利用TOPEX卫星高度计资料分析东中国海的风、浪场特征

利用TOPEX卫星高度计和日本气象厅浮标观测资料,对东中国海的有效波高和风速进行比较,分析了卫星高度计资料的有效性。利用有效波高和风速的3种概率密度函数分布,结合TOPEX卫星高度计资料,并采用最大似然方法对统计分布参数进行估计,结果表明,有效波高的对数-正态概率密度分布与观测资料的直方图在有效波高的整个范围内符合较好,风速的直方图与Weibul概率密度分布符合较好。同时,分析了有效波高大于4 m的巨浪在东中国海的时空分布特征,表明巨浪多出现在冬、秋两季,平均有效波高最大值出现在夏季,且主要分布在东中国海东南部。     

HY-2B卫星载荷联合观测海面阵风的一种反演方法

国内外对海上阵风的研究并不多,且大多集中在阵风预报和应用研究方面,对于海洋阵风数据的获取技术未见文献系统论述。本文利用HY-2B卫星雷达高度计观测的后向散射系数,结合校正微波辐射计观测的亮度温度信息,提出联合反演阵风风速的方法。两个遥感载荷联合反演得到的阵风风速与2019–2021年美国国家浮标数据中心（NDBC）浮标数据进行真实性检验,结果显示：阵风风速均方根误差（RMSE）为0.98 m/s,相关系数为0.82;基于本方法利用国外同类卫星Jason-3得到的阵风风速与2016–2018年NDBC浮标数据的RMSE为0.96 m/s,相关系数为0.88。本文在HY-2B卫星雷达高度计海面风速观测的基础上,纳入同一卫星平台校正微波辐射计的同步观测信息联合实现了海面阵风的观测,数据的比对结果证明文中方法具有较高的观测精度。同时,该方法对于具有相同观测体制的国内外卫星也适用。     

基于近30 a多源卫星高度计数据的东中国海潮汐信息提取

我国HY-2B卫星已成功运行3 a多,本文首次将 HY-2B测高数据用于计算潮汐。将HY-2B与相同时间段的Jason-3在东中国海分别进行潮汐信息提取,验证了其结果的一致性。建立了基于 10 颗国内外卫星高度计(TOPEX/Poseidon、Jason-1、Jason-2、Jason-3、ENVISAT、ERS-1、ERS-2、Sentinel-3A、Sentinel-3B、HY-2B)数据的时间序列,得到东中国海近30 a时间序列的较高空间分辨率网格化海面高度。利用该数据提取了东中国海12个分潮(O₁、K₁、Q₁、P₁、M₂、S₂、N₂、K₂、S_A、S_Sa、M_m、M_f)的潮汐调和常数,并将 4 个主要分潮M₂、S₂、K₁、O₁的调和常数...     

高度计大气湿度校正的方法及其应用分析

大气中水汽造成的路径延迟的测量误差是目前卫星高度计存在误差的重要原因,这种误差对高度计数据的分析应用产生很大的影响.介绍了高度计大气湿度校正的2种方法,并对它们的结果做了比较.最后分析了大气湿度校正对高度计数据应用的影响.     

多源卫星高度计有效波高数据融合方法研究

有效波高数据融合可以弥补单颗卫星高度计数据存在的时间和空间分辨率不足的问题,为有效波高的海洋学应用提供更精确的分析资料.对反距离加权法、克里金插值法和逐步订正法等数据融合方法进行了研究,得到了适合于有效波高数据融合的模型和参数,并利用GFO,Jason-1和Envisat高度计获取的我国海域及其邻近海域有效波高数据,对不同融合方法、滤波器窗口和卫星个数等影响融合结果的因素进行了分析,结果表明:(1)融合后的有效波高分布特征与前人多年统计分析结果基本一致;(2)数据较密集时,不同融合方法的结果差别不大;(3)选择的滤波器窗口大小与时间分辨率有关,对于时间分辨率为10d的融合而言,采用2.5°×2.5°~3°×3°大小的滤波器窗口所得到的融合结果最合适;(4)参加融合的卫星个数至少为3颗.     

Improving the wind and wave estimation of dual-frequency altimeter JASON1 in Typhoon Shanshan and considering the rain effects

Altimetry data have been widely used in various fiehts of oceanography, including the extreme weather events such as tropical cyclones, typhoons, and hurricanes. The performance of JASON1 in Typhoon Shanshan is assessed by examining the sensor geophysical data record and illustrates how the measured return waveform, significant wave height, and backscatter are all affected by various factors associated with the typhoon, with details by the rain are illustrated. The correction method to maintain accurate wave height and wind speed measurements in Typhoon Shanshan and the results are presented. Furthermore, the additional results of rain rate and typhoon eye diameter can be retrieved. Because of the lack of in-situ measurements of wind, wave, and rain rate at Typhoon Shanshan, results are compared with the forecasted typhoon data and a good agreement is found.     

