1. 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
March 2012
Prague, Czech Republic

2. 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
March 2012
Prague, Czech Republic

3. 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
March 2012
Prague, Czech Republic

4. 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 ( )
Results from LIS/OTD: Global lightning distribution
Annual flash density
LIS (1997-present)

5. 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)
Geostationary Lightning Imager (GLI) on FY-4 (China)
Lightning Imager (LI) on MTG (Europe)
2015 
2018 
2014 ?
EUM/MTG/VWG/12/0278
March 2012
Prague, Czech Republic

6. Main benefit from GEO observations:
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
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
LIS/OTD flash density in
the MTG LI field of view

7. ...Air Traffic is one area of application, and not just around major airports...

8. 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
March 2012
Prague, Czech Republic

9. Detection of a Lightning Optical Signal
Lightning with a background signal changing with 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)
Lightning signal
Background
Time
Radiation
energy
Night
Day
EUM/MTG/VWG/12/0278
March 2012
Prague, Czech Republic

10. From a Lightning Optical Signal to MTG LI Events
Detection of events in a nutshell:
Output (=events) of the Lightning Imager at L0 is two-fold:
Background scene tracking and removal
Thresholding
Event
detection
False event filtering needed in L0-L1 processing
True lightning events (triggered by a lightning optical signal)
False events (not related to lightning)
EUM/MTG/VWG/12/0278
March 2012
Prague, Czech Republic

11. 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”
Background scene tracking and removal
Thresholding
Event detection
etc...
Optical pattern of lightning on cloud surface (observed from space shuttle)
Possible schema of detected lightning pulses
EUM/MTG/VWG/12/0278
March 2012
Prague, Czech Republic

12. 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
March 2012
Prague, Czech Republic

13. MTG LI Product Processing – L1b and L2 products
Product processing in a nutshell
Example L2
Sequence:
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)
“Events”
“Groups”
“Flashes”
EUM/MTG/VWG/12/0278
March 2012
Prague, Czech Republic

14. 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
Events density simulation based on converted LINET data from 2 July 2009
(15 minutes density)
EUM/MTG/VWG/12/0278
March 2012
Prague, Czech Republic

15. From events/groups/flashes towards DENSITY (2)
Animation of EVENT DENSITY simulation -
Based on converted LINET data from 2 July 2009
(15 minutes density)

16. 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
March 2012
Prague, Czech Republic

17. 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
March 2012
Prague, Czech Republic

18. 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
March 2012
Prague, Czech Republic

19. 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:
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
March 2012
Prague, Czech Republic

20. 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
March 2012
Prague, Czech Republic

21. 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
March 2012
Prague, Czech Republic

22. 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
March 2012
Prague, Czech Republic

23. 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)
EUM/MTG/VWG/12/0278
March 2012
Prague, Czech Republic

24. Thank you!
EUM/MTG/VWG/12/0278
March 2012
Prague, Czech Republic

25. How noise looks like on a 0.5s period
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How noise looks like on a 0.5s period
All noise events in 500 milliseconds!
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26. 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 UTC UTC

27. 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 UTC UTC

28. 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 UTC UTC

29. 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 UTC UTC

30. 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 UTC UTC

31. 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 UTC UTC

32. Effect of Microvibrations (“jitter”) on Lightning Detection
Assuming that this is what the
Lightning Imager is looking at...
Background
energy
Cloud
Distance
Darker (ocean)
background
Cloud
Darker (ocean)
background

33. Effect of Microvibrations (“jitter”) on Lightning Detection
What if the instrument (satellite) moves slightly between integration frames...?
Cloud
Darker (ocean)
background
Background
energy
Distance
Frame #1
Background removal
(Frame #2 – Frame #1)
Distance
But this is
not lightning!
Frame #2

34. Meteosat Third Generation (MTG):
Continuity and Evolution of EUMETSAT Services
1977
2002
and
MOP/MTP
MSG
MOP/MTP
MSG
MTG-I and MTG-S
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
Observation missions:
- SEVIRI: 12 channels
GERB
Spinning satellite
Class 2-ton
Observation mission:
MVIRI: 3 channels
Spinning satellite
Class 800 kg
Implementation of the EUMETSAT Mandate
for the Geostationary Programme
Atmospheric Chemistry Mission (UVN-S4):
via GMES Sentinel 4

35. 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
2019 – 2035: years of Operational Service – Sounding Mission

36. 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

37. 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

38. 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