Evaluation of High-Resolution FY-4B AMV and Temperature Products in Tracking the Northeast China Cold Vortex

The Northeast China Cold Vortex (NECV) is a significant atmospheric circulation system that triggers severe weather in mid-to-high latitudes of Asia. Fengyun-4B (FY-4B) satellite provides 15-min atmospheric motion vector (AMV) and 2-h three-dimensional temperature profiles, enabling unprecedented high spatiotemporal resolution for real-time vortex tracking. This study evaluates the effectiveness of FY-4B AMV and temperature products in tracking 24 NECVs in 2023, among which two strong NECVs in winter and summer 2023 were carefully examined. We first assessed the accuracy of wind speed and direction of the AMVs in the NECV monitoring region by comparing them with radiosonde observations, revealing reasonable correlation coefficients (CC), mean absolute errors (MAE), and root mean square errors (RMSE). NECVs and their centers were identified by using AMV data from four channels (CH09, CH10, CH11, and CH13) within the 200–500-hPa layer, employing the “8-point method” that sets specific criteria for the wind directions at 8 surrounding points to ensure a consistent cyclonic pattern around the central point. The NECV centers identified from AMVs are found to be close (mean distance of 181.9 km) to those determined by ERA5 geopotential height. The retrieved FY-4B temperature data are also evaluated against radiosonde observations, showing a high CC of 0.996 and RMSE of 1.87 K, indicating reliable temperature retrievals for NECV tracking. Based on the FY-4B/Geostationary Interferometric Infrared Sounder (GIIRS) 500-hPa temperature, the NECV cold centers are obtained and cross-validated against ERA5 reanalysis temperature at 500 hPa, revealing a mean distance deviation of 140.6 km. The real-time operational NECV monitoring based on the FY-4B AMV and temperature products on high spatiotemporal resolutions in this study provides valuable information for disaster prevention and mitigation.