A Survey of Landnet Sites Focusing on Tuz Gölü Salt Lake, Turkey

Abstract

Abstract. Radiometric calibration is critical to ensure the accuracy, veracity, continuity and reliability of satellite data measured from multiple sensors and platforms, and is thus recognized as a key activity by all satellite operators. For imaging sensors, vicarious methods using natural targets (such as salt lakes, deserts, or flatlands that are well-characterized and preferably temporally and spatially stable) as a reference are similarly well established. However, while selecting a target site, it is important that its quality and location are selected to minimize sources of uncertainty for any given sensor. To maximize the benefit from limited resources and minimize the impact on satellite operators, the Infrared Visible Optical Sensor (IVOS) sub-group of Committee on Earth Observation Satellites (CEOS) Working Group on Calibration and Validation (WGCV) has selected a few, well-characterized, regularly instrumented target sites, which have since become known as LANDNET sites. Currently, there are eight LANDNET sites: 1) Dome C, Antarctica; 2) Dunhuang, China, Asia; 3) Lspec Frenchman Flat, NV, USA, North America; 4) Ivanpah, NV/CA, USA, North America; 5) La Crau, France, Europe; 6) Negev, Southern Israel, Asia; 7) Railroad Valley Playa, NV, USA, North America; 8) Tuz Gölü, Central Anatolia, Turkey, Asia. This work summarizes the key characteristics, and areas of application of each of the LANDNET sites, especially that of Tuz Gölü, to guide and inform researchers on site selection, and increase international awareness and collaboration in this field. Additionally, detailed information about the Tuz Gölü, Turkey test site is provided, including geographical characteristics, spatial uniformity qualities, and opportunities for international researchers to conduct experiments and measurements. Practical, technical, and logistical experience gained through the international field campaigns organized over the last few years at Tuz Gölü is also shared in detail.

Radiometric Cross-Calibration of the Chilean Satellite FASat-C Using RapidEye and EO-1 Hyperion Data and a Simultaneous Nadir Overpass Approach

“…Moreover, according to Gürbüz et al [6] and CEOS [31], the calibration site presents some debris from weapon tests; this can be another possible factor influencing the response of some validation samples at the sub-pixel level.…”

“…This is especially valid when the information provided by a specific mission must be integrated with data from other platforms, either into models or multitemporal datasets [6][7][8].…”

Preliminary Selection and Characterization of Pseudo-Invariant Calibration Sites in Northwest China

“…However, CV s is related to the pixel size or window size. Gürbüz et al investigated this effect using multi-scale HRV (High Resolution Visible), TM (Thematic Mapper), and AVHRR image data acquired over the Railroad Valley Playa (NV, USA) test site [39], one of eight well-characterized calibration test sites (known as a LANDNET site) endorsed by the Infrared Visible Optical Sensors (IVOS) subgroup of the CEOS [1,35]. The results indicated that the CV s were <1.5% when HRV and TM data with smaller pixel sizes (30 m) were used but increased to 2.5-3.5% when AVHRR data with a larger pixel size (1.1 km) were used.…”