOT-Image 26/08/2000
© Radarsat 26/10/1996
Raw Image
D.E.M.
- Geometric and radiometric corrections, ratios thresholds (PCI inc. )
- annual ELA digitized measurement
++
8th Circumpolar Symposium on Remote Sensing of Polar Environments - June 8 -12, 2004 Chamonix, France
2. Ground data :2. Ground data : direct measurements (stakes)
Bilan Argentière 2001-2002
19021802
1702
20022102
2302
2402
602702
1002y = 0,0115x - 33,213R2 = 0,9776
-3
-2,5
-2
-1,5
-1
-0,5
0
0,5
1
2600 2700 2800 2900 3000
Bilan Argentière-2000-2001
5011001
601
801
21012001
1901
1701201
y = 0,0087x - 23,478R2 = 0,9594
-2,00
-1,50
-1,00
-0,50
0,00
0,50
1,00
1,50
2,00
2,50
3,00
2500 2600 2700 2800 2900 3000 3100
Regression line = ELA, d(b)/d(z)8th Circumpolar Symposium on Remote Sensing of Polar Environments - June 8 -12, 2004 Chamonix, France
1 . E L A V a r ia tio n 1 9 9 4 -2 00 2 (G ro u n d m ea su rem en ts )
2 6 0 0
2 7 0 0
2 8 0 0
2 9 0 0
3 0 0 0
3 1 0 0
3 2 0 0
3 3 0 0
1 9 9 4 -1 9 9 5
1 9 9 5 -1 9 9 6
1 9 9 6 -1 9 9 7
1 9 9 7 -1 9 9 8
1 9 9 8 -1 9 9 9
1 9 9 9 -2 0 0 0
2 0 0 0 -2 0 0 1
2 0 0 1 -2 0 0 2
A rge n t iè reSa in t So r linGébr o ulaz
-
-A n n é e A rg e n tiè re S a in t-S o rl in G é b ro u la z1994-1995 2674 2788 28251995-1996 2821 3016 31001996-1997 2777 2906 30461997-1998 2946 3094 31951998-1999 2811 2946 30401999-2000 2829 2969 30412000-2001 2695 2837 29132001-2002 2888 3003 3044
Err e u r -Ty p e 2 4 3 3 7 3
EL A (m . a .s. l . )
R esu lts
8th Circumpolar Symposium on Remote Sensing of Polar Environments - June 8 -12, 2004 Chamonix, France
2. db/dz variation 1994-2002:2. db/dz variation 1994-2002:
Mean Value St.Sorlin/Gébroulaz/Argentière : 0,78 0,78 m water equivalentm water equivalent
0,000
0,002
0,004
0,006
0,008
0,010
0,012
0,014
1994-1995
1995-1996
1996-1997
1997-1998
1998-1999
1999-2000
2000-2001
2001-2002
ArgentièreSaint SorlinGébroulaz
--
Année Saint Sorlin Argentière Gébroulaz1994-1995 0,51 0,78 0,331995-1996 0,85 0,66 0,471996-1997 0,75 0,83 0,51997-1998 0,96 1,04 0,691998-1999 0,86 1,01 0,561999-2000 1,1 0,99 0,592000-2001 0,83 0,75 0,462001-2002 1,15 1,11 0,7
Moyenne 0,88 0,90 0,54
Erreur-Type 0,06 0,11 0,07
Coefficient d'activité db/dz (m eq. eau)
8th Circumpolar Symposium on Remote Sensing of Polar Environments - June 8 -12, 2004 Chamonix, France
3. ELAs and specific net balance comparison (1994-2002):
ELA vs b(t). 1994-2002
R2 = 0,8365
R2 = 0,8068
R2 = 0,8813
2500
2700
2900
3100
3300
-2,5 -2 -1,5 -1 -0,5 0 0,5 1
b(t) m.w.e
EL
A m
.
Argentière Saint Sorlin Gébroulaz
a. Field measurements (stakes)
R2 = 0,938
R2 = 0,9822R2 = 0,9296
2500
2600
2700
2800
2900
3000
3100
3200
3300
2600 2700 2800 2900 3000 3100 3200 3300
Measured ELAs (m. asl)C
ompu
ted
EL
As
(m. a
sl)
Argentiere
St. Sorlin
Gebroulaz
Linéaire(Argentiere)Linéaire(Gebroulaz)Linéaire (St.Sorlin)
b. Field versus Remote Sensing
8th Circumpolar Symposium on Remote Sensing of Polar Environments - June 8 -12, 2004 Chamonix, France
4. Comparison of cumulative specific net balance between reconstructed and direct measurements
b(t) = ( ELAeq – ELAi ) * db/dz, where ELAeq = 1/n ΣELAi - < b(t) > * db/dz
© SPOT-Image 1986 SPOT-Image 1986
4.1. Methodology: Gebroulaz glacier (1986-2003)
8th Circumpolar Symposium on Remote Sensing of Polar Environments - June 8 -12, 2004 Chamonix, France
Hydrological Remoted ELA b(t) b(t) Cumulative b(t) b(t) cumulativeYear ELA variation Remoted Remoted Ground Ground
