measuring atmospheric humidity from commercial aircraft ... · h2o from mozaic-iagos // herman...

H2O from MOZAIC-IAGOS // Herman Smit/FZJ WaVacs-WG1 Lindenberg 21-23 May 2008

1

Measuring Atmospheric Humidityfrom Commercial Aircraft:

Insights from MOZAIC and IAGOSHerman G. J. Smit ([email protected])

Forschungszentrum Juelich (ICG-2)

H 2 O -S e n s o r

A I R C R A F TS K I N

S E N S O R SR H : H U M I C A P - HT : P T 1 0 0

D E I C IN GH E A T E R

B O U N D A R Y L A Y E R SC O N T R O L H O L E S

R IG H T A N G L EP R O D U C E SP A R T I C L E

S E P A R A T I O N

Past and Present: MOZAIC

HumiditySampling

Quality Assurance & Synergy of Data

Future:IAGOS

Ice

Liquid

0

2

4

6

8

10

Pro

babi

lity

[%]

0 25 50 75 100 125 150 175Relative Humidity [%]

40N-60N

Ice

Liquid

0

2

4

6

8

10

Pro

babi

lity

[%]


40N-60N

Ice

Liquid

0

2

4

6

8

10

Pro

babi

lity

[%]


40N-60N

MOZAIC

Ice

Liquid

0

2

4

6

8

10

Pro

babi

lity

[%]


40N-60N

Ice

Liquid

0

2

4

6

8

10

Pro

babi

lity

[%]


40N-60N

Ice

Liquid

0

2

4

6

8

10

Pro

babi

lity

[%]


40N-60N

MOZAIC

-60 -40 -20 0 20Static Air Temperature

0

2

4

6

8

10

Abs

.Err

or o

f Rel.H

umi.

[% R

H]

12 9 6 3 0

Altitude [km]

All Data 1999/2000

In: Helten et al., J.Geophys.Res., 1998


0

2

4

6

8

10

Abs

.Err

or o

f Rel.H

umi.

[% R

H]

12 9 6 3 0

Altitude [km]

All Data 1999/2000



0

2

4

6

8

10

Abs

.Err

or o

f Rel.H

umi.

[% R

H]

12 9 6 3 0

Altitude [km]

All Data 1999/2000



2

Doubling CO2-concentration: 2-5oC Temperature increase1/3-part: direct via CO22/3-part: via positive feedback of water vapor+clouds

Wat

erV

apor

Mas

s(r

elat

ive

to p

re-in

dust

rialv

alue

)

Change in Global MeanWater Vapor (NOAA/GDFL-GCM ScenarioRun)

P≈200 hPa

P≈900 hPa

Wat

erV

apor

Mas

s(r

elat

ive

to p

re-in

dust

rialv

alue

)

Change in Global MeanWater Vapor (NOAA/GDFL-GCM ScenarioRun)

P≈200 hPa

P≈900 hPa

(WV)

Wat

er

Vapo

r

(C) C

loud

(LR

) La

pse

Rat

e

WV+

LR

(A)

Alb

edo ALL

FeedbackType

Feed

back

Str

engt

h(W

m-2

K-1

-1

0

1

2

(WV)

Wat

er

Vapo

r

(C) C

loud

(LR

) La

pse

Rat

e

WV+

LR

(A)

Alb

edo ALL

FeedbackType

(C) C

loud

(LR

) La

pse

Rat

e

WV+

LR

(A)

Alb

edo ALL

FeedbackType

FeedbackType

Feed

back

Str

engt

h(W

m-2

K-1

-1

0

1

2

Feed

back

Str

engt

h(W

m-2

K-1

-1

0

1

2

Most Prominent Climate Feedbacks

(WV)

Wat

er

Vapo

r

(C) C

loud

(LR

) La

pse

Rat

e

WV+

LR

(A)

Alb

edo ALL

FeedbackType

Feed

back

Str

engt

h(W

m-2

K-1

-1

0

1

2

(WV)

Wat

er

Vapo

r

(C) C

loud

(LR

) La

pse

Rat

e

WV+

LR

(A)

Alb

edo ALL

FeedbackType

(C) C

loud

(LR

) La

pse

Rat

e

WV+

LR

(A)

Alb

edo ALL

FeedbackType

FeedbackType

Feed

back

Str

engt

h(W

m-2

K-1

-1

0

1

2

Feed

back

Str

engt

h(W

m-2

K-1

-1

0

1

2

Most Prominent Climate Feedbacks

Upper troposphere most sensitive region in climate change

Why Monitoring Humidity in Upper Troposphere ??


