Osamu IjimaRadiation Section,

Atmospheric Environment Division,

Global Environment and Marine Department,

Japan Meteorological Agency (JMA)

Oct. 2010, IPC-XI, Davos, Switzerland1

RRC Regional Association (RA) II (Asia)

• JMA (Tokyo) has been serving as RRC in the WMO Regional Association (RA) II (Asia) since 1965.

Region II ASIA MAP 2

1964 Pyrheliometer Intercomparison : India - Japan

(Pune, India)

1965 Regional Radiation Centre Establish

(RA II Res.20, CIMO IV Rec.1,3,9)

1968 Pyrheliometer Intercomparison : Thailand - Japan

(Tsukuba, Japan)

1970 Join in IPC-III (WRC/Davos, Switzerland)

1975 Join in IPC-IV (WRC/Davos, Switzerland)

Pyrheliometer Intercomparison : China - Japan

(Tsukuba, Japan) 

1980 Join in IPC-V (WRC/Davos, Switzerland)

1983 Pyrheliometer Intercomparison : Hong Kong - Japan

(Tsukuba, Japan)

1985 Join in IPC-VI (WRC/Davos, Switzerland)

Activities of RRC RA-II Tokyo No.1

- History and main activities -

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1985 Join in IPC-VI (WRC/Davos, Switzerland)

1989 RPC-I : Regional Pyrheliometer Comparison of

RA II & RA V (Tsukuba, Japan) 

1990 Join in IPC-VII (WRC/Davos, Switzerland)

1994 Reference Pyranometer Calibration : Thailand

(Tsukuba, Japan)

1995 Pyrheliometer Intercomparison : China - Japan

(Tsukuba, Japan)

Reference Pyranometer Calibration : Korea

(Tsukuba, Japan)

Join in IPC-VIII (WRC/Davos, Switzerland)

1996 Training for Calibration of Pyrheliometers : Korea

(Tsukuba, Japan)

Activities of RRC RA-II Tokyo No.2

- History and main activities -

4

1997 Pyrheliometer Intercomparison :

Hong Kong & Korea - Japan (Tsukuba, Japan)

Training for Reference Pyranometer Calibration :

Philippines (Tsukuba, Japan)

2000 Join in IPC-IX (WRC/Davos, Switzerland)

2002 Pyrheliometer Intercomparison :

Hong Kong, China & Korea - Japan

(Tsukuba, Japan) 

2005 Join in IPC-X (WRC/Davos, Switzerland)

2007 RPC-II : Regional Pyrheliometer Comparison

of RA II (Tsukuba, Japan)

2010 Join in IPC-XI (WRC/Davos, Switzerland)

20122012 RPC-III (planned)RPC-III (planned)

Activities of RRC RA-II Tokyo No.3

- History and main activities -

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World Radiation Center

Solar Radiometry Section （ WRC-SRS ）

PMOD (Davos, Switzerland)

Regional Radiaton Centre （ RRC ）

RRC-Tokyo (Japan), RRC-Pune (India)

National Radiation Centre （ NRC ）

RIC-Beijing (China), RIC-Tsukuba (Japan)

World Standard Group (WSG)

Regional Standard Group

National Standard Group

Operational instruments

International Pyrheliometer International Pyrheliometer Comparison (IPC)Comparison (IPC)

Regional Pyrheliometer Regional Pyrheliometer Comparison (RPC)Comparison (RPC)

Conceptual diagram of calibration of solar radiation instruments within the framework of WMO

Calibration system within the framework of WMO

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RPC at Mt.Tsukuba in 2007

Regional Pyrheliometer Comparison (RPC)

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• RPCs are held once every 5 years, in principle in the next year of IPC.

• Last RPC was held from Jan. to Jan. 2007 at Tsukuba, Japan with 4 NRC in RAII and WRC.

• The next RPC is planned in 2012.

RPC at Mt. Tsukuba

Aerological Observatory (BSRN Site: Tateno　　　 at Tsukuba City)

Mt. Tsukuba (877m)

Mt. Tsukuba

●Tokyo

●Narita

50km0

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Keisei Hotel (560m)

• Intercomparisons are held once a year among the regional and national standard groups to maintain their accuracy.

