1. MTG Lightning Imager Proxy Data Zagreb, Croatia 9 April 2014 Jochen Grandell Presentation to the Convection Working Group

2. Convection Workingf Group 9 April 2014 Topics Putting the MTG Lightning Imager (LI) into context MTG LI status update MTG LI products Heritage products from LEO experiences Accumulated products Proxy data basics LINET-based proxy data L2 Prototype processor L2 accumulated (proxy) product examples Summary

3. Convection Workingf Group 9 April 2014 The LI activities have been supported by the Lightning Imager Science Team (LIST) in 2009-2013 Due to program evolution, a new team (Mission Advisory Group) has been set up in early 2014. First meeting took place on 18-19 Feb 2014 Slide: 3 Lightning Imager Science Team & Mission Advisory Group

4. Convection Workingf Group 9 April 2014 Topics Putting the MTG Lightning Imager (LI) into context MTG LI status update MTG LI products Heritage products from LEO experiences Accumulated products Proxy data basics LINET-based proxy data L2 Prototype processor L2 accumulated (proxy) product examples Summary

5. Convection Workingf Group 9 April 2014 MSG MOP/MTP Observation mission: - MVIRI: 3 channels Spinning satellite Class 800 kg Observation missions: - SEVIRI: 12 channels - GERB Spinning satellite Class 2-ton 1977 2018/2019 and 2021 2002 Atmospheric Chemistry Mission (UVN-S4): via GMES Sentinel 4 (Ultraviolet Visible Near-infrared spectrometer) Implementation of the EUMETSAT Mandate for the Geostationary Programme MTG to Secure Continuity and Evolution of EUMETSAT Services 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 3.6-ton Slide: 5

6. Convection Workingf Group 9 April 2014 Lightning Detection from Space – from LEO to GEO OTD (1995-2000) LIS (1997-present) Feasibility of lightning detection from space by optical sensors has been proven by NASA instruments since 1995 on low earth orbits (LEO) Results from LIS/OTD: Global lightning distribution Annual flash density

7. Convection Workingf Group 9 April 2014 The LI on MTG measures Total Lightning: Cloud-to-Cloud Lightning (IC) and Cloud-to-Ground Lightning (CG) Geostationary lightning imaging – objectives and benefits Main objectives are to detect, monitor, track and extrapolate in time: Development of active convective areas and storm lifecycle Lightning climatology Chemistry (NOx production) 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

8. Convection Workingf Group 9 April 2014 Lightning Detection from Space – from LEO to GEO Geostationary Lightning Imager (GLI) on FY-4 (China) Lightning Imager (LI) on MTG (Europe) 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) 2015  2018  2015/2016

9. Convection Workingf Group 9 April 2014 Topics Putting the MTG Lightning Imager (LI) into context MTG LI status update MTG LI products Heritage products from LEO experiences Accumulated products Proxy data basics LINET-based proxy data L2 Prototype processor L2 accumulated (proxy) product examples Summary

10. Convection Workingf Group 9 April 2014 Lightning Imager (LI) main characteristics Slide: 10 CMOS Back-thinned backside illuminated detectors with integrated ADCs The baseline for the LI is a 4-camera solution 1170 x 1000 pixels per camera. Coverage close to visible disc

11. Convection Workingf Group 9 April 2014 Lightning Imager (LI) Status Update LI instrument and mission prime contractor is Selex ES from Italy, which includes the: Development of the LI instrument...and also the L0-L1b data processing software MTG LI Phase B2 has been kicked off in 2012 SRR (System Requirements Review) done in two parts, finished in spring 2013 PDR (Preliminary Design Review) started towards end of 2013 at instrument level – Mission level PDR in late spring 2014. Slide: 11

12. Convection Workingf Group 9 April 2014 Lightning Imager (LI) main characteristics LI main characteristics: Measurements at 777.4 nm Coverage close to visible disc Continuous measurements of (lightning) triggered events – in addition, background images typically once every minute Ground sample distance at SSP ~4.5 km => 4.7 million pixels Integration time per frame 1 ms (parameterised) Background subtraction and event detection in on-board electronics Data rate <30 Mbps; Mass < 110Kg; Power < 320W Slide: 12

13. Convection Workingf Group 9 April 2014 Topics Putting the MTG Lightning Imager (LI) into context MTG LI status update MTG LI products Heritage products from LEO experiences Accumulated products Proxy data basics LINET-based proxy data L2 Prototype processor L2 accumulated (proxy) product examples Summary

14. Convection Workingf Group 9 April 2014 L2 Flashes/Groups/Events Product Terminology: Events:what the instrument measures, a triggered pixel in the detector grid Groups:collection of neighbouring triggered events in the same integration period (1-2 ms), representing roughly a lightning stroke in nature Flashes:a collection of groups in temporal and spatial vicinity (XX km, YY ms), representing a “geophysical” flash.

