In this section, Information regarding the Test Sites are contained

The Sites can be classified as follow:

• LES : Land Equipped Sites (e.g. LANDNET)
• LNES: Land Non Equipped Sites
• SES: Sea Equipped Sites
• SNES: Sea Non Equipped Sites

Reference Site key principles

The Cal/Val community has a broad consensus on the ideal characteristics for a reference site, these include ^{[1],[2],[3],[4]}:

• The higher the spatial uniformity of the area, the less the impact of assigning a “generalised” reflectance value to represent the full test site.
• A high-reflectance results in higher signal-to-noise ratio (SNR), which, in return, increases overall accuracy.
• Spectral uniformity of the site simplifies the calibration process.
• Temporal uniformity of the site enables greater flexibility in usage.
• A Lambertian reflecting surface is preferable as it simplifies corrections due to solar and view geometry.
• The site should have little or no vegetation as this can affect spectral, spatial and temporal uniformity.
• High elevation reduces the error due to aerosols.
• High probability of cloud free days increases usability.
• Long distance from densely populated areas and/or industrial facilities decreases the effect of anthropogenic aerosols.
• A location far from the seas or other large water bodies minimizes the influence of atmospheric water vapour.
• Having a site in an arid region minimizes probability of precipitation, which in turn may change the surface BRDF. Also, in arid regions, the probability of cloudy weather is at a minimum.
• A large site minimizes the effects of scattered light from areas outside the target area.
• Easy access to the site is an advantage.
• Instrumented test sites are preferable and a key requirement for CEOS endorsement as a reference standard for radiometric gain. 

References

[1] Morain S., and Budge M. A., Post-Launch Calibration of Satellite Sensors, ISPRS Book Series – Volume 2, pp.181-187, 2004.
[2] Teillet, P.M., Barsi, J.A., Chander, G., and Thome, K.J. Prime candidate earth targets for the post-launch radiometric calibration of space-based optical imaging instruments. Proceedings of SPIE, vol. 6677, 66770S, 2007.
[3] Thome, K. Paper on the ISPRS Commission I Mid-Term Symposium in conjunction with Pecora 15/Land Satellite Information IV Conference “Ground look radiometric calibration approaches for remote sensing imagers in the solar reflective”, Denver, CO USA. PDF , 2002.
[4]  Scott, K. P., Thome, K., Brownlee, M. R., Evaluation of the Railroad Valley playa for use in vicarious calibration. Proceedings of SPIE, vol. 2818, pp. 158-166, 1996.

Links

1. Calibration Test Sites Selection and Characterization - Documentation