PhysikFachbereich 1
Institut für Umweltphysik
Satellite Based Retrieval of Desert DustDeposition into the Atlantic Ocean
SeaWIFS AOT June 2008
Jäger, Malte1; Lelli, Luca1; von Hoyningen-Huene, Wolfgang1; Vountas, Marco1; Burrows, John Philip1
*Institute of Environmental Physics (IUP), Bremen
Project information:
• working group: CASPAR @ IUP (Cloud Aerosol Surface PArameter Retrieval group)• cooperation with MARUM: Jan-Berend Stuut, Ute Merkel, Gerhard Fischer, Carmen Friese
Frascati, 30.10.2014
PhysikFachbereich 1
Institut für UmweltphysikSatellite Based Retrieval of Desert Dust
Deposition into the Atlantic Ocean
Content
• Motivation• The whole project• Study area & aims• Retrieval method• Preliminary results• Summary & outlook
Frascati, 30.10.20142 / 14
PhysikFachbereich 1
Institut für UmweltphysikSatellite Based Retrieval of Desert Dust
Deposition into the Atlantic Ocean
Motivation
[Winckler, et. al.]
Frascati, 30.10.20143 / 14
PhysikFachbereich 1
Institut für Umweltphysik
Study Area & Aims
SeaWIFS AOT June 2008
Dust deposition: estimation of mass loss along transport trajectory
Comparison with sedimentation records
Satellite Based Retrieval of Desert DustDeposition into the Atlantic Ocean
Atlantic Ocean west of Sahara, e.g. Cape Blanc
Frascati, 30.10.20144 / 14
PhysikFachbereich 1
Institut für Umweltphysik
Main Goal:
Establish the relationship between dust sedimentation at sea bottom and atmospheric dust load
S edim entation record fromsea bottom
R econstruction of AO T of past tim es
M odelling aerosol radiative forc ing and SST change of the past
D erive present atm osphericdust deposition in N -A tlanticfrom satellite observations of AO T
M odellingsedim entation process of dustto the ocean bottom
M odelling of present aerosol radiative forc ingand e ffect on S STfrom AO T andsedim ent data
Calibra tion of dust deposition m assin term s of AO T
Sedim entationm easurem ents(Sedim ent traps)
The whole project
Satellite Based Retrieval of Desert DustDeposition into the Atlantic Ocean
Interdisciplinary ProjectInstitute of EnvironmentalPhysics,Uni Bremen
Frascati, 30.10.20145 / 14
PhysikFachbereich 1
Institut für Umweltphysik
Retrieval Method
Satellite Based Retrieval of Desert DustDeposition into the Atlantic Ocean
• Step 1: Aerosol / dust data
• AOT data (BAER SeaWiFS, BAER OE MERIS, MISR, …)
• Identification of aerosol type (dust): AAIUV
• Estimation of the columnar aerosol load from AOT
3 ( ) log ( )4 logAer ext Col Aer Aer
dM rQ d r xxxxxxxxdz M f ar d r
xx
Aerosol optical thickness columnar aerosol mass
size distribution & density of dust needed.. … …. .
.. … …. ... … …. .
.. … …
.. ..… …. .
.. … …. ... … …. .
.. … …. ... … …
.. ..… …. .
h
Frascati, 30.10.20146 / 14
PhysikFachbereich 1
Institut für Umweltphysik
Retrieval Method
Satellite Based Retrieval of Desert DustDeposition into the Atlantic Ocean
• Step 2A: Deposition estimation
• Dust deposition: estimation of mass loss along transport trajectory
• Definition of several boxes along trajectory of dust transport
• Difference in AOT between boxes -> deposition
M2 M1
1 2 ( )I IIAer Aer
SedaM Mc
A t A t
Using long term averages of dust mass change over a reference area
Frascati, 30.10.20147 / 14
PhysikFachbereich 1
Institut für Umweltphysik
Retrieval Method
Satellite Based Retrieval of Desert DustDeposition into the Atlantic Ocean
• Step 2B: Transport trajectories
• Wind data: ECMWF reanalysis {+ satellite data}
• Transport level / altitude:1. wind data ~ 1.5km2. retrieval run3. new wind level adapted to situation: assumption: high deposition <-> lot of dust at low level -> the higher the deposition from 1st run, the lower the relevant wind level4. 2nd retrieval run with adapted wind data
• Box orientation and form adapted to trajectory
• Future improvements: aerosol profiles, e.g. CALIPSO CALIOP
Frascati, 30.10.20148 / 14
PhysikFachbereich 1
Institut für Umweltphysik
First test and visualization
Satellite Based Retrieval of Desert DustDeposition into the Atlantic Ocean
Limitations:
• Transport:• Real wind not considered• Assumption: easterly-winds
• Coarse spatial resolution: ~1° AOT, deposition fields 2° x 2°
• Low temporal resolution: monthly mean AOT
Frascati, 30.10.20149 / 14
PhysikFachbereich 1
Institut für Umweltphysik
Preliminary Results 1Example: MISR L3 AOT: Time series and images
Satellite Based Retrieval of Desert DustDeposition into the Atlantic Ocean
Two boxes (M1, M2):
AOT:• strong maximum in
summer• clear and repeating
minimum around winter (+ small maximum)
Deposition:• AOTM2 < AOTM1 => deposition• strong signal during
summer
Frascati, 30.10.201410 / 14
PhysikFachbereich 1
Institut für Umweltphysik
Preliminary Results 2: SeaWiFSData: 1997 - 2010
Boxes:Latitude for all: 20-22°N
1. 13,5 - 15,5 ° W2. 15,5 - 17,5 ° W3. 17,5 - 19,5 ° W
4. 19,5 - 21,5 ° W5. 21,5 - 23,5 ° W
Satellite Based Retrieval of Desert DustDeposition into the Atlantic Ocean
1996 2000 2004 2008 2012Tim e
-0.40
0.00
0.40
0.80
1.20
1.60
AO
T(0.
