scholarly journals Role Of the Sun and the Middle atmosphere/thermosphere/ionosphere In Climate (ROSMIC): a retrospective and prospective view

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
William Ward ◽  
Annika Seppälä ◽  
Erdal Yiğit ◽  
Takuji Nakamura ◽  
Claudia Stolle ◽  
...  
Keyword(s):  
Structural Changes ◽  
Middle Atmosphere ◽  
Lower Thermosphere ◽  
Primary Energy ◽  
Lower Atmosphere ◽  
Quasi Equilibrium ◽  
The Sun ◽  
Terrestrial System ◽  
Solar Influence ◽  
Made In

AbstractWhile knowledge of the energy inputs from the Sun (as it is the primary energy source) is important for understanding the solar-terrestrial system, of equal importance is the manner in which the terrestrial part of the system organizes itself in a quasi-equilibrium state to accommodate and re-emit this energy. The ROSMIC project (2014–2018 inclusive) was the component of SCOSTEP’s Variability of the Sun and Its Terrestrial Impact (VarSITI) program which supported research into the terrestrial component of this system. The four themes supported under ROSMIC are solar influence on climate, coupling by dynamics, trends in the mesosphere lower thermosphere, and trends and solar influence in the thermosphere. Over the course of the VarSITI program, scientific advances were made in all four themes. This included improvements in understanding (1) the transport of photochemically produced species from the thermosphere into the lower atmosphere; (2) the manner in which waves produced in the lower atmosphere propagate upward and influence the winds, dynamical variability, and transport of constituents in the mesosphere, ionosphere, and thermosphere; (3) the character of the long-term trends in the mesosphere and lower thermosphere; and (4) the trends and structural changes taking place in the thermosphere. This paper reviews the progress made in these four areas over the past 5 years and summarizes the anticipated research directions in these areas in the future. It also provides a physical context of the elements which maintain the structure of the terrestrial component of this system. The effects that changes to the atmosphere (such as those currently occurring as a result of anthropogenic influences) as well as plausible variations in solar activity may have on the solar terrestrial system need to be understood to support and guide future human activities on Earth.

Formation of the double stratopause and elevated stratopause associated with the major stratospheric sudden warming in 2018/19

2021 ◽  
Author(s):  
Haruka Okui ◽  
Kaoru Sato ◽  
Dai Koshin ◽  
Shingo Watanabe
Keyword(s):  
General Circulation ◽  
Middle Atmosphere ◽  
Baroclinic Instability ◽  
Lower Thermosphere ◽  
Circulation Model ◽  
Lower Atmosphere ◽  
Temperature Structure ◽  
Residual Circulation ◽  
Stratospheric Sudden Warming

<p>After several recent stratospheric sudden warming (SSW) events, the stratopause disappeared and reformed at a higher altitude, forming an elevated stratopause (ES). The relative roles of atmospheric waves in the mechanism of ES formation are still not fully understood. We performed a hindcast of the 2018/19 SSW event using a gravity-wave (GW) permitting general circulation model containing the mesosphere and lower thermosphere (MLT), and analyzed dynamical phenomena throughout the entire middle atmosphere. An ES formed after the major warming on 1 January 2019. There was a marked temperature maximum in the polar upper mesosphere around 28 December 2018 prior to the disappearance of the descending stratopause associated with the SSW. This temperature structure with two maxima in the vertical is referred to as a double stratopause (DS). We showed that adiabatic heating from the residual circulation driven by GW forcing (GWF) causes barotropic and/or baroclinic instability before DS formation, causing in situ generation of planetary waves (PWs). These PWs propagate into the MLT and exert negative forcing, which contributes to DS formation. Both negative GWF and PWF above the recovered eastward jet play crucial roles in ES formation. The altitude of the recovered eastward jet, which regulates GWF and PWF height, is likely affected by the DS structure. Simple vertical propagation from the lower atmosphere is insufficient to explain the presence of the GWs observed in this event.</p>

scholarly journals Effects of Latitude-Dependent Gravity Wave Source Variations on the Middle and Upper Atmosphere

