Space technology:A powerful tool for safeguarding world heritage

WORLD HERITAGE AND SPACE TECHNOLOGY The Convention Concerning the Protection of the World Cultural and Natural Heritage(WHC),adopted by United Nations Educational,Scientific and Cultural Organization(UNESCO)on November 16,1972,aims to ensure the identification,protection,conservation,presentation,and transmission to future generations of the world’s cultural and natural heritage.The WHC works toward these goals by emphasizing the Outstanding Universal Value(OUV)of heritage sites and the unique contribution such places can make to conservation and human development agendas.1 As of the end of January 2023,theWHC has been signed by 194 state parties,covering 1,157 sites(including 900 cultural,218 natural,and 39 mixed properties),55 of which are considered to be in danger.These sites,totaling an area of more than 370 million hectares are designated as World Heritage(WH)sites(https://whc.unesco.org/en/list/).WH sites have played a significant role in the sustainable development of society globally and helped effectively maintain and preserve the cultural diversity and global biodiversity of the Earth.

Multi-frequency satellite radar imaging of cultural heritage:the case studies of the Yumen Frontier Pass and Niya ruins in the Western Regions of the Silk Road Corridor

Synthetic Aperture Radar(SAR)remote sensing is increasingly favoured in archaeological applications.However,the effectiveness of this technology for archaeological prospection has so far not been fully assessed.In this study,an integrated single-date and multi-temporal SAR data-processing chain was proposed to sharpen archaeological signs and hence their detection and monitoring.In total,14 scenes of X-band Cosmo-SkyMed,C-band Sentinel-1 and L-band PALSAR data covering the Western Regions of the Silk Road Corridor in China were employed for two important archaeological sites including the Yumen Frontier Pass with emerging archaeological traces and Niya ruins with subsurface remains.The results pointed out that single-date satellite radar data were useful for the identification of subsurface traces buried under desert in the landscape-scale,whereas for the identification of emerging monuments,Sentinel-1 was limited by its lower spatial resolution compared to TerraSAR and PALSAR data.Multi-date products,such as interferometric coherence,the averaged radar signatures and RGB multi-temporal composites,were effective to sharpen archaeological traces as well as for change detection in Yumen Frontier Pass.This study presents a pilot assessment of satellite SAR data for the analysis and monitoring of archaeological features in the predominantly arid-sandy environmental characteristic of investigated sites.

Archeological crop marks identified from Cosmo-SkyMed time series: the case of Han-Wei capital city, Luoyang, China

The development of spaceborne Synthetic Aperture Radar(SAR)technology declares that the golden era of SAR remote sensing in archeology is approaching;however,nowadays its methodology framework is still lacking due to the inadequate case studies validated by ground-truths.In this study,we investigated the crop marks using multi-temporal Cosmo-SkyMed data acquired in 2013 by applying a twostep decision-tree classifier in conjunction with a spatial analysis in an area of archeological interest nearby the archeological site of Han-Wei capital city(1900–1500 BP),in Luoyang,China.The time-series backscattering anomalies related to the wheat growth cycle were identified and then further validated in two zones by geophysical investigations(Ground Penetration Radar and electrical measurements)and in a third zone by archeological excavations made after the SAR data acquisition.This study provides a new approach for the relic detection,shallowly buried and covered by the crop vegetation,by temporal crop marks on spaceborne SAR images.We also emphasize the necessity to establish a satellite-to-ground methodology framework for the promotion of remote-sensing technology in archeology.