scholarly journals Self-consistent global transport of metallic ions with WACCM-X

2021 ◽  
Vol 21 (20) ◽  
pp. 15619-15630
Author(s):  
Jianfei Wu ◽  
Wuhu Feng ◽  
Han-Li Liu ◽  
Xianghui Xue ◽  
Daniel Robert Marsh ◽  
...  
Keyword(s):  
Ion Transport ◽  
Climate Model ◽  
Lower Thermosphere ◽  
Molecular Ions ◽  
The Self ◽  
Metallic Ions ◽  
Peak Density ◽  
Global Transport ◽  
Self Consistent ◽  
The Impact

Abstract. The NCAR Whole Atmosphere Community Climate Model with thermosphere and ionosphere eXtension (WACCM-X) v2.1 has been extended to include the neutral and ion–molecule chemistry and dynamics of three metals (Mg, Na, and Fe), which are injected into the upper mesosphere–lower thermosphere by meteoric ablation. Here we focus on the self-consistent electrodynamical transport of metallic ions in both the E and F regions. The model with full ion transport significantly improves the simulation of global distribution and seasonal variations of Mg+, although the peak density is slightly lower (about 35 % lower in peak density) compared with the SCIAMACHY measurements. Near the magnetic equator, the diurnal variation in upward and downward transport of Mg+ is generally consistent with the “ionosphere fountain effect”. The thermospheric distribution of Fe is shown to be closely coupled to the transport of Fe+. The effect of ion mass on ion transport is also examined: the lighter ions (Mg+ and Na+) are transported above 150 km more easily than the heavy Fe+. We also examine the impact of the transport of major molecular ions, NO+ and O2+, on the distribution of metallic ions.

scholarly journals Self-consistent Global Transport of Metallic Ions with WACCM-X

2021 ◽  
Author(s):  
Jianfei Wu ◽  
Wuhu Feng ◽  
Han-Li Liu ◽  
Xianghui Xue ◽  
Daniel R. Marsh ◽  
...  
Keyword(s):  
Ion Transport ◽  
Seasonal Variations ◽  
Climate Model ◽  
Lower Thermosphere ◽  
Molecular Ions ◽  
The Self ◽  
Metallic Ions ◽  
Global Transport ◽  
Self Consistent ◽  
The Impact

Abstract. The NCAR Whole Atmosphere Community Climate Model with thermosphere and ionosphere eXtension (WACCM-X) v2.1 has been developed to include the neutral and ion-molecule chemistry and dynamics of three metals (Mg, Na, and Fe), which are injected into the upper mesosphere/lower thermosphere by meteoric ablation. Here we focus on the self-consistent electrodynamical transport of metallic ions in both the E and F regions. The model with full ion transport significantly improves the simulation of global distribution and seasonal variations of Mg+. Near the magnetic equator, the diurnal variation in upward and downward transport of Mg+ is generally consistent with the ''ionosphere fountain effect''. The thermospheric distribution of Fe is shown to be closely coupled to the transport of Fe+. The effect of ion mass on ion transport is also examined: the lighter ions (Mg+ and Na+) are transported above 150 km more easily than the heavy Fe+. We also examine the impact of the transport of major molecular ions, NO+ and O2+, on the distribution of metallic ions.

scholarly journals Production and transport mechanisms of NO in observations and models

2018 ◽  
Author(s):  
Koen Hendrickx ◽  
Linda Megner ◽  
Daniel R. Marsh ◽  
Christine Smith-Johnsen
Keyword(s):  
Geomagnetic Activity ◽  
Climate Models ◽  
Climate Model ◽  
Heat Budget ◽  
Lower Thermosphere ◽  
Polar Vortex ◽  
Detailed Comparison ◽  
No Production ◽  
The Impact ◽  
Mlt Region

