论文部分内容阅读
湍流对光在大气中的传播有重要影响。光波段折射率结构常数是描述湍流强度的物理量。通过风廓线雷达回波分析是研究湍流强度的新方法。利用风廓线雷达计算出湍流耗散率和平均风的垂直梯度,结合温度、气压等常规气象参数,可估算光波段折射率结构常数,计算的量级在10-18～10-13 m-2/3之间,符合实际情况,证明了方法的可行性。同时对不同等压面上压强梯度、温度梯度及湿度对折射率结构常数的影响进行了数值计算。结果表明,同一等压面上压强梯度改变对Cn2影响很小,可忽略不计;而温度梯度改变对结果有较大影响,故对温度廓线的测量有较高的精度要求;相对湿度10%～90%的变化对光波段折射率结构常数的影响低于一个量级,因此在晴空大气条件下,湿度项可以忽略。
Turbulence has a major impact on the propagation of light in the atmosphere. Optical Band Refractive Index Structure constants are physical quantities that describe the intensity of turbulence. Wind profiler radar echo analysis is a new method to study the intensity of turbulence. Using the wind profiler radar to calculate the turbulence dissipation rate and the average wind vertical gradient, the refractive index constants in the optical band can be estimated by combining the conventional meteorological parameters such as temperature and pressure. The calculated magnitude is in the range of 10-18-10-13 m- 2/3, in line with the actual situation, proved the feasibility of the method. Meanwhile, the influence of pressure gradient, temperature gradient and humidity on the refractive index structure constant of different isobaric surfaces was numerically calculated. The results show that the change of pressure gradient on the same isobaric surface has little effect on Cn2, which is negligible. However, the change of temperature gradient has a greater impact on the result, so the accuracy of the temperature profile is higher. The relative humidity of 10% The effect of ~90% change on the structure constant of the refractive index in the optical band is less than one order of magnitude, so the humidity term can be neglected in a clear-air atmosphere.