Archaeological Application of Airborne Synthetic Aperture Radar Technology in Southern Mexico and Central America

在美国国家科学基金会的支持下，一个由多国、多机构组成的考古学家团队将与美国宇航局喷气推进实验室合作，于2004年春天在中美洲南部和中美洲部署机载合成孔径雷达（AIRSAR）系统。AIRSAR调查的重点区域将包括：尤卡坦半岛西北部（墨西哥）；乌苏马辛塔河地区（墨西哥和危地马拉）、帕西翁河地区（危地马拉）、佩滕中部和北部（危地马拉）；哥斯达黎加的大西洋中部斜坡；以及迪奎斯地区/将军谷（哥斯达黎加），其连接的横断面包括尼加拉瓜、洪都拉斯和萨尔瓦多的部分地区。本研究的目的是：(1)检验和完善AIRSAR在热带和亚热带地区考古应用中的有效性；(2)通过AIRSAR地图与考古地面调查相结合，扩大对中南美洲各地区占领历史的认识。AIRSAR可以说是世界上最复杂、最通用的机载雷达平台，具有表征环境和探测人类对环境的改变的能力，这些能力现在才得到充分开发。AIRSAR是一种独特的系统，可提供广泛区域的多波段、多极和多频率数据，其分辨率明显高于公开可用的卫星和航天飞机图像。此外，AIRSAR的长波长低频雷达信号穿透森林冠层，在热带环境下的考古应用中具有前所未有的潜力。简而言之，AIRSAR可以获得其他仪器或研究方法无法提供的数据。我们目前对墨西哥南部和中美洲前哥伦布时期社会经济和政治组织的理解，是基于一个非常有限的考古样本，跨越了一个巨大的文化景观。许多地区茂密的森林覆盖限制了以往遥感技术和地面调查的应用。AIRSAR任务提供了一个独特而有前途的机会，可以穿透森林冠层，探测一系列重要的考古和相关的生态特征。如果该系统的功能如预期的那样，结果可能是新遗址的突破性发现，并提供新的或修订的考古特征图像，包括定居点的规模和密度、农业系统、堤道系统、贸易网络和防御工事。因此，来自AIRSAR的地面检查数据将对我们对墨西哥和中美洲前哥伦布社会的理解做出重大贡献。此外，AIRSAR的成功应用远远超出了考古学的范畴。由于农业、伐木和开发以及人为的气候变化，中美洲南部的多种生态系统，包括热带雨林、云雾林、湿地和沿海洪泛平原，正以惊人的速度遭到破坏。它们的消失意味着对当地天气模式、淡水供应、众多物种栖息地和全球气候的重大影响。通过AIRSAR的数据将有关现代和古代景观的数据联系起来的能力，为这些脆弱的生态系统的人为环境变化提供了一个长期的视角。

With the support of the National Science Foundation, a multi-national, multi-institutional team of archaeologists will work with NASA's Jet Propulsion Lab to deploy the Airborne Synthetic Aperture Radar (AIRSAR) system in southern Mesoamerica and Central America in the spring of 2004. The focal areas of AIRSAR survey will include: northwest Yucatan (Mexico); the Usumacinta River region (Mexico and Guatemala), the Pasion River region (Guatemala), the central and northern Peten (Guatemala); the Central Atlantic Slope of Costa Rica; and the Diquis Region/General Valley (Costa Rica), with connecting transects to include portions of Nicaragua, Honduras, and El Salvador. This research has the following objectives: (1) To test and refine the effectiveness of the AIRSAR in archaeological applications in tropical and subtropical regions; (2) To expand our understanding of the occupation history in various regions of southern Mesoamerica and Central America through the combination of AIRSAR maps and archaeological ground survey. AIRSAR is arguably the most sophisticated and versatile airborne radar platform in the world, with capacities to characterize environments and to detect human alterations to environments that are only now being fully developed. AIRSAR is a unique system that provides multi-band, multi-polar and multi-frequency data of broad areas with resolutions significantly higher than those of publicly available satellite and shuttle images. In addition, the long wavelength, low frequency radar signals of AIRSAR penetrate through forest canopy, which presents an unprecedented potential for archaeological applications in the tropical environment. Simply put, AIRSAR can acquire data that can be provided by no other instrument or research methodology. Our present understanding of Precolumbian socioeconomic and political organization in southern Mexico and Central America is based on evidence from a very limited sample of archaeological features across an enormous cultural landscape. Dense forest coverage in many regions has limited the application of previous remote sensing technologies and ground survey. The AIRSAR mission presents a unique and promising opportunity to penetrate the forest canopy and detect an array of critical archaeological and associated ecological features. If the system functions as anticipated, results could be breakthrough discoveries of new sites, and offer new or revised images of archaeological features including settlement size and density, agricultural systems, systems of causeways, trade networks, and fortifications. Thus, ground checked data derived from AIRSAR would make a significant contribution to our understandings of Precolumbian societies in Mexico and Central America. Furthermore, the successful application of AIRSAR has implications far beyond archaeology. Diverse ecosystems of southern Mesoamerica and Central America, including rainforests, cloud forests, wetlands, and coastal floodplains, are being destroyed at an alarming rate, because of agriculture, logging, and development, as well as anthropogenic climate change. Their loss implies significant effects on local weather patterns, freshwater supplies, habitats for numerous species, and global climate. The ability to link data pertaining to the modern and ancient landscapes through data from AIRSAR offers a long-term perspective on anthropogenic environmental change in these vulnerable ecosystems.