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Slide: 12nd SALGEE Training Workshop,Antalya, 4 – 7 April 2011 SEVIRI Active Fire products Hans-Joachim Lutz

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Presentation on theme: "Slide: 12nd SALGEE Training Workshop,Antalya, 4 – 7 April 2011 SEVIRI Active Fire products Hans-Joachim Lutz"— Presentation transcript:

1 Slide: 12nd SALGEE Training Workshop,Antalya, 4 – 7 April 2011 SEVIRI Active Fire products Hans-Joachim Lutz

2 Slide: 2 SEVIRI Active Fire products 2nd SALGEE Training Workshop,Antalya, 4 – 7 April 2011 Introduction Description of the algorithm Results Some critical issues Future plans MTG Summary and Conclusions

3 Slide: 3 SEVIRI Active Fire products 2nd SALGEE Training Workshop,Antalya, 4 – 7 April 2011 Description of the algorithm

4 Slide: 4 SEVIRI Active Fire products 2nd SALGEE Training Workshop,Antalya, 4 – 7 April 2011 The active fire detection algorithm is based on a simple threshold test technique, using SEVIRI channels 4 (3.9 μm) and 9 (10.8 μm). The algorithm is applied for all SEVIRI repeat cycles (15 Minutes) and for all land surface pixels, excluding desert/bare soil surface pixels and coastal pixels. The algorithm does not need any cloud masking as an input. However it uses SEVIRI channel 1 (0.6 μm) to eliminate (low) clouds with a high reflectance.

5 Slide: 5 SEVIRI Active Fire products 2nd SALGEE Training Workshop,Antalya, 4 – 7 April 2011 StdDev Jan 2009, 12 UTC StdDev3.9-StdDev10.8

6 Slide: 6 SEVIRI Active Fire products 2nd SALGEE Training Workshop,Antalya, 4 – 7 April 2011 BTD( ) 15 Jan 2009, 12 UTC StdDev3.9-StdDev10.8

7 Slide: 7 SEVIRI Active Fire products 2nd SALGEE Training Workshop,Antalya, 4 – 7 April 2011 The setting of the thresholds is crucial for the fire detection !!! In our scheme we use: Forecast data and RTTOV for tests 1 and 5 Static thresholds (corrected for viewing angle) for tests 2, 3, and 4. HOWEVER:

8 Slide: 8 SEVIRI Active Fire products 2nd SALGEE Training Workshop,Antalya, 4 – 7 April 2011 Emissivity plays an important rôle Emissivity more variable near 3.9  m Sandy areas appear 5-10 K cooler at IR3.9 than at IR10.8 (at night, dry atmosphere) IR3.9IR10.8 Dry sand:

9 Slide: 9 SEVIRI Active Fire products 2nd SALGEE Training Workshop,Antalya, 4 – 7 April 2011 Emissivity map channel 4 (3.9 µm) for January

10 Slide: 10 SEVIRI Active Fire products 2nd SALGEE Training Workshop,Antalya, 4 – 7 April Use RTM output (RTTOV) with the following parameter: TOA clear sky radiance (ε=1) Surface skin radiance (ε=1) Downward radiance at surface level Total Transmittance 2. Interpolate the gridded data to pixel location 3. Calculate the atmospheric contribution to the TOA radiance 4. Calculate the correct surface skin radiance using the emissivity, the reflected downward radiance at surface level and the reflected solar radiance (at daytime)

11 Slide: 11 SEVIRI Active Fire products 2nd SALGEE Training Workshop,Antalya, 4 – 7 April 2011 r TOA = B(T s ).  s.  s + r down. (1-  s ).  s + r solar.  s. (1-  s ).  s + r ATM please note:  s has been calculated for the satellite viewing angle and is not corrected for the solar zenith angle. that no bi-directional effects are included (1-  s )

12 Slide: 12 SEVIRI Active Fire products 2nd SALGEE Training Workshop,Antalya, 4 – 7 April 2011 The following threshold tests are used: 1. Brightness temperature IR Standard Deviation difference (StdDev3.9–StdDev10.8) 3. Brightness temperature difference (IR3.9-IR10.8) 4. Standard Deviation IR10.8

13 Slide: 13 SEVIRI Active Fire products 2nd SALGEE Training Workshop,Antalya, 4 – 7 April 2011 TB (3.9  m) - TB (10.8  m) Its strong sensitivity to sub-pixel "hot areas" makes the IR3.9 channel very useful in fire detection. If only 5% of the pixel is at 500 K, the IR3.9 channel measures 360 K, while the IR10.8 measures less than 320 K.

