Satellite observations of the meso- and submesoscale eddies in the Baltic and Black Seas Svetlana...
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Transcript of Satellite observations of the meso- and submesoscale eddies in the Baltic and Black Seas Svetlana...
Satellite observations of the meso- and submesoscale
eddies in the Baltic and Black Seas
Svetlana [email protected]
M.Sc. in oceanography – Lomonosov Moscow State University
Ph.D. student – Space Research Institute of RAS (IKI)
Department of the Earth investigations from space
Space Radar Laboratory
Research topics
Mesoscale and submesoscale eddies of the Black and Baltic Seas as seen by satellite radiometer and synthetic aperture radar (SAR) data:
Ways of eddies visualization in satellite images Generic types Spatial and temporal parameters Areas of distribution Seasonal and interannual dynamics Influence on vertical water structure and
bioproductivity
2INTRODUCTION
Motivations• Mesoscale eddies:
– horizontal water transport– upwelling/downwelling– contamination dilute and water self-
cleaning– seawaters bioproductivity
• Submesoscale eddies:– reasons and mechanisms of generation– lifetime– depth– contribution to water transport and mixing
3INTRODUCTION
Areas of interest4INTRODUCTION
Baltic Sea
Black Sea
Baltic Sea
Black Sea
Satellite radiometer data
•MODIS Aqua, spatial resolution 1 km, time coverage 04.2006-12.2009, total number of images 1100 Water-leaving radiance 551 nm (WLR) Chlorophyll-а concentration (Chl-a) Sea surface temperature (SST)
•AVHRR NOAA/MetOp-2, SST, spatial resolution 1 км, time coverage 09.2004-12.2009, total number of images 4400
5MESOSCALE EDDIES: GENERAL INFORMATION
Image examples (20.06.2006) 6MESOSCALE EDDIES
MODIS WLR
MODIS SST
AVHRR SST
MODIS Chl-a
The Black Sea mesoscale eddies• The Rim Current meanders and rings• Quasistationary anticyclonic eddies• Near-shore anticyclonic eddies (NAEs)• Mushroom-like currents (eddy dipoles)• Eddies of the Anatolian Coast• Shear eddy chains
7MESOSCALE EDDIES: GENERAL INFORMATION
Mushroom-like currents 8
2008
interannual variability
Mushroom-like currents:
9
Winter
Spring
Summer Autumn
10
Seasonal variability
Mushroom-like currents’ scale
Mushroom cap width (km)
Number
11MESOSCALE EDDIES: GENERAL INFORMATION
Eddy-induced chl-a transport12MESOSCALE EDDIES: INFLUENCE ON WATER STRUCTURE
MODIS WLR MODIS WLR 20.05.200920.05.2009
Eddy-induced chl-a productionAVHRR SST 5.08.
2008MODIS Chl-a 8.08.2008
13MESOSCALE EDDIES: INFLUENCE ON WATER STRUCTURE
Mushroom-like current
Cruise11-17.08.2004
MODIS Aqua Chl-a
14.08.2004
14MESOSCALE EDDIES: INFLUENCE ON WATER STRUCTURE
SeaWiFS Chl-a
Density section 1814-1825
15MESOSCALE EDDIES: INFLUENCE ON WATER STRUCTURE
Synthetic Aperture Radar (SAR) imagesEnvisat ASAR and ERS-2 SAR. Spatial
resolution 12.5 or 75 m depending on image mode
Black Sea:• Since 1998• 2006-2008: 390 images (Russian part of the sea)• 2009: 315 imagesTotal: 875 images
Baltic Sea:• 2009: 336 images
16SUBMESOSCALE EDDIES
Spiral lines of natural films (“black eddies”). The Baltic
Sea
Envisat ASAR WSM, 25.04.2009, 09:09 GMT
17SUBMESOSCALE EDDIES
Spiral lines of natural films (“black eddies”).The Baltic Sea
ERS-2 SAR IMM, 21.06.2009, 09:47 GMT
©ESA 200918
Wave/current interaction
(“white” eddies)Envisat ASAR:
a) 26.01.2010 07:58 GMTb) 18.02.2010 07:37 GMTc) 05.11.2009 07:37 GMT
19SUBMESOSCALE EDDIES
Eddies visualized by ice tracers. The Kattegat Strait
Envisat ASAR WSM 26.01.2010, 09:36 GMT
©ESA 201020
Number of the eddies discovered in SAR images of the Black Sea
Generally: 845 eddies in 875 images (1 eddy per image) 845 eddies in 186 images (4,5 eddies per image)
In 2009: 553 eddies in 311 images (1,8 eddies per image) 553 eddies in 100 images (5,5 eddies per image)
“Black” and “white”
“Black”
“White”
Number
Relation of the “black” and “white” eddies detected in SAR images
21SUBMESOSCALE EDDIES
The Black Sea eddy size
“Black” eddies size
Diameter (km)
Number
Number
“White” eddies size
Diameter (km)
Baltic
Black
“Black” 3-5 6-7“White” 5-6 4-5
Size comparing
22
“Black” eddies in the
Baltic Sea
LEGEND:• Winter• Spring• Summer• Autumn
23
“Black” eddies in the Black SeaLegend:• Winter• Spring• Summer• Autumn
24SUBMESOSCALE EDDIES DISTRIBUTION
(а) Envisat ASAR 23.07.2008; (b) ASAR&MERIS; (c) Envisat MERIS 24.07.2008(а) Envisat ASAR 01.08.2008; (b) ASAR&MERIS; (c) Envisat MERIS 31.07.2008
25SAR AND RADIOMETER DATA COMPARISON
(a) Envisat ASAR 17.07.2009;(b) Landsat ETM+ 17.07.2009 (bands 3, 2, 1)
26SAR AND RADIOMETER DATA COMPARISON
Frontal
eddies
Envisat ASAR 08.04.2009 08:07 GMT
WLR Chl-a SST
27SAR AND RADIOMETER DATA COMPARISON
Space Research Institute, Moscow
28EDDIES IN THE BALTIC AND BLACK SEAS