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1 SKYNET 放射計測と検定千葉大学環境リモートセンシング研究センター高村民雄 1 放射計の較正に関する専門家会合平成 22 年 12 月 20 日地球温暖化観測推進事務局 / 環境省気象庁

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3 沖縄辺戸岬観測施設 ( 放射関連観測 A 棟 ) Direct aerosol sampling SCA (z 0 ), σ ABS (z 0 )] [σ SCA 3

4 sky radiometer POM-01, POM-02 (Prede) LIDAR NIES model(japan) integrating nephelometer absorption meter aethalometer(ae-31,magee Sci) BC monitor(thermo MAAP5012) sampling photometer (SP-Y01) Particle counter OPC(MetOne 237B), OPC(Rion KC-01D) microwave radiometer WVR-1100/1500(Radiometrics) cloud camera PSV-100(Prede) Pyrheliometer MS-53(EKO), CH01(Kipp & Zonen) Pyranometer(CM21) Spectro-pyranometer pyranometer with SB Pyrgeometer PIR(Eppley), CG4(Kipp & Zonen) Instrumentation at SKYNET super sites Phimai (Thailand) POM-01 POM-02 NIES model M903 SP-Y WVR-1100 PSV-100 MS-53 CM21(U) CM21(D) PIR(U) PIR(D) Hefei (China) POM-02 NIES model M903 SP-Y WVR-1100 PSV-100 MS-53 CM21(U) CM21(D) PIR(U) PIR(D) Hedo-misaki (Japan) POM-01 POM-02 NIES model AE-31 MAAP5012 SP-Y02 4 M903 TSI B KC-01D WVR-1100 PSV-100 CH01 CM21 PIR Fukue (Japan) POM-01 POM-02 NIES model M903 AE-31 SP-Y02 KC-01D RPG-LWP PSV-100 CH01 CM21 CG4 Miyako (Japan) POM M903 PSAP 237B WVR-1500 PSV-100 CH01 CM21 PIR Chiba (Japan) POM-01 POM-02 NIES model M WVR-1100 PSV-100 CH01 CM21 PIR CG4

5 何を求めるのか? Sky Sky radiometer radiometer (POM-01/02) (POM-01/02) Validation??? Spectro-pyranometer Spectro-pyranometer ( ( with with SB) SB) Analysis Data Archive Basic Basic aerosol aerosol parameter parameter Optical Optical thickness(aot) thickness(aot) Single Single Scattering Scattering albedo(ssa) albedo(ssa) (size (size distribution, distribution, refractive refractive index) index) validation Analysis Pyranometer Pyranometer (CM21) (CM21) Pyrheliometer Pyrheliometer (CH1) (CH1) 5

6 AOT correction(tuning) with with direct solar radiation and and estimate of of SSA SSA fitted to to observed diffuse radiation Data Data selection <solar <solar radiation> radiation> STD{F STD{F dir.obs (t):5min}<10w/m dir.obs (t):5min}<10w/m 2 2 STD{F STD{F dif.obs (t):5min}<10w/m dif.obs (t):5min}<10w/m 2 2 tuned tuned AOT, AOT, ββ Data Data Approximation <AOT <AOT by by sky sky radiometer> radiometer> τ λ β = ( ) λ 0.5 α With fixed α RT RT calculation F dir.calc (τ dir.calc (τ,, β) β) with with observed observed PWCs PWCs RT RT calculation F dif.calc (τ, dif.calc (τ, β, β, SSA) SSA) with with observed observed PWCs PWCs F dif. obs ( τ ) F dif. calc 10.0( W ( τ, β, SSA) / m 2 ) abs( F dir. obs ( τ ) F 10.0( W / m dir. calc 2 ) ( τ, β )) tuned tuned AOT, AOT, ββ SSA SSA POM-02 POM-02 AOT, AOT, SSA SSA 6

7 Comparison of of Direct/Diffuse Solar radiation between before and and after after tuning with with observed direct and and diffuse radiation SKYNET Fukue-jima, Mar-Apr,

8 AOT AOT corrected by by direct radiation and and estimated SSA SSA at at SKYNET Cape Hedo Ang. Exp Tunned SSA(500nm) SSA (0.5um) Original SSA(0.5um) Tunned SSA (0.5) that agrees diffuse flux (0.315um 2.8um) Hedo (2009) Julian day Tuned beta (0.5um) y = x R² = Original beta (0.5um) 8 Tuned SSA(0.5um) y = x R² = Original SSA (0.5um)