14 Slide: 14 SEVIRI Active Fire products 2nd SALGEE Training Workshop,Antalya, 4 – 7 April 2011 BTD ( ) 15 Jan 2009, 12 UTC For fire (and most clouds) BT3.9 >> BT10.8 For most other surfaces BT3.9 ≈ BT10.8

15 Slide: 15 SEVIRI Active Fire products 2nd SALGEE Training Workshop,Antalya, 4 – 7 April 2011 Results of test 5 (BTD of ch. 4 and 9) for possible fire 15 January UTC

16 Slide: 16 SEVIRI Active Fire products 2nd SALGEE Training Workshop,Antalya, 4 – 7 April 2011 StdDev3.9-StdDev Jan 2009, 12 UTC For fire StdDev3.9 >> StdDev10.8 For clouds/cloud edges StdDev3.9 ≤ StdDev10.8 For other surfaces StdDev3.9 ≈ StdDev10.8

17 Slide: 17 SEVIRI Active Fire products 2nd SALGEE Training Workshop,Antalya, 4 – 7 April 2011 Results of test 4 (Standard Dev. Diff. of ch. 4 and 9) added to test 5 for possible fire 15 January UTC

18 Slide: 18 SEVIRI Active Fire products 2nd SALGEE Training Workshop,Antalya, 4 – 7 April 2011 Results of test 2 and 3 (Standard Dev. of ch. 4 and 9) added to tests 4 and 5 for possible fire 15 January UTC

19 Slide: 19 SEVIRI Active Fire products 2nd SALGEE Training Workshop,Antalya, 4 – 7 April 2011 BT Jan 2009, 12 UTC

20 Slide: 20 SEVIRI Active Fire products 2nd SALGEE Training Workshop,Antalya, 4 – 7 April 2011 Results of test 1 (BT of ch. 4) added to tests for possible fire 15 January UTC

21 Slide: 21 SEVIRI Active Fire products 2nd SALGEE Training Workshop,Antalya, 4 – 7 April 2011 Results of test 5 (BTD of ch. 4 and 9) for probable fire 15 January UTC

22 Slide: 22 SEVIRI Active Fire products 2nd SALGEE Training Workshop,Antalya, 4 – 7 April 2011 Results of test 4 (Standard Dev. Diff. of ch. 4 and 9) added to test 5 for probable fire 15 January UTC

23 Slide: 23 SEVIRI Active Fire products 2nd SALGEE Training Workshop,Antalya, 4 – 7 April 2011 Results of test 2 and 3 (Standard Dev. of ch. 4 and 9) added to tests 4 and 5 for probable fire 15 January UTC

24 Slide: 24 SEVIRI Active Fire products 2nd SALGEE Training Workshop,Antalya, 4 – 7 April 2011 Results of test 1 (BT of ch. 4) added to tests for probable fire 15 January UTC

25 Slide: 25 SEVIRI Active Fire products 2nd SALGEE Training Workshop,Antalya, 4 – 7 April 2011 Final results combining all possible and probable fires 15 January UTC

26 Slide: 26 SEVIRI Active Fire products 2nd SALGEE Training Workshop,Antalya, 4 – 7 April 2011 Diurnal cycle of number of fires for 15 January 2009

27 Slide: 27 SEVIRI Active Fire products 2nd SALGEE Training Workshop,Antalya, 4 – 7 April 2011 Some critical issues

28 Slide: 28 SEVIRI Active Fire products 2nd SALGEE Training Workshop,Antalya, 4 – 7 April 2011 Artefacts coming from Digital Filter MSG-1, 7 August 2006, IR3.9 Channel (inverted) 18:00 18:15 18:30 18:45

29 Slide: 29 SEVIRI Active Fire products 2nd SALGEE Training Workshop,Antalya, 4 – 7 April 2011 Impact of Sunglint There is very strong reflection of solar radiation at 3.9  m (sunglint) Features such as rivers in sunglint are obvious, but “illuminated” lakes could take on the appearance of fires