3

MOZAIC - OperationPartners: CNRS, FZJ, CNRM, UCAM, Lufthansa, AIRBUS

LIMA

SAN FRANCISCO

LOS ANGELES NEW ORLEANS

MEXICO

DALLAS

BOSTON

HOUSTON

CINCINNATI

MIAMI

CHICAGO

ANTIGUASAN DOMINGO

ATLANTA

CARACAS

SANTIAGO

MONTREAL

PLATA PUERTOPUERTO RICO

QUAYAQUIL

TORONTO

QUITO

WASHINGTON

BOGOTA

NEW YORK

SAINT MARTINPOINTE A PITRE

CAYENNE

BUENOS AIRES

MONTEVIDEO

DAKAR

SAO PAULO RIO

RECIFE

BANJOUL

ABIDJAN

LONDON

COTONOU

BRUXELLES

PARIS

LAGOS

AMSTERDAM

FRANKFURTVIENNA

LIBREVILLE

DOUALAYAOUNDE

LUANDABRAZZAVILLE

WINDHOEK

ATHENES

HERAKLION

JOHANNESBURG

ISTANBUL

ANTALYA

KIGALIENTEBBE

ANKARA

TEL AVIV

NAIROBI

ANTANANARIVO

TEHERAN

DUBAI

MUMBAI

MALE

DELHI

COLOMBOMADRAS

BANGKOK

HANOI

SINGAPORE

JAKARTA

SAIGON

BEIJING

SHANGAI

SEOUL

OSAKANAGOYA

TOKYO

>20000 flights since 1994

Instruments deployed on five Airbus A340 aircraft operated by European airlines: DLH (2), AF, AUA, AN2500 longhaul flights per year (5000 vertical profiles)> 20 000 flights since 1994 for O3 and H2OCO and NOy since 2001


4

From a research project to sustainable Earth observations

In-Service Aircraft for a Global Observing System

Coordination: Andreas Volz-Thomas ([email protected]://www.fz-juelich.de/icg/icg-2/iagos


5

MOZAIC: Humidity Sampling

H 2O -Sen sor

AIRCRAFTSKIN

SENSORSRH: HUMICAP-HT : PT100

DEICINGHEATER

BOUNDARY LAYERSCONTROL HOLES

RIGHT ANGLEPRODUCESPARTICLE

SEPARATION


6

SAT

TAT

0

5

10

15

Adia

batic

Fac

tor R

HS

/RH

D

0 2 4 6 8 10 12 14

Altitude [km]

-60

-40

-20

0

20

Tem

pera

ture

[°C

] RHS/RHD

MOZAIC: Humidity Sensor in Rosemount Air Inlet System

H 2 O -S e n s o r

AIRCRAFTSKIN

SENSORSRH: HUMICAP-HT : PT100

DEICINGHEATER



SEPARATION

TAT, RHD

SAT

RHS

Rosemount HousingTotal TemperatureModel 102 BX

In inlet speed reduction (Mach≈0.8 to 0) with adiabaticconversion: ► Heating (SAT to TAT) : in UT ≈ 30oC

► Compression (PS to PD): in UT ≈ Factor 1.6RH at detector (RHD) << RH sampled air (RHS)

► At cruise altitude RHS ≈ 13 x RHD


7

MOZAIC-Humidity: Pre-&Post Flight Calibration

♦ Regular calibration (every 500 flight hours)♦ In environmental simulation chamber♦ Against Lyman(α)-fluorescence hygrometer♦ Under realistic flight conditions of humidity,

temperature and pressure

♦ Evaluation of two year record of pre-and post-flight calibrations

♦ Results agree well with in-flightintercomparisons

[Helten et al. Geophys.Res.1998, 1999]


0

2

4

6

8

10

Abs

.Err

or o

f Rel

.Hum

i. [%

RH

]

12 9 6 3 0

Altitude [km]

All Data 1999/2000



8

MOZAIC Relative Humidity in Upper Troposphere (UT) over Atlantic

• MOZAIC provided the firstclimatology of humidity in the UT

• Large variability in time and space

-20

0

20

40

60La

titud

e

5102030405060708090100

Jan

95

Jan

96

Jan

97

Jan

98

Jan

99

Jan

00

• More than 30% of UTH-dataare Ice Super Saturated (ISS)

• But less than 0.5-1% of dataare Saturated to Liquid

%

Control of Humidity in UT??Long Term Changes ??

