The climatology of significant wave height（SWH） and sea surface wind speed are matters of concern in the fields of both meteorology and oceanography because they are very important parameters for planning offshore s...The climatology of significant wave height（SWH） and sea surface wind speed are matters of concern in the fields of both meteorology and oceanography because they are very important parameters for planning offshore structures and ship routings. The TOPEX/Poseidon altimeter, which collected data for about 13 years from September 1992 to October 2005, has measured SWHs and surface wind speeds over most of the world＇s oceans. In this paper, a study of the global spatiotemporal distributions and variations of SWH and sea surface wind speed was conducted using the TOPEX/Poseidon altimeter data set. The range and characteristics of the variations were analyzed quantitatively for the Pacific, Atlantic, and Indian oceans. Areas of rough waves and strong sea surface winds were localized precisely, and the correlation between SWH and sea surface wind speed analyzed.展开更多
Helicity is defined as H ： V ω, where V and ω are the velocity and vorticity vectors, respectively. Many works have pointed out that the larger the helicity is, the longer the life cycle of the weather system is. H...Helicity is defined as H ： V ω, where V and ω are the velocity and vorticity vectors, respectively. Many works have pointed out that the larger the helicity is, the longer the life cycle of the weather system is. However, the direct relationship of the helicity to the evolution of the weather system is not quite clear. In this paper, the concept of helicity is generalized as shearing wind helicity （SWH）. Dynamically, it is found that the average SWH is directly related to the increase of the average cyclonic rotation of the weather system. Physically, it is also pointed out that the SWH, as a matter of fact, is the sum of the torsion terms and the divergence term in the vorticity equation. Thermal wind helicity （TWH）, as a derivative of SWH, is also discussed here because it links the temperature field and the vertical wind field. These two quantities may be effective for diagnosing a weather system. This paper applies these two quantities in cylindrical coordinates to study the development of Hurricane Andrew to validate their practical use. Through analyzing the hurricane, it is found that TWH can well describe the characteristics of the hurricane such as the strong convection and release of latent heat. SWH is not only a good quantity for diagnosing the weather system, but also an effective one for diagnosing the development of the hurricane.展开更多
This study investigated the interannual wave climate variability in the Taiwan Strait(TS) and its relationship to the El Ni?o-Southern Oscillation(ENSO) phenomenon using a high-resolution numerical wave model. The res...This study investigated the interannual wave climate variability in the Taiwan Strait(TS) and its relationship to the El Ni?o-Southern Oscillation(ENSO) phenomenon using a high-resolution numerical wave model. The results showed the interannual variability of significant wave height(SWH) in the TS, which exhibits significant spatial and seasonal variations, is typically weaker than the seasonal variability. The standard deviation of the interannual SWH anomaly(SWHA) showed similar spatial variations in the TS throughout the year, being largest in the middle of the strait and decreasing shoreward, except in summer, when there was no local maximum in the middle of the TS. Further analyses proved the interannual wave climate variability in the TS is controlled predominantly by tropical cyclone activities in summer and by the northeasterly monsoon winds in winter. Furthermore, the interannual SWHA in the TS was found correlated highly negatively with the ENSO phenomenon. This relationship mainly derives from that during the northeasterly monsoon seasons. During the northeasterly monsoon seasons in El Ni?o(La Ni?a) years, the negative(positive) SWHA in the TS derives from weakened(strengthened) northeasterly monsoon winds induced by a lower-tropospheric anomalous anticyclone(cyclone) over the western Pacific Ocean and the South China Sea. During the southwesterly monsoon season in El Ni?o(La Ni?a) years, however, the SWH in the TS tends to increase(decrease) anomalously because of intensified(weakened) TC activities over the western North Pacific Ocean and adjacent seas.展开更多
全球导航卫星系统反射信号GNSS-R(Global Navigation Satellite System Reflection)可以用来探测海面状态,如海面有效波高。介绍了利用GNSS反射信号测量海面有效波高的观测设备和技术原理,对2009年博贺实验的数据进行了分析,证实了反射...全球导航卫星系统反射信号GNSS-R(Global Navigation Satellite System Reflection)可以用来探测海面状态,如海面有效波高。介绍了利用GNSS反射信号测量海面有效波高的观测设备和技术原理,对2009年博贺实验的数据进行了分析,证实了反射信号相关复数场的有效相关时间与有效波高之间存在相关,利用前期观测的数据进行拟合,得出反演公式,并与测波雷达数据进行了结果对比,平均误差0.136m,相对偏差12.02%,均方根偏差0.169m。展开更多
基金The National Natural Science Foundation of China under contract No.41076003
文摘The climatology of significant wave height（SWH） and sea surface wind speed are matters of concern in the fields of both meteorology and oceanography because they are very important parameters for planning offshore structures and ship routings. The TOPEX/Poseidon altimeter, which collected data for about 13 years from September 1992 to October 2005, has measured SWHs and surface wind speeds over most of the world＇s oceans. In this paper, a study of the global spatiotemporal distributions and variations of SWH and sea surface wind speed was conducted using the TOPEX/Poseidon altimeter data set. The range and characteristics of the variations were analyzed quantitatively for the Pacific, Atlantic, and Indian oceans. Areas of rough waves and strong sea surface winds were localized precisely, and the correlation between SWH and sea surface wind speed analyzed.
