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Analysis bias induced in assimilation of the radio occultation bending angle with complex structures in the tropical troposphere
Author(s) -
Liu Hui,
Kuo YingHwa,
Sokolovskiy Sergey,
Zou Xiaolei,
Zeng Zhen
Publication year - 2020
Publication title -
quarterly journal of the royal meteorological society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.744
H-Index - 143
eISSN - 1477-870X
pISSN - 0035-9009
DOI - 10.1002/qj.3887
Subject(s) - radio occultation , troposphere , data assimilation , atmospheric sciences , weather research and forecasting model , environmental science , meteorology , bending , cosmic cancer database , zenith , physics , geology , remote sensing , astrophysics , thermodynamics
In the tropical lower troposphere, the radio occultation (RO) bending angle can have complex and sharp structures. In current numerical weather prediction data assimilation, the estimated observation uncertainty (or error) of the RO bending angle is typically derived from a fixed‐fraction uncertainty model of the RO bending angle. Therefore, the complex and sharp structures can exist in the observation uncertainty as well. This study investigates a potential analysis bias induced in the assimilation of COSMIC (Constellation Observing System for Meteorology, Ionosphere, and Climate) RO bending angles as a result of these complex and sharp structures in the observation uncertainty in the tropical troposphere. It is demonstrated that the complex structures can create a clear negative bias, up to −0.7%, in the bending angle space in the regional analysis with the Weather Research and Forecasting (WRF) model. The WRF analyses and backgrounds also show a larger bias from the COSMIC RO bending angles.