In order to better support Antarctic inland ice sheet expedition from Zhongshan Station to Dome A,the topographic data are necessary.At present,although the entire Antarctic DEM provided by RAMP(Ra-darsat Antarctic Ma...In order to better support Antarctic inland ice sheet expedition from Zhongshan Station to Dome A,the topographic data are necessary.At present,although the entire Antarctic DEM provided by RAMP(Ra-darsat Antarctic Mapping Project) was estimated at the highest horizontal(spatial) resolution of about 200 m,the real horizontal resolution of the DEM varies from place to place depending on the density and scale of the original source data.For ice shelves and the inland ice sheet,the horizontal resolution is about 5 km;the vertical accuracy is estimated to be ±50 m in interior East Antarctic ice sheet and away from the mountain ranges.Therefore,more accurate topographic data are unavailable in Antarc-tica.In order to meet the requirements of high-accuracy topographic information for further researches,this paper mainly addresses a fusion study of ASTER stereo pairs and ICESat/GLAS altimetry data for extraction of high-accuracy DEM in East Antarctica,based on the high horizontal resolution(15 m) of ASTER and vertical accuracy(13.8 cm) of ICESat/GLAS.First,some altimetry data were selected as vertical control points to reduce errors of image correlation matching during the extraction of ASTER-based DEM.Second,ice sheet altimetry data derived from ICESat were used to generate DEM ranging from 75° to 81°S because existing ASTER data do not cover this area and high density of the coverage of ICESat altimetry data.Finally,the DEM in coverage of the expedition route was produced.The analysis of result reveals that the DEM accuracy is improved significantly.The absolute vertical accuracy of DEM is higher than 15 m in some cases and higher than 30 m for all the areas along the expedition route except from the 009-001 scene;the interior accuracy is higher than 15 m and higher than 7 m in some cases.It can meet the requirements of topographic map at 1:50000 scale,which is an economic and advantageous method to produce the topographic products.展开更多
It is more than 30 years since the first Chinese National Antarctic Research Expedition(CHINARE) landed in Antarctica in 1984, representing China’s initiation in polar research. This review briefly summarizes the Chi...It is more than 30 years since the first Chinese National Antarctic Research Expedition(CHINARE) landed in Antarctica in 1984, representing China’s initiation in polar research. This review briefly summarizes the Chinese Antarctic scientific research and output accomplished over the past 30 years. The developments and progress in Antarctic research and the enhancement of international scientific cooperation achieved through the implementation of the CHINARE program have been remarkable. Since the 1980 s, four permanent Chinese Antarctic research stations have been established successively and 33 CHINAREs have been completed. The research results have been derived from a series of spatiotemporal observations in association with various projects and multidisciplinary studies in the fields of oceanography, glaciology, geology, geophysics, geochemistry, atmospheric science, upper atmospheric physics, Antarctic astronomy, biology and ecology, human medicine, polar environment observation, and polar engineering.展开更多
Zhongshan HF radar, as one component of SuperDARN, has been established and in operation since April, 2010. Using data from the first two years of its operation, this paper investigates the radar＇s performance, the d...Zhongshan HF radar, as one component of SuperDARN, has been established and in operation since April, 2010. Using data from the first two years of its operation, this paper investigates the radar＇s performance, the diurnal and seasonal variations o1 ionospheric echoes, and their dependence on geomagnetic activity. Statistical studies show that the occurrence of echoes in different beams varies at different frequencies, which arises from the direction of the beam and the area over which the beam can achieve the orthogonality condition between the wave vector and the Earth＇s magnetic field. The diurnal variation is obvious with double peak structures both in the occurrence rate and average power at 04-08 UT and 16-17 UT. The line-of-sight velocities are mainly positive on the dayside and negative on the nightside for Beam 0, which is the opposite of the trend for Beam 15. The spec- tral widths on the dayside are often higher than those on the nightside owing to the high energy particle precipitation in the cusp region. The seasonal variations are more obvious for those beams with larger numbers. The occurrence, the average power, the line-of-sight velocity, and the spectral widths are generally larger in the winter months than in the summer months. The influence of geomagnetic activity on radar echoes is significant. The peak echo occurrence appears on the dayside during geomagnetically quiet times, and shifts toward the nightside and exhibits an obvious decrease with increasing Kp. With increasing geomagnetic activity, the line-of-sight velocities increase, whereas the spectral widths decrease. The frequency dependence is investigated and it is found that in the operating frequency bands in 2010, 9-10 MHz is the most appropriate band for the SuperDARN Zhongshan radar.展开更多
