Journal cover Journal topic
Atmospheric Measurement Techniques An interactive open-access journal of the European Geosciences Union
Journal topic

Journal metrics

Journal metrics

  • IF value: 3.400 IF 3.400
  • IF 5-year value: 3.841 IF 5-year
    3.841
  • CiteScore value: 3.71 CiteScore
    3.71
  • SNIP value: 1.472 SNIP 1.472
  • IPP value: 3.57 IPP 3.57
  • SJR value: 1.770 SJR 1.770
  • Scimago H <br class='hide-on-tablet hide-on-mobile'>index value: 70 Scimago H
    index 70
  • h5-index value: 49 h5-index 49
Discussion papers
https://doi.org/10.5194/amt-2019-230
© Author(s) 2019. This work is distributed under
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/amt-2019-230
© Author(s) 2019. This work is distributed under
the Creative Commons Attribution 4.0 License.

Submitted as: research article 05 Jul 2019

Submitted as: research article | 05 Jul 2019

Review status
This discussion paper is a preprint. It is a manuscript under review for the journal Atmospheric Measurement Techniques (AMT).

Nocturnal aerosol optical depth measurements with modified skyradiometer POM-02 using the moon as a light source

Akihiro Uchiyama1, Masataka Shiobara2, Hiroshi Kobayashi3, Tsuneo Matsunaga1, Akihiro Yamazaki4, Kazunori Inei5, Kazuhiro Kawai5, and Yoshiaki Watanabe5 Akihiro Uchiyama et al.
  • 1Center for Global Environmental Research, National Institute for Environmental Studies, Tsukuba, Ibaraki 305-8506, Japan
  • 2National Institute of Polar Research, Midoricho, Tachikawa, Tokyo 190-8518, Japan
  • 3University of Yamanashi, Takeda, Kofu, Yamanashi 400-8510, Japan
  • 4Meteorological Research Institute, Japan Meteorological Agency, Tsukuba, Ibaraki 305-0052, Japan
  • 5Prede Co., Ltd., Kamidaira, Fussa, Tokyo 197-0012, Japan

Abstract. The majority of aerosol data are obtained from daytime measurements, and there are few datasets available for studying nighttime aerosol characteristics. In order to estimate the aerosol optical depth (AOD) and the precipitable water vapor (PWV) during the nighttime using the moon as a light source, a skyradiometer POM-02 (Prede Ltd., Japan) was modified. The amplifier was adjusted so that POM-02 could measure lower levels of input irradiance. In order to track the moon based on the calculated values, a simplified formula was incorporated into the firmware. A new position sensor with a four-quadrant detector to adjust tracking of the sun and the moon was also developed.

The calibration constant, which is the sensor output for the extra-terrestrial solar and lunar irradiance at the mean earth-sun distance, was determined by using the Langley method. The measurements for the Langley calibration were conducted at the NOAA/MLO in October and November 2017. By assuming that the relative variation of the reflectance of the Robotic Lunar Observatory (ROLO) irradiance model is correct, the calibration constant for the lunar direct irradiance was successfully determined using the Langley method. The ratio of the calibration constant for the moon to that for the sun was often greater than 1; the value of the ratio was 0.95 to 1.18 in the visible near-infrared wavelength region. This means that the ROLO model often underestimates the reflectance. In addition, this ratio depended on the phase angle. In this study, this ratio was approximated by a quadratic expression of the phase angle. By using this approximation, the reflectance of the moon can be calculated to within an accuracy of 1 % or less.

In order to validate the estimates of the AOD and PWV, continuous measurements with POM-02 were conducted at MRI/JMA from January 2018 to May 2018, and the AOD and PWV were estimated. The results were compared with the AOD and PWV obtained by independent methods. The AOD was compared with that estimated from NIES High Spectral Resolution Lidar measurements (wavelength: 532 nm), and the PWV was compared with the PWV obtained from a radiosonde and the Global Positioning System. As a result, the estimations of the AOD and the PWV using the moon as the light source were made with the same degree of precision and accuracy as the estimates using the sun as the light source.

Akihiro Uchiyama et al.
Interactive discussion
Status: final response (author comments only)
Status: final response (author comments only)
AC: Author comment | RC: Referee comment | SC: Short comment | EC: Editor comment
Akihiro Uchiyama et al.
Akihiro Uchiyama et al.
Viewed  
Total article views: 444 (including HTML, PDF, and XML)
HTML PDF XML Total BibTeX EndNote
378 63 3 444 6 7
  • HTML: 378
  • PDF: 63
  • XML: 3
  • Total: 444
  • BibTeX: 6
  • EndNote: 7
Views and downloads (calculated since 05 Jul 2019)
Cumulative views and downloads (calculated since 05 Jul 2019)
Viewed (geographical distribution)  
Total article views: 435 (including HTML, PDF, and XML) Thereof 425 with geography defined and 10 with unknown origin.
Country # Views %
  • 1
1
 
 
 
 
Cited  
Saved  
No saved metrics found.
Discussed  
No discussed metrics found.
Latest update: 20 Oct 2019
Publications Copernicus
Download
Short summary
The majority of aerosol data are obtained from daytime measurements using the sun as a light source, and there are few datasets available for studying nighttime aerosol characteristics. To estimate the aerosol optical depth (AOD) during the nighttime using the moon as a light source, a radiometer for the daytime was modified, and a new calibration method was developed. As a result, the estimations of the nighttime AOD were made with the same degree of precision and accuracy during the daytime.
The majority of aerosol data are obtained from daytime measurements using the sun as a light...
Citation