2021 ◽  
Vol 7 ◽  
Author(s):  
Erdal Yiğit ◽  
Alexander S. Medvedev ◽  
Manfred Ern
Keyword(s):  
General Circulation ◽  
Middle Atmosphere ◽  
Lower Thermosphere ◽  
Three Dimensional ◽  
Circulation Model ◽  
Wave Activity ◽  
Upper Atmosphere ◽  
Lower Atmosphere ◽  
Boreal Summer ◽  
Wave Source

Atmospheric gravity waves (GWs) are generated in the lower atmosphere by various weather phenomena. They propagate upward, carry energy and momentum to higher altitudes, and appreciably influence the general circulation upon depositing them in the middle and upper atmosphere. We use a three-dimensional first-principle general circulation model (GCM) with implemented nonlinear whole atmosphere GW parameterization to study the global climatology of wave activity and produced effects at altitudes up to the upper thermosphere. The numerical experiments were guided by the GW momentum fluxes and temperature variances as measured in 2010 by the SABER (Sounding of the Atmosphere using Broadband Emission Radiometry) instrument onboard NASA’s TIMED (Thermosphere Ionosphere Mesosphere Energetics Dynamics) satellite. This includes the latitudinal dependence and magnitude of GW activity in the lower stratosphere for the boreal summer season. The modeling results were compared to the SABER temperature and total absolute momentum flux and Upper Atmosphere Research Satellite (UARS) data in the mesosphere and lower thermosphere. Simulations suggest that, in order to reproduce the observed circulation and wave activity in the middle atmosphere, GW fluxes that are smaller than observed fluxes have to be used at the source level in the lower atmosphere. This is because observations contain a broader spectrum of GWs, while parameterizations capture only a portion relevant to the middle and upper atmosphere dynamics. Accounting for the latitudinal variations of the source appreciably improves simulations.

scholarly journals Statistical characteristics of gravity wave activities observed by an OH airglow imager at Xinglong, in northern China

2011 ◽  
Vol 29 (8) ◽  
pp. 1401-1410 ◽  
Author(s):  
Q. Li ◽  
J. Xu ◽  
J. Yue ◽  
W. Yuan ◽  
X. Liu
Keyword(s):  
Middle Atmosphere ◽  
Lower Thermosphere ◽  
Northern China ◽  
Lower Atmosphere ◽  
Statistical Characteristics ◽  
Meridional Direction ◽  
Short Period ◽  
Different Seasons ◽  
One Year ◽  
Almost All

Abstract. An all-sky airglow imager (ASAI) was installed at Xinglong, in northern China (40.2° N, 117.4° E) in November 2009 to study the morphology of atmospheric gravity waves (AGWs) in the mesosphere and lower thermosphere (MLT) region. Using one year of OH airglow imager data from December 2009 to November 2010, the characteristics of short-period AGWs are investigated and a yearlong AGW climatology in northern China is first ever reported. AGW occurrence frequency in summer and winter is higher than that in equinoctial months. Observed bands mainly have horizontal wavelengths from 10 to 35 km, observed periods from 4 to 14 min and observed horizontal phase speeds in the range of 30 to 60 m s−1. Most of the bands propagate in the meridional direction. The propagation directions of the bands show a strong southwestward preference in winter, while almost all bands propagate northeastward in summer. Although the wind filtering in the middle atmosphere may control AGW propagations in the zonal direction, the non-uniform distribution of wave sources in the lower atmosphere may contribute to the anisotropy in the meridional direction in different seasons. Additionally, as an indication of local instability, the characteristics of ripples are also analyzed. It also shows seasonal variations, occurring more often in summer and winter and mainly moving westward in summer and eastward in winter.

scholarly journals Cooling of the mesosphere and lower thermosphere due to doubling of CO2

1998 ◽  
Vol 16 (11) ◽  
pp. 1501-1512 ◽  
Author(s):  
R. A. Akmaev ◽  
V. I. Fomichev
Keyword(s):  
Middle Atmosphere ◽  
Thermal Structure ◽  
Lower Thermosphere ◽  
Thermal Response ◽  
Co2 Concentration ◽  
Lower Atmosphere ◽  
Heating Rates ◽  
Density Reduction ◽  
Mesosphere And Lower Thermosphere ◽  
Thermospheric Dynamics

