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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