Abstract. A reservoir of Nitric Oxide (NO) in the lower thermosphere efficiently cools the atmosphere after periods of enhanced geomagnetic activity. Transport from this reservoir to the stratosphere within the winter polar vortex allows NO to deplete ozone levels and thereby affect the middle atmospheric heat budget. As more climate models resolve the mesosphere and lower thermosphere (MLT) region, the need for an improved representation of NO related processes increases. This work presents a detailed comparison of NO in the Antarctic MLT region between observations made by the Solar Occultation for Ice Experiment (SOFIE) instrument onboard the Aeronomy of Ice in the Mesosphere (AIM) satellite and simulations performed by the Whole Atmosphere Community Climate Model with Specified Dynamics (SD-WACCM). We investigate 7 years of SOFIE observations and focus on the Southern hemisphere, rather than on dynamical variability in the Northern hemisphere or a specific geomagnetic perturbed event. The morphology of the simulated NO is in agreement with observations though the long term mean is too high and the short term variability is too low. Number densities are more similar during winter, though the altitude of peak densities, which reaches between 102–106 km in WACCM and between 98–104 km in SOFIE, is most separated during winter. Using multiple linear regressions and superposed epoch analyses we investigate how well the NO production and transport are represented in the model. The impact of geomagnetic activity is shown to drive NO variations in the lower thermosphere similarly across both datasets. The dynamical transport from the lower thermosphere into the mesosphere during polar winter is found to agree very well, with a descent rate of about 2.2 km/day in the 80–110 km region in both datasets. The downward transported NO fluxes are however too low in WACCM, which is likely due to medium energy electrons and D-region chemistry that are not represented in the model.

scholarly journals Production and transport mechanisms of NO in the polar upper mesosphere and lower thermosphere in observations and models

2018 ◽  
Vol 18 (12) ◽  
pp. 9075-9089 ◽  
Author(s):  
Koen Hendrickx ◽  
Linda Megner ◽  
Daniel R. Marsh ◽  
Christine Smith-Johnsen
Keyword(s):  
Geomagnetic Activity ◽  
Climate Models ◽  
Climate Model ◽  
Heat Budget ◽  
Lower Thermosphere ◽  
No Production ◽  
Superposed Epoch Analysis ◽  
Mesosphere And Lower Thermosphere ◽  
The Impact ◽  
Mlt Region

Abstract. A reservoir of nitric oxide (NO) in the lower thermosphere efficiently cools the atmosphere after periods of enhanced geomagnetic activity. Transport from this reservoir to the stratosphere within the winter polar vortex allows NO to deplete ozone levels and thereby affect the middle atmospheric heat budget. As more climate models resolve the mesosphere and lower thermosphere (MLT) region, the need for an improved representation of NO-related processes increases. This work presents a detailed comparison of NO in the Antarctic MLT region between observations made by the Solar Occultation for Ice Experiment (SOFIE) instrument on-board the Aeronomy of Ice in the Mesosphere (AIM) satellite and simulations performed by the Whole Atmosphere Community Climate Model with Specified Dynamics (SD-WACCM). We investigate 8 years of SOFIE observations, covering the period 2007–2015, and focus on the Southern Hemisphere (SH), rather than on dynamical variability in the Northern Hemisphere (NH) or a specific geomagnetic perturbed event. The morphology of the simulated NO is in agreement with observations though the long-term mean is too high and the short-term variability is too low in the thermosphere. Number densities are more similar during winter, though the altitude of peak NO density, which reaches between 102 and 106 km in WACCM and between 98 and 104 km in SOFIE, is most separated during winter. Using multiple linear regression (MLR) and superposed epoch analysis (SEA) methods, we investigate how well the NO production and transport are represented in the model. The impact of geomagnetic activity is shown to drive NO variations in the lower thermosphere similarly across both datasets. The dynamical transport from the lower thermosphere into the mesosphere during polar winter is found to agree very well with a descent rate of about 2.2 km day−1 in the 80–110 km region in both datasets. The downward-transported NO fluxes are, however, too low in WACCM, which is likely due to medium energy electrons (MEE) and D-region ion chemistry that are not represented in the model.

The mid- to high-latitude migrating semidiurnal tide: Results from a mechanistic tide model and SuperDARN observations

2021 ◽  
Author(s):  
Willem van Caspel ◽  
Patrick Espy
Keyword(s):  
High Latitude ◽  
Seasonal Variations ◽  
Climate Model ◽  
Middle Atmosphere ◽  
Lower Thermosphere ◽  
Surface Friction ◽  
Equation Model ◽  
Tidal Forcing ◽  
Hourly Temperature ◽  
The Impact

