Outline Results from AIRS validation campaign 2002

IMK-IFU, Research Center Karlsruhe, Garmisch-Partenkirchen, Ralf Sussmann

Partial columns retrieval from Zugspitze and Garmisch FTIR measurements

Outline• Results from AIRS validation campaign 2002• Combination of Zugspitze (mountain) and Garmisch (ground site) FTIR• Water vapor columns variability and profile covariance above Zugspitze/Garmisch • Columns/partial columns retrieval characteristics and validation



IFU

Garmisch, 734 m

FTIR

GPS

Radio sondes

Zugspitze, 2964 m

LIDAR

IFU

IFU

GPSFTIR

FTIR

IFUIn situ

In situ

LIDAR

UV

UV

IMK-IFU Working Group „Variability and Trends“

Scientists R. Sussmann W. Junkermann H.E. Scheel T. Trickl H. Vogelmann P. Werle Engineers H. Giehl M. Rettinger A. Rockmann PhD students W. Stremme T. Borsdorff

Triple NDACC Primary Station: FTIR, Aerosol, UV.

Permanent Ground-Truthing Facility Zugspitze/Garmisch according to the WMO requirements.

MAPS,CRISTA,MOPITT, SAGE, GOME,AIRS,SCIAMACHY,ACE, IASI,CALIPSO, OCO, TCCON,GOSAT, …



IFU

Garmisch, 734 m

FTIR

GPS

Radio sondes

Zugspitze, 2964 m

LIDAR

IFU

IFU

GPSFTIR

FTIR

IFUIn situ

In situ

Zugspitze/Garmisch instrumentation for water vapor columns/profiles



Campaign duration: 3 Months (19 Aug 2002 - 17 Nov 2002)

Validation measurements: 7 days a week,2-hours-period around each overpass delivered,for 2 EOS-Aqua overpasses per day

• Zugspitze FTIR: clear sky operation, typically, 20-min-integration intervals

• Radio Sondes (Garmisch): 4 sondes a day (two per overpass)

• GPS Garmisch+ Zugspitze, permanent operation, half hourly mean values

• In-Situ Met Data (Garmisch + Zugspitze): 1-min-values

• Cloud/weather information (Zugspitze: hourly; Garmisch: 1 fish eye image per overpass)

2002 AIRS validation campaign at Zugspitze/Garmisch: Schedule

Data delivery: within 12 h

for both day- and night-overpasses



2002 AIRS validation campaign at Zugspitze/Garmisch: Radio Sounding

Sonde 1 launched 1h before overpassSonde 2 launched 5 min before overpass

Vaisala RS 80-30 G sondesTOTEX-800-g balloons2 x Digicora III (Marvin 21, SPS220G)

TOBIN-Inter-/Extrapolation between both soundings:

qTobin(z, top) = qsonde(z, t0) + (dq(z)/dt) (top – t0)

Tobin, D., W. Feltz, B. Knuteson, H. Revercomb, “ARM T/q Best Estimate Profiles for AIRS validation”, 1 March 2000



2002 AIRS validation campaign at Zugspitze/Garmisch: Radio Sounding

delivered within 12 hours



IFU

Garmisch, 734 m

GPS

Zugspitze, 2964 m

GPS

Water vapor columns: Zugspitze+Garmisch GPS

GPS (1.6 / 1.2 GHz) Receivers

Collaboration with Geoforschungszentrum Potsdam (Ch. Reigber)

11:30 12:00 12:30 13:00 13:30 14:00 14:300,0

1,0

2,0

3,0

4,0

5,0

6,0

7,0

8,0

9,0

10,0

Col

umn

abun

danc

e (

mm

)

Time of day

GPS: ifu1 GPS: zugsGarmisch GPS

Zugspitze GPS



ColumnsaboveGarmisch, 734 m

2-h-meanvalues

integrated Tobin-profiles

GPS bias 1-2 mm, precision 1 mm

Water vapor columns: Validation of Garmisch GPS with radio sondes

Ralf Sussmann and Claude Camy-Peyret, Ground-Truthing Center Zugspitze, Germany for AIRS/IASI Validation, EUMETSAT Contract No. EUM/CO/01/892/PS, Phase II Report, 28 March 2003

0 5 10 15 20 25 300

5

10

15

20

25

30

Y = A + B * X

Parameter Value Error------------------------------------------A 0,5699 0,25176B 1,036 0,01497------------------------------------------

R N------------------------------------------0,98331 166------------------------------------------

Linear Fit Upper 95% Confidence Limit Lower 95% Confidence Limit

Wat

er

Co

lum

n fr

om G

arm

isch

GP

S (

mm

)

Water Column from Radio Sondes (mm)



ColumnsaboveZugspitze, 2964 m

2-h-meanvalues

integrated Tobin-profiles

GPS bias 1-2 mm, precision 1 mm


Water vapor columns: Validation of Zugspitze GPS with radio sondes

0 2 4 6 8 10 12 140

2

4

6

8

10

12

14

Y = A + B * X

Parameter Value Error---------------------------------------------A 1,62739 0,12615B 0,95162 0,02186---------------------------------------------

R N----------------------------0,95773 173----------------------------

Linear Regression Upper 95% Confidence Limit Lower 95% Confidence Limit

To

tal W

ate

r C

olu

mn

from

Zu

gspi

tze

GP

S (

mm

)

Total Water Column from Radio Sondes (mm)



IFU

Garmisch 734 m

FTIR

Zugspitze2964 m

IFU

FTIR

FTIR

IFU

H2O columns and profiles

“Differential FTIR” with Zugspitze: H2O columns and profiles

Garmisch operational since 200494 measurement days in 2004 147 measurement days in 2005