1986-1987 2950 -31,12 -0,17 -0,84 -0,89 -0,891987-1988 2880 38,88 0,21 -0,63 0,14 -0,751988-1989 3050 -131,12 -0,71 -1,34 -1,76 -2,511989-1990 2980 -61,12 -0,33 -1,67 -0,36 -2,871990-1991 3037 -118,12 -0,64 -2,30 -0,87 -3,741991-1992 3026 -107,12 -0,58 -2,88 -1,17 -4,911992-1993 2980 -61,12 -0,33 -3,21 0,94 -3,971993-1994 2982 -63,12 -0,34 -3,55 -0,64 -4,611994-1995 2800 118,88 0,64 -2,91 0,50 -4,111995-1996 2984 -65,12 -0,35 -3,26 -0,50 -4,611996-1997 3012 -93,12 -0,50 -3,77 -0,21 -4,821997-1998 3175 -256,12 -1,38 -5,15 -1,54 -6,361998-1999 2981 -62,12 -0,34 -5,48 -0,29 -6,651999-2000 3034 -115,12 -0,62 -6,11 -0,17 -6,822000-2001 2900 18,88 0,10 -6,00 0,46 -6,362001-2002 3050 -131,12 -0,71 -6,71 -0,40 -6,762002-2003 3250 -331,12 -1,79 -8,50 -1,65 -8,41
Mean Value 3006,33
Total Mass balance -8,50Annual mean value -0,47
ELAeq (m.a.s.l) 2919
Specific d(b)/d(z) 0,0066 mwe
Photogrammetric Balance 1986-2003
8th Circumpolar Symposium on Remote Sensing of Polar Environments - June 8 -12, 2004 Chamonix, France
4.2. Preliminary results: Gebroulaz glacier (1986-2003)
a. Surface mass balance (t) at ELA area
b. Cumulative specific mass balance b(t)
-2,00
-1,50
-1,00
-0,50
0,00
0,50
1,00
1,50
1986-1987 1989-1990 1992-1993 1995-1996 1998-1999 2001-2002
Hydrological year
Mass b
ala
nce (
mw
e)
B(t) Remoted
B(t) Ground
-10,00
-9,00
-8,00
-7,00
-6,00
-5,00
-4,00
-3,00
-2,00
-1,00
0,00
1986-1987 1989-1990 1992-1993 1995-1996 1998-1999 2001-2002
Hydrological year
Cu
mu
lati
ve m
ass b
ala
nce (
m.w
.e)
b(t) cumulative remoted
b(t) cumulative ground
4.3. Meteorological corrections and final results (1994-2002)
Gébroulaz corrected
-3,00
-2,50
-2,00
-1,50
-1,00
-0,50
0,00
0,50
1,00
1,50
19
94
-19
95
19
95
-19
96
19
96
-19
97
19
97
-19
98
19
98
-19
99
19
99
-20
00
20
00
-20
01
20
01
-20
02
b(t) Remoted cumulb(t) Ground cumul
Gébroulaz
-3,50-3,00-2,50-2,00-1,50-1,00-0,500,000,501,001,502,00
19
94
-19
95
19
95
-19
96
19
96
-19
97
19
97
-19
98
19
98
-19
99
19
99
-20
00
20
00
-20
01
20
01
-20
02
b(t) Remoted cumulb(t) Ground cumul
Saint Sorlin
-7,00
-6,00
-5,00
-4,00
-3,00
-2,00
-1,00
0,00
1,00
19
94
-19
95
19
95
-19
96
19
96
-19
97
19
97
-19
98
19
98
-19
99
19
99
-20
00
20
00
-20
01
20
01
-20
02
b(t) Remoted cumulb(t) Ground cumul
St.Sorlin corrected
-7,00
-6,00
-5,00
-4,00
-3,00
-2,00
-1,00
0,00
1,00
1994
-199
5
1995
-199
6
1996
-199
7
1997
-199
8
1998
-199
9
1999
-200
0
2000
-200
1
2001
-200
2
b(t) Remoted cumulb(t) Ground cumul
Argentière
-5,00
-4,00
-3,00
-2,00
-1,00
0,00
1,00
19
94
-19
95
19
95
-19
96
19
96
-19
97
19
97
-19
98
19
98
-19
99
19
99
-20
00
20
00
-20
01
20
01
-20
02
b(t) Remoted cumulb(t) Ground cumul
Argentière corrected
-5,00
-4,00
-3,00
-2,00
-1,00
0,00
1,00
19
94
-19
95
19
95
-19
96
19
96
-19
97
19
97
-19
98
19
98
-19
99
19
99
-20
00
20
00
-20
01
20
01
-20
02
b(t) Remoted cumulb(t) Ground cumul
a. Raw remoted b(t) before correction
b. after Cumulated Positive Degree-Day correction (Meteo-France data)
8th Circumpolar Symposium on Remote Sensing of Polar Environments - June 8 -12, 2004 Chamonix, France
Limitations :The extreme summer 2003 and its effects on alpine glaciers
Glacier b(t) m we 2002-2003 ELA m asl
Argentière (19 km2, N) - 2.10 3200 St. Sorlin (3 km2, NE) - 2.80 3400 Gebroulaz (3 km2, N) - 1.65 3220 Sarennes (0.5 km2, S) - 3.15 3400
© Landsat TM5 26/09/1985© Landsat TM5 26/09/1985 © ASTER 12/08/2003© ASTER 12/08/2003
Sarennes Glacier (Cemagref, since 1949)
Ice Snow Rocks
Conclusions and outlook
• Mass balance reconstruction results are validated
by direct ground measurements on :
2 glaciers + 8 cycles, 1 glacier + 17 cycles to study deeply
• ELAs yearly maps can be produced by Remote Sensing at the mountain range scale (gradient)
• Method of interest for climate change impact
8th Circumpolar Symposium on Remote Sensing of Polar Environments - June 8 -12, 2004 Chamonix, France
St. Sorlin Glacier , 1987
Thanks for your attention . . .Thanks for your attention . . .