Long-term monitoring of the tropospheric aerosol vertical structure and optical properties by active and passive remote-sensing at Ny-Aales

und, Svalbard

M. Shiobara 1), M. Yabuki 1), R. Neuber 2), E.J. Welton 3),

T.A. Berkoff 3), J.R. Campbell 3), and J.D. Spinhirne 3)

1) National Institute of Polar Research, Tokyo, Japan2) Alfred Wegener Institute for Polar and Marine Research, Potsdam, Germany

3) NASA Goddard Space Flight Center, Greenbelt, MD, USA

8th Circumpolar Symposium on Remote Sensing of Polar Environments, 8-12 June 2004, Chamonix, France

(IPCC, 2001)

Objectives of aerosol remote sensing in the Arctic

1. Climatology of aerosol optical/physical properties in the Arctic:

# Aerosol optical depth

# Aerosol size distribution

# Single scattering albedo

# Scattering phase function

2. Aerosol-cloud interaction:

# Arctic haze and arctic stratus clouds

# Formation and dissipation processes of aerosol and clouds

3. Contribution to MPLNET: # Data transfer to the NASA/GSFC aerosol/cloud group # Validation of satellite retrievals from ICESat/GLAS

Ny-Alesund

Location of the NIPR Arctic Observation Site

Ny-Aalesund, a unique international research site in Svalbard

NIPR Rabben Observatory is located 1.5km west of downtown Ny-Aalesund

AnemometerThermometer

POSSX-band 10GHz radar

All-sky cameraSky-radiometer

Microwave radiometer

Remote-sensing instrumentation for atmospheric research at Rabben

Sky radiometer, Prede POM-01

Specifications

Wavelength 315, 400, 500, 675, 870, 940, 1020 nmMonochromator Narrow-band interference filterFWHM of filter 3 nm for 315, 10 nm for othersDetector Silicon photodiodeElec. dynamic range 107

FOV angle 1 deg in full angleAmbient environment -30 to +35 (sensor unit)℃ 0 to +35 (control unit)℃

[ Analysis method ]

Sky-radiance inversion method, SKYRAD ( Nakajima et al., 1996 )

1.0E-08

1.0E-07

1.0E-06

1.0E-05

0.01 0.1 1 10 100Radius (μ m）

dV/d

lnr

(cm

3 /cm

2 )

15:1715:3215:4716:0016:1416:2416:34

1.0E-08

1.0E-07

1.0E-06

1.0E-05

0.01 0.1 1 10 100Radius (μ m）

dV/d

lnr

(cm

3 /cm

2 )

10:04

10:22

10:42

11:02

11:22

11:47

12:02

( a ) 23 March 2000 ( b ) 17 April 2000

BackgroundHaze

Volume size distribution for the haze and background days during the ASTAR 2000 campaign. The number of the smaller particles for the haze case was larger than that

for the background case.

Cloud detection from all-sky images

All-sky camera with a fish-eye lens

All-sky image over Ny-Alesund on 30 May 2004, 13UTC

Micro-Pulse Lidar System in Ny-Alesund, Svalbard

MPL operated at NIPR Rabben Observatory since March 1998 until June 2003

MPL operated at AWI Koldewey Station since June 2003 to present

Micro-Pulse Lidar (MPL)

Specifications

Laser Diode-pumped Nd/YLF laserWavelength 523 nmPulse energy 8-10 JPulse frequency 2500 HzDetector Single photon counting APDRange resolution 30 m

Range corrected relative backscatter profile and the temporal variation over Ny-Alesund on 13 May 2004

5

4

3

2

1

025 (12:00) 26 (00:00)25 (18:00) 26 (12:00)26 (06:00)

Alt

itud

e (k

m)

March 2000

Cloud formation process associated with development of a haze layer

Vertical structure and temporal variation of aerosol and cloud layer observed by a Micro-Pulse Lidar at Ny-Aalesund, Svalbard

Analysis of passive/active remote sensing using sky-radiometer and MPL

Analysis focuses on the difference of aerosol optical properties for the haze condition and for the background condition in the Arctic.

