Post on 23-Aug-2020
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This slideshow gives an overview of the CMEMS Sea Surface Temperature Satellite Products
LEVEL1 – For Beginners- Slides have been prepared in Nov 2016
C M E M S S e a S u r f a c e T e m p e r a t u r e
S a t e l l i t e p r o d u c t s
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O u t l i n e
• What is Satellite Sea Surface Temperature (SST)?
• Which Characteristics and Parameters?
• What is CMEMS added value?
• Who are the CMEMS SST data producers?
• Which Satellite SST products in CMEMS catalogue?
Marine Monitoring
O u t l i n e
• What is Satellite Sea Surface Temperature (SST)?
• Which Characteristics and Parameters?
• What is CMEMS added value?
• Who are the CMEMS SST data producers?
• Which Satellite SST products in CMEMS catalogue?
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W H A T I S S A T E L L I T E S E A S U R F A C E T E M P E R A T U R E ? ( 1 / 4 )
• SATELLITE SEA SURFACE TEMPERATURE (SST) is
measured by a sensor called « radiometer » on board of
several satellites.
• CMEMS Satellite SST is obtained by Microwave (MW) and/or
Thermal Infrared radiometers (IR).
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W H A T D O E S S A T E L L I T E M E A S U R E ? ( 2 / 4 )
On the one hand, satellite radiometers retrieve the spectral
radiance signal.
On the other hand, the PLANCK function (Planck, 1918) gives
the relationship between the spectral radiance and the
temperature of the blackbody and its wavelength.
Higher-order computations may be required under unfavorable
atmospheric and surface conditions along with regression
techniques that employ independent in situ measurements.
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W H I C H S A T E L L I T E S A N D S E N S O R S ( 3 / 4 )
• Microwave radiometer SST
Strengths:
• Clouds are mostly transparent
• Relatively insensitive to atmospheric effects
Weaknesses:
• Poorer accuracy and resolution
• Sensitive to surface roughness and precipitation
• Thermal Infrared radiometer SST
Strengths:
• Good resolution and accuracy
• Long heritage (~ 20 years)
Weaknesses:
• Obscured by clouds
• Atmospheric corrections required
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W H I C H S A T E L L I T E S A N D S E N S O R S ( 4 / 4 )
Given the desire to combine the high accuracy and resolution of
the thermal infrared SST with the better temporal and spatial
coverage of passive microwave SST, CMEMS creates blended
products which combines these strengths.
Hence most CMEMS SEA SURFACE TEMPERATURE Satellite
products merge SST originating from :
• Microwave
• and Thermal Infrared radiometers
Marine Monitoring
O u t l i n e
• What is Satellite Sea Surface Temperature (SST)?
• Which Characteristics and Parameters?
• What is CMEMS added value?
• Who are the CMEMS SST data producers?
• Which Satellite SST products in CMEMS catalogue?
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WHICH CHARACTERISTICS? (1/3)
SST satellite data provide with Sea Surface Temperature properties:
• In 2 dimensions (at the ocean surface, displayed on a 2D grid)
• Through a period of time:
• A reprocessing of the past (CMEMS provides with ~20 years in
the past)
• An analysis of the current conditions
• No forecast into the future is provided.
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W H I C H P A R A M E T E R S ? ( 2 / 3 )
• CMEMS Satellite SST is obtained by Microwave (MW) and/or
Thermal Infrared radiometers (IR). Those 2 sensors measure
SST at different depths related to the frequency of the satellite
sensor.
• For example, IR sensors measure SST at a depth of about 20
micrometers, while MW sensors measure SST at a depth of a
few millimeters. More info here and here.
Credits: from GHRSST web site
http://ghrsst-pp.metoffice.com/pages/sst_definitions/
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W H I C H P A R A M E T E R S ? ( 3 / 3 )
In order to avoid confusion between various SST at different depth, CMEMS
SEA SURFACE TEMPERATURE Satellite products provide with the following
information:
• SEA SURFACE TEMPERATURE (SST):
• Foundation SST (SST at a depth of about 10 meters,
i.e. not influenced by diurnal cycle) (all SST products except one)
• Skin SST (SST at a depth of about 10 micrometers,
i.e. influenced by diurnal cycle) (only 1 product
SST_GLO_SST_L4_NRT_OBSERVATIONS_010_014)
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O u t l i n e
• What is Satellite Sea Surface Temperature (SST)?
• Which Characteristics and Parameters?
• What is CMEMS added value?
• Who are the CMEMS SST data producers?
• Which Satellite SST products in CMEMS catalogue?
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W H A T I S C M E M S A D D E D V A L U E ? ( 1 / 3 )
L0 L1 L2 L3 L4
CMEMS PRODUCTS PROCESSING LEVEL
Raw Satellite
Data Raw Satellite
Data with
correction
Derived
geophysical
variables at
same
resolution and
location as L1
Variables
mapped on
space-time
grid, with
calibration,
merging&
validation
Same as L3
but Gap Free
Grid and with
additional
annexed
information
INCREASING ADDED VALUE OF SATELLITE DATA
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W H A T I S C M E M S A D D E D V A L U E ? ( 2 / 3 )
Reprocessed products: A new product every 1 to 2 years with optimal
accuracy and homogeneous time series
Real time products: A new product update every day, a few hours after
sensing
REPROCESSING (20years in the past) Real Time
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W H A T I S C M E M S A D D E D V A L U E ? ( 3 / 3 )
• Calibration: all satellites are inter-calibrated, i.e. all satellites use
the same reference level.
• Merging and Interpolation: satellite measures from one or several
satellites are condensed as ONE VALUE on a REGULAR GRID :
gridded product with gaps (L3) and gridded product without gaps
(L4).
• Validation: products are scientifically validated following a
thorough methodology.
• Algorithm and Corrections are specific to each European Sea
characteristics.
Marine Monitoring
O u t l i n e
• What is Satellite Sea Surface Temperature (SST)?
• Which Characteristics and Parameters?
• What is CMEMS added value?
• Who are the CMEMS SST data producers?
• Which Satellite SST products in CMEMS catalogue?
Marine Monitoring
C M E M S O c e a n S e a I c e T A C D A T A P R O D U C E R S
Marine Monitoring
O u t l i n e
• What is Satellite Sea Surface Temperature (SST)?
• Which Characteristics and Parameters?
• What is CMEMS added value?
• Who are the CMEMS SST data producers?
• Which Satellite SST products in CMEMS catalogue?
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WHICH PRODUCTS IN CMEMS CATALOGUE?
SEA SURFACE TEMPERATURE Satellite products over the GLOBAL
Ocean and all European Seas are sorted into 2 categories:
• Gridded with gaps - Sea Surface Temperature L3 - Real Time and Reprocessed SST_(AREA)_SST_L3_(NRT)or(REP)_OBSERVATIONS_010_XXX
• Gridded gap-free - Sea Surface Temperature
L4 - Real Time and Reprocessed
SST_(AREA)_SST_L4_(NRT )or (REP)_OBSERVATIONS_0010_XXX
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A n y q u e s t i o n , a n y t i m e : s e r v i c e d e s k . c m e m s @ m e r c a t o r - o c e a n . e u