AI 中文总结
该研究针对快扫描单偏振天气雷达的降水反演逆问题，提出将伽马雨滴谱参数作为中间变量的联合反演方法，通过模拟与真实数据实验验证了其对中值直径等物理量的反演优势。
AI 中文摘要
本文研究快扫描单偏振X波段天气雷达多普勒功率谱密度测量的降水反演逆问题，所构建的公式围绕短相干处理间隔内保持可解释性和稳定性的物理量展开：径向风均值、径向风谱宽、反射率加权终端下落速度及中值体积直径。伽马雨滴谱分布参数作为潜在变量保留在谱正演模型中，而非作为主要反演结果输出，该选择源于似然分析结果，其表明逆问题对潜在分布参数的可识别性较弱，而推导得到的上述物理量则显著更稳定。模拟数据实验在短相干处理间隔场景下，将所提方法与利用外部提供风信息的矩法反演进行对比；真实数据实验则通过一次扫描的平面位置指示器反演实现同扫描空间似然池化，并将33次扫描的时间序列与雷达覆盖区域内的两台雨滴谱仪进行对比。结果显示，潜在分布参数应被视为中间拟合变量而非主要最终产物；所提方法在非相干短记录运行场景下，对中值体积直径和反射率加权终端下落速度展现出最明确的实际优势，当每个多普勒谱仅包含少数慢时间样本时，空间池化可实现这两个量的高效全扫描映射；即便谱拟合和时间演化合理，雷达与雨滴谱仪的差异仍具有物理意义。
英文摘要
The inverse problem of precipitation retrieval from Doppler power spectral density measurements of a fast-scanning single-polarization X-band weather radar is addressed. The formulation is developed around quantities that remain interpretable and stable across short coherent processing intervals: radial-wind mean, radial-wind spectral width, reflectivity-weighted terminal fall velocity, and median volume diameter. The gamma drop-size distribution parameters are retained as latent variables within the spectral forward model rather than reported as primary retrieval products. This choice is motivated by likelihood analyses showing that the inverse problem is weakly identifiable with respect to the latent distribution parameters, whereas the derived quantities remain substantially more stable. Simulated-data experiments compare the proposed approach with a moment-based retrieval using externally supplied wind information in the short-coherent-processing-interval regime. Real-data experiments demonstrate same-scan spatial likelihood pooling through a one-scan plan-position-indicator retrieval and 33-scan time-series comparisons against two disdrometers within the radar coverage region. The results show that the latent distribution parameters should be treated as intermediate fitting variables rather than primary end products. The proposed approach shows its clearest practical benefit for median volume diameter and reflectivity-weighted terminal fall velocity under incoherent short-record operation. Spatial pooling allows efficient full-scan mapping of both quantities when each Doppler spectrum contains only a few slow-time samples. Radar-disdrometer discrepancies remain physically meaningful even when the spectral fit and temporal evolution are reasonable.
Comments21 pages, 10 figures. Preprint