HZ : Averaged optical thickness > 0.1

BG : Averaged optical thickness < 0.07

Sky-radiometer

Size distribution

Optical thickness

Single scattering albedo

Angstrom parameter

MPL

Vertical profile of the extinction coefficient

S1 parameter (Lidar ratio)τ- matching method

0.5 1.01.5

2.02.5

0

10

20

30

40

50

60

Freq

uenc

y

Angstrom parameter

BG [Ave.=1.52, S.D.=0.337]HZ [Ave.=1.66, S.D.=0.226]

0.00 0.05 0.10 0.15 0.20 0.25

0

10

20

30

40

50

60

Freq

uenc

y

τ (500nm)

BG [Ave.=0.057, S.D.=0.017]HZ [Ave.=0.126, S.D.=0.035]

0.80 0.85 0.90 0.951.00

0

20

40

60

80

100

120

140

Freq

uenc

y

ω 0 (500nm)

BG [Ave.=0.975, S.D.=0.039]HZ [Ave.=0.974, S.D.=0.031]

Angstrom parameterAerosol optical depth

Single scattering albedoResults from ASTAR 2000 campaign1. AOD: HZ>0.1, BG<0.072. Angstrom parameter: HZ>BG3. Single scattering albedo: HZ=BG

AOD of arctic haze became larger with contribution of small particles such as sulfate aerosol.

Sometimes arctic haze includes absorptive aerosol such as soot.

0

10

20

30

40

50

60

0.5 1.0 1.5 2.0Angstrom parameter

S1

para

met

er (sr

)

BGHZ

Fig. (a): Relation between the τ(523 nm) and S1 parameter at 523 nm. S1 parameter has a positive correlation with the optical depth τ(523nm). The averaged S1 parameter of the background case (BG) is 11.4 sr and that of the haze case (HZ) is 21.2 sr.

Fig. (b) shows the relation between the Angstrom parameter and S1 parameter.

0

10

20

30

40

50

60

0.00 0.05 0.10 0.15 0.20τ (523nm)

S1

para

met

er (sr

)

BG [Ave.=11.4, S.D.=3.9] HZ [Ave.=21.2, S.D.=8.5]

(a) (b)

absorptive aerosol?

MPLNET Sites

(From http://mplnet.gsfc.nasa.gov)

Syowa (69S, 40E)

Ny-Alesund (79N, 12E)

MPLNET is operated by NASA/GSFC and participating partners including NIPR’s polar sites

ICESat/GLASTable 1. GLAS Science Products

Measurement

Spatial

Horizontal

Resolution

Vertical

Expected

Accuracy

Range of

Measureme

nt

Cloud Optical Depth 10 km ___ 50% 0.01 - 2.0

Cloud Scattering Cross

Section

10 km 76 m 10% 10-6 - 10-1

(1/m-sr)

Aerosol Scattering

Cross Section

30 km 76 m 10% 10-7 - 10-4

(1/m-sr)

Aerosol Optical Depth 30 km ___ 50% 0.01 - 2.0

Cloud Top Height 200 m 76 m 100 m 300 m-22

km

Cloud Bottom Height 200 m 76 m 200 m 150 m-22

km

Tropospheric Aerosol

Top and Bottom Height

30 km 76 m 150 m 400 m-38

km

PBL Height 2 km 76 m 150 m 150 m-6 km

Ice, Cloud, and land Elevation Satellite

Geoscience Laser Altimeter System

Launched on 12 January 2003

ICESat/GLAS passed over Ny-Alesund on 21 May 2004, around 01:40 UTC

Tracks of ICESat

All-sky image

MPL, Ny-Alesund

ICESat/GLAS

1. Combined remote sensing with active/passive instruments is being continued at Ny-Aalesund, Svalbard for the atmospheric environment research in the Arctic.

2. Aerosol optical properties and their vertical/temporal variations are investigated for their climate impact based on long-term monitoring with Sky-Radiometer and Micro-Pulse Lidar.

3. These measurements are expected to also contribute to ground validation of satellite aerosol/cloud retrievals from space-borne active sensors such as ICESat/GLAS.

　

Summary

Acknowledgments: Operations of MPL at Rabben Station in Ny-Alesund until June 2003 were helped by the on-site engineers of Norwegian Polar Institute. Operations of MPL at Koldewey Station since June 2003 were helped by the on-site engineers of Alfred Wegener Institute for Polar and Marine Research.

8th Circumpolar Symposium on Remote Sensing of Polar Environments, 8-12 June 2004, Chamonix, France