U.S.-Japan Cooperative Science: Studies of Mantle Electrical Conductivity Beneath the Pacific Basin

9909931查夫该奖项支持马萨诸塞州的伍兹霍尔海洋研究所的艾伦·查夫教授和日本东京大学的宇多田恒教授之间为期两年的合作研究项目。 研究人员将对太平洋盆地下的地幔电导率进行研究。 由于商业运营商最近拒绝使用模拟海底电话电缆，因此出现了在世界许多地方对无动力电缆上的地电场进行行星尺度测量的机会。 目前，调查人员已经对六条太平洋和两条大西洋电缆进行了测量，日本正在对另外四条西太平洋电缆进行类似的测量。 这些数据将合并起来，用于两个目的：1）使用至少比以往任何数据长4倍的时间序列，研究地核中产生的极向电场的大小和空间变异性; 2）使用大地电磁/地磁联合测深方法，研究太平洋盆地下的中地幔电导率及其横向变异性。 在利用电缆数据对地球导电性结构进行深大地电磁探测方面取得了实质性进展，他们希望扩大和改进这类结果。 该项目汇集了两个具有互补专业知识和研究能力的实验室的努力。 通过检测地磁发电机（其磁场在地球表面消失）的环形磁分量的漏电流，可以将超长周期海底电缆数据应用于研究地核过程。 这项研究通过一名年轻科学家的参与促进了国际人力资源的发展。 通过交流思想和技术，该项目将扩大我们的基础知识，促进国际理解与合作。 研究人员计划将研究结果发布在网站上（www.whoi

9909931ChaveThis award supports a two year collaborative research project between Professor Alan Chave of the Woods Hole Oceanographic Institute in Massachusetts and Professor Hisashi Utada of the University of Tokyo in Japan. The researchers will be undertaking a study of mantle electrical conductivity beneath the Pacific basin. Due to the recent turn down of analog submarine telephone cables by their commercial operators, an opportunity has arisen to make planetary scale measurements of the geoelectric field on unpowered cables at many places around the world. Currently, investigators have instrumented a total of six Pacific Ocean and two Atlantic Ocean cables and the Japanese are making similar measurements on four other western Pacific cables. These data will be merged and used for two purposes: 1) a study of the size and spatial variability of the poloidal electric field produced in the core using time series that are at least 4 times longer than any previously available, and 2) a study of mid-mantle electrical conductivity and its lateral variability beneath the Pacific basin using a combined magnetotelluric/geomagnetic depth sounding approach. Substantial progress has been made in using cable data for deep magnetotelluric sounding of Earth's conductivity structure and they hope to extend and improve that type of result. The project brings together the efforts of two laboratories that have complementary expertise and research capabilities. Very long period submarine cable data have application to studies of core processes by detecting leakage currents from the toroidal magnetic component of the geomagnetic dynamo (whose magnetic field vanishes at the earth's surface). This research advances international human resources through the participation of a younger scientist. Through the exchange of ideas and technology, this project will broaden our base of basic knowledge and promote international understanding and cooperation. The researchers plan to publish results of the research on the web (www.whoi