Abstract. A new parameterization of infrared radiative transfer in the 15-μm CO2 band has been incorporated into the Spectral mesosphere/lower thermosphere model (SMLTM). The parameterization is applicable to calculations of heating rates above approximately 15 km for arbitrary vertical profiles of the CO2 concentration corresponding to the surface mixing ratio in the range 150–720 ppm. The sensitivity of the mesosphere and lower thermosphere (MLT) to doubling of CO2 has been studied. The thermal response in the MLT is mostly negative (cooling) and much stronger than in the lower atmosphere. An average cooling at the stratopause is about 14 K. It gradually decreases to approximately 8 K in the upper mesosphere and again increases to about 40–50 K in the thermosphere. The cooling and associated thermal shrinking result in a substantial density reduction in the MLT that reaches 40–45% in the thermosphere. Various radiative, chemical, and dynamical feedbacks potentially important for the thermal response in the MLT are discussed. It is noted that the results of simulations are strikingly similar to observations of long-term trends in the MLT. This suggests that during the last 3–4 decades the thermal structure in the real upper atmosphere has undergone substantial changes driven by forcing comparable with that due to doubling of CO2.Key words. Meteorology and atmospheric dynamics (Climatology · Middle atmosphere dynamics · Thermospheric dynamics)

scholarly journals Stratospheric warming influence on the mesosphere/lower thermosphere as seen by the extended CMAM

2014 ◽  
Vol 32 (6) ◽  
pp. 589-608 ◽  
Author(s):  
M. G. Shepherd ◽  
S. R. Beagley ◽  
V. I. Fomichev
Keyword(s):  
Atmospheric Chemistry ◽  
Middle Atmosphere ◽  
Lower Thermosphere ◽  
Lower Atmosphere ◽  
Fourier Transform Spectrometer ◽  
Stratospheric Warming ◽  
Sudden Stratospheric Warming ◽  
New Information ◽  
The Impact ◽  
Chemistry Experiment

Abstract. The response of the upper mesosphere/lower thermosphere region to major sudden stratospheric warming (SSW) is examined employing temperature, winds, NOX and CO constituents from the extended Canadian Middle Atmosphere Model (CMAM) with continuous incremental nudging below 10 hPa (~ 30 km). The model results considered cover high latitudes (60–85° N) from 10 to 150 km height for the December–March period of 2003/2004, 2005/2006 and 2008/2009, when some of the strongest SSWs in recent years were observed. NOX and CO are used as proxies for examining transport. Comparisons with ACE-FTS (Atmospheric Chemistry Experiment–Fourier Transform Spectrometer) satellite observations show that the model represents well the dynamics of the upper mesosphere/lower thermosphere region, the coupling of the stratosphere–mesosphere, and the NOX and CO transport. New information is obtained on the upper mesosphere/lower thermosphere up to 150 km showing that the NOX volume mixing ratio in the 2003/2004 winter was very perturbed indicating transport from the lower atmosphere and intense mixing with large NOX influx from the thermosphere compared to 2006 and 2009. These results, together with those from other models and observations, clearly show the impact of stratospheric warmings on the thermosphere.

scholarly journals Lower and middle atmosphere and ozone layer responses to solar variation

2009 ◽  
Vol 5 (S264) ◽  
pp. 336-342 ◽  
Author(s):  
Ana G. Elias
Keyword(s):  
Greenhouse Gases ◽  
Middle Atmosphere ◽  
Geomagnetic Storms ◽  
Stratospheric Ozone ◽  
Climate Science ◽  
Volcanic Eruptions ◽  
Ozone Layer ◽  
Lower Atmosphere ◽  
Global Changes ◽  
The Sun

AbstractGlobal warming in the troposphere and the decrease of stratospheric ozone concentration has become a major concern to the scientific community. The increase in greenhouse gases and aerosols concentration is believed to be the main cause of this global change in the lower atmosphere and in stratospheric ozone, which is corresponded by a cooling in the middle and upper atmosphere. However, there are natural sources, such as the sun and volcanic eruptions, with the same ability to produce global changes in the atmosphere. The present work will focus on solar variation and its signature in lower and middle atmosphere parameters. The Sun can influence the Earth and its climate through electromagnetic radiation variations and also through changes in the solar wind which causes geomagnetic storms. The effects of both mechanisms over the lower and middle atmosphere and ozone layer will be discussed through an overview of selected papers, which by no means cover this subject that is extremely wide and complex. A fundamental understanding of the atmosphere response to solar variations is required for understanding and interpreting the causes of atmospheric variability. This is an essential focus of climate science, which is seeking to determine the extent to which human activities are altering the planetary energy balance through the emission of greenhouse gases and pollutants.

