Geostationary lightning
monitoring with the Meteosat
Third Generation Lightning
Imager (MTG LI)
Jochen Grandell
Convection Working Group Meeting
27 – 30 March 2012, Prague
EUM/MTG/VWG/12/0278
EUM/
March
Issue 2012
<No.>
Prague,
<Date>Czech Republic
Slide: 1
Topics of Presentation
• Lightning Detection from Space – from LEO to GEO
observations
• EUMETSAT Meteosat Third Generation (MTG) – Lightning
Imager
• Concept
• Product processing
• Challenges
• User Readiness
• Summary
EUM/MTG/VWG/12/0278
EUM/
March
Issue 2012
<No.>
Prague,
<Date>Czech Republic
Topics of Presentation
• Lightning Detection from Space – from LEO to GEO
observations
• EUMETSAT Meteosat Third Generation (MTG) – Lightning
Imager
• Concept
• Product processing
• Challenges
• User Readiness
• Summary
EUM/MTG/VWG/12/0278
EUM/
March
Issue 2012
<No.>
Prague,
<Date>Czech Republic
Lightning Detection from Space – from LEO to GEO
Feasibility of lightning detection from space by optical sensors has
been proven by NASA instruments since 1995 on low earth orbits (LEO)
OTD (1995-2000)
Results from LIS/OTD: Global lightning distribution
Annual flash density
LIS (1997-present)
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Lightning Detection from Space – from LEO to GEO
GEO lightning missions in preparation by several agencies
(in USA, Europe, China) for this decade...
...all of these are building on LIS/OTD heritage
Geostationary Lightning
Mapper (GLM)
on GOES-R (USA)
Lightning Imager (LI)
on MTG (Europe)
Geostationary
Lightning Imager (GLI)
on FY-4 (China)
2015 
2018 
2014 ?
EUM/MTG/VWG/12/0278
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March
Issue 2012
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The MTG Lightning Imager (LI)
The LI on MTG measures Total Lightning:
Cloud-to-Cloud Lightning (IC) and Cloud-to-Ground Lightning (CG)
Main benefit from GEO
observations:
homogeneous and continuous
observations delivering
information on location and
strength of lightning flashes to
the users with a timeliness of 30
seconds
LIS/OTD flash
density in
the MTG LI
field of view
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Main objectives are to detect,
monitor, and extrapolate in time:
•
•
•
Development
(Intensity/Movement) of active
convective areas
Monitoring of storm lifecycle
Lightning climatology &
Chemistry (NOx production)
GEO observation of lightning is
complementary to ground-based
networks, some of which are for
local applications very good
...Air Traffic is one area of application, and not just
around major airports...
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Issue <No.>
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Slide: 7
Topics of Presentation
• Lightning Detection from Space – from LEO to GEO
observations
• EUMETSAT Meteosat Third Generation (MTG) – Lightning
Imager
• Concept
• Product processing
• Challenges
• User Readiness
• Summary
EUM/MTG/VWG/12/0278
EUM/
March
Issue 2012
<No.>
Prague,
<Date>Czech Republic
Detection of a Lightning Optical Signal
• Lightning with a background signal changing with time:
Radiation
energy
Background
Lightning signal
Day
Night
Time
• Lightning on top of a bright background is not recognised by its bright
radiance, but by its transient short pulse character
• For detection of lightning, a variable adapting threshold has to be used for
each pixel which takes into account the change in the background radiance
• (in LIS: background calculated as a moving average)
EUM/MTG/VWG/12/0278
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March
Issue 2012
<No.>
Prague,
<Date>Czech Republic
Slide: 9
From aaLightning
Lightning Optical
Events
From
Optical Signal
Signalto
toMTG
MTGLILI
Events
• Detection of events in a nutshell:
Background
scene tracking
and removal
Thresholding
Event
detection
• Output (=events) of the Lightning Imager at L0 is two-fold:
• True lightning events
(triggered by a lightning
optical signal)
• False events
(not related to lightning)
EUM/MTG/VWG/12/0278
EUM/
March
Issue 2012
<No.>
Prague,
<Date>Czech Republic
False event filtering
needed in L0-L1
processing
Spatial Pattern of Lightning from Space
• Characteristics:
– Size scales with cloud thickness above source
– Mean area of lightning pulses corresponds well to a 10 km x 10 km footprint
“MTG LI Events”
1.