15. Convection Workingf Group 9 April 2014 L2 Flashes/Groups/Events Triggered event #1 Triggered event #2 Triggered event #3 Triggered event #4 Triggered event #5 Triggered event #6 Group #1.1 Group #1.2 Flash A The “Flash tree” combining the events and the groups into one flash

16. Convection Workingf Group 9 April 2014 Example/Conceptual representation of a L2 processing sequence: “Flashes” “Groups” Groups and Flashes – LIS approach followed “Events”

17. Convection Workingf Group 9 April 2014 Topics Putting the MTG Lightning Imager (LI) into context MTG LI status update MTG LI products Heritage products from LEO experiences Accumulated products Proxy data basics LINET-based proxy data L2 Prototype processor L2 accumulated (proxy) product examples Summary

18. Convection Workingf Group 9 April 2014 L2 Accumulated Products Accumulated products: Collecting samples from a 30 second buffer Resampled to the 2-km FCI-IR grid for simple visualising with FCI data Events define the extent in the products Flashes define the values in the products For a longer temporal accumulation, the 30 second products can be stacked Three products in all: Accumulated flashes Accumulated flash index Accumulated flash radiance Slide: 18

19. Convection Workingf Group 9 April 2014 Topics Putting the MTG Lightning Imager (LI) into context MTG LI status update MTG LI products Heritage products from LEO experiences Accumulated products Proxy data basics LINET-based proxy data L2 Prototype processor L2 accumulated (proxy) product examples Summary

20. Convection Workingf Group 9 April 2014 Proxy data basics (1) MTG LI is without heritage in GEO orbit, and the closest comparison is the Lightning Imaging Sensor (LIS) on TRMM – currently still in operation However, LIS flying on LEO orbit can only monitor storms for less than 2 minutes at a time In addition, coverage is limited to +/- 35 deg Lat => Europe is excluded Use of ground-based Lightning Location System (LLS) networks as a source of proxy data is not straightforward, as they are based on RF observations of lightning and are sensitive to different parts of the lightning process “apples and oranges”

21. Convection Workingf Group 9 April 2014 Proxy data basics (2) The best compromise is to use ground-based lightning data, but converted to optical pulses based on case study comparisons with LIS data. One of the networks in operation in Europe (LINET) is currently the main source of such proxy data for the LI activities. LINET data has been compared in measurement campaigns to other ground-based systems and to LIS As an outcome, a model for transforming the LINET stroke data into optical emission (“pulses”) has been created

22. Convection Workingf Group 9 April 2014 Thunderstorm Electrification Lightning and its Emissions VHF – Very High Frequency, (V)LF – (Very) Low Frequency

23. Convection Workingf Group 9 April 2014 Topics Putting the MTG Lightning Imager (LI) into context MTG LI status update MTG LI products Heritage products from LEO experiences Accumulated products Proxy data basics LINET-based proxy data L2 Prototype processor L2 accumulated (proxy) product examples Summary

24. Convection Workingf Group 9 April 2014 LINET network coverage Central Europe well covered (2008 data) Sensor baselines highly varying across the network (= distance between sensors)

25. Convection Workingf Group 9 April 2014 Slide 25 > Eumetsat, Vienna, September 2013 > Hartmut Höller Modeling of MTG-LI Optical Signals Strategy for Proxy Data Generation Transformation of LINET RF stroke data into optical groups by modeling of cloud top optical emission: Simulation of the number of optical groups per stroke (depending on LINET detection efficiency, i.e. sensor baseline, in the area) If this number is ≥ 1: Generation of one direct coincident optical group per LINET stroke Random generation of additional optical groups per LINET stroke according to a log-normal model for radiance, footprint and time Generation of optical events from RF stroke data

26. Convection Workingf Group 9 April 2014 Topics Putting the MTG Lightning Imager (LI) into context MTG LI status update MTG LI products Heritage products from LEO experiences Accumulated products Proxy data basics LINET-based proxy data L2 Prototype processor L2 accumulated (proxy) product examples Summary

27. Convection Workingf Group 9 April 2014 L2 prototype processor Flash/group clustering parameters easily set for each individual run A prototype L2 processor in Matlab The main objectives of the prototype processor are: Implementation, testing and verification of the L2 algorithms. Verification and validation of the proxy data

28. Convection Workingf Group 9 April 2014 Topics Putting the MTG Lightning Imager (LI) into context MTG LI status update MTG LI products Heritage products from LEO experiences Accumulated products Proxy data basics LINET-based proxy data L2 Prototype processor L2 accumulated (proxy) product examples Summary

29. Convection Workingf Group 9 April 2014 L2 Accumulated products => Proxy data examples Example animations shown for the Accumulated flash index product Proxy data pulses  LI proxy events  L2 processor  L2 flashes + Accumulated products The original 30 sec product stacked into several longer periods for demonstration purposes: 15 min (= SEVIRI Full Disk Service today) 10 min (= FCI Full Disk Scanning Service FDC) 5 min (= FCI Rapid Scanning Service FDC/2) 2.5 min (= FCI Rapid Scanning Service FDC/4)

