scholarly journals Correction to “First simulations with a whole atmosphere data assimilation and forecast system: The January 2009 major sudden stratospheric warming”

2012 ◽  
Vol 117 (A3) ◽  
pp. n/a-n/a ◽  
Author(s):  
H. Wang ◽  
T. J. Fuller-Rowell ◽  
R. A. Akmaev ◽  
M. Hu ◽  
D. T. Kleist ◽  
...  
Keyword(s):  
Data Assimilation ◽  
Stratospheric Warming ◽  
Sudden Stratospheric Warming ◽  
Forecast System

First simulations with a whole atmosphere data assimilation and forecast system: The January 2009 major sudden stratospheric warming

2011 ◽  
Vol 116 (A12) ◽  
pp. n/a-n/a ◽  
Author(s):  
H. Wang ◽  
T. J. Fuller-Rowell ◽  
R. A. Akmaev ◽  
M. Hu ◽  
D. T. Kleist ◽  
...  
Keyword(s):  
Data Assimilation ◽  
Stratospheric Warming ◽  
Sudden Stratospheric Warming ◽  
Forecast System

scholarly journals Hindcasting the January 2009 Arctic Sudden Stratospheric Warming with Unified Parameterization of Orographic Drag in NOGAPS. Part II: Short-Range Data-Assimilated Forecast and the Impacts of Calibrated Radiance Bias Correction

2011 ◽  
Vol 26 (6) ◽  
pp. 993-1007 ◽  
Author(s):  
Young-Joon Kim ◽  
William Campbell ◽  
Benjamin Ruston
Keyword(s):  
Data Assimilation ◽  
Bias Correction ◽  
Variational Data Assimilation ◽  
The Arctic ◽  
Naval Research ◽  
Range Data ◽  
Stratospheric Warming ◽  
Sudden Stratospheric Warming ◽  
The Arctic Oscillation ◽  
Orographic Drag

Abstract This study is Part II of the effort to improve the forecasting of sudden stratospheric warming (SSW) events by using a version of the Navy Operational Global Atmospheric Prediction System (NOGAPS) that covers the full stratosphere. In Part I, extended-range (3 week) hindcast experiments (without data assimilation) for the January 2009 Arctic major SSW were performed using NOGAPS with a unified orographic drag parameterization that consists of the schemes employed by Webster et al., as well as Kim and Arakawa and Kim and Doyle. Part I demonstrated that the model with upgraded middle-atmospheric orographic drag physics better forecasts the magnitude and evolution of the SSW and better simulates the trend of the Arctic Oscillation (AO) index. In this study (Part II), a series of 5-day hindcast experiments is performed with cycling data assimilation using the Naval Research Laboratory Atmospheric Variational Data Assimilation System-Accelerated Representer (NAVDAS-AR), a four-dimensional variational data assimilation (4DVAR) system. Further efforts are made to improve the hindcasting of SSW by improving the satellite radiance bias correction process that strongly affects the data assimilation. The innovation (observation minus background) limit is optimally determined to reduce the rejection of useful radiance data. It is found that when the innovation limit is properly set, both the analysis and forecast of the SSW event can be improved, and that the orographic drag helps improve the SSW forecast.

scholarly journals Identification of the mechanisms responsible for anomalies in the tropical lower thermosphere/ionosphere caused by the January 2009 sudden stratospheric warming

2019 ◽  
Vol 9 ◽  
pp. A39 ◽  
Author(s):  
Maxim V. Klimenko ◽  
Vladimir V. Klimenko ◽  
Fedor S. Bessarab ◽  
Timofei V. Sukhodolov ◽  
Pavel A. Vasilev ◽  
...  
Keyword(s):  
Electric Field ◽  
Phase Change ◽  
Lower Thermosphere ◽  
Upper Atmosphere ◽  
Electron Content ◽  
Stratospheric Warming ◽  
Sudden Stratospheric Warming ◽  
Low Latitude ◽  
Plasma Drift ◽  
Solar Tide

We apply the Entire Atmosphere GLobal (EAGLE) model to investigate the upper atmosphere response to the January 2009 sudden stratospheric warming (SSW) event. The model successfully reproduces neutral temperature and total electron content (TEC) observations. Using both model and observational data, we identify a cooling in the tropical lower thermosphere caused by the SSW. This cooling affects the zonal electric field close to the equator, leading to an enhanced vertical plasma drift. We demonstrate that along with a SSW-related wind disturbance, which is the main source to form a dynamo electric field in the ionosphere, perturbations of the ionospheric conductivity also make a significant contribution to the formation of the electric field response to SSW. The post-sunset TEC enhancement and pre-sunrise electron content reduction are revealed as a response to the 2009 SSW. We show that at post-sunset hours the SSW affects low-latitude TEC via a disturbance of the meridional electric field. We also show that the phase change of the semidiurnal migrating solar tide (SW2) in the neutral wind caused by the 2009 SSW at the altitude of the dynamo electric field generation has a crucial importance for the SW2 phase change in the zonal electric field. Such changes lead to the appearance of anomalous diurnal variability of the equatorial electromagnetic plasma drift and subsequent low-latitudinal TEC disturbances in agreement with available observations. Plain Language Summary – Entire Atmosphere GLobal model (EAGLE) interactively calculates the troposphere, stratosphere, mesosphere, thermosphere, and plasmasphere–ionosphere system states and their response to various natural and anthropogenic forcing. In this paper, we study the upper atmosphere response to the major sudden stratospheric warming that occurred in January 2009. Our results agree well with the observed evolution of the neutral temperature in the upper atmosphere and with low-latitude ionospheric disturbances over America. For the first time, we identify an SSW-related cooling in the tropical lower thermosphere that, in turn, could provide additional information for understanding the mechanisms for the generation of electric field disturbances observed at low latitudes. We show that the SSW-related vertical electromagnetic drift due to electric field disturbances is a key mechanism for interpretation of an observed anomalous diurnal development of the equatorial ionization anomaly during the 2009 SSW event. We demonstrate that the link between thermospheric winds and the ionospheric dynamo electric field during the SSW is attained through the modulation of the semidiurnal migrating solar tide.

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