中文版

Aerosol Optical Properties and Solar Irradiance Measurement by AS-RCEC and NTU-DAS 

 

Facilities and measured parameters

Item

parameter

Instrument (amount)

manufacturor

Wave-length

1

Global solar irradiance

Precision Spectral Pyranometer (8)

Eppley

0.295~3mm

0.395~3mm

0.695~3mm

2

Global solar irradiance

Pyranometer Meter (1)

Licor

0.28~3mm

3

Direct solar irradiance

Sunphotometer (2)

Cimel

340,380,440,500,

675,870,936,1020nm

4

Direct solar irradiance

Ozonemeter (2)

Solar Light

305.5,312.5,320,936,

1020nm

5

Global terrestrial irradiance

Precision Infrared Radiometer (1)

Eppley

3~50nm

6

Diffuse solar irradianc

Shader (1)

Eppley

 

 

The item #1, #3, #5 and #6 are installed on two aluminun portable benchs for field operation (Taipei and Tainan cities) from 2001 until now. Data sampling in one-second resolution is archived and processed in RCEC. The field observation is terminated during summertime for instrumental calibration in RCEC, except the CIMEL sunphotometer. This sunphotometer instrument is recommended by SANA/Aeronet project (Goddard Space Flight Center, Maryland, U.S.A.) and it calibrates all CIMEL sunphotometers around the world for free and for data quality assurance. All pyranometers in RCEC are calibrated ourselves by two steps. First step is using standard lamp in the air conditoning darkroom to check the electrical response of pyranometers. Then we make a inter-comparison of pyranometers outdoor. The standard pyranometers belonged to Central Weather Bureau (CWB) are also joined this intercomparison. Item #2 and #4 are light instruments for traveling comparison in the field experiment.

 

Darkroom for Pyranometer calibration

The darkroom in RCEC is under air conditioning status with temperature and humidity monitoring. Black-painted walls and cloths ensure that the standard lamp is the only light source and no reflective light existed during calibration process. The lamp and pyranometer are mounted on the accurate tracker which is put on a level optical table. Qualified power supply provides stable current for the standard lamp, and one diaphragm is used to control the light spot on the pyranometer dome exactly. The standard lamp is 100-hour life and is traced back to NIST reference. We also keep one pyranometer in RCEC darkroom for reference to compare other pyranometers used in field experiment. The calibrated pyranometer can be rotated by step-motor for cosine response test.

 

Testbed outdoor

RCEC cooperates with the Meteorological Instrument Center of Central Weather Bureau (CWB/MIC) to review the CWB long-term solar radiation data quality. CWB/MIC provides their testbed on the roof for the pyranometer intercomparison in the outdoor. RCEC tests the necessity of pyranometer ventilator and the dome clearance, and study the methodology of cloud amount counting with infrared radiometer.

 

Data quality control

(1)   Cimel Sunphotometer

NASA/GSFC Aeronet processes the raw data into three quality levels：

Level-1

Binary to Ascii data format converting

Level-1.5

Passing cloud screened filter and give aerosol optical depth

Level-2

Retriving single scattering albedo, asymmetric Factor，and size distribution parameters under some higher zenith angle and almucantar-symmetric sky conditions.

 

(2)   Pyranometer

Following the technical report of Baseline Surface Radiation Network (BSRN) in World Meteorological Organization (WMO) World Climate Research Program (WCRP)，five quality-checking steps for pyranometer measurement are listed below:

1.      Physically possible

2.      Extremely rare

3.      Across quantities

4.      comparison with a model

5.      eye check of time series plots

 

Field Campaign

March-May, 2000: Pre-study for Main Theme Project (Taipei)

February-May, 2001:ACE-Asia (Wanli and Lanyu)

March-May, October-December, 2002: ECRP/EPA project (Taipei and Tainan)

January-May, October-December, 2003-5: ECRP/EPA project (Taipei and Tainan)

 

Members:

Po-Hsiung Lin (PI)

Ho-Juin, Lin (full-time Assistant)

 

Radiation-related Publication in 2000-2004

1.conference

林博雄, 陳奕良, 2001: 地面短波輻射之精確量測及其應用. 第七屆全國大氣科學研討會, 台北.

林博雄, 林和駿, 陳奕良, 劉紹臣, 2001: ACE-Asia實驗期間蘭嶼懸浮微粒光學特性觀測之初步結果. 第七屆全國大氣科學研討會, 台北.

林博雄,林和駿,劉紹臣,張修武，2003: The Temporal Characteristics of Aerosol Optical Depth at Taipei，第六屆區域氣候研討會，中壢。

林博雄,劉紹臣,馮欽賜,周宗玄,葉瑞元,2004:台灣地區太陽輻射量之校驗與長期趨勢. 第八屆全國大氣科學研討會, 桃園龍潭.

陳詠昌,林博雄,劉紹臣,朱定中,2004: 台灣地區懸浮微粒光學厚度之衛星觀測與校驗. 第八屆全國大氣科學研討會, 桃園龍潭.

Lin, P. H., I. L. Chen, and S. C. Liu, 2000: Aerosol Optical Depth over Taipei, Seventh International Conference on Atmospheric Sciences and Applications to Air Quality (ASAAQ), Taipei.

Lin, P. H., S. C. Liu and S.W. Chang, 2003: The Temporal Characteristics of Aerosol Optical Depth at Taipei. 10th Conference of Aerosol Reserch in Taiwan, Kaohsiung.

 

2.journals

Lin, P. H., M. D. Chou, Q. Ji and S. C. Tsay, 2002: Clear-sky Surface Radiation During South China Sea Monsoon Experiment. J. Terrestrial, Atmospheric and Oceanic Science.,13,185-196.