2.
3.
Optical pattern of lightning
on cloud surface (observed
from space shuttle)
EUM/MTG/VWG/12/0278
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March
Issue 2012
<No.>
Prague,
<Date>Czech Republic
Background
scene tracking
and removal
Thresholding
Event detection
etc...
Possible schema of detected
lightning pulses
Topics of Presentation
• Lightning Detection from Space – from LEO to GEO
observations
• EUMETSAT Meteosat Third Generation (MTG) – Lightning
Imager
• Concept
• Product processing
• Challenges
• User Readiness
• Summary
EUM/MTG/VWG/12/0278
EUM/
March
Issue 2012
<No.>
Prague,
<Date>Czech Republic
Product
processing
in a nutshell
MTG LI Product
Processing
– L1b and L2 products
• The following products are resulting
from the L1b processing:
– Events with geolocation, UTC time
stamp and calibrated radiance
– background images, mainly
supporting navigation
• The baseline L2 product, which is a
result of clustering of events in time
and space, consists of:
– Groups (representing lightning
strokes)
– Flashes (1st priority for many users)
EUM/MTG/VWG/12/0278
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March
Issue 2012
<No.>
Prague,
<Date>Czech Republic
Example L2
Sequence:
“Events”
“Groups”
“Flashes”
From events/groups/flashes towards DENSITY (1)
• For a quick-look, a
forecaster or other
operational user
might prefer a
density product.
• Can be based on:
• Events
• groups
• flashes
• ...and with a variety
of temporal
windows
EUM/MTG/VWG/12/0278
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March
Issue 2012
<No.>
Prague,
<Date>Czech Republic
Events density simulation based on
converted LINET data from 2 July 2009
(15 minutes density)
Slide: 14
From events/groups/flashes towards DENSITY (2)
Animation of
EVENT DENSITY
simulation
Based on
converted LINET
data from 2 July
2009
(15 minutes
density)
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Issue <No.>
<Date>
Slide: 15
Topics of Presentation
• Lightning Detection from Space – from LEO to GEO
observations
• EUMETSAT Meteosat Third Generation (MTG) – Lightning
Imager
• Concept
• Product processing
• Challenges
• User Readiness
• Summary
EUM/MTG/VWG/12/0278
EUM/
March
Issue 2012
<No.>
Prague,
<Date>Czech Republic
Challenge for processing: “False Events”
• False events are typically
caused by:
• High energy particle
collisions
• Noise (instrument,
spacecraft etc)
• Solar glint
• Spacecraft motion
(“jitter”)
• Specific filters are required for
each case:
 Radiation filter
 Shot noise/coherency filter
 Solar glint filter
 Contrast filter
Rough order of severity (based on GLM analysis):
Spacecraft motion, Photon/electronics noise, Solar glint, Radiation
EUM/MTG/VWG/12/0278
EUM/
March
Issue 2012
<No.>
Prague,
<Date>Czech Republic
Topics of Presentation
• Lightning Detection from Space – from LEO to GEO
observations
• EUMETSAT Meteosat Third Generation (MTG) – Lightning
Imager
• Concept
• Product processing
• Challenges
• User Readiness
• Summary
EUM/MTG/VWG/12/0278
EUM/
March
Issue 2012
<No.>
Prague,
<Date>Czech Republic
User Readiness (1)
• User readiness, as discussed here is to be understood as
activities similar to what NOAA is attempting with the "GOES-R
Proving Ground" framework of activities.
• Within this framework, an approach of creating "pseudo-GLM"
data based on averaging and resampling ground-based
Lightning Mapping Array (LMA) lightning density data has been
developed:
http://www.goes-r.gov/users/pg-activities.html
• This “pseudo-GLM” data has been provided to forecasters in
real-time along with other data to support their daily work.