WWATCH Ⅲ模式模拟南海冷空气过程海浪场的有效性检验

利用Jason-1卫星高度计观测资料,验证了WWATCH Ⅲ海浪模式在模拟南海冷空气过程海浪场的有效性和准确性.结果发现,以NCEP再分析风场驱动的WWATCH Ⅲ模式能够较好地模拟冷空气影响南海时的海浪变化,模拟结果与Jason-1卫星高度计的观测资料有比较好的一致性.在近海岸地区以及冷空气活动末期,模拟值与观测值的相关系数有所降低,但平均相对误差和均方根误差均在可以接受的范围内.说明WWATCH Ⅲ模式可以作为我国南海地区海浪模拟预测研究的有效工具之一.     

基于贝塞尔曲线的波形重跟踪改进算法

针对贝塞尔曲线在拟合内陆湖泊复杂波形存在误差,进而影响波形重跟踪的问题,提出了一种基于主波峰提取的贝塞尔曲线拟合方法,并采用拟合后波形峰值的50%作为重跟踪点。对经过巢湖流域的CryoSat-2雷达高度计L1b数据进行处理得到了8月9日的水位值,观测水位的最大与实际水位相比仅相差0.12m,在与L2I数据中提供的水位值对比中发现,本文算法的结果与精度最高的改进的传统重心偏移（OCOG）算法对比,绝对值差值最大值和最小值分别为0.870 m和0.087 m,均方根误差为0.770,相关系数为0.892．均优于L2I中的改进的用户定制法（CFI）和伦敦大学学院法（UCL）算法,同时本文算法可以得到更多有效观测值,保证了水位观测的连续性。     

The Kuroshio transport east of taiwan and the Sea Surface Height Anomaly from the interior ocean

1　Introduction　TheKuroshioflowsthroughtheEastTaiwanChan nel (ETC)betweenthenortheastcoastofTaiwanandtheJapaneseRyukyuIslandbeforeenteringintotheEastChinaSea (ECS)astheextendingflowoftheNorthEquatorialCurrent (NEC)whichbifurcatestotheeastofthePhilippines…     

Annual and interannual variations of sea-level anomaly in the Bay of Bengal and the Andaman Sea

Annual and interannual variations of sea-level anomaly (SLA) in the Bay of Bengal and the Andaman Sea are investigated using altimeter-derived SLA data from 1993 to 2003. It is found that the SLA annual variation in the study area can be divided into three phases with distinctive patterns. During the southwest monsoon (May-September), positive SLA presents in the equatorial region and extends northward along the eastern boundary of the bay, and the SLA distribution in the interior bay appears to be high in the east and low in the west with two cyclonic cells developing in the north and south of the western bay respectively, between which an anticyclonic cell exists. During the early northeast monsoon (October-December), the whole bay is dominated by a large cyclonic cell with the pattern of high SLA in the east and low in the west still retained, and the SLA distribution outside the bay is changed in response to the reversal of the Indian Monsoon Current (IMC) in November. During the late northeast monsoon (January-April), a large anticyclonic cell of SLA develops in the bay with negative SLA prevailing in the equatorial region and extending northward along the eastern boundary of bay. Therefore, the SLA distribution in the interior bay reverses to be high in the west and low in the east. It is suggested that the SLA annual variation in the bay is primarily driven by the local wind stress curl, involving Sverdrup balance while the abrupt SLA variation during the peak of northeast monsoon may be partly caused by the semiannual fluctuation of wind in the equatorial region. This fast adjustment in the interior bay is induced by the upwelling coastal Kelvin wave excited by the decay of Wyrtki jet during December through January. Besides the annual variation, in the bay, there are obvious SLA fluctuations with the periods of 2 and 3~7 a, which are driven by the interannual variability of large-scale wind field in the equatorial region. The coastal Kelvin wave also provides an important link for the SLA interannual variation between the equatorial region and the interior bay. It is found that the El Nio-Southern Oscillation (ENSO)-induced influence on the SLA interannual variation in the interior bay is stronger than the Indian Ocean dipole (IOD) with the associated pattern of low sea-level presenting along the periphery of the bay and high sea-level in the northeast of Sri Lanka.