sasze: Shortwave Array Spectroradiometer-Zenith

The Shortwave Array Spectroradiometer—Zenith (SASZE) measures the zenith sky shortwave radiance over the spectral range from the near infrared to the ultraviolet.

The SASZE measures sky radiance throughout the day, including twilight before sunrise and after sunset. The SASZE rack with spectroradiometers and data acquisition system is located in a temperature-controlled building isolated from the elements. The SAS measurements can be used to:

  • Retrieve cloud optical depth, particle size, and cloud water path.
  • Test the cloud optical depth retrieval for overcast and broken cloud fields.
  • Validation/comparison with Southern Great Plains site surface remote sensors and future cloud field campaigns.
  • Multivariate analysis to derive information content in hyper-spectral data sets and to improve cloud retrieval algorithm development.
  • Compare with radiative transfer models for testing and validating retrieval procedures.

The SASZE incorporates two Avantes fiber-coupled spectroradiometers (Avaspec ULS 2048 CCD and Avaspec NIR256-1.7) for visible and near-infrared detection in the wavelength range 350-1700 nm. The sampling frequency is 1 Hz.

The spectral resolution is 2.4 nm for the ULS 2048 CCD and 6 nm for the NIR256-1.7. The light collector has a narrow-field-of-view (1° full-angle) collimator at the front end of a high-grade fiber optic.



  • Fixed
  • AMF1
  • AMF2
  • AMF3

Related Publications


PZ, M Alvarado, C Chiu, S DeSzoeke, C Fairall, G Feingold, A Freedman, S Ghan, J Haywood, P Kollias, E Lewis, G McFarquhar, A McComiskey, D Mechem, T Onasch, J Redemann, D Romps, D Turner, H Wang, R Wood, S Yuter, and P Zhu. 2018. Layered Atlantic Smoke Interactions with Clouds (LASIC) Field Campaign Report. Ed. by Robert Stafford, ARM Climate Research Facility. DOE/SC-ARM-18-018.


Yang W, A Marshak, PJ McBride, JC Chiu, Y Knyazikhin, KS Schmidt, C Flynn, ER Lewis, and EW Eloranta. 2016. "Observation of the spectrally invariant properties of clouds in cloudy-to-clear transition zones during the MAGIC field campaign." Atmospheric Research, 182, 10.1016/j.atmosres.2016.08.004.
Research Highlight

Flynn CJ. 2016. Shortwave Array Spectroradiometer–Zenith Instrument Handbook. Ed. by Robert Stafford, DOE ARM Climate Research Facility. DOE/SC-ARM-TR-178.


McBride P, A Marshak, Y Knyazkhin, J Chiu, and W Wiscombe. 2013. What Can Be Learned from ARM Shortwave Hyperspectral Observations? Presented at 4th Atmospheric System Research (ASR) Science Team Meeting. Potomac, MD.

Mather JH and JW Voyles. 2013. "The Arm Climate Research Facility: A Review of Structure and Capabilities." Bulletin of the American Meteorological Society, 94(3), 10.1175/bams-d-11-00218.1.
Research Highlight


McBride PJ, A Marshak, WJ Wiscombe, CJ Flynn, and AM Vogelmann. 2012. Assessing Spectral Shortwave Cloud Observations at the Southern Great Plains Facility. Presented at Fall American Geophysical Union Meeting. San Francisco, CA.


Flynn C, J Barnard, D Hopkins, A Mendoza, D Nelson, R Norheim, L Rochette, A Lanouette, and M Gaudreau. 2011. Combining New and Legacy Instruments Yields Routine Measurements of Absolute Spectral Radiation Spanning the Thermal IR, Near-IR, Visible, and UV. Presented at 2nd Atmospheric System Research (ASR) Science Team Meeting. San Antonio, TX.

View All Related Publications