Ice

Liquid

0

2

4

6

8

10

Pro

bab i

li ty

[ %]


40N-60N

Ice

Liquid

0

2

4

6

8

10

Pro

bab i

li ty

[ %]


40N-60N

Ice

Liquid

0

2

4

6

8

10

Pro

bab i

li ty

[ %]


40N-60N

Ice

Liquid

0

2

4

6

8

10

Pro

bab i

li ty

[ %]


40N-60N

Ice

Liquid

0

2

4

6

8

10

Pro

bab i

li ty

[ %]


40N-60N

Ice

Liquid

0

2

4

6

8

10

Pro

bab i

li ty

[ %]


Ice

Liquid

0

2

4

6

8

10

Pro

bab i

li ty

[ %]


40N-60N

Ice

Liquid

0

2

4

6

8

10

Pro

bab i

li ty

[ %]


40N-60N

Ice

Liquid

0

2

4

6

8

10

Pro

bab i

li ty

[ %]


Ice

Liquid

0

2

4

6

8

10

Pro

bab i

li ty

[ %]


40N-60N

Ice

Liquid

0

2

4

6

8

10

Pro

bab i

li ty

[ %]


40N-60N

Ice

Liquid

0

2

4

6

8

10

Pro

bab i

li ty

[ %]


Ice

Liquid

0

2

4

6

8

10

Pro

bab i

li ty

[ %]


40N-60N


9

Performance MOZAIC Humidity Device in Clouds:Evaporation of Ice Crystals ???????

• Clouds are clearly detected as „RHI-burst“ to 200% by Ly(α)-Total H2O • In clouds the MOZAIC-Humidity Device not exceeding 100% RHI

13:00 13:30 14:00 14:30 15:00Time / UTC

0

50

100

150

200

Rel

. Hum

idity

ove

r Ice

/ %

MOZAIC FISH Total H2O

SPURT : MOZAIC and FISH aboard Learjet-aircraft, 22-08-2002: Monastir (Algeria) - Hohn (Germany)


10

• Small scale phenomenon(ΔX < 200 km, ΔZ < 1-2 km)

• Difficult to see by satellites• Importance:

contrail & cirrus formation;radiative balance; OH formation

0 50 100 150 200 250 300 350 400 450 5000

500

1000

1500

2000

2500Summer |pv| < 2 Δ time < 0.0022

Freq

uenc

y

ISS horizontal extent [km]

Freq

uenc

y


0 50 100 150 200 250 300 350 400 450 5000

500

1000

1500

2000

2500Summer |pv| < 2 Δ time < 0.0022

Freq

uenc

y


Freq

uenc

y


0 50 100 150 200 250 300 350 400 450 5000

500

1000

1500

2000

2500Summer |pv| < 2 Δ time < 0.0022

Freq

uenc

y


Freq

uenc

y


0 50 100 150 200 250 300 350 400 450 5000

500

1000

1500

2000

2500Summer |pv| < 2 Δ time < 0.0022

Freq

uenc

y


Freq

uenc

y


0 50 100 150 200 250 300 350 400 450 5000

500

1000

1500

2000

2500Summer |pv| < 2 Δ time < 0.0022

Freq

uenc

y


Freq

uenc

y


0 50 100 150 200 250 300 350 400 450 5000

500

1000

1500

2000

2500Summer |pv| < 2 Δ time < 0.0022

Freq

uenc

y


Freq

uenc

y


0 50 100 150 200 250 300 350 400 450 5000

500

1000

1500

2000

2500Summer |pv| < 2 Δ time < 0.0022

Freq

uenc

y


Freq

uenc

y


0 50 100 150 200 250 300 350 400 450 5000

500

1000

1500

2000

2500Summer |pv| < 2 Δ time < 0.0022

Freq

uenc

y


Freq

uenc

y


0 25 50 75 100 125 150 175Relative Humidity [% , Ice]

