等效球理论计算冰晶粒子毫米波散射的误差分析

Error Analysis of Equivalent Sphere Theory for Calculating the Scattering Properties of Ice Crystals at Millimeter Wavelength

利用4种等效Lorenz-Mie理论以及离散偶极子近似理论(DDA)计算了毫米波频率下卷云中随机取向六角形冰晶粒子的散射特性.对比结果表明:在毫米波频率下,利用等效体积与投影面积比值(V/A)Lorenz-Mie理论计算的结果与DDA的结果最接近,最后利用最小二乘法拟合出误差公式,为等效球理论代替DDA计算复杂的六角形冰晶粒子散射特性提供参考依据.

The scattering properties of randomly oriented hexagonal ice crystals was studied by four equivalent LorenzMie theory and the discrete dipole approximation method（DDA） at 94 GHz. The results show that the equivalent V/A is most accurate compared with DDA results. The fitted relationships between equivalent V/A and DDA are gained by polynomial least squares methods, the relationships provide a basis for substituting equivalent Lorenz-Mie theory for DDA theory when we compute the scattering properties of cirrus ice particles.