A brief climatology of eddy diffusivities over White Sands Missile Range, New Mexico
A brief climatology of eddy diffusivities over White Sands Missile Range, New Mexico
复制标题
新墨西哥州白沙导弹靶场涡流扩散率的简要气候学
DOI：
10.1029/97jd02208
复制
发表时间：
1997
影响因子：
--
通讯作者：
F. Eaton
中科院分区：
文献类型：
--
作者：
G. Nastrom;F. Eaton
使用新墨西哥州白沙导弹靶场的 VHF 轮廓仪雷达对多普勒谱宽度进行观测，用于估计每小时 5-20 公里处的涡流扩散系数 Kz。使用的数据涵盖 1991 年至 1995 年期间。 Kz 每小时值的中值范围从 5 公里附近的 ∼3 m2/s 到 14 公里附近的约 0.3 m2/s。各个小时值的对数近似呈正态分布。从秋季到春季的所有高度，log Kz 的季节性中值几乎相同，而夏季值大约是其他季节值的两倍。 log Kz 的逐时值与静稳定性呈负相关，与水平风垂直切变呈正相关，与理查森数在所有季节均呈弱负相关。 log Kz 与水平风速的相关性在冬季为正相关，表明 Kz 的大小由天气系统决定；在夏季为负相关，表明对流过程对夏季 Kz 的确定最为重要。随着垂直分离的增加，对流层中的 log Kz 自相关作为垂直分离的函数比平流层中的下降得更慢。我们发现的 log Kz 中值与过去在对流层顶水平附近及以上的研究的中值非常吻合，但在对流层中，它们明显大于日本中高层大气雷达报告的值；这种差异是根据当地地形和对流层气候的差异来讨论的。
Observations of the Doppler spectral width made using the VHF profiler radar at White Sands Missile Range, New Mexico, are used to estimate the eddy diffusion coefficient Kz at 5–20 km on an hourly basis. The data used span the period 1991–1995. Medians of the hourly values of Kz range from ∼3 m2/s near 5km to about 0.3 m2/s near 14km. The logarithms of the individual hourly values are approximately normally distributed. Seasonal median values of log Kz are nearly the same at all heights during autumn through spring, while the summer values are about twice as large as the values for other seasons. Hourly values of log Kz are negatively correlated with the static stability, are positively correlated with the vertical shear of the horizontal wind, and show weak negative correlation with the Richardson number during all seasons. The correlation of log Kz with the horizontal wind speed is positive in the winter, indicating that the magnitude of Kz is determined by synoptic weather systems then, and negative in the summer, indicating that convective processes are most important in determining Kz in the summer. The autocorrelation of log Kz as a function of vertical separation decreases more slowly with increasing vertical separation in the troposphere than in the stratosphere. The median values of log Kz that we find compare very well with those of past studies near the tropopause level and above, but in the troposphere they are significantly larger than those reported from the middle and upper atmosphere radar in Japan; this difference is discussed in terms of differences in the local terrain and the climate of the troposphere.
T.Tsuda：“低层大气中甚高频镜面反射回波的天顶角依赖性。”
DOI：
--
发表时间：
--
期刊：
影响因子：
--
作者：
通讯作者：
--