0

2

4

6

8

10

Prop

abilit

y [%

]

ECMWF

MOZAIC

40N-60N

• 30% of the UT showsice super saturation (ISS)

• Global models do not reproduceISS

• ISS relates with sub-visiblecirrus

Horizontal extentof ISS regions

MOZAIC: Ice Super Saturation (ISS) in the UT


11

-100 100-50 0AIRS - MOZAIC RH (liq.%)

50

RH (liq.%)

MOZAIC

0

AIRS

20 40 60 80 100 120

MOZAIC- UTH: Comparison with AIRS-Satellite over 2003(Work by Co PI: Andrew Gettelman, NCAR, Boulder, USA)

Development of „matching“ citeria of coincidence in space and time:A priori estimation of contribution of natural variabilityDirect comparison at (x,y,z,t)Indirect by optimizing statistics of coincidence by using backward trajectories


12

-3 -2.5 -2 -1.5 -1 -0.5 0 0.5 1 1.5 2 2.5 3Temperature Difference Aircraft minus MOZAIC (K)

0

2

4

6

8

10

12

Rel

ativ

e O

ccur

ence

(Bin

=0.1

K) i

n %

Temperature Measurements Using TAT-Housings: Comparison Temperature Aircraft versus MOZAIC

Temp.

Spec.Hum.

Rel.Hum.

In addition, important aspect at low temperatures: Which H2O-saturation pressure Es(T)-table has been applied ???


13

Development of automatic In-flight Calibration (IFC)[Smit et al., Journal of Oceanic and Atmospheric Technology, May 2008]

Based on the technology and experience obtainedduring 8 years of MOZAIC-operation.

Long-term zero drift of MOZAIC-device,particularlyat low temperatures, is the critical and accuracydetermining parameter

On-line determination of long term zero drift duringdry stratospheric episodes (5ppmv water vapor)as a function of temperature.On-Line correction of zero drift of RH-measurements


14

MOZAIC In-Flight Calibration (IFC): Validation

15:00 16:00 17:00Time / UTC

0

10

20

30

RH

I / %

0

1

2

3

Pote

ntia

l Vor

ticity

/ pv

u

CASHAICLyman-AlphaPV

-60

-55

-50

Tem

pera

ture

/ °C

-8 -4 0 4 8RH(AIC) - RH(MOZAIC) [% RH]

0

2

4

6

8

10

12

Alti

tude

[km

]Comparison with MOZAIC In-flight comparison during SPURT

with Ly(α)-Hygrometer (FISH)

RH(IFC) – RH (MOZAIC) [%RH]

IFC


15

Candidates for Automatic Monitoring Humidityby Commercial Aircraft

WVSS-II

H 2 O -S e n s o r

AIRCRAFTSKIN

SENSORSRH: HUM ICAP-HT : PT100

DEICINGHEATER



SEPARATION


16

Only internal reports

Not known

Not known

4 s

0.5 ppmv

5-10% of Mix. Ratio

6-12 km

Not proven

Rosemount (??)-Not known

Lyman(α) Fluorescence

~20 (estimated)

~20x8x8 cm

2 kg

FLASH

Under investigation (IAGOS)???Only internal

reportsPeer reviewed

literatureDocumentation of performance

Not KnownNot KnownNot ProvenProven, every ½yearMaintenance

Not KnownNot KnownNot provenProven (12 yrs MOZAIC)

Long term stability

1s1s2s 5s (0km), 60s (12km)Time response

Not known1 ppmv70 ppmv5% Rel. Hum.Detection Limit

Not known5-10% of Mix. Ratio

5-10% of Mix. Ratio

5-10% of Rel. Hum.Accuracy

0-12 km0-12 km0-6 km0-12 kmAltitude Range

Not provenNot provenNot proven every 6 monthsCalibration frequency

Rosemount- Not known

External mounting of optical cell

Wall plate in AC skin

- Not known

Rosemount- No wall effects

Inlet system- Wall effects

Frostpoint (Surface acoustic wave chip)

