A Simple Empirical Equation to Calculate Cloud Optical Thickness Using Shortwave Broadband Measurements

Journal Article · Thu Jul 01 00:00:00 EDT 2004 · Journal of Applied Meteorology, 43(7):1057-1066

DOI:https://doi.org/10.1175/1520-0450(2004)043<1057:ASEETC>2.0.CO;2· OSTI ID:15020838

Barnard, James C; Long, Charles N

In this paper, we present an empirical equation that can be used to estimate shortwave cloud optical thickness from measurements and analysis of shortwave broadband irradiances. When applied to a time series of broadband observations, this method can predict cloud optical thickness distributions that are very similar to those obtained using the Min algorithm (Min and Harrison, 1996). When considering a number of geographically diverse sites, medians of equation-derived distributions and Min-derived distributions differ by less than 10%. The equation is designed for fully overcast skies, surface albedos less than 0.3, and the cosine of the solar zenith angle must be greater than 0.15.

• Research Organization: Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-76RL01830
• OSTI ID: 15020838
• Report Number(s): PNNL-SA-38513; KP1201030; TRN: US200521%%288
• Journal Information: Journal of Applied Meteorology, 43(7):1057-1066, Vol. 43, Issue 7
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
99 GENERAL AND MISCELLANEOUS//MATHEMATICS, COMPUTING, AND INFORMATION SCIENCE
ALGORITHMS
CLOUDS
THICKNESS
OPTICAL PROPERTIES
CALCULATION METHODS
cloud optical depth
broadband irradiance