Zugspitze operational since 1995typ. 130 measurement days per year



HITRAN96

010-010R10, R14water lines

solar OH

Zugspitze solar FTIR retrieval: Micro windows



HITRAN2000, solar OH removed

010-010R10, R14water lines




HITRAN96

010-010R11water line




HITRAN2000

010-010R11water line




HITRAN96

010-010R10, R13, R16water lines




HITRAN2000

010-010R10, R13, R16water lines




ColumnsaboveZugspitze, 2964 m

2-h-meanvalues

integrated Tobin-profiles0 1 2 3 4 5 6 7 8 9

0

1

2

3

4

5

6

7

8

9

Y = A + B * X

Parameter Value Error-------------------------------------------A 0,04386 0,12322B 1,05399 0,03245-------------------------------------------

R N-------------------------------------------0,98928 25-------------------------------------------

Linear Fit Upper 95% Confidence Limit Lower 95% Confidence Limit

To

tal W

ate

r C

olu

mn

fro

m F

TIR

(m

m)

Total Water Column from Radio Sondes (mm)

Water vapor columns Zugspitze/Garmisch: Validation of solar FTIR with sondes


FTIR is probably one of the most accurate techniques to quantify columnar water vapor, with an accuracy around 0.1 mm



0.734

2

4

6

8

10

12

14

0.000 0.005 0.010 0.015 0.020

volume mixing ratio

alti

tud

e [k

m]

Garmisch radio sonde profiles

Zugspitze/Garmisch FTIR profile retrieval: A priori information used (I)



0.734 2 4 6 8 10 12 140.734

2

4

6

8

10

12

14

altitude [km]

alti

tud

e [k

m]

- 0

- 0.05

- 0.10

- 0.15

- 0.20

- 0.25

- 0.30

- 0.35

- 0.40

- 0.44

0.734

2

4

6

8

10

12

14

0 10 20 30 40 50 60 70

standard deviation of H2O variability [%]

altit

ude

[km

]

water vapor covariance

VMRUnit: covariances of VMR-layer scaling factors

Zugspitze/Garmisch FTIR profile retrieval: A priori information used (II)

water vapor variability (stdv)



2.964

4

6

8

10

12

14

-0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0

averaging kernel

alti

tud

e [k

m]

1 mm water vapor column

Zugspitze/Garmisch FTIR profile retrieval: Averaging kernels

dofs 3 (snr 100)

dofs-1-layers: 3 - 4 km4 - 7 km7 – 15 km



Zugspitze/Garmisch FTIR profile retrieval: Smoothing error

2.9644

6

8

10

12

14

16

18

20

22

24

26

0 20 40 60 80 100 120 140 160 180

10 mm water vapor column 1 mm water vapor column stdv of true water vapor variability

smoothing error [%]

alti

tud

e [k

m]

Smoothing error/altitude range does not dependupon absolute column level



Zugspitze FTIR profile retrieval: Retrieved profiles versus sondes

2.9644

6

8

10

12

14

16

18

20

22

24

0 500 1000 1500 2000

FTIR radio sonde

H2O volume mixing ratio [ppm]

alti

tud

e [k

m]



Zugspitze FTIR profile retrieval: Retrieved profiles versus sondes

0 1 20

1

2

FT

IR p

arti

al c

olu

mn

[10

21 c

m-2]

radio sonde partial column [1021 cm-2]

0 5 100

5

10

FT

IR p

arti

al c

olu

mn

[10

21 c

m-2]

radio sonde partial column [1021 cm-2]0 1 2

0

1

2

FT

IR p

arti

al c

olu

mn

[10

21 c

m-2]

radio sonde partial column [1021 cm-2]

partial column 3 - 4 km partial column 4 - 7 km partial column 7 - 15 km



Zugspitze FTIR profile retrieval: Retrieved profile versus sonde

2.9644

6

8

10

12

14

16

18

20

22

24

0 500 1000 1500 2000

FTIR radio sonde


alti

tud

e [k

m]

snr = 155.938column = 2.98 mm

2.9644

6

8

10

12

14

16

18

20

22

24

0 500 1000 1500 2000

FTIR radio sonde

snr = 174.032column = 1.51 mm


alti

tud

e [k

m]

2.9644

6

8

10

12

14

16

18

20

22

24

0 500 1000 1500 2000

FTIR radio sonde

snr = 126.952column = 2.17 mm


alti

tud

e [k

m]

2.9644

6

8

10

12

14

16

18

20

22

24

0 500 1000 1500 2000

FTIR radio sonde

snr = 179.151column = 1.36 mm


alti

tud

e [k

m]

2.9644

6

8

10

12

14

16

18

20

22

24

0 500 1000 1500 2000

FTIR radio sonde

snr = 154.527column = 2.22 mm


alti

tud

e [k

m]

2.9644

6

8

10

12

14

16

18

20

22

24

0 500 1000 1500 2000

FTIR radio sonde

snr = 163.892column = 1.85 mm


alti

tud

e [k

m]


EPS/MetOp validation at Ground-Truthing Center Zugspitze/Garmisch

Summary/Outlook: FTIR water vapor retrievals at Zugspitze + Garmisch

Summary • found interference-free micro-window set

• FTIR yields very very high accuracy total columns

• Zugspitze – Garmisch „differential FTIR“

• OE with climatological a priori covariance from sondes works fine

• dofs 3, i.e., layers 3 - 4 km, 4 - 7 km, 7 – 15 km

• smooting error/altitude range does not significantly depend on absolute water column level

• validation against sondes good, given high quality spectra (snr > 120)

Outlook• synergistic combination with Zugspitze water lidar measurements

• Zugspitze/Garmisch EPS-MetOp IASI validation campaign in 2007


Outline Results from AIRS validation campaign 2002

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