EUM/MTG/VWG/12/0278
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March
Issue 2012
<No.>
Prague,
<Date>Czech Republic
Slide: 19
User Readiness (2)
• The idea is to make the forecaster end-user aware, and used
to, the kind of product that would be available from the GLM.
• This is not perfect proxy data: It merely gives an
"impression" of how the real GLM product could look like.
• EUMETSAT is planning a similar activity by using the existing
proxy data methodology with the ground-based LINET data in
Europe
• A near-real time application of the proxy data will be needed
• Data to be disseminated to selected Meteorological Services
for evaluation and feedback
EUM/MTG/VWG/12/0278
EUM/
March
Issue 2012
<No.>
Prague,
<Date>Czech Republic
Slide: 20
Topics of Presentation
• Lightning Detection from Space – from LEO to GEO
observations
• EUMETSAT Meteosat Third Generation (MTG) – Lightning
Imager
• Concept
• Product processing
• Challenges
• User Readiness
• Summary
EUM/MTG/VWG/12/0278
EUM/
March
Issue 2012
<No.>
Prague,
<Date>Czech Republic
Summary
• One of the new instruments on the Meteosat Third
Generation (MTG) is the Lightning Imager (LI),
• geostationary services from 2017 onwards
• continuous lightning observation (CG+CC) over almost
the full disk (at 0 deg).
• Algorithm and processor development for baseline L2
products (event/group/flash –tree) currently ongoing
• Supported by a MTG Lightning Imager Science Team
(LIST) set up in 2009
• Interacting with potential users (such as CWG) an important
topic in coming years
EUM/MTG/VWG/12/0278
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March
Issue 2012
<No.>
Prague,
<Date>Czech Republic
MTG Lightning Imager Science Team (LIST)
• The MTG LI Science Team currently consists of the following members:
–
–
–
–
–
–
–
–
–
N.N. (MetOffice – UK)
Daniele Biron (USAM – Italy)
Eric Defer (LERMA – France)
Ullrich Finke (U. Hannover – Germany)
Hartmut Höller (DLR – Germany)
Philippe Lopez (ECMWF)
Douglas Mach (NASA – USA)
Antti Mäkelä (FMI – Finland)
Serge Soula (Laboratoire d'Aerologie – France)
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EUM/MTG/VWG/12/0278
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March
Issue 2012
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<Date>Czech Republic
FER = 1 000 /s
FER = 30 000 /s
FER = 200 000 /s
How noise looks like on a 0.5s period
All noise events in 500 milliseconds!
FER = 5 000 /s
FER = 40 000 /s
FER = 300 000 /s
FER = 10 000 /s
FER = 100 000 /s
FER = 400 000 /s
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Issue <No.>
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Slide: 25
Background radiance: Solar reflection on clouds
and ground surfaces
• Background radiation from
clouds determines the signal to
noise ratio for detection of
transient lightning signals
• Challenges:
• Day-night contrast in
FOV
• Microvibrations (fast
changing background)
• Sun glint
0 UTC
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Issue <No.>
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12 UTC
22 UTC
Background radiance: Solar reflection on clouds
and ground surfaces
• Background radiation from
clouds determines the signal to
noise ratio for detection of
transient lightning signals
• Challenges:
• Day-night contrast in
FOV
• Microvibrations (fast
changing background)
• Sun glint
0 UTC
EUM/
Issue <No.>
<Date>
12 UTC
22 UTC
Background radiance: Solar reflection on clouds
and ground surfaces
• Background radiation from
clouds determines the signal to
noise ratio for detection of
transient lightning signals
• Challenges:
• Day-night contrast in
FOV
• Microvibrations (fast
changing background)
• Sun glint
0 UTC
EUM/
Issue <No.>
<Date>
12 UTC
22 UTC
Background radiance: Solar reflection on clouds
and ground surfaces
• Background radiation from
clouds determines the signal to
noise ratio for detection of
transient lightning signals
• Challenges:
• Day-night contrast in
FOV
• Microvibrations (fast
changing background)
• Sun glint
0 UTC
EUM/
Issue <No.>
<Date>
12 UTC
22 UTC
Background radiance: Solar reflection on clouds
and ground surfaces
• Background radiation from
clouds determines the signal to
noise ratio for detection of
transient lightning signals
• Challenges:
• Day-night contrast in
FOV
• Microvibrations (fast
changing background)
• Sun glint
0 UTC
EUM/
Issue <No.>
<Date>
12 UTC
22 UTC
Background radiance: Solar reflection on clouds
and ground surfaces
• Background radiation from
clouds determines the signal to
noise ratio for detection of
transient lightning signals
• Challenges:
• Day-night contrast in
FOV
• Microvibrations (fast
changing background)
• Sun glint
0 UTC
EUM/
Issue <No.>
<Date>
12 UTC
22 UTC
Effect of Microvibrations (“jitter”)
on Lightning Detection
Assuming that this is what the
Lightning Imager is looking at...
