Ver2. Atmosphere Products1

Evaluation SummaryProductReleasethreshold

Standard
accuracy

Targetaccuracy

Status*1

Evaluation Methods

Comparison with in-situ observation (sky-camera images)
for release threshold. Evaluations for standard and target
accuracies were performed as the Classified cloud fraction
products.
Comparison of SGLI-derived solar irradiance using cloud
products including cloud flag, cloud fraction etc. withground-measured solar irradiance.
Evaluation was made as vi-cal. of SGLI TIR bands for therelease threshold. In addition, comparison with othersatellite data for evaluating the achievement of thestandard accuracy.

10% (withCloud
whole-skyflag/Classification camera)

Incl. below cloud Incl. below cloudamountamount☆

Classified cloud
fraction

20% (on solarirradiance)

15% (on solarirradiance)

10% (on solarirradiance)☆

Cloud top
temp/height

1K

3 K/2 km (toptemp/height)

1.5 K/1 km(temp/height)◎

10%/30%100% (as cloud(CloudOT/radiusliquid water))

50% / 20%○

Comparison with other satellite (MODIS) data.

30%

70%20%○

Comparison with other satellite (MODIS) data.

0.1 (Monthly
a_670,865)

0.1 (scenea_670,865)

0.05 (scenea_670,865)○Comparison with other satellite (MODIS) data.

0.15 (Monthly
a_380)0.15 (scenea_380)

0.1 (scenea_380 )Water cloudOT/effective
radiusIce cloud optical
thickness
Aerosol over theoceanLand aerosol bynear ultra violet
Aerosol by
Polarization

0.15
0.15 (scene(Monthlya_670,
a_670,865)
865)

0.1 (scenea_670,865)

with in-situ observation and other satellite○ → ◎ Comparison(MODIS) data.

◎Comparison with in-situ observation and other satellite(MODIS) data.

*1 Symbols denote as follows; 〇: the release threshold achieved, ◎: the standard accuracy achieved, ☆: the target accuracy achieved.

2ARNP
Atmosphere Product- Aerosol over Land and Ocean with Near UV■Changes from Ver. 1・Aerosol retrieval by inputting model forecast of AHI as an initial value
・Simultaneous estimation of 3 variables with canonical correlation analysis(Optical thickness, Angstrom exponent, Single scattering albedo)■Using channels
・Land ：VN01, VN02, VN03, VN05, VN08
・Ocean：VN10, SW01, SW03, SW04
■Ver. 2 algorithm
SGLI
Observed
brightness

Retrieval

Aerosolestimation( 𝒙𝒐 ’)

Restec / Yoshida

Priori (𝒙𝒑 )AHIObservedbrightness

Retrieval

Aerosolestimation( 𝒙𝒐 )

Adaptation

Analyzed
Value( 𝒙𝒂 )Forecast

Forecast( 𝒙𝒇 )3

ARNP
Validation methods■Validation Method:
・Aerosol over ocean:Standard accuracy: RMS errors are evaluated comparing SGLI derived AOT withthose from other satellite sensors and shipborne in-situ observations(AERONET/Maritime Aerosol Network) (scene by scene).
・Aerosol over land:Standard accuracy: RMS errors are evaluated comparing SGLI derived AOT withthose from other satellite sensors and sky-radiometer at ground observation network(Skynet and AERONET) (scene by scene).
■Validation data and condition etc.:
The SGLI data within 10 km from the in-situ sites were used and averaged forcomparison with the in-situ data.
■Validation period:(1) Land: Sky-radiometer
Source – Irie PI@Chiba univ. (SKYNET), Aoki PI@Toyama univ., JMA,AERONET
Period – March 2018, June 2018, Feb. 2018, Jan. 2020, Feb. 2020(2) Ocean: Microtops on ships
Source – AERONET/Maritime Aerosol Network
Period – March 2018, June 2018, Feb. 2019

4

ARNP

ARNP
Validation Results
Aerosol over land with near UV (ARNP_land)
AOT over land（Ver. 1）
Averaged SGLI within 10km vs.
Sky-radiometer at the same time

AOT over land（Ver. 2）
Averaged SGLI within 10km vs.
Sky-radiometer at the same time

R=0.82
Bias=0.08
RMSE
=0.16
Data num=37

Product
AOT over land

Estimated RMSE

Standard accuracy

Target accuracy

Ver. 1Ver. 2

(L+5)

(L+5)

0.16

0.13 (Scene)

0.15 (Scene)

0.10 (Scene)

Standard accuracy is archived.
5ARNP

ARNP
Validation Results
Aerosol over ocean with near UV (ARNP_ocean)
AOT over ocean（Ver. 1）
Averaged SGLI within 10km vs.
shipborne microtops at the same time

AOT over ocean（Ver. 2）
Averaged SGLI within 10km vs.
shipborne microtops at the same timeAOT(670nm)

AOT(670nm)

R
=0.91
Bias
=0.05
RMSE
=0.12
Data num=8R=0.94
Bias=0.04
RMSE
=0.09
Data num=8

Estimated RMSE

ProductAOT over oceanStandard accuracy

Target accuracy

Ver. 1Ver. 2(L+5)

(L+5)

0.12

0.09 (Scene)

0.10 (Scene)

0.05 (Scene)

It has potential to archive standard accuracy.
6

ARNP

ARNP
Validation Results
Aerosol over land with near UV (Monthly ARNP_land)
Ver1

Ver2

Aerosol over ocean with near UV (Monthly ARNP_ocean)
Ver1

Ver2

The cloud contamination reduced over both land and ocean.
7Validation results of Aerosol by Polarization (1/2)•

Algorithm Overview•••

Algorithm PI: Dr. Sonoyo Mukai (The Kyoto College of Graduate Studies for Informatics)
Dr. Itaru Sano (Kindai Univ.)
Features：• Retrieval methods of aerosol properties based on POLDER research.
• Improvements of the precision of aerosol properties by using polarization and near
ultraviolet wavelength.

Issues in V1

GC1SG1_20190501D01M_D0000_3MSG_AOTLF_1000

a. Large deviation of validation resultsb. False detection of AOT in clear-sky areac. Low AOT in dirty sky area•

V2 update① Cloud screening using polarization bands(←a)② Masking snow cover area (see cloud-flag product)（ ← b）
＊Issue c will continue to be considered for the next version•Validation data••In-situ: SKYNET, AERONET
Match-up:• distance±10km(ave.) / time±30min.
• Period: Apr.1st to Dec. 26 2018

Validation results of Aerosol by Polarization (2/2)
AOT＠670nm(V1)

AOT@670nm(V2)
Decreased in thedeviation and false
detection of AOT insnow area.
However, match-up points are notenough in higher AOT area (due tocloud screening, etc.)

2019年5月1日daily全球

False detection ofAOT in clear-sky area

Results
RMSE=0.137（scene）
Conclusion••

Decreased false detectionof AOTRelease threshold

Standard accuracy

Target accuracy

0.15 （monthly average）

0.15 （scene）

0.10 （scene）

Decreased in deviation and false detection of AOT in snow area at V2.
Plan to consider the following for V3:•
Re-examination of cloud screening threshold in high AOT region.
•
Detailed investigation of high AOT event cases. (air pollution, forest fires, etc.)•
Re-examination of radiative transfer. (including LUT)