30. Convection Workingf Group 9 April 2014 Preparing for a user readiness study Because of no heritage in orbit or business-as-usual products, feedback and comments regarding the data usage and upcoming end-products delivered by EUMETSAT are needed. Charting the readiness of the main data users (i.e., National Meteorological and Hydrological Services, NMHS). Ensuring that the users are able to give valuable input already before the instrument is launched. End-users getting a first glimpse on the data before the LI instrument itself is operational. In addition to LINET as input data, an extension of the method is in development to have a similar approach applicable to the NORDLIS/EUCLID network as well (work in progress). Slide: 30 EUM/KOEEEE Issue

31. Convection Workingf Group 9 April 2014 L2 Accumulated products Animations: All for 20 June 2013, different accumulation times

32. Convection Workingf Group 9 April 2014 Full Domain: 150 s Accumulation Time

33. Convection Workingf Group 9 April 2014 Zoom: 150 s Accumulation Time

34. Convection Workingf Group 9 April 2014 Full Domain: 300 s Accumulation Time

35. Convection Workingf Group 9 April 2014 Zoom: 300 s Accumulation Time

36. Convection Workingf Group 9 April 2014 Full Domain: 600 s Accumulation Time

37. Convection Workingf Group 9 April 2014 Zoom: 600 s Accumulation Time

38. Convection Workingf Group 9 April 2014 Full Domain: 900 s Accumulation Time

39. Convection Workingf Group 9 April 2014 Zoom: 900 s Accumulation Time

40. Convection Workingf Group 9 April 2014 Topics Putting the MTG Lightning Imager (LI) into context MTG LI status update MTG LI products Heritage products from LEO experiences Accumulated products Proxy data basics LINET-based proxy data L2 Prototype processor L2 accumulated (proxy) product examples Summary

41. Convection Workingf Group 9 April 2014 Summary Proxy data needed for product/algorithm development, system level testing, and user readiness preparation For the Lightning Imager, being without heritage, the creation of representative proxy data has been a top priority LINET, a ground-based system covering much of Europe has been used as a vehicle for developing the proxy data Based on LIS-LINET comparisons, as well as comparison to other networks’ data (CHUVA campaign) LIST activity started in 2009 and continued since through various activities The accumulated flash product demonstration presented User readiness study employing the proxy data in preparation

42. Convection Workingf Group 9 April 2014 Back-up slides

43. Convection Workingf Group 9 April 2014 Accumulated flashes, status at t = 10s Slide: 43 EUM/ Issue Event count in the 30 sec buffer (still in LI grid) Flash count in the 30 sec buffer (still in LI grid) 2 11 1 312 1 11 1 111 = Events in Flash #1 Conceptual illustration

44. Convection Workingf Group 9 April 2014 Accumulated flashes, status at t = 20s Slide: 44 EUM/ Issue Event count in the 30 sec buffer (still in LI grid) Flash count in the 30 sec buffer (still in LI grid) 2 11 1 422 1 11 1 221 1 1 12 1 1 11 = Events in Flash #1 = Events in Flash #2 Conceptual illustration

45. Convection Workingf Group 9 April 2014 Accumulated flashes, status at t = 29s Slide: 45 EUM/ Issue Event count in the 30 sec buffer (still in LI grid) Flash count in the 30 sec buffer (still in LI grid) = Events in Flash #1 = Events in Flash #2 = Events in Flash #3 2 11 1 623 1 11 1 322 1 1 12 1 1 11 2 11 1 11 Conceptual illustration

46. Convection Workingf Group 9 April 2014 Slide: 46 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

47. Convection Workingf Group 9 April 2014 Detection of events in a nutshell: From a Lightning Optical Signal to MTG LI Events Background scene tracking and removal Thresholding Event detection 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) From a Lightning Optical Signal to MTG LI Events This is taking place in every 1 ms frame (1 kHz):

48. Convection Workingf Group 9 April 2014 Use of proxy data within the MTG program activities Data is being and will be used in: Algorithm development & testing System level testing User readiness activities Proxy data also shared with other agencies NOAA GOES-R GLM team – Steve Goodman In talks to cooperate also with CMA on proxy data

49. Convection Workingf Group 9 April 2014 LINET operating principle LINET operating at the VLF/LF frequency range Slide 49 > Eumetsat, Vienna, September 2013 > Hartmut Höller Lightning Detection Network LINET observes sferics at VLF/LF from larger discharges Lightning Mapping Array LMA observes VHF pulses from small-scale breakdown

50. Convection Workingf Group 9 April 2014 L2 prototype processor (2) Screenshot of the prototype processor Matlab GUI - Flash/group clustering parameters easily set for each individual run

51. Convection Workingf Group 9 April 2014 L2 prototype processor (1) A prototype L2 processor has been developed in the EUMETSAT TCE environment using the Matlab language. The main objectives of the prototype processor are: Implementation, testing and verification of the L2 algorithms. Verification and validation of the various proxy data used for L2 (and L0-L1) processor development.