9 Aerosol retrieval by using a spectral pyranometer Irr 2 Irr 3 Irr 4 Instrument Type: with shadow band Manufacturer: EKO Co., Ltd., Japan A major difficulty to use data Cosine correction factors for diffuse and global irradiances are not known. Spectral irradiance(w/m 2 /um) Spectral irradiance [ W/m2/um ] Irr 1 Measurement technique 2010/01/22 09:02:01 [ 50msec] a= h= AM= Irr 1 Measured data Graph Title Observation at Chiba-u (SN S JAXA) Irr 3 T= 24.6[deg.C] PAR : [W/m2] PHOTON : [umol/m2/s] LUM : [lux] Irr 2 Irr Wavelength(nm) [nm] Spectral global irradiance = Irr 1 (λ) Spectral diffuse irradiance = Irr 3 (λ)+ Irr 1 (λ)-(irr(irr 2 (λ)+irr 4 (λ))/2 9

reconstructed using standard grating sun

10 Re-calibration for spectro-pyranometer pyranometer with collimination tube Standard GER 2600 grating sun photometer Sun tracker Sun tracker Calibration constants of are reconstructed using standard grating sun photometer (GER 2600) at MRI, Tsukuba SN:S (HEDO) 10

Cosine characteristics of sensor and correction factor only for direct radiance EKO provided data Original Original Data Data calibrated calibrated by by EKO EKO Radiance Radiance data data at at 4 4

11 Cosine characteristics of sensor and correction factor only for direct radiance EKO provided data Original Original Data Data calibrated calibrated by by EKO EKO Radiance Radiance data data at at 4 4 azimuth azimuth and and 9 9 zenith zenith angles angles Calculation of correction factors CF = E dir ( θ = 0).cos( θ ) E ( θ ) dir Extrapolation and Interpolation SZA SZA SZA SZA upper lower CF( SZA) = * CF + * CF 10 SZAlower, 10 SZAupper, Interpolation for full zenith and azimuth angles 11 AZIupper AZI AZI AZIlower CF ( AZI) = * CFAZI, lower + * CF, AZI upper

March 2009 May 2009 12 Correlations between sky

12 Aerosol optical thickness VS Sky radiometer (POM-02) Observation area: Cape-Hedo, Japan Observation period: March 2009 May Correlations between sky radiometer and AOTs are good (Relatively large RMSE for 400nm channel)

13 Single scattering albedo(ssa) Diffuse Diffuse MS700Equiv. MS700Equiv. Simulated Simulated diffuse diffuse irradiance irradiance equivalent equivalent to to measured measured irradiance irradiance by by Diffuse Diffuse MS700 Diffuse MS700 Diffuse irradiance irradiance measured measured by by Condition for SSA reterieval using data Diffuse Diffuse MS700Equiv.-Diffuse MS700Equiv.-Diffuse MS700 <1Wm MS700 <1Wm -2-2 um um

14 SSA scatter-plot between sky radiometer (POM-02) and measurement Site: Cape Hedo Period: Mar.10-May 5, 2009 SSA(POM-02): Skyrad.pack ver.4.2 SSA(): AOT no tuned by CH01, and forward calc for 0.7 to 1 with cosine correction. 14

15 Which instruments are more accurate? Direct fluxes are modeled using spectralaots from Direct fluxes are modeled using Spectral AOTs from sky radiometer Method of correcting excess diffuse flux blocked by shadow band Cosine error correction factors provided by the manufacturer Calibration constant for direct irradiances Spectral solar irradiance at the top of the atmosphere Diffuse fluxes are modeled using spectral SSAs and AOTs from Diffuse fluxes are modeled using spectral SSAs and AOTs from sky radiometer 15

16 Correction factor of at Cape Hedo for direct and diffuse spectral irradiance measurement 16

17 まとめ全天分光日射計によるエアロゾルの波長別光学特性の推定を行った AOT の推定結果では sky radiometer と比較して良い一致を示している SSA を推定するにはセンサーの Cosine 特性に方位角依存がありこれを組み込んだ補正をすることが必要である精度の高い SSA の推定には散乱日射量の精度維持が必須である 17

The Optical Characteristics of the Fore-Optics and the Calibration for. Direct-Sun UV Observation with Brewer Spectrophotometers

The Optical Characteristics of the Fore-Optics and the Calibration for Direct-Sun UV Observation with Brewer Spectrophotometers Mahito ITO * Abstract The UV network of JMA has been made the direct sun