Characteristics of Fengyun-4A Satellite Atmospheric Motion Vectors and Their Impacts on Data Assimilation
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• Original Paper •
Characteristics of Fengyun-4A Satellite Atmospheric Motion Vectors and Their Impacts on Data Assimilation Yaodeng CHEN*1, Jie SHEN1, Shuiyong FAN*2, Deming MENG1, and Cheng WANG1 1Key
Laboratory of Meteorological Disaster of Ministry of Education/Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters, Nanjing University of Information Science and Technology, Nanjing 210044, China 2Institute
of Urban Meteorology, China Meteorological Administration, Beijing 100089, China (Received 19 April 2020; revised 10 July 2020; accepted 27 July 2020) ABSTRACT
The high observation efficiency, scanning speed and observation frequency of the Fengyun-4A (FY-4A) satellite indicates the progress of Chinese geostationary meteorological satellites. The characteristics of FY-4A atmospheric motion vectors (AMVs) derived from the high-level water vapor (WV-High) channel, mid-level water vapor (WV-Mid) channel, and infrared (IR) channel of FY-4A are analyzed, and their corresponding observation errors estimated. Then, the impacts of single-channel and multi-channel FY-4A AMVs on RMAPS-ST (the Rapid-refresh Multi-scale Analysis and Prediction System—Short Term) are evaluated based on one-month data assimilation cycling and forecasting experiments. Results show that the observation errors of FY-4A AMVs from the three channels have an explicit vertical structure. Results from the cycling experiments indicate that the assimilation of AMVs from WV-High produces more apparent improvement of the wind in the upper layer, while a more positive effect in the lower layer is achieved by the assimilation of AMVs from IR. Furthermore, the assimilation of AMVs from IR is more skillful for medium and moderate precipitation than from other channels owing to the good quality of data in the lower layer in the AMVs from IR. Assimilation of FY-4A AMVs from the three channels could combine the advantages of assimilation from each individual channel to improve the wind in the upper, middle and lower layers simultaneously. Key words: data assimilation, FY-4A satellite, atmospheric motion vector, observation error Citation: Chen, Y. D., J. Shen, S. Y. Fan, D. M. Meng, and C. Wang, 2020: Characteristics of Fengyun-4A satellite atmospheric motion vectors and their impacts on data assimilation. Adv. Atmos. Sci., 37(11), 1222−1238, https://doi.org/10.1007/ s00376-020-0080-0. Article Highlights:
• New observation errors of FY-4A AMVs show a more obvious vertical structure, which may be more reasonable for the use of AMVs
• FY-4A AMVs from water vapor channels improve wind in the upper layer, while AMVs from the infrared channel improve the lower layer
• Multi-channel assimilation of FY-4A AMVs could combine advantage of assimilation from each channel and improve
most layers simultaneously
1. Introduction Atmospheric motion vectors (AMVs) are wind observations derived from consecutive satellite images by tracking features such as cirrus edges, gradients in water vapor, or small cumulus clusters
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