利用落球探测资料分析临近空间大气重力波
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摘要
目的探究利用落球探测数据分析临近空间大气重力波特征的优势。方法基于中国首次进行的火箭落球实验过程中,雷达跟踪获得的落球位置信息,计算得到大气水平风场廓线,并利用最大熵法提取重力波参数。与此同时,基于TIMED/SABER卫星在对应时间以及位置上探测得到的温度廓线,利用最大熵法和S变换方法同样获得相应的重力波参数。针对两种方法获得的重力波参数进行对比分析。结果利用最大熵法对火箭探测得到的水平风场扰动廓线和卫星探测得到的温度扰动廓线进行分析,发现纬向风场中的主导重力波的垂直波长约为4 km左右,而经向风场主导重力波的波长集中在6.5 km左右,由温度扰动廓线提取出的主导重力波垂直波长集中在12 km左右。利用S变换再次对卫星探测得到的温度扰动廓线进行分析,重力波垂直波长仍集中于10～12 km左右。这表明从风场廓线和温度廓线中提取出的重力波垂直波长的差异主要是由于卫星探测数据的分辨率不足产生的。结论相比较卫星探测的温度廓线,火箭探测得到的风场廓线数据对重力波的分辨率更高,能够分辨出垂直波长更小的精细结构,具有重要的精度优势。
Objective To research the strength of falling-sphere detection to gravity wave in the near space. Methods The maximum entropy method was used to extract vertical wavelength of dominant gravity wave based on the horizontal winds profiles calculated with the falling sphere position information obtained through radar tracking during the first falling-sphere experiment in China. Meanwhile, the maximum entropy method and S transform were also used to obtain the corresponding gravity wave parameters based on temperature profile measured at the corresponding time and position by the TIMED/SABER satellite. The gravity wave parameters obtained through two methods were compared. Results The wind field disturbance profile and the temperature disturbance profile were analyzed with the maximum entropy. It was found that the vertical wavelength of main gravity wave was about 4 km(zonal wind) 6.5 km(meridional wind) and 12 km(temp) respectively. The vertical wavelength obtained by S-transform from temp profile was concentrated at 10-12 km. It meant that the different gravity wave of wind field profile and temperature profile was mainly caused by insufficient resolution of satellite detection data. Conclusion Compared with the temperature profile, the wind field profile data detected rocket has more resolution ratio of gravity wave. It could recognize smaller and finer structure of vertical wavelength. The rocket falling-sphere detection is more precise.
Objective To research the strength of falling-sphere detection to gravity wave in the near space. Methods The maximum entropy method was used to extract vertical wavelength of dominant gravity wave based on the horizontal winds profiles calculated with the falling sphere position information obtained through radar tracking during the first falling-sphere experiment in China. Meanwhile, the maximum entropy method and S transform were also used to obtain the corresponding gravity wave parameters based on temperature profile measured at the corresponding time and position by the TIMED/SABER satellite. The gravity wave parameters obtained through two methods were compared. Results The wind field disturbance profile and the temperature disturbance profile were analyzed with the maximum entropy. It was found that the vertical wavelength of main gravity wave was about 4 km(zonal wind) 6.5 km(meridional wind) and 12 km(temp) respectively. The vertical wavelength obtained by S-transform from temp profile was concentrated at 10-12 km. It meant that the different gravity wave of wind field profile and temperature profile was mainly caused by insufficient resolution of satellite detection data. Conclusion Compared with the temperature profile, the wind field profile data detected rocket has more resolution ratio of gravity wave. It could recognize smaller and finer structure of vertical wavelength. The rocket falling-sphere detection is more precise.
引文
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[3]易帆.中高层大气重力波的研究——辨明近地空间环境扰动的关键过程[J].中国科学基金, 1997(3):43-48.
[4]肖存英,胡雄,王博,等.临近空间大气扰动变化特性的定量研究[J].地球物理学报, 2016, 59(4):1211-1221.
[5]帅晶.全球重力波活动的SABER/TIMED观测研究[D].武汉:武汉大学, 2013.
[6]徐晓华,郭金城,罗佳.利用COSMIC掩星资料分析大气重力波参数的全球分布特征[J].武汉大学学报(信息科学版), 2015, 40(11):1493-1498.
[7]程胡华,钟中,岑瑾.曲线拟合背景场在提取大气重力波参数中的缺陷[J].气象科学, 2013, 33(1):19-25.
[8]姜国英,徐寄遥,史东波,等.子午工程首枚气象火箭大气探测结果分析[J].科学通报,2011,56(19):1568-1574.
[9]GEWei,SHENGZheng,ZHANGYi-yao,etal.The Study of in Situ Wind and Gravity Wave Determination by the First Passive Falling-sphere Experiment in China's NorthwestRegion[J].JournalofAtmosphericandSolar-Terrestrial Physics, 2019, 182:130-137.
[10]STOCKWELL R G, MANSINHA L, LOWE R P. LocalizationoftheComplexSpectrum:TheSTransform[J].IEEETransactionsonSignalProcessing,1996,44(4):998-1001.