Home > 2014, 33(5) > Validation of the “HY-2” altimeter wet tropospheric path delay correction based on radiosonde data

Citation: WANG Jin, ZHANG Jie, FAN Chenqing and WANG Jing, . Validation of the “HY-2” altimeter wet tropospheric path delay correction based on radiosonde data. ACTA OCEANOLOGICA SINICA, 2014, 33(5): 48-53. doi: 10.1007/s13131-014-0473-y

2014, 33(5): 48-53. doi: 10.1007/s13131-014-0473-y

Validation of the “HY-2” altimeter wet tropospheric path delay correction based on radiosonde data

1.  Ocean University of China, Qingdao 266003, China
2.  Qingdao University, Qingdao 266071, China
3.  The First Institute of Oceanography, State Oceanic Administration, Qingdao 266061, China

Received Date: 2013-03-05
Accepted Date: 2013-10-25

Fund Project: the National High-Tech Project of China under contract No. 2013AA09A505.The Marine Public Welfare Project of China under contract No. 201105032-1

Wet tropospheric path delay (PD) is a highly variable term for the altimeter measurement of a sea surface height, caused by the refraction effect of atmospheric water vapor and cloud liquid water. In order to estimate PD values, the "HY-2" system includes a calibration microwave radiometer (CMR) operating at 18.7, 23.8 and 37 GHz. The PD data of the CMR were compared and validated by coincident radiosonde profiles from ten globally distributed radiosonde stations during October 2011 to August 2012. The temporal interval was 1 h. In order to avoid land contamination, different spatial intervals between these two data sets were tested. The empirical fit function of PD uncertainty and spatial interval was found and extrapolated to the ideal situation that the data of CMR and radiosonde were totally coincident. The stability of the brightness temperature of the CMR and its impact on the PD correction was also studied. Consequently, the uncertainty of the PD algorithm of the CMR was estimated to be 2.1 cm.

Key words: path delay

湿对流层延迟是大气中水汽和云液水的折射效应所导致的高度计海面高度测量中的修正项。HY-2卫星搭载一个工作频率为18.7GHz、 23.8GHz 和 37GHz的校正辐射计,以对湿对流层延迟进行修正。本文利用2011年10月至 2012年8月期间的10个无线电探空仪站同步测量的大气廓线计算了路径延迟量,对HY-2校正辐射计的测量结果进行了比对与检验。数据匹配的时间窗口为1h。为了避免陆地污染,采用不同的空间窗口对数据进行匹配,获得了湿对流层校正RMS误差与空间匹配窗口的经验函数,并将该函数外推到校正辐射计数据和探空仪数据时空完全匹配的理想情况。文章同时研究了HY-2校正辐射计亮温数据的稳定性及其对湿对流层校正的影响,最终得到校正辐射计湿对流层延迟算法误差为2.1cm。

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Validation of the “HY-2” altimeter wet tropospheric path delay correction based on radiosonde data

WANG Jin, ZHANG Jie, FAN Chenqing and WANG Jing,