Copyright© Weathernews Inc. All rights reserved. “Confidential” Oct.25th,2017 Takuro HANYU Weathernews Inc. Cloud Top Height Estimation using Satellite Image and Ground Based Image
Copyright© Weathernews Inc. All rights reserved.
“Confidential”
Oct.25th,2017
Takuro HANYUWeathernews Inc.
CloudTopHeightEstimationusingSatelliteImage andGroundBasedImage
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Howwonderfulisnovelty usinggroundbasedimagetakenbyyoutogetdetailedinformationoftheupperlayer.
Conclusion
22
Satelliteimage
Groundbasedimage
Skylineofscreenimage
correct
GPSazimuthelevation
Standardatmosphere
&Coordinate
transformation
ex)Lowerthanestimationbysatellite
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Purpose
33
l Benefits・Touseasobservationaldata.・TocorrectoftheuppertemperatureasinitialvalueofNWPfordataassimilation.
・Tocorrectthe3Dformforvisualization.
● Background・Satellitedataupgrading:Highresolution&Highfrequency- 2017Nov.30th~ GOES-16- 2015Jul.HIMAWARI-8
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Outline
44
● Data・Satelliteimage:HIMAWARI-8・Groundbasedimage:weatherreport
● Method・Geometricapproach :Coordinatetransformation,
Perspectiveprojection, Cross-correlationfunction
● Results・errorevaluationh_real- h_img> f(FOV,pix,G,AD),range,growthspeed
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Data
55
l SatelliteimageHimawari-8infrared(Band13:10.4μm)Resolution:2km , Timefrequency:2.5min
l Groundbasedimage・Weatherreport
PicturetakenbysupporterGPS,azimuth,elevation
・WebcameraTimefrequency:1minGPS,azimuth,elevation
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Pixel(x,y,brightness temerature) → lon,lat,height
→Earth-fixedcoordinatesystem
ISA (InternationalStandard Atmosphere)
Processing(1/3)
66
→Viewpointcoordinatesystem
6.5K/1000m
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Processing(2/3)
77
→ Perspectiveprojection(toreproducelikeaimagetakenbysmartphone)
→Shadowprocessing(togettheskylinefromimage)
→Skylineimagefromsatellite
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→Cross-correlationfunction(Azimuthwiththehighestcorrelationistakenaspositive)
Processing(3/3)
88
𝝓𝒙𝒚 𝒎 =𝟏𝑵) 𝒙 𝒏 𝒚(𝒏 +𝒎)
𝑵.𝟏
𝒏/𝟎
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<INPUT> <OUTPUT>report2015-08-0307:52:01(UTC)
satellite2015-08-0207:51:44(UTC)
Azimuth:ENE/Elevation:39.8°
Sampleresults(1/3)
99
h_img(satellite) 8,567mh_real(report) 7,310mbrightnesstemp 232.5K
cross-correlationcoefficient :0.82
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<INPUT> <OUTPUT>report2017-08-1906:42:53(UTC)
satellite2017-08-1906:41:46(UTC)
Azimuth:ENE/Elevation:24.5°
Sampleresults(2/3)
1010
cross-correlationcoefficient :0.88
h_img(satellite) 7,897mh_real(report) 8,793mbrightnesstemp 236.8K
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<INPUT> <OUTPUT>report2015-08-0206:05:24(UTC)
satellite2015-08-0206:01:49(UTC)
Azimuth:ESE/Elevation:23.2°
Sampleresults(3/3)
1111
cross-correlationcoefficient :0.58
h_img(satellite) 8,712mh_real(report) 10,146mbrightnesstemp 231.5K
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Consideration:errorevaluation
1212
(1)resolutionfromcameraspecex)~25m
(2)elevationfromaccelerometerex)~90m
(3)rangeex)3km~ (needtoseethecloudtopofcg,cb)
(4)growthspeedex)~480m/1min(Thecaseoftheearliestcumulonimbus)
h_real- h_img>f(FOV,pix,G,ADC) +range,+growthspeed
(1)(2)(3)(4)
(2)
(3)
(4)
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Resolutionfromcameraspec
1313
(example)・Model:iPhone6plus・Imagesize:width2448pix,height3264pix・Focallength:29mm・FOV:73° (horizontal64° :vertical45°)
・Resolution= Distance× tan 𝜃≈ ~25m
𝜃 = FOV/pix=0.0138°0
10
20
30
distance[m]
resolution[m]
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Accelerometer
1414
(example:iPhone6plus)・ADCrange:14bit・Accelerationrange:±2g→ errorrange=±1mg=±0.05°
0
20
40
60
80
100
distance[m]
errorrange[m]
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Summary
1515
● ConclusionProposalnewmethodtoestimatecloudtopheight&correctthetemperatureoftheupperlayer.
● MethodTocorrecttheheightcomparedtotheskylinebetweensatelliteandgroundbasedimagebygeometricapproach.
● Consideration (Errorevaluation)h_real- h_img>f (FOV,pix,G,AD)+range,+growthspeed
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