Spectroscopic(Tunable Diode

Laser)

Spectroscopic(Tunable Diode

Laser)

Capacitive (Humicap)Principle

~20 (estimated)~50 (estimated)~20~20Price (kEuro)

~15x15x10 cm~25x25x15 cm23x13x8 cm14x12x7 cmInternal Box Size

2 kg103 kg2 kgWeight

SAW-FrostpointOpen Path TDLWVSS-IIMOZAIC

Compact Sensors for Measuring Humidity on In-Service Aircraft


17

US-NWS has installed on 25 UPS aircraft since 2005 , now in evaluation phase but with plans to extend to large numberPoor documentation on evaluation of performanceFZJ has evaluated in the laboratory in 2005 DWD has installed on three A320 of Lufthansa since 2007In the loop: plans to install on a MOZAIC/IAGOS A340 of Lufthansa ?

Can new airborne WVSS-II measure humidity in UT and LS?:State of the Art

Diode laser(2f-detection)

Compact(≈ 2.5 kg)

Designed for automatic on-line sampling ofhumidity from aircraft for weather forecasting

AMDAR

Goal NWS: Reduce radiosounding network and replace by AMDAR


18

Reports:• Aircraft Identification• Date • Time (UTC)• Position• Altitude (Pressure)• Temperature• Windspeed• Wind Direction• Planned: Water Vapor

Mass Mixing Ratio

AMDAR = Aircraft Meteorological DAta RelayAboard Commercial Aircraft For Weather Forecasting


19

190 210 230 250 270 290 310Frostpoint Temperature Reference Hygrometer [K]

-0.2

-0.1

0

0.1

0.2

0.3

0.4

Rel

. Dev

iatio

n W

VSS

from

Ref

. [(W

VSS

-Ref

.)/R

ef.]

(WV

SS a

nd R

ef. i

n vo

lum

e m

ixin

g ra

tio)

190

210

230

250

270

290

310

Fros

tpoi

nt T

empe

ratu

re W

VSS

II [K

]

190 210 230 250 270 290 310Frostpoint Temperature Reference Hygrometer [K]

-0.2

-0.1

0

0.1

0.2

0.3

0.4

Rel

. Dev

iatio

n W

VSS

from

Ref

. [(W

VSS

-Ref

.)/R

ef.]

(WV

SS a

nd R

ef. i

n vo

lum

e m

ixin

g ra

tio)

190

210

230

250

270

290

310

Fros

tpoi

nt T

empe

ratu

re W

VSS

II [K

]

Frost Point TemperatureRel.Deviation WVSS from Ref.

Can new airborne WVSS-II measure humidity in UT and LS???:Performance tests at Environmental Simulation Facility at Jülich, Germany

WVSS at Frostpoint Temperatures:Above ~290 K: No reliable signal225 K – 290 K: Good performance:

Accuracy ±(5-10)%215 K – 225 K: Rapid declining sensitivity,

Limited accuracy: <±(10-15)% Below ~ 215 K: Below detection limit (80 ppmv)

Poor to bad performance in UT/LS

Diode laser(2f-detection)

Compact(≈ 2.5 kg)

Designed for automatic on-line sampling ofhumidity from aircraft for weather forecasting

AMDAR


20

Pre-and Post flight calibration every 500 flight hours) [Helten et al. 1998]In-flight comparisons (In-service & Research) [Helten et al., 1999]Evaluation in first SPARC-water vapor assessment [2000 report]Development in-flight calibration (IFC) method [Smit et al., 2008]Evaluation of detection of ice superation saturation [in-preparation]Assessment of performance of 12 years of MOZAIC-flight operation[in preparation]

12 year climatology of MOZAIC-H2O/T data available in MOZAIC-database at ToulouseParticipating in COST-action: WaVaCS (Water Vapor in the Climate System)

Participating in new, second SPARC water vapor assessmentNew instruments are under investigations.

