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Zhu C.-D.,Chinese Academy of Sciences | Zhu C.-D.,University of Chinese Academy of Sciences | Lu Y.,Chinese Academy of Sciences | Shi H.-L.,Chinese Academy of Sciences | And 8 more authors.
Chinese Journal of Geophysics (Acta Geophysica Sinica) | Year: 2015

The High Asia is the largest glacierized region over low-and mid-latitudes. During the last decade, the Gravity Recovery and Climate Experiment (GRACE) satellite mission has provided valuable data for monitoring glacial mass changes in High Asia. The new released GRACE RL05 data is used to estimate the glacial mass changes in High Asia from April 2002 to July 2013. After removing glacial isostatic adjustment (GIA) and hydrological contributions from GRACE RL05 data, the least square fitting in the spectral domain and iteration in the spatial domain are used to separate the equivalent water mass changes in 17 mascons over High Asia and 15 mascons over the plains of northern India, and quantify more reliable mass changes in High Asia during the period 2002 to 2013. The impacts of groundwater signal leakage from the plains of northern India on GRACE estimates are discussed in detail based on 17 mascons over High Asia. The equivalent water mass changes in mascons are obtained in the spectral and spatial domain. The equivalent water height changes estimated from spectral and spatial domain show a good agreement in the spatial distribution. The largest equivalent water height change trends of Tianshan, Pamirs and Kunlun shan, Himalaya and Karakorum, Inner Tibet Plateau estimated from spectral and spatial domain are -1.7 cm·a-1 and -2.1 cm·a-1, -1.5 cm·a-1 and -2.0 cm·a-1, -10.9 cm·a-1 and -16.3 cm·a-1, 2.2 cm·a-1 and 2.6 cm·a-1, respectively. The average glacial mass change trends of Tian Shan, Pamirs and Kunlun Shan, Himalaya and Karakorum, Inner Tibetan Plateau are -2.8±0.9 Gt/a, -3.3±1.5 Gt/a, -9.9±2.1 Gt/a, 5.0±0.8 Gt/a, respectively. The average glacial mass change trend of High Asia is -11.0±2.9 Gt/a. The groundwater in the plains of northern India shows obviously mass loss at rate of -35.0±4.2 Gt/a. Without considering the leakage effects from the plains of northern India, the average glacial mass change trends of four sub regions in High Asia are -2.7±1.0 Gt/a, -1.5±1.5 Gt/a, -15.7±1.8 Gt/a, 5.0±0.8 Gt/a, respectively, and average glacial mass change trend of High Asia is -14.9±2.7 Gt/a. The spatial pattern of the glacial mass changes in High Asia is dominated by increases in the inland of the Tibetan Plateau, and by decreases at the margin, respectively. And the largest mass loss occurs at the margin of the southeastern Tibetan Plateau. The glacial mass change trends of Tian Shan, Pamirs and Kunlun Shan, Himalaya and Karakorum, Inner Tibetan Plateau are -2.8±0.9 Gt/a, -3.3±1.5 Gt/a, -9.9±2.1 Gt/a, 5.0±0.8 Gt/a, respectively. The average glacial mass change trend of High Asia is -11.0±2.9 Gt/a. The groundwater signal leakage from the plains of northern India is the key factor to study the estimations of the glacial mass changes in High Asia with GRACE data, and have significant impact on estimates in Pamirs and Kunlun Shan, Himalaya and Karakorum. The impact of such leakage can be effectively corrected by the spectral and spatial domain methods. Because GRACE senses the total mass change, the estimations of the glacial mass changes can be affected by various model errors. It is necessary to have a long and continuous measurement of satellite gravity, and combine the satellite gravity data with other space geodesy techniques to understand the mass change mechanism in High Asia. ©, 2015, Science Press. All right reserved.


