Insights into the Microwave Instruments Onboard the Fengyun 3D Satellite: Data Quality and Assimilation in the Met Office NWP System
Insights into the Microwave Instruments Onboard the Fengyun 3D Satellite: Data Quality and Assimilation in the Met Office NWP System
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DOI：
10.1007/s00376-020-0010-1
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发表时间：
2020-07
影响因子：
5.8
通讯作者：
F. Carminati;N. Atkinson;B. Candy;Q. Lu
中科院分区：
文献类型：
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作者：
F. Carminati;N. Atkinson;B. Candy;Q. Lu
本文对我国最新的极轨卫星风云三号D（FY-3D）上的微波仪器进行了评估。将微波温度探测器2（MWTS-2），微波湿度探测器2（MWHS-2）和微波辐射成像仪（MWRI）的三个月观测结果与气象局短期预报进行比较，我们描述了仪器偏差，显示了这些偏差相对于FY-3C上的前辈如何变化，以及它们与NOAA-20机载先进技术微波探测器（ATMS）和全球降水测量微波成像仪（GMI）的比较。MWTS-2的全局偏差相对于其前身大大降低，并且在等效信道频率下与ATMS相当，平均仅相差0.36 ± 0.28 K（1σ）。原始数字计数的次优平均被发现会导致条带噪声和上升-下降偏置的增加。MWHS-2受益于一种新的校准方法，相对于其前身，改进了183-GHz湿度通道，这些通道的偏差在± 1.9 K到ATMS范围内。MWRI提出了最大的改进，减少全球偏差和标准偏差相对于FY-3C;虽然，虚假的，看似短暂的，亮度温度已被检测到在36.5 GHz的观测（垂直极化）。影响FY-3C仪器的强太阳依赖性偏差已降低到FY-3D MWRI平均小于0.2 K。从这些仪器的辐射被同化的实验上一个完整的全球系统表现出中性到积极的影响的预测，以及适合独立的仪器的背景。
This paper evaluates the microwave instruments onboard the latest Chinese polar-orbiting satellite, Feng-Yun 3D (FY-3D). Comparing three months of observations from the Microwave Temperature Sounder 2 (MWTS-2), the Microwave Humidity Sounder 2 (MWHS-2), and the Microwave Radiation Imager (MWRI) to Met Office short-range forecasts, we characterize the instrumental biases, show how those biases have changed with respect to their predecessors onboard FY-3C, and how they compare to the Advanced Technology Microwave Sounder (ATMS) onboard NOAA-20 and the Global Precipitation Measurement Microwave Imager (GMI). The MWTS-2 global bias is much reduced with respect to its predecessor and compares well to ATMS at equivalent channel frequencies, differing only by 0.36 ± 0.28 K (1σ) on average. A suboptimal averaging of raw digital counts is found to cause an increase in striping noise and an ascending—descending bias. MWHS-2 benefits from a new calibration method improving the 183-GHz humidity channels with respect to its predecessor and biases for these channels are within ± 1.9 K to ATMS. MWRI presents the largest improvements, with reduced global bias and standard deviation with respect to FY-3C; although, spurious, seemingly transient, brightness temperatures have been detected in the observations at 36.5 GHz (vertical polarization). The strong solar-dependent bias that affects the instrument on FY-3C has been reduced to less than 0.2 K on average for FY-3D MWRI. Experiments where radiances from these instruments were assimilated on top of a full global system demonstrated a neutral to positive impact on the forecasts, as well as on the fit to the background of independent instruments.