MOZAIC/IAGOS: Summary QA-H2O/T Performance


21

Thank You


22

Extra Material


23

Source: Tompkins, Gierens and Rädel, Quart.J.Roy.Met.Soc, 2007

ECMWF Model Include Ice Super-Saturation


24

-3 -2.5 -2 -1.5 -1 -0.5 0 0.5 1 1.5 2 2.5 3Temperature Difference Aircraft minus MOZAIC (K)

0

2

4

6

8

10

12

Rel

ativ

e O

ccur

ence

(Bin

=0.1

K) i

n %

MOZAIC: Comparison Temperature Aircraft versus MOZAIC]

⎟⎟⎠

⎞⎜⎜⎝

⎛⋅⎟⎟⎠

⎞⎜⎜⎝

⎛ −+⋅= 2

V

VP Mc2

cc1SATTAT

Both measured with Rosemount TATAssumption full adiabatic conversion:

Measurement of TAT (σ=±0.25K)Determination M from TAP (σ=±0.25hPa)& SAP (σ=±0.35hPa)Determination SAT (σ=±0.50K)

Practice: TAT-recovery 99.5-99.7% Correction tables based on wind ductmeasurements (made in 1960/1970‘s)

Dependece on angle of attackDependence on location at aircraft skinRemaining sources of uncertainties

TAT = Total Air TemperatureSAT = Static Air TemperatureTAP = Total Air PressureSAT = Static Air Pressure

=0.2


25

Rosemount-TAT inlet systems: No indication of evaporation of ice crystalsEvaporation of liquid droplets

Large temperature sensitivity of H2O-saturation:Review of water vapor saturation tables at low temperaturesTemperature measurement needs more attention:

- Adiabatic recovery factor- Location at aircraft- Comparison with other in-situ temperature sensing technics

Scale analysis of spatial and temporal distribution of ISS

Climate impact of ISS

Outstanding Issues UTH-ISS Observations


26

MOZAIC Humidity Device: Performance and Quality Assurance

♦ Evaluation of two year record of pre- and post-flight calibrations

♦ Results agree well with in-flightinter comparisons[Helten et al., J.Geophys.Res.1999]

Calibration procedure:1. Pre-flight calibration: a1(Ti) & b1(Ti)

- Installation in A340- ≈500 h of flight operation- Exchange of MHD

2. Post-flight calibration: a2(Ti) & b2(Ti)- Cleaning RH- & T-sensor

3. Pre-flight calibration- Etc. etc.

RHCAL(Ti) =a (Ti)+b (Ti) x RHUNCAL (Ti)

Uncertainty of RH is derived from:• Difference between pre-and post

flight calibration of RH• Uncertainty Temperature


0

2

4

6

8

10

Abs

.Err

or o

f Rel

.Hum

i. [%

RH

]

12 9 6 3 0

Altitude [km]

All Data 1999/2000



27

-13 -12 -11 -10 -9 -8 -7Longitude

70

80

90

100

110

120H

2O M

ixin

g R

atio

[ppm

v]

POLINATMOZAIC

Section ASection B Section C

POLINAT

MOZAIC

MOZAIC-Humidity: In-Flight Comparison with Frost Point Hygrometer (Ovarlaz) on Falcon (DLR/Nov.1997)

[Helten et al., J.Geophys.Res.1999]


28

MOZAIC-UTH: Comparison with POEM III Satellite

POEM III= Polar Ozone and Aerosol Measurement III satellite operational sinceApril 1998Good agreement POEMwith MOZAIC (Slope=0.98)

Large variations due toAtmospheric variability &Limited resolution of POEM (ΔX=250 km)

Source: Nedoluha et al., POAM III measurements of water vapor in the upper troposphere and lower moststratosphere, J. Geophys. Res., 2002

Coincidence criterion: 2.5º x 2.5º x 1 km x 6 hTotal: 200 Coincidences April 1998-Feb.2000

Slope = 0.98 (r=0.70)Offset= 3.6 ppmv

0 200100 300 400

200

100

300

400

POEM-UTH (ppmv)

MO

ZAIC

-UTH

(ppm

v)


29

MOZAIC-UTH: Comparison with MLS/UARS Satellite

MLS observe no ice supersaturation (retrieval and/orlimited horizontal resolution)MLS lower than MOZAIC(Slope=0.64)

Large variations due toAtmospheric variability &Limited resolution of POEM (ΔZ=4-5 km)

Source: Read et al., UARS MicrowaveLimb Sounder upper tropospheric humidity measurement: Method and validation, J. Geophys. Res., 2001

