scholarly journals WACCM-D-Improved modeling of nitric acid and active chlorine during energetic particle precipitation

2016 ◽  
Vol 121 (17) ◽  
pp. 10,328-10,341 ◽  
Author(s):  
M. E. Andersson ◽  
P. T. Verronen ◽  
D. R. Marsh ◽  
S.-M. Päivärinta ◽  
J. M. C. Plane
Keyword(s):  
Nitric Acid ◽  
Energetic Particle ◽  
Active Chlorine ◽  
Particle Precipitation ◽  
Energetic Particle Precipitation

scholarly journals Nitric acid in the stratosphere based on Odin observations from 2001 to 2007 – Part 2: High-altitude polar enhancements

2008 ◽  
Vol 8 (3) ◽  
pp. 9591-9605 ◽  
Author(s):  
Y. J. Orsolini ◽  
J. Urban ◽  
D. P. Murtagh
Keyword(s):  
Nitric Acid ◽  
Energetic Particle ◽  
Polar Vortex ◽  
Solar Proton ◽  
Auroral Zone ◽  
Lower Atmosphere ◽  
Particle Precipitation ◽  
Annual Cycles ◽  
Energetic Particle Precipitation ◽  
Solar Proton Events

Abstract. The wintertime abundance of nitric acid (HNO3) in the polar upper stratosphere displays a strong inter-annual variability, and is known to be strongly influenced by energetic particle precipitation, primarily during solar proton events, but also by precipitating electrons in the auroral zone. While wintertime HNO3 enhancements in the polar upper stratosphere had been occasionally observed before, from the ground or from satellite, we present here measurements by the Sub-Millimeter Radiometer instrument aboard the Odin satellite through 6 full annual cycles (2001 to 2007). Major solar proton events, e.g. during November 2001 or the Halloween solar storms of autumn 2003, lead to a two-stage HNO3 enhancement, likely involving different chemical reactions: a fast (about 1 week) in-situ enhancement from the mid to the upper stratosphere is followed by a slower, longer-lasting one, whereby anomalies originating in the upper stratosphere can descend within the polar vortex into the lower stratosphere. We highlight the fact that the actual chemical coupling between the upper and lower atmosphere involves a complex interplay of chemistry, dynamics and energetic particle precipitation.

scholarly journals Impact of energetic particle precipitation on stratospheric polar constituents: an assessment using MIPAS data monitoring and assimilation

2009 ◽  
Vol 9 (5) ◽  
pp. 22459-22504
Author(s):  
A. Robichaud ◽  
R. Ménard ◽  
S. Chabrillat ◽  
J. de Grandpré ◽  
Y. J. Rochon ◽  
...  
Keyword(s):  
Gas Phase ◽  
Energetic Particle ◽  
Solar Proton ◽  
Significant Loss ◽  
Proton Event ◽  
Particle Precipitation ◽  
Gas Phase Chemistry ◽  
Energetic Particle Precipitation ◽  
Phase Chemistry ◽  
Assimilation System

Abstract. In 2003, strong geomagnetic events occurred which produced massive amounts of energetic particles penetrating the top of the atmospheric polar region, significantly perturbing its chemical state down to the middle stratosphere. These events and their effects are generally left unaccounted for in current models of stratospheric chemistry and large differences between observations and models are then noted. In this study, we use a coupled 3-D stratospheric dynamical-chemical model and assimilation system to ingest MIPAS temperature and chemical observations. The goal is to gain further understanding and to evaluate the impacts of EPP (energetic particle precipitation) on stratospheric polar chemistry. Moreover, we investigate the feasibility of assimilating valid "outlier" observations associated with such events. We focus our analysis on OmF (Observation minus Forecast) residuals as they filter out phenomena well reproduced by the model (such as gas phase chemistry, transport, diurnal and seasonal cycles) thus revealing a clear trace of the EPP. Inspection of OmF statistics in both the passive (without chemical assimilation) and active (with chemical assimilation) cases altogether provides a powerful diagnostic tool to assess the model and assimilation system. We also show that passive OmF can permit a satisfactory evaluation of the ozone partial column loss due to EPP effects. Results suggest a small but significant loss of 5–6 DU (Dobson Units) during an EPP-IE (EPP indirect effects) event in the Antarctic winter of 2003, and about only 1 DU for the SPE (solar proton event) of October/November 2003. Despite large differences between the model and MIPAS chemical observations (NO2, HNO3, CH4 and O3), we demonstrate that a careful assimilation of these constituents with only gas phase chemistry included in the model (i.e. no provision for EPP impacts) and with relaxed quality control nearly eliminated the short-term bias and significantly reduced the standard deviation error below 1 hPa.

scholarly journals Energetic particle precipitation in the Brazilian geomagnetic anomaly during the “Bastille Day storm” of July 2000

2006 ◽  
Vol 58 (5) ◽  
pp. 607-616 ◽  
Author(s):  
Masanori Nishino ◽  
Kazuo Makita ◽  
Kiyofumi Yumoto ◽  
Yoshizumi Miyoshi ◽  
Nelson J. Schuch ◽  
...  
Keyword(s):  
Energetic Particle ◽  
Particle Precipitation ◽  
Energetic Particle Precipitation ◽  
Geomagnetic Anomaly

scholarly journals Changes in upper mesospheric and lower thermospheric temperatures caused by energetic particle precipitation

2010 ◽  
Vol 115 (A10) ◽  
pp. n/a-n/a ◽  
Author(s):  
H. Nesse Tyssøy ◽  
J. Stadsnes ◽  
M. Sørbø ◽  
C. J. Mertens ◽  
D. S. Evans
Keyword(s):  
Energetic Particle ◽  
Particle Precipitation ◽  
Energetic Particle Precipitation
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