| Jiang Xingwei,Jia Yongjun,Zhang Youguang. 2019. Measurement analyses and evaluations of sea-level heights using the HY-2A satellite’s radar altimeter. Acta Oceanologica Sinica, 38(11):134－139 |
| Measurement analyses and evaluations of sea-level heights using the HY-2A satellite’s radar altimeter |
| HY-2A卫星雷达高度计海面高度测量分析与评估 |
| Received:June 12, 2018 |
| DOI：10.1007/s13131-019-1503-6 |
| Key words:HY-2A satellite|radar altimeter|sea level anomalies |
| 中文关键词: HY-2A卫星、雷达高度计、海面高度异常 |
| 基金项目:The National Key Research and Development Program of China under contract No. 2016YFC1401004; the National Natural Science Foundation of China under contract No. 41406207. |
| Author Name | Affiliation | E-mail | | Jiang Xingwei | National Satellite Ocean Application Service, Beijing 100081, China
Key Laboratory of Space Ocean Remote Sensing and Application (MNR), Beijing 100081, China | | | Jia Yongjun | National Satellite Ocean Application Service, Beijing 100081, China
Key Laboratory of Space Ocean Remote Sensing and Application (MNR), Beijing 100081, China | jiayongjun@mail.nsoas.org.cn | | Zhang Youguang | National Satellite Ocean Application Service, Beijing 100081, China
Key Laboratory of Space Ocean Remote Sensing and Application (MNR), Beijing 100081, China | |
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| Abstract: |
| The HY-2A satellite is China’s first independent oceanic dynamic environmental satellite, and has been operating continuously for more than six years. The satellite’s radar altimeter, which is one of the main loads on the satellite, has the ability to realize all-weather and all-day observations of global sea-surface heights, as well as significant wave heights and sea-surface wind speeds. These observed data have been widely used in marine disaster prevention and reduction, along with resource development, maritime security and other fields. In order to achieve a comprehensive understanding of the multi-year overall observational performances of the HY-2A satellite’s radar altimeter, all of the observational data of the IGDR product from October 26, 2012 to August 27, 2017 were selected in this study for a comprehensive evaluation. The height measurement capability of the HY-2A satellite’s radar altimeter was evaluated using self-crossover and Jason-2 crossover methods. The height discrepancies at the self-crossover point of the HY-2A satellite’s ascending and descending orbits were also calculated. It was found that for the HY-2A satellite’s radar altimeter in global waters under the restriction conditions of ascending and descending orbits, the height anomaly differences were within a range of less than 30 cm. The absolute mean error was determined to be 5.81 cm, and the height anomaly standard deviation was 7.76 cm. Under the conditions of the observational areas being limited within a scope of 60° from the Equator, it was determined that the sea-level height anomaly differences were less than 10 cm at the junction of the ascending and descending orbits, the absolute mean error was 3.95 cm. In addition, the sea-level height anomaly standard deviation was observed to be 4.76 cm. Using a mutual cross method with the Jason-2 satellite, it was found that under the conditions of the observational area being within the scope of 66° from the equator, the height anomaly differences at the junction were less than 30 cm, and the absolute mean error of HY-2A and Jason-2 sea level height anomaly was 5.86 cm, with a standard deviation of 7.52 cm. It was observed that, if within the sea area the sea level height anomaly difference was limited to within 10 cm, then the absolute mean error and standard deviation could reach 4.19 cm and 4.98 cm, respectively. It was confirmed that the HY-2A satellite’s radar altimeter had successfully reached the height measurement level of similar international altimeters. Therefore, it had the ability to meet the needs of marine scientific research and ocean circulation inversions. |
| 中文摘要: |
HY-2A卫星是我国首颗自主海洋动力环境卫星，已连续运行6年多。卫星上搭载的主载荷雷达高度计能够实现全天候、全天时全球海面高度、有效波高和海面风速的观测，这些观测数据已经广泛用于海洋防灾减灾、资源开发和海上安全等领域。
为了全面了解HY-2A卫星雷达高度计多年来的整体观测性能，本文选取了2012年10月26日至2017年8月27日间的全部观测数据IGDR产品进行综合评价。通过自交叉和与Jason-2互交叉两种手段对HY-2A卫星雷达高度计测高能力进行评估。计算HY-2A升降轨自交叉点的测高不符值，发现HY-2A卫星雷达高度计在近全球海域内、升降轨高度异常差小于30cm的限制条件下，平均绝对高度误差为5.81cm，高度异常标准差为7.76cm；限制观测区域为南北纬60°范围内、海面高度异常升降轨交叉点处的差小于10cm的情况下，平均绝对误差可达3.95cm，海面高度异常标准差达4.76cm。通过和Jason-2卫星的互交叉，发现在南北纬66°范围内，交叉点高度异常差小于30cm的情况下，HY-2A和Jason-2的海面高度异常平均绝对误差为5.86cm，标准差为7.52cm，如果在该海域内将海面高度异常差限制在10cm内，平均绝对误差和标准差分别达到4.19cm和4.98cm。HY-2A卫星雷达高度计已经达到国际同类卫星雷达高度计测高水平，可以满足海洋科学研究、海洋环流反演等的需求。 |
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