cloud top height estimation using satellite imageand ...€¦ · copyright© weathernews inc. all...

Copyright© Weathernews Inc. All rights reserved.

“Confidential”

Oct.25th,2017

Takuro HANYUWeathernews Inc.

CloudTopHeightEstimationusingSatelliteImage andGroundBasedImage


Howwonderfulisnovelty usinggroundbasedimagetakenbyyoutogetdetailedinformationoftheupperlayer.

Conclusion

22

Satelliteimage

Groundbasedimage

Skylineofscreenimage

correct

GPSazimuthelevation

Standardatmosphere

&Coordinate

transformation

ex)Lowerthanestimationbysatellite


Purpose

33

l Benefits・Touseasobservationaldata.・TocorrectoftheuppertemperatureasinitialvalueofNWPfordataassimilation.

・Tocorrectthe3Dformforvisualization.

● Background・Satellitedataupgrading:Highresolution&Highfrequency- 2017Nov.30th~ GOES-16- 2015Jul.HIMAWARI-8


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


Data

55

l SatelliteimageHimawari-8infrared(Band13:10.4μm)Resolution:2km , Timefrequency:2.5min

l Groundbasedimage・Weatherreport

PicturetakenbysupporterGPS,azimuth,elevation

・WebcameraTimefrequency:1minGPS,azimuth,elevation


Pixel(x,y,brightness temerature) → lon,lat,height

→Earth-fixedcoordinatesystem

ISA (InternationalStandard Atmosphere)

Processing（1/3）

66

→Viewpointcoordinatesystem

6.5K/1000m


Processing（2/3）

77

→ Perspectiveprojection(toreproducelikeaimagetakenbysmartphone)

→Shadowprocessing(togettheskylinefromimage)

→Skylineimagefromsatellite


→Cross-correlationfunction(Azimuthwiththehighestcorrelationistakenaspositive)

Processing（3/3）

88

𝝓𝒙𝒚 𝒎 =𝟏𝑵) 𝒙 𝒏 𝒚(𝒏 +𝒎)

𝑵.𝟏

𝒏/𝟎


＜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



satellite2017-08-1906:41:46(UTC)

Azimuth:ENE/Elevation:24.5°

Sampleresults(2/3)

1010





satellite2015-08-0206:01:49(UTC)

Azimuth:ESE/Elevation:23.2°

Sampleresults(3/3)

1111




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)


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]


Accelerometer

1414

(example:iPhone6plus)・ADCrange:14bit・Accelerationrange:±2g→ errorrange=±1mg=±0.05°

0

20

40

60

80

100

distance[m]

errorrange[m]


Summary

1515

● ConclusionProposalnewmethodtoestimatecloudtopheight&correctthetemperatureoftheupperlayer.

● MethodTocorrecttheheightcomparedtotheskylinebetweensatelliteandgroundbasedimagebygeometricapproach.

● Consideration (Errorevaluation)h_real- h_img>f (FOV,pix,G,AD)+range,+growthspeed

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