基金This work was supported by the National Natural Science Foundation of China （Grant Nos. 40475024 and 40333025）, the foundation for Ph.D specialty of the Ministry of Education （Grant No. 20020284016）.
文摘Helicity is defined as H ： V ω, where V and ω are the velocity and vorticity vectors, respectively. Many works have pointed out that the larger the helicity is, the longer the life cycle of the weather system is. However, the direct relationship of the helicity to the evolution of the weather system is not quite clear. In this paper, the concept of helicity is generalized as shearing wind helicity （SWH）. Dynamically, it is found that the average SWH is directly related to the increase of the average cyclonic rotation of the weather system. Physically, it is also pointed out that the SWH, as a matter of fact, is the sum of the torsion terms and the divergence term in the vorticity equation. Thermal wind helicity （TWH）, as a derivative of SWH, is also discussed here because it links the temperature field and the vertical wind field. These two quantities may be effective for diagnosing a weather system. This paper applies these two quantities in cylindrical coordinates to study the development of Hurricane Andrew to validate their practical use. Through analyzing the hurricane, it is found that TWH can well describe the characteristics of the hurricane such as the strong convection and release of latent heat. SWH is not only a good quantity for diagnosing the weather system, but also an effective one for diagnosing the development of the hurricane.
基金Supported by the National Natural Science Foundation of China(Nos.41506008,41476002)the Shandong Provincial Natural Science Foundation(No.ZR2015DQ006)the Shandong Provincial Key Research and Development Program(No.2016ZDJS09A02)
文摘This study investigated the interannual wave climate variability in the Taiwan Strait(TS) and its relationship to the El Ni?o-Southern Oscillation(ENSO) phenomenon using a high-resolution numerical wave model. The results showed the interannual variability of significant wave height(SWH) in the TS, which exhibits significant spatial and seasonal variations, is typically weaker than the seasonal variability. The standard deviation of the interannual SWH anomaly(SWHA) showed similar spatial variations in the TS throughout the year, being largest in the middle of the strait and decreasing shoreward, except in summer, when there was no local maximum in the middle of the TS. Further analyses proved the interannual wave climate variability in the TS is controlled predominantly by tropical cyclone activities in summer and by the northeasterly monsoon winds in winter. Furthermore, the interannual SWHA in the TS was found correlated highly negatively with the ENSO phenomenon. This relationship mainly derives from that during the northeasterly monsoon seasons. During the northeasterly monsoon seasons in El Ni?o(La Ni?a) years, the negative(positive) SWHA in the TS derives from weakened(strengthened) northeasterly monsoon winds induced by a lower-tropospheric anomalous anticyclone(cyclone) over the western Pacific Ocean and the South China Sea. During the southwesterly monsoon season in El Ni?o(La Ni?a) years, however, the SWH in the TS tends to increase(decrease) anomalously because of intensified(weakened) TC activities over the western North Pacific Ocean and adjacent seas.
文摘全球导航卫星系统反射信号GNSS-R(Global Navigation Satellite System Reflection)可以用来探测海面状态,如海面有效波高。介绍了利用GNSS反射信号测量海面有效波高的观测设备和技术原理,对2009年博贺实验的数据进行了分析,证实了反射信号相关复数场的有效相关时间与有效波高之间存在相关,利用前期观测的数据进行拟合,得出反演公式,并与测波雷达数据进行了结果对比,平均误差0.136m,相对偏差12.02%,均方根偏差0.169m。
