Foreword

正Rapid changes of Arctic sea ice cover have been in the focus of the international climate research community in recent years.Quite a few of nations have completed a large number of related surveys and research projects in the Arctic Ocean.Up to now,China has performed six research cruises to the Arctic Ocean resulting in a significant volume of research output.Improved knowledge on the atmospheree-sea ice-ocean interactions in the Arctic is a     

Foreword

This special issue is based on the presentations at the 13th Annual General Meeting of the Asian Forum for Polar Sci- ences （AFoPS-13） in New Delhi on 6-7 August 2012, chaired by Dr. Shri Rasik Ravindra, Director of National Center for Antarctic and Ocean Research of India. To strengthen both scientific and logistic collaboration among Asian countries in- volved in polar research is AFoPS＇s main purpose. During the AFoPS-13, it was decided to publish the AFoPS proceedings annually by each member countries in turn to demonstrate progresses in Polar Science of Asian countries. On the meeting, China was given the great honor to publish the first AFoPS proceedings as a special issue of the Advances in Polar Science （APS）, which is a peer-reviewed journal, published in English. APS is a comprehensive scientific journal dedicated to polar research in all scientific disciplines.     

Foreword

This special issue is based on the research reports presented at the 2012 Super Dual Auroral Radar Network (SuperDARN) workshop held at Polar Research Institute of China,Shanghai,China,during May 27-June 1,2012. SuperDARN is an international collaboration involving scientists and engineers from more than 10 countries.So far,SuperDARN has more than 30 high frequency coherent radars covering the middle latitudes to very high latitudes in both hemispheres,and has become the most powerful tool for monitoring large scale ionospheric convection.The backscatter targets of SuperDARN radars are ionospheric plasma irregularities aligned along the geomagnetic field.The Doppler velocity of the irregularities can be used to infer the strength and direction of the ionospheric electric field.These measurements,obtained continuously,provide valuable information about the electrodynamics of the coupled magnetosphere-ionosphere system over extended spatial scales and with high time resolution.     

Foreword to the Special Issue

The China National Group of the International Association of Engineering Geology and the Environment (IAEG) and the State Key Laboratory for Geo-hazard Prevention and     

对空间数据库更新进展的思考——空间数据库更新专题前言

现势性是地理信息系统的"生命",直接影响着其使用价值与可持续发展.随着地理信息系统建设的不断推进与广泛应用,地理信息系统建设的工作重心已经由初始的数据生产向数据更新与服务进行转变.生产与应用的迫切需求提出了很多新的问题,同时也极大地推动了相关理论、技术及方法的发展.其中,空间数据库更新即是这一背景下提出的新问题,相关的理论和关键技术已经成为当前空间信息科学领域的国际研究与应用前沿.