基金Supported by National Natural Science Foundation (Grant No. 40606002)Surveying and Mapping in Chinese Antarctic Expedition Area (Grant No. 1469990711109-1)+1 种基金National Key Technology R & D Program (Grant No. 2006BAD18B01)GLA12 dataset of ICESat/GLAS in National Snow and Ice Data Center (NSIDC)
文摘In order to better support Antarctic inland ice sheet expedition from Zhongshan Station to Dome A,the topographic data are necessary.At present,although the entire Antarctic DEM provided by RAMP(Ra-darsat Antarctic Mapping Project) was estimated at the highest horizontal(spatial) resolution of about 200 m,the real horizontal resolution of the DEM varies from place to place depending on the density and scale of the original source data.For ice shelves and the inland ice sheet,the horizontal resolution is about 5 km;the vertical accuracy is estimated to be ±50 m in interior East Antarctic ice sheet and away from the mountain ranges.Therefore,more accurate topographic data are unavailable in Antarc-tica.In order to meet the requirements of high-accuracy topographic information for further researches,this paper mainly addresses a fusion study of ASTER stereo pairs and ICESat/GLAS altimetry data for extraction of high-accuracy DEM in East Antarctica,based on the high horizontal resolution(15 m) of ASTER and vertical accuracy(13.8 cm) of ICESat/GLAS.First,some altimetry data were selected as vertical control points to reduce errors of image correlation matching during the extraction of ASTER-based DEM.Second,ice sheet altimetry data derived from ICESat were used to generate DEM ranging from 75° to 81°S because existing ASTER data do not cover this area and high density of the coverage of ICESat altimetry data.Finally,the DEM in coverage of the expedition route was produced.The analysis of result reveals that the DEM accuracy is improved significantly.The absolute vertical accuracy of DEM is higher than 15 m in some cases and higher than 30 m for all the areas along the expedition route except from the 009-001 scene;the interior accuracy is higher than 15 m and higher than 7 m in some cases.It can meet the requirements of topographic map at 1:50000 scale,which is an economic and advantageous method to produce the topographic products.
文摘It is more than 30 years since the first Chinese National Antarctic Research Expedition(CHINARE) landed in Antarctica in 1984, representing China’s initiation in polar research. This review briefly summarizes the Chinese Antarctic scientific research and output accomplished over the past 30 years. The developments and progress in Antarctic research and the enhancement of international scientific cooperation achieved through the implementation of the CHINARE program have been remarkable. Since the 1980 s, four permanent Chinese Antarctic research stations have been established successively and 33 CHINAREs have been completed. The research results have been derived from a series of spatiotemporal observations in association with various projects and multidisciplinary studies in the fields of oceanography, glaciology, geology, geophysics, geochemistry, atmospheric science, upper atmospheric physics, Antarctic astronomy, biology and ecology, human medicine, polar environment observation, and polar engineering.
基金supported by the National Natural Science Foundation of China (Grant no. 41031064)the Ocean Public Welfare Scientific Research Project of China (Grant no. 201005017)the Chinese Meridian Project,the Chinese Polar Environment Comprehensive Investigation & Assessment Programmes (Grant no. CHINARE 2012-02-03)
文摘Zhongshan HF radar, as one component of SuperDARN, has been established and in operation since April, 2010. Using data from the first two years of its operation, this paper investigates the radar＇s performance, the diurnal and seasonal variations o1 ionospheric echoes, and their dependence on geomagnetic activity. Statistical studies show that the occurrence of echoes in different beams varies at different frequencies, which arises from the direction of the beam and the area over which the beam can achieve the orthogonality condition between the wave vector and the Earth＇s magnetic field. The diurnal variation is obvious with double peak structures both in the occurrence rate and average power at 04-08 UT and 16-17 UT. The line-of-sight velocities are mainly positive on the dayside and negative on the nightside for Beam 0, which is the opposite of the trend for Beam 15. The spec- tral widths on the dayside are often higher than those on the nightside owing to the high energy particle precipitation in the cusp region. The seasonal variations are more obvious for those beams with larger numbers. The occurrence, the average power, the line-of-sight velocity, and the spectral widths are generally larger in the winter months than in the summer months. The influence of geomagnetic activity on radar echoes is significant. The peak echo occurrence appears on the dayside during geomagnetically quiet times, and shifts toward the nightside and exhibits an obvious decrease with increasing Kp. With increasing geomagnetic activity, the line-of-sight velocities increase, whereas the spectral widths decrease. The frequency dependence is investigated and it is found that in the operating frequency bands in 2010, 9-10 MHz is the most appropriate band for the SuperDARN Zhongshan radar.