Annual internal pyrheliometer comparison at Mt.Tsukuba in 2010 Left: Regional standard group (pyrheliometers) Right: National standard group (pyranometers with collimation tubes)

National Radiation Centre （ NRC ）

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Reference(Standard Instrument, Absolute Pyrheliometer)

Pyranometer (CM21:970409 CMP21:070107)

Reference(Pyrheliometer CH1: PKT10359)

Collimation tube method Sun and shade method (ISO9846)

Method Date ReferenceLight

sourcePyranomet

erCM21

970409

Pyranometer

CMP21070107

Collimation tube method

2009/1/25～

2009/1/28

Absolute PyrheliometerAHF 32446

Outdoor 12.20 8.79

Sun and shade method(ISO9846 ）

2009/2/6 PyrheliometerCH1

PKT10359

Outdoor － 8.77

2009/2/12

Outdoor 12.19 8.76

calibrationcalibration

calibrationcalibration

calibration

calibration

Pyrheliometer(CH1 : PKT10359)

Pyranometer (CM21:970409 CMP21:070107)

Pyranometer Calibration Result

(AHF: 32446)

Coefficient (mV/W/m^2)

（ Opening full-angle 5° Slope angle 1° ）

Target

DiaphragmThe scattered light is effectively suppressed by the diaphragms.

Pyranometer

The Pyranometer is set at the bottom of the tube, so it has the same structure as the Pyrheliometer.

A B

Comparison between the Sun and shade method （ A ） and the Collimation tube method （ B ）

Mt.Tsukuba in 2009

Structure of the Collimation tube

Calibration of infrared radiation instruments within the framework of WMO

• The world infrared irradiance standard developed at PMOD based on the World Infrared Standard Group (WISG) in 2004.

• RRCs are recommended to have a regional standard group of pyrgeometers and send them every three years to the WRC-IRS for calibration.

World Infrared Standard Group (WISG)

Regional Standard Group

Current state of calibration of infrared radiation instruments within the framework of WMO

World Radiation Centre

Infrared Radiometry Section (WRC-IRS)

PMOD (Davos, Switzerland)

Regional Radiaton Centre （ RRC ）

RRC-Tokyo (Japan), RRC-Pune (India)

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• List of pyrgeometers making up

the regional standard group (calibration date)

Eppley PIR/32205F3 (Dec, 2006)

Kipp&Zonen CG4/010567 (Jan, 2007)

Kipp&Zonen CGR4/070037 (Dec, 2008)

Kipp&Zonen CGR4/070038 (Dec, 2009)

Kipp&Zonen CGR4/070039 (in calibration at PMOD, Now)

• Each reference pyrgeometer is sent to WRC-IRS every 3 years for calibration.

The regional standard group at RRC-Tokyoc

the regional standard group in a desiccator

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Outdoor comparisons with the pyrgeometer standard group

inspected pyrgeometersinspected pyrgeometers

the standard groupthe standard group

• Adopt the same procedure as the WRC-IRS’s

• The pyrgeometers are calibrated outdoors by comparisng with the standard group. traceable to the WISG

The pyrgeometer calibration procedure at RRC

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Picture and schematic figure of JMA’s BB cavity

pyrgeometer

conical cavity desiccant

bath vessel Pbath vessel pump

thermocontroller thermocontroller Pertierthermocontroller

PC

data logger

(cavity temp.) (body temp.) (dome temp.)

heat transfer liquid

dry air

signal

cavity temp. controller (bath vessel)

pyrgeometer body temp. controller (bath vessel)

data logger

black body cavity dry air temp. controller (pyrgeometer dome temp.)

CoefficientWRC

(Dec. 2006)JMA

(Jun. 2004)JMA

(Jan. 2007)

C 3.91 3.9647 3.9328

k1 0.01 0.0146 0.0143

k2 1.0024 1.0025 1.0028

k3 3.2 2.8752 2.9012

Calibration coefficients for Eppley/PIR (s/n:32205F3) by WMO/World Radiation Center(WRC) and JMA

Performance of JMA’s Black body (BB) cavity

Temp. class (deg.C)

difference without BB calibration

(W/m2)

difference with BB calibration

(W/m2)

0 - 10 -0.58 0.13

10 - 20 0.02 -0.06

20 - 30 0.40 -0.30

Comparisons of mean difference from reference longwave radiation by class of pyrgeometer body temperature (for K&Z CG4 s/n:050798).

contribution for improvements of pyrgeometer calibration within the framework of WMO.

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• In January 2007, the RRC of Tokyo organized a regional intercomparison at Mt Tsukuba, attended by experts from China including Hong Kong, the Republic of Korea, Japan and the WRC. The report of the regional intercomparison has been published from WMO as WMO/TD-No. 1494.

• Next RPC is planned in 2012 at Mt. Tsukuba. The details of the RRC will be announced to participants in due course.

Summary

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• RRC-Tokyo has established a pyrgeometer calibration procedure for Eppley PIR and Kipp&Zonen CG4/CGR4 pyrgeometers.

• RRC-Tokyo would like to cooperate in calibration of radiation instruments for the improvements of surface radiation measurements.

• RRC-Tokyo has been serving as RRC in RA II since 1965.

at Tateno

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