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Institute of Environmental Physics University of Bremen
Retrieval of Tropospheric Water Vapour from FTIR Solar Absorption Measurements
1 Department of Physics, Addis Ababa University, Addis Ababa, Ethiopia2 Department of Physics, University of Bremen, Bremen, Germany3 Alfred-Wegener-Institute for Polar and Marine Research, Bremerhaven, Germany
1G. Mengistu Tsidu, 2J. Notholt, 2T. Warneke and 3O. Schrems
Remote sensing of in the infrared using the Fourier Transform Infrared Spectroscopy (FTIR)
wavenumber (cm-1)
inte
nsi
ty (
arb.
Uni
ts)
wavelength (m) 13.0 10.0 8.0
8.725 8.720
wavenumber (cm-1)
wavelength (m)
tran
smis
sion
total columns (molec. cm-2) 20 trace gases
profiles (vmr)for 10 trace gases
Spectral lines
ALFIP: Automatic Line Finding Programhttp://www.iup.physik.uni-bremen.de/ftir/alfip
Automatic search for lines with highest signal contribution in defined altitude region
Tropics:H2
160: 2429.5, 2485.3, 2497.1, 2940.9, 3145.5, 3147.8, 3158.6HDO: 2660.3, 2672.2, 2675.0, 2725.5, 2737.8, 2747.3, 2854.5, 2860.4H2
18O: 2900.4, 2942.55, 2954.95, 3000.45
Midlatitudes:H2
16O: 2911.2, 2930.6, 3050.55, 3146.75, 3147.9, 3152.5, 3189.6HDO: 2657.1, 2660.4, 2671.9, 2722.5, 2730.5, 2737.8, 2747.2H2
18O: 2955.0, 2976.2, 3001.0, 3023.6, 3043.6, 3091.0
Observations onboard of Polarstern
Polarstern campaign Oct./Nov. 1996
Oct/Nov 1996
0.0E+00
5.0E+22
1.0E+23
1.5E+23
2.0E+23
-60 -40 -20 0 20 40 60
latitude
H216
O
Oct/Nov 1996
-300
-250
-200
-150
-100
-50
0
-60 -40 -20 0 20 40 60
latitude
δH
DO
Oct/Nov 1996
0
5
10
15
20
25
30
-60 -40 -20 0 20 40 60
latitude
T s
urf
ac
e
Polarstern cruise
Oct./Nov. 1996
200
180
160
140
120
100
80
60
40
20
vmr (ppbv)
Dependancy of vmr-profile results on a-priori
Sensitive to a-priori profile, Adhoc covariance
Sensitive to a-priori profile, modified Tikhonov
balloon sonde constant vmr
modified TikhonovAdhoc approach
Spitsbergen, 79°N, 12°E
y = 1.321x + 2E+21
0
1E+22
2E+22
3E+22
4E+22
5E+22
6E+22
7E+22
0 1E+22 2E+22 3E+22 4E+22 5E+22
HDO
H216
O
Spitsbergen 2001
Temperature dependance
of HDO
y = 7.1384x - 332.98
R2 = 0.6729
-600
-500
-400
-300
-200
-100
0
-25 -20 -15 -10 -5 0 5 10
T surface
δ H
DO
y = 0.0317x - 1.224
R2 = 0.7484
-2.5
-2
-1.5
-1
-0.5
0
-25 -20 -15 -10 -5 0 5 10
T surface
δ H
DO
/ T
y = 0.0001x - 0.0045
R2 = 0.802
-0.01
-0.008
-0.006
-0.004
-0.002
0
-25 -20 -15 -10 -5 0 5 10
T surface
δ H
DO
/ T
2
y = 8.0229x + 8.9567
R2 = 0.9718
y = 1.4397x - 215.74
R2 = 0.3638
-600
-500
-400
-300
-200
-100
0
-200 -180 -160 -140 -120 -100 -80 -60 -40 -20 0
δ H218O
δ H
DO
Meteoric Water Line: δ HDO = 8 * δ H218O + 10
0
12
3
4
56
7
89
10
60 110 160 210 260
day of 2001
δ H
DO
/ δ
H218
OFTIR GNIP
Summary and conclusions
total columns of H216O, H2
18O and HDO
profiles with 2-3 degrees of freedom
tropopause region difficult to reach
work in progress
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