<p>Simulations of the solar thermal migrating semidiurnal (SW2) tide in the mesosphere-lower-thermosphere (MLT) are compared against meteor wind observations from a longitudinal chain of high-latitude SuperDARN radars. The simulations span two full years and are performed using a 3D non-linear mechanistic primitive equation model. In our model, the background Middle Atmosphere is specified to daily mean zonal mean winds and temperatures from the Navy Global Environmental Model - High Altitude (NAVGEM-HA) meteorological analysis system. Thermal tides are forced from the surface to the thermosphere using 3-hourly temperature tendency fields from the Specified Dynamics Whole Atmosphere Community Climate Model With Thermosphere and Ionosphere Extension (SD-WACCMX). Our model accurately reproduces the observed seasonal cycle in the SW2 amplitude and phase, with the exception of summertime amplitudes being overestimated. Sensitivity studies reveal the impact of the seasonal variations in the background atmosphere and tidal forcing. The tropospheric forcing response is found to be highly sensitive to the seasonal variations in the background atmosphere, leading to strong amplification during the summer and mid-winter months. In contrast, the stratospheric forcing response is found to be much less sensitive to the background atmosphere, while being similar in magnitude to the tropospheric forcing response. Based on simulations using a zero-wind atmosphere, the impact of seasonal variations in the tidal forcing is found to be very small for both the tropospheric and stratospheric forcing response. Furthermore, the inclusion of an idealized surface friction profile is found to delay the phase of the tropospheric forcing response, which can strongly impact the simulated tide at MLT altitudes. Both the tropospheric forcing response and the surface friction specification are identified as being possible factors contributing to summertime amplitudes being overestimated.</p>

scholarly journals Radar observations of winds, waves and tides in the mesosphere and lower thermosphere over South Georgia island (54°S, 36°W) and comparison to WACCM simulations

2021 ◽  
Author(s):  
Neil P. Hindley ◽  
Neil Cobbett ◽  
David C. Fritts ◽  
Diego Janchez ◽  
Nicholas J. Mitchell ◽  
...  
Keyword(s):  
Large Scale ◽  
Climate Model ◽  
Lower Thermosphere ◽  
Neutral Atmosphere ◽  
Residual Circulation ◽  
Radar Observations ◽  
South Georgia ◽  
Global Circulation Models ◽  
Mesosphere And Lower Thermosphere ◽  
The Impact

Abstract. The mesosphere and lower thermosphere (MLT) is a dynamic layer of the earth’s atmosphere. This region marks the interface at which neutral atmosphere dynamics begin to influence the ionosphere and space weather. However, our understanding of this region and our ability to accurately simulate it in global circulation models (GCMs) is limited by a lack of observations, especially in remote locations. To this end, a meteor radar was deployed on the remote mountainous island of South Georgia (54° S, 36° W) in the Southern Ocean from 2016 to 2020. The goal of this study is to use these new measurements to characterise the fundamental dynamics of the MLT above South Georgia including large-scale winds, solar tides, planetary waves (PWs) and mesoscale gravity waves (GWs). We first present an improved method for time-height localisation of radar wind measurements and characterise the large-scale MLT winds. We then explore the amplitudes and phases of the diurnal (24 h), semidiurnal (12 h) and terdiurnal (8 h) solar tides at this latitude. We also explore PW activity and find very large amplitudes up to 30 ms−1 for the quasi-2 day wave in summer and show that the dominant modes of the quasi-5, 10 and 16 day waves are westward W1 and W2. We investigate wind variance due to GWs in the MLT and use a new method to show an east-west tendency of GW variance of up to 20 % during summer and a weaker north-south tendency of 0–5 % during winter. This is contrary to the expected tendency of GW directions in the winter stratosphere below, which is a strong suggestion of secondary GW (2GW) observations in the MLT. Lastly, comparison of radar winds to a climatological Whole Atmosphere Community Climate Model (WACCM) simulation reveals a simulated summertime mesopause and zonal wind shear that occur at altitudes around 10 km lower than observed, and southward winds during winter above 90 km altitude in the model that are not seen in observations. Further, wintertime zonal winds above 85 km altitude are eastward in radar observations but in WACCM they are found to weaken and reverse to westward. Recent studies have linked this discrepancy to the impact of 2GWs on the residual circulation which are not included in WACCM. These measurements therefore provide vital constraints that can guide the development of GCMs as they extend upwards into this important region of the atmosphere.

