不同强度云系的双偏振雷达特征

Dual polarization radar characteristics of clouds with different intensities

利用S波段双偏振雷达观测到的层状云、非降雹对流云以及冰雹云三种不同强度云系的雷达数据,对其双偏振参量的特征差异进行分析。结果表明,层状云的差分反射率Z_(DR)、差分相移率K_(DP)接近0值,差分相移Φ_(DP)随径向距离廓线变化小,与初始相位保持一致;在非降雹对流云中,CC值基本稳定在0.95以上,回波强度大于35dBZ时,Z_(DR)、K_(DP)和Φ_(DP)均显著递增,K_(DP)和Φ_(DP)变化尤为明显,其表现出对强降水的敏感特征;冰雹云的双偏振特征整体与非降雹对流云一致,但在冰雹区域内反射率ZH大于62dBZ时,Z_(DR)迅速降低至0附近,少数冰雹区域对应K_(DP)为空值(显示背景色)K_(DP)原始算法存在明显缺陷,应当加以其他条件(如信噪比)作为约束。

Based on the radar data of stratiform clouds,non-hail convective clouds and hail clouds with different intensities observed by S-band dual polarization radar,the characteristic differences of dual polarization parameters were analyzed.The results showed that the difference reflectivity Z_(DR) and the difference phase shift rate K_(DP) of stratiform clouds were close to zero.The difference phase shift Φ_(DP) changed little with the radial distance profile and was consistent with the initial phase.In the non-hail convective clouds,the CC value was basically stable above 0.95.When the echo intensity was greater than 35 dBZ,Z_(DR),K_(DP) and Φ_(DP)i ncreased significantly;the variation of K_(DP) and Φ_(DP) was especially obvious,which was sensitive to heavy rainfall.The dual polarization characteristic of hail clouds was consistent with that of non-hail convective clouds.However,when the reflectivity ZH was greater than 62 dbz in hail region,Z_(DR) decreased rapidly to near zero.The K_(DP) corresponding to a few hail regions was null(displaying background color).The original K_(DP) algorithm has obvious defects,and other conditions(such as signal-to-noise ratio)should be taken as constraints.