Hao W.,Wuhan University | Hao W.,Key Laboratory of Polar Surveying and Mapping | Li F.,Wuhan University | Ye M.,Wuhan University | Zhang J.,Wuhan University
Wuhan Daxue Xuebao (Xinxi Kexue Ban)/Geomatics and Information Science of Wuhan University | Year: 2012

If a deep space tracking station is founded in Earth's Antarctic area, communication conditions will be greatly improved attributing to its broader vision. This paper assumes the deep space station is established in Chinese Antarctica Great-Wall station, and simulates the communication accessibility between the lunar rover and the Great-Wall tracking station. Through the comparison with the domestic tracking station's communication condition, the results show that: (1) The influence of communication condition by topography between the lunar rover in lunar south pole and Great-Wall tracking station is less than that between the lunar rover in lunar south pole and the domestic tracking stations. (2) The longitude is about 180° from the Chinese Antarctic Great-Wall station to the domestic tracking station. Integrated with all of the tracking stations, including Chinese Antarctic Great-Wall station and domestic tracking stations, the impact of the stations away from the Moon due to the Earth's rotation can be reduced and the tracking time can be lengthened. The simulation and analysis of communication accessibility for choosing Antarctic Great-Wall station as deep space tracking station, can provide a suggestion for the feasibility of construction of the next deep space tracking stations.


Deng F.,Wuhan University | Deng F.,Key Laboratory of Polar Surveying and Mapping | Zhou C.,Wuhan University | Zhou C.,Key Laboratory of Polar Surveying and Mapping | And 5 more authors.
Wuhan Daxue Xuebao (Xinxi Kexue Ban)/Geomatics and Information Science of Wuhan University | Year: 2015

Three pairs of Envisat ASAR images at a 35 days interval were utilized to map the ice velocity in the confluence zone of the Amery ice shelf in the East Antarctica using an offset-tracking method. Accuracy assessment and comparative analysis were conducted, which confirmed the reliability of our results. The ice velocity reached as high as 800 m/a at the confluence zone of the Lambert, Mellor, and Fisher Glaciers. There were certain variation characteristics of ice velocity near the grounding line, which provided important references when determining the position of the grounding line.


Ji Q.,Wuhan University | Pang X.,Wuhan University | Pang X.,Key Laboratory of Polar Surveying and Mapping | Zhao X.,Wuhan University | And 2 more authors.
Wuhan Daxue Xuebao (Xinxi Kexue Ban)/Geomatics and Information Science of Wuhan University | Year: 2015

Sea ice thickness is an important parameter and indicator of climate change, sensitive to ecosystem in Polar Regions. For accurate forecasting of climate change, sea ice mass balance, ocean circulation and sea-atmosphere interactions, it is required to have long term records of sea ice thickness. Satellite altimetry provide useful technology for obtaining time series sea ice thickness information on hemispheric scale. So far, four mainstream algorithms based on satellite altimeter data have been used to estimate sea ice thickness effectively. Different algorithms and parameter values as selected by different researchers will lead to results unsuitable for comparison and large uncertainties. To solve this problem, this study compared sea ice thickness over the Arctic research area retrieved from these four mainstream algorithms based on CryoSat-2 satellite altimeter data. Our results demonstrate that: (1) when compared to each other, the retrieved mean sea ice thickness estimated from these four algorithms have similar spatial distribution, but with larger difference in the value, up to 0.476 m; (2) the sequence of estimated sea ice thickness for the Arctic spatial average based on four algorithms is Laxon03 algorithm, Yi11 algorithm, Laxon13 algorithm and Kurtz09 algorithm; (3) the difference of the mean sea ice thickness from these four algorithms was higher in Beaufort Sea than in Central Arctic or Greenland Sea; (4) The Laxon13 algorithm was the optimal algorithm, with the minimum bias and RMSE when compared to IceBridge sea ice thickness measurements. These results can provide useful reference and basis for further study to improve algorithms, so as to quantify dynamic changes of sea ice thickness more accurately. © 2015, Wuhan University All right reserved.


Liu H.,Wuhan University | Liu H.,Key Laboratory of Polar Surveying and Mapping | Pang X.,Wuhan University | Pang X.,Key Laboratory of Polar Surveying and Mapping
Wuhan Daxue Xuebao (Xinxi Kexue Ban)/Geomatics and Information Science of Wuhan University | Year: 2015

Site selection for the Antarctic research stations affects safety, functionality, and operational efficiency of the stations. This study aims to build a criteria system and conduct the site selection aided by Geographical Information Systems and a Fuzzy Analytical Hierarchy Process. Fifteen criteria were proposed as multiple evaluation sub-criteria and were grouped into four main criteria: scientific interest, environment, accessibility and topography. Comparisons were made between the predicted suitable areas and locations of existing stations in Antarctica to show the fitness-for-use of allocation results. This work offers a comprehensive allocation methodology for decision-makers in the assessment of Antarctic station allocation problems. ©, 2015, Wuhan University. All right reserved.

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