Modification of the Gravity Wave Parameterization in the Whole Atmosphere Community Climate Model: Motivation and Results

2017 ◽  
Vol 74 (1) ◽  
pp. 275-291 ◽  
Author(s):  
Rolando R. Garcia ◽  
Anne K. Smith ◽  
Douglas E. Kinnison ◽  
Álvaro de la Cámara ◽  
Damian J. Murphy
Keyword(s):  
Gravity Wave ◽  
Southern Hemisphere ◽  
Gravity Waves ◽  
Climate Model ◽  
Lower Thermosphere ◽  
Careful Examination ◽  
Control Analysis ◽  
Community Climate Model ◽  
The Impact ◽  
Community Climate

Abstract The current standard version of the Whole Atmosphere Community Climate Model (WACCM) simulates Southern Hemisphere winter and spring temperatures that are too cold compared with observations. This “cold-pole bias” leads to unrealistically low ozone column amounts in Antarctic spring. Here, the cold-pole problem is addressed by introducing additional mechanical forcing of the circulation via parameterized gravity waves. Insofar as observational guidance is ambiguous regarding the gravity waves that might be important in the Southern Hemisphere stratosphere, the impact of increasing the forcing by orographic gravity waves was investigated. This reduces the strength of the Antarctic polar vortex in WACCM, bringing it into closer agreement with observations, and accelerates the Brewer–Dobson circulation in the polar stratosphere, which warms the polar cap and improves substantially the simulation of Antarctic temperature. These improvements are achieved without degrading the performance of the model in the Northern Hemisphere stratosphere or in the mesosphere and lower thermosphere of either hemisphere. It is shown, finally, that other approaches that enhance gravity wave forcing can also reduce the cold-pole bias such that careful examination of observational evidence and model performance will be required to establish which gravity wave sources are dominant in the real atmosphere. This is especially important because a “downward control” analysis of these results suggests that the improvement of the cold-pole bias itself is not very sensitive to the details of how gravity wave drag is altered.

Self-Compassion and Quality of Life in Adults Who Stutter

2020 ◽  
Vol 29 (4) ◽  
pp. 2097-2108
Author(s):  
Robyn L. Croft ◽  
Courtney T. Byrd
Keyword(s):  
Quality Of Life ◽  
Social Connectedness ◽  
The Self ◽  
Future Research ◽  
Self Compassion ◽  
Adults Who Stutter ◽  
And Gender ◽  
Relationship Of ◽  
The Impact

Purpose The purpose of this study was to identify levels of self-compassion in adults who do and do not stutter and to determine whether self-compassion predicts the impact of stuttering on quality of life in adults who stutter. Method Participants included 140 adults who do and do not stutter matched for age and gender. All participants completed the Self-Compassion Scale. Adults who stutter also completed the Overall Assessment of the Speaker's Experience of Stuttering. Data were analyzed for self-compassion differences between and within adults who do and do not stutter and to predict self-compassion on quality of life in adults who stutter. Results Adults who do and do not stutter exhibited no significant differences in total self-compassion, regardless of participant gender. A simple linear regression of the total self-compassion score and total Overall Assessment of the Speaker's Experience of Stuttering score showed a significant, negative linear relationship of self-compassion predicting the impact of stuttering on quality of life. Conclusions Data suggest that higher levels of self-kindness, mindfulness, and social connectedness (i.e., self-compassion) are related to reduced negative reactions to stuttering, an increased participation in daily communication situations, and an improved overall quality of life. Future research should replicate current findings and identify moderators of the self-compassion–quality of life relationship.

Effect of Parental Modernity on Rejection Sensitivity and Self-Esteem of Adolescents

2016 ◽  
Vol 3 (2) ◽  
Author(s):  
Ritu ◽  
Madhu Anand
Keyword(s):  
Social Development ◽  
Rejection Sensitivity ◽  
Self Esteem ◽  
The Self ◽  
Negatively Associated ◽  
Individual Modernity ◽  
The Impact ◽  
The Relationship

Parental Modernity is an important aspect for the psycho-social development of the child. The present study aims to study the effect of parental modernity on rejection sensitivity and self-esteem of adolescents and the relationship between rejection sensitivity and self-esteem. The research is carried out on a sample of 240 parents (including 120 fathers and 120 mothers) and their 120 children. For observing the impact of modernity of parents on their children, Individual Modernity Scale was used and administered on father and mother. Rejection Sensitivity Questionnaire and Self-Esteem Inventory were used to measure the rejection sensitivity and self-esteem of children (age ranges from 14 to 19 years). The results suggest that parental modernity has an effect on the rejection sensitivity and personally perceived self of the self – esteem of adolescents. Furthermore, the rejection sensitivity has been found negatively associated with self-esteem.

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