30 Slide: 30 SEVIRI Active Fire products 2nd SALGEE Training Workshop,Antalya, 4 – 7 April 2011 Midday sun glint over the Congo river MSG-1, 24 March 2004, 09:00 UTC, Channel 04 (3.9  m)

31 Slide: 31 SEVIRI Active Fire products 2nd SALGEE Training Workshop,Antalya, 4 – 7 April 2011 Frequency of Saturated IR3.9 Pixels

32 Slide: 32 SEVIRI Active Fire products 2nd SALGEE Training Workshop,Antalya, 4 – 7 April 2011 Working without cloud mask – “hot clouds” 15 January UTC Low-level water clouds are relatively warm They have a high reflectance in ch. 4 (3.9 µm) These clouds appear as “hot spots” in ch. 4

33 Slide: 33 SEVIRI Active Fire products 2nd SALGEE Training Workshop,Antalya, 4 – 7 April 2011 Working without cloud mask – “hot clouds” 15 January UTC The BTD ch.4 (3.9 µm) – ch.9 (10.8 µm) These clouds appear as “hot spots” in ch. 4

34 Slide: 34 SEVIRI Active Fire products 2nd SALGEE Training Workshop,Antalya, 4 – 7 April 2011 (Not really) Working without cloud mask – “hot clouds” 15 January UTC Using channel VIS0.6, helps to filter out all “hot clouds”

35 Slide: 35 SEVIRI Active Fire products 2nd SALGEE Training Workshop,Antalya, 4 – 7 April 2011 Future plans

36 Slide: 36 SEVIRI Active Fire products 2nd SALGEE Training Workshop,Antalya, 4 – 7 April Use the improved ECMWF forecast model The operational algorithm works with a 1º / 6-hourly forecast The prototype algorithm uses a 0.25º / 3-hourly forecast In the near future ECMWF will provide a 0.125º forecast grid 2.Include solar transmittance The transmittance calculation for channel 4 is only done with the viewing angle, but needs also to be done with the solar zenith angle for the downwelling solar part.

37 Slide: 37 SEVIRI Active Fire products 2nd SALGEE Training Workshop,Antalya, 4 – 7 April Create a MSG emissivity map There are plans to create a “MSG” emissivity map instead of using a map derived from other sources and then interpolated in space and spectra to the MSG channels 4.Make use of the temporal filtering Currently the algorithm is not using temporal filtering for both the diurnal cycle of the temperatures and the tracking of fires for a single pixel throughout the day

38 Slide: 38 SEVIRI Active Fire products 2nd SALGEE Training Workshop,Antalya, 4 – 7 April 2011 MTG

39 Slide: 39 SEVIRI Active Fire products 2nd SALGEE Training Workshop,Antalya, 4 – 7 April 2011 The imager mission (FCI) of the third generation of Meteosat (MTG) will have 16 channels which are scanning the full disk every 10 minutes. The channels will be located at the following wavelengths: MTG Imager - Full Disk Mission

40 Slide: 40 SEVIRI Active Fire products 2nd SALGEE Training Workshop,Antalya, 4 – 7 April 2011 MTG Imagery Band Central Wavel. (µm) Spatial resolution (km) Objective FDHSI Aerosol optical depth, aerosol particle size, volcanic ash concentration FDHSI Aerosol optical depth, aerosol particle size, volcanic ash concentration FDHSI Cloud detection, AMV, cloud type, cloud optical depth, snow cover, vegetation stress, smoke detection, volcanic ash detection, volcanic ash concentration FDHSI Cloud detection, AMV, cloud type, cloud phase, cloud optical depth, cloud microphysics, snow cover, vegetation stress, smoke detection, volcanic ash detection, volcanic ash concentration FDHSI Total column humidity FDHSI Cirrus detection, water vapour imagery FDHSI Cloud phase, cloud microphysics, cloud detection, cloud type, snow cover, vegetation stress, smoke detection FDHSI Cloud microphysics FDHSI Cloud detection, cloud type, AMV, LST/SST, cloud phase, cloud microphysics, snow cover, sea ice temperature, fire detection/monitoring, volcanic ash detection, volcanic ash concentration FDHSI AMV, tracer heights, instability (grad T/Hu), column humidities FDHSI AMV, tracer heights, instability (grad T/Hu), column humidities FDHSI Cloud detection, cloud type, cloud top height, LST/SST, cloud phase, cloud drop size, instability (grad T/Hu), sea ice temperature, volcanic SO2 detection, sand/dust storm detection FDHSI Total Column ozone FDHSI Cloud detection, cloud type, cloud top height, AMV, tracer heights, LST/SST, instability (grad T/Hu), total column humidity, sea ice temperature, fire detection/monitoring, volcanic ash detection, volcanic ash concentration, sand/dust storm detection FDHSI Cloud detection, cloud type, cloud top height, AMV, tracer heights, LST/SST, instability (grad T/Hu), total column humidity, sea ice temperature, volcanic ash detection, volcanic ash concentration, sand/dust storm detection FDHSI Cloud top height, tracer heights, instability (grad T/Hu), volcanic ash detection MTG Imager - Full Disk Mission