Darker (ocean)
background
Cloud
Background
energy
Cloud
Distance
Darker (ocean)
background
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Issue <No.>
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Slide: 32
Effect of Microvibrations (“jitter”)
on Lightning Detection
What if the instrument (satellite) moves slightly between integration frames...?
Background
energy
Background removal
(Frame #2 – Frame #1)
But this is
not lightning!
Frame #1
Cloud
Distance
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Issue <No.>
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Darker (ocean)
background
Frame #2
Distance
Slide: 33
Meteosat Third Generation (MTG):
Continuity and Evolution of EUMETSAT Services
2002
1977
MOP/MTP
2017
and
2019
MSG
MSG
MOP/MTP
MTG-I and MTG-S
Observation mission:
- MVIRI: 3 channels
Observation missions:
- SEVIRI: 12 channels
- GERB
Spinning satellite
Class 800 kg
Spinning satellite
Class 2-ton
Implementation of the EUMETSAT Mandate
for the Geostationary Programme
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Observation missions:
- Flex.Comb. Imager: 16 channels
- Infra-Red Sounder
- Lightning Imager
- UVN
3-axis stabilised satellites
Twin Sat configuration
Class 2,5 - 3 ton
Atmospheric Chemistry Mission (UVN-S4):
via GMES Sentinel 4
MTG in Orbit Deployment Scenario
MSG-4
MTG-I1 Dec. 2016
MTG-I2 Dec. 2022
MTG-I3 Jan. 2025
MTG-I4 Dec. 2029
2017 – 2038: 20 years of Operational Service – Imaging Missions
MTG-S1 June 2018
MTG-S2 June 2026
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2019 – 2035: 15.5 years of Operational Service – Sounding
Mission
MTG Lightning Imager Science Team (LIST)
• EUMETSAT has identified the need to establish a scientific baseline for the
operational processor of the MTG mission.
• In support of these scientific developments, a science team has been
established – MTG LI Science Team (LIST).
• The main objectives of the team is to:
• Assist EUMETSAT with the implementation of the MTG LI L2
scientific baseline processor.
• Prepare an Algorithm Theoretical Baseline Document (ATBD). It
includes also a description of the proxy dataset, to be used for
algorithm development and processor development.
• The ATBD will be subject for review at the Preliminary Design
Review (PDR) concluding the MTG system Phase B activities
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Slide: 36
EUMETSAT, MTG LI and LINET
• EUMETSAT has now several years of experience in cooperating
with Nowcast and DLR in using LINET data:
• Especially in developing proxy data...
• ...Latest activity has been in contributing to the
CHUVA campaign in Brazil with the mobile LINET unit
(DLR), which should after evaluation of the joint
measurements with LMA and LIS allow a further
enhancement of the proxy data
• Based on these experiences, it looks like LINET data
could play an important role in “user readiness”
activities as well as validation/monitoring of the
operational product(s) from the MTG LI
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Slide: 37
MTG LI – Main Mission Requirements
• Wavelength
 777.4 nm
• Sensitivity
 pulses as small as 100 km2 with energies down to 4 µJ/(m2sr) should be
detected
• Spatial sampling
 Less or equal to 10 km at 45oN for the sub-satellite longitude
• Detection Efficiency
 70% in average, 90% over central Europe, 40% as a minimum over EUMETSAT
member states
• False Alarm Rate
 2.5 false flashes/s
• Background images
 every 60 seconds
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