412
µm)
SeaW iFS , C ape B lanc, m onth ly AO T(412 nm )G rid B oxes 20-22 N
13.5-15.5 W
15.5-17.5 W
17.5-19.5 W
19.5-21.5 W
21.5-23.5 W
[Hoyningen-Huene]
Frascati, 30.10.201411 / 14
PhysikFachbereich 1
Institut für Umweltphysik
Preliminary Results 2: SeaWiFS
Satellite Based Retrieval of Desert DustDeposition into the Atlantic Ocean
[Hoyningen-Huene]
( )I IIIAer Aer
Sed AerM aA t
1996.00 2000.00 2004.00 2008.00 2012.00T im e / years /
0.00
0.02
0.04
0.06
0.08
Del
ta A
OTR
2R3*
AO
TR2
0
200
400
600
Dus
t Sed
imen
tatio
n /
mg/
(m²*
day)
/
-0.02 0.00 0.02 0.04 0.06grad(AO TR 2R 3)*AO T(R 2)
0.00
100.00
200.00
300.00
400.00
Dus
t Sed
imen
tatio
n /
mg/
(m² d
ay)
/
[data: Hoyningen-Huene, Yoon, Fischer]
Deposition derived from AOT and real sedimentationSediment trap,Picture: Stuut
Correlation:Data:
Frascati, 30.10.201412 / 14
PhysikFachbereich 1
Institut für Umweltphysik
Summary & outlook
Satellite Based Retrieval of Desert DustDeposition into the Atlantic Ocean
Frascati, 30.10.2014
Article summarizing the project:Luca Lelli, W. von Hoyningen-Huene, M. Vountas, M. Jäger and J.P. Burrows ; Dust deposition rates derived from optical satellite observations; Past Global Changes Magazine; Volume 22, 2014http://www.pages.unibe.ch/download/docs/magazine/2014-2/PAGESmagazine_2014(2)_64-65_Lelli.pdf
13 / 14
• First retrieval to measure dust deposition from satellites• Main idea: evaluation of AOT changes along transport path of dust• Promising results from first tests, even though these included many simplifying assumptions -> correlation with in-situ observations
• Implementation of real trajectories upcoming• Calibration for mass deposition rates (using particle size distribution and in-situ measured deposition rates)• Identification of mineral dust via AAIUV
• Detailled comparison with in-situ data from sediment traps and surface dust collectors
PhysikFachbereich 1
Institut für UmweltphysikSatellite Based Retrieval of Desert Dust
Deposition into the Atlantic Ocean
Thank you for your attention
Questions?
Frascati, 30.10.201414 / 14
PhysikFachbereich 1
Institut für UmweltphysikSatellite Based Retrieval of Desert Dust
Deposition into the Atlantic Ocean
Thank you for your attention
Questions?
Frascati, 30.10.2014
PhysikFachbereich 1
Institut für UmweltphysikSatellite Based Retrieval of Desert Dust
Deposition into the Atlantic Ocean
Frascati, 30.10.2014
PhysikFachbereich 1
Institut für UmweltphysikSatellite Based Retrieval of Desert Dust
Deposition into the Atlantic Ocean
Instrument: SeaWiFS
[NASA]
SeaStar satellite with SeaWiFS on board
Instrument BandsBand Wavelength
1 402-422 nm2 433-453 nm3 480-500 nm4 500-520 nm5 545-565 nm6 660-680 nm7 745-785 nm8 845-885 nm
instrument characteristics:Mission Characteristics
Orbit Type Sun Synchronousat 705 km
Equator Crossing Noon +20 min, descending
Orbital Period 99 minutes
Swath Width 2,801 km LAC/HRPT (58.3 degrees)
Swath Width 1,502 km GAC (45 degrees)
Spatial Resolution 1.1 km LAC, 4.5 km GACRevisit Time 1 day
time of operation: 1997 - 2010
Frascati, 30.10.2014
PhysikFachbereich 1
Institut für UmweltphysikSatellite Based Retrieval of Desert Dust
Deposition into the Atlantic Ocean
Motivation
• Aerosols play an important role in climate development:• warming effect• cooling effect (mineral dust)
[IPCC 2013]
Frascati, 30.10.20143 / 14
PhysikFachbereich 1
Institut für UmweltphysikSatellite Based Retrieval of Desert Dust
Deposition into the Atlantic Ocean
Motivation
[ESA: ENVISAT MERIS]
• Mineral dust has an influence on the oceans
-> Fertilisation
Climate …
Frascati, 30.10.2014
PhysikFachbereich 1
Institut für UmweltphysikSatellite Based Retrieval of Desert Dust
Deposition into the Atlantic Ocean
Aerosol Absorbing Index (UV)
Frascati, 30.10.2014
[Pepijn Veefkind, et. al., KNMI]
PhysikFachbereich 1
Institut für UmweltphysikSatellite Based Retrieval of Desert Dust
Deposition into the Atlantic Ocean
Aerosol Absorbing Index (UV)
Frascati, 30.10.2014
[Pepijn Veefkind, et. al., KNMI]
PhysikFachbereich 1
Institut für UmweltphysikSatellite Based Retrieval of Desert Dust
Deposition into the Atlantic Ocean
Aerosol Absorbing Index (UV)
Frascati, 30.10.2014
[Pepijn Veefkind, et. al., KNMI]