41 Slide: 41 SEVIRI Active Fire products 2nd SALGEE Training Workshop,Antalya, 4 – 7 April 2011 True Color 1 km Vertical integrierter Wassrdampf über Land 1 km Extrem dünne Zirrusbewölkung 1 km Wolkenteilchengröße und Phase 0.5 km MTG Imager - Full Disk Mission

42 Slide: 42 SEVIRI Active Fire products 2nd SALGEE Training Workshop,Antalya, 4 – 7 April 2011 MTG hat die gleichen Kanäle wie MSG im thermischen Bereich 2 km nominale Auflösung 1 km Auflösung für 3.8µm and 10.5 mm Kanäle (rapid scan) MTG Imager Full Disk Mission

43 Slide: 43 SEVIRI Active Fire products 2nd SALGEE Training Workshop,Antalya, 4 – 7 April 2011 It will be possible to setup a high resolution rapid scanning for the northern 25% of the disk (Europe) at 4 channels which are scanning the area every 2.5 minutes. These channels will be located at the following wavelengths: MTG Imager - High Resolution Mission

44 Slide: 44 SEVIRI Active Fire products 2nd SALGEE Training Workshop,Antalya, 4 – 7 April 2011 MTG Imagery Band Central Wavel. (µm) Spatial resolution (km) Objective HRFI Cloud detection, AMV HRFI Cloud microphysics HRFI Cloud detection, cloud microphysics, (fire detection/monitoring) HRFI Cloud detection, cloud top height, AMV, (fire detection/monitoring) MTG Imager - High Resolution Mission

45 Slide: 45 SEVIRI Active Fire products 2nd SALGEE Training Workshop,Antalya, 4 – 7 April 2011 MODIS ch. 7 (2.1 µm) 1 km resolution (28 Aug 2007, 11:10 UTC) Similar to the planned MTG ch. FDHSI-8 at 2.26 µm The hot spots appear already at 2.1  m

46 Slide: 46 SEVIRI Active Fire products 2nd SALGEE Training Workshop,Antalya, 4 – 7 April 2011 But the main (big) points of the MTG Imager for the fire community are: The “fire channel” centered at 3.8 µm avoiding the CO 2 absorption The temporal and spatial resolution will be higher (10 minutes and 2 km) The dynamic range of the 3.8 µm channel will be extended to 450 K MTG Imager

47 Slide: 47 SEVIRI Active Fire products 2nd SALGEE Training Workshop,Antalya, 4 – 7 April 2011 Summary and Conclusions

48 Slide: 48 SEVIRI Active Fire products 2nd SALGEE Training Workshop,Antalya, 4 – 7 April 2011 Active Fire detection considers: Spectral signals and its spatial distribution (channels IR3.9, IR10.8, IR3.9-IR10.8 ) Uses ECMWF Forecast data to derive thresholds Uses channel VIS0.6 to eliminate “hot clouds”

49 Slide: 49 SEVIRI Active Fire products 2nd SALGEE Training Workshop,Antalya, 4 – 7 April 2011 Problems still to be solved are: Sunglint areas Better forecast/emissivity information Use of temporal signals (temporal filtering)


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