Coincidence criterion: 1º x 1º x 1 km x 3 hTotal: 384 Coincidences Aug.1994-Dec.1997


30

Ice

Liquid

0

2

4

6

8

10

12

Pro

babi

lity

[%]


00N-20N

Ice

Liquid

0

2

4

6

8

10

12

Pro

babi

lity

[%]


20N-30N

Ice

Liquid

0

2

4

6

8

10

Pro

babi

lity

[%]


30N-40N

Ice

Liquid

0

2

4

6

8

10

Pro

babi

lity

[%]


40N-60N

MOZAIC: Distribution Relative Humidity in UT over AtlanticZ = 9-12 km, PV ≤ 2.0pvu, 10oW-70oW, Aug 1994 - June 2000

≈38% ISS

≈15% ISS≈15% ISS

≈22% ISS


31

Critical aspects on inlet system

Ice Super Saturation over North Atlantic:More than 35% of UTH ice super saturatedBut less than 1% of observations aresaturated to liquid

Separation solid / gas phaseParticle enhancementEvaporation droplets & crystalsWall memory effectsWell defined P & T (cq. SH & RH)-conditions

Ice

Liquid

0

2

4

6

8

10

Pro

babi

lity

[%]


40N-60N

Ice

Liquid

0

2

4

6

8

10

Pro

babi

lity

[%]


40N-60N

Ice

Liquid

0

2

4

6

8

10

Pro

babi

lity

[%]


40N-60N

MOZAIC


32

Performance MOZAIC Humidity Device & ISS:Artifacts due to Evaporation of Ice Crystals ???????

10 0 -10 -20 -30 -40 -50 -60 -70Temperature Ambient Air [oC]

0

10

20

30

40

50

60P

erce

ntag

e of

Mea

sure

men

ts

With

Sup

er S

atur

atio

n [%

]

SS to 100% RH to Liquid

SS to 100% RH to Ice(Corrected for Liquid Fraction)

SS to 100% RH to Liquid & Ice


33

MOZAIC-IFC: In-Flight Correction of Zero Drift of RH-measurements

230 240 250 260 270 280Sensor Temperature, TD [K]

-0.25

0

0.25

0.5

0.75

Sens

or S

igna

l Vol

tage

UD

[V]

D0

D0

UD,LS


-0.25

0

0.25

0.5

0.75

Sens

or S

igna

l Vol

tage

UD

[V]

D0

D0

UD,LS


-0.25

0

0.25

0.5

0.75

Sens

or S

igna

l Vol

tage

UD

[V]

D0D0

D0D0

UD,LS


34

Every 6 months cleaning sensor at airport:rins with destilled water (1 min) rins with alcohol ( 1min)heat out (1 min @ ~90oC)

Every 2 year overal check at service company:exchange humidity device and send to service companyoverall check of device (new sensors, calibration etc.).

Outlook:automatic cleaning procedure at airportcollaborations with companies for instrumental and QA

support (e.g.Vaisala)

Operational Aspects of MOZAIC-Humidity DeviceFrom Board Commercial Aircraft


35

Routine Aircraft Measurements in the Global Observing System:The Link Between Surface and Space


36

IAGOS-ERI

Integration of routine Aircraft measurements into a Global Observing System –

a European Research Infrastructure

Routine Aircraft Measurements Routine Aircraft Measurements in a Global Observing System:in a Global Observing System:

The Link Between Surface and SpaceThe Link Between Surface and Space

http://www.fz-juelich.de/icg/icg-2/iagos


37

• 4/2009 IAGOS Design Study completed, - Prototypes available, - Partner airlines committed

• 2009 First aircraft equipped and commissioned: O3, CO, H2O, Cloud Droplet Probe, NOy

• 2010 Certification for CO2 and aerosol• 2016 20 aircraft equipped and commissioned• 2028 20 years of data available

~ 150 000 flights

http://www.fz-juelich.de/icg/icg-ii/iagosCoordinator: Dr. Andreas Volz-Thomas

E-mail: [email protected]

IAGOS-ERI: Time Table

measuring atmospheric humidity from commercial aircraft ... · h2o from mozaic-iagos // herman...

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