scholarly journals Structural changes in lower ionosphere wind trends at midlatitudes

2010 ◽  
Vol 8 ◽  
pp. 231-236
Author(s):  
C. Jacobi ◽  
E. G. Merzlyakov ◽  
R. Q. Liu ◽  
T. V. Solovjova ◽  
Y. I. Portnyagin
Keyword(s):  
Structural Changes ◽  
Linear Trend ◽  
Piecewise Linear ◽  
A Priori ◽  
Lower Thermosphere ◽  
Lower Ionosphere ◽  
Lower Atmosphere ◽  
Data Series ◽  
E Region ◽  
Straight Lines

Abstract. Long-term variability of the mesosphere/lower thermosphere (lower E region ionosphere) since 1970 has been analyzed using wind data series obtained at Collm (52° N, 15° E) using the LF drift method and at Obninsk (55° N, 37° E) applying VHF meteor radar. Applying piecewise linear trend analysis with a priori unknown number and positions of breakpoints shows that trend models with breakpoints are generally to be preferred against straight lines. There is a strong indication for a change of trends in wind parameters around 1975–1980. Similar changes are also found in the lower atmosphere, e.g., in tropospheric temperatures. This indicates a coupling between atmospheric layers at time scales of decades.

Examination of Thermal and Electrical Performance of Cassegrain Concentrator System

2019 ◽  
Vol 8 (6S2) ◽  
pp. 96-98
Keyword(s):  
Stainless Steel ◽  
Great Degree ◽  
Electrical Performance ◽  
Personal Satisfaction ◽  
The Sun ◽  
Supporting Structure ◽  
Apex Point ◽  
Control Water ◽  
Working Liquid ◽  
Made In

The sun oriented power (SP) is a one of a kind renewable vitality innovation. SP frameworks can give control, water warming and water decontamination in one unit. This innovation will be to a great degree accommodating in enhancing the personal satisfaction for some individuals around the globe who do not have the vitality expected to carry on with a sound life. A financial allegorical dish sort Cassegrain concentrating framework was created at the foundation of Energy Studies, Anna University Chennai. An old microwave media transmission reception apparatus having a paraboloidal shape made in aluminum frames an essential reflector which guarantees effortlessness of generation and operation. The essential concentrator was settled with mirror cleaned stainless steel with reasonable cement .The optional concentrator is inward mirror .Suitable supporting structure was developed for supporting the cassegrain concentrator. Double hub following framework is mounted for adjusting the concentrator to azimuth and apex point by utilizing DC engine and direct actuator individually. Water goes about as working liquid to expel warm from .The tank is protected with thermocol material upheld with wooden structure on all sides to maintain a strategic distance from convection misfortunes. The material Cost for the framework was Rs 15000

The Starry Universe of Jacques Cassini: Century-old Echoes of Kepler

2021 ◽  
Vol 52 (2) ◽  
pp. 147-167
Author(s):  
Christopher M. Graney
Keyword(s):  
18Th Century ◽  
The Sun ◽  
Johannes Kepler ◽  
Apparent Diameter ◽  
Early 18Th Century ◽  
Made In

This paper discusses measurements of the apparent diameter and parallax of the star Sirius, made in the early 18th century by Jacques Cassini, and how those measurements were discussed by other writers. Of particular interest is how other writers accepted Cassini’s measurements, but then discussed Sirius and other stars as though they were all the same size as the sun. Cassini’s measurements, by contrast, required Sirius and other stars to dwarf the sun—something Cassini explicitly noted, and something that echoed the ideas of Johannes Kepler more than a century earlier.

scholarly journals III. On the nature and construction of the sun and fixed stars

1795 ◽  
Vol 85 ◽  
pp. 46-72 ◽  
Keyword(s):  
Central Body ◽  
Planetary System ◽  
Considerable Progress ◽  
The Sun ◽  
Great Satisfaction ◽  
The Earth ◽  
The World ◽  
Celestial Bodies ◽  
The Universe ◽  
Made In

Among the celestial bodies the sun is certainly the first which should attract our notice. It is a fountain of light that illuminates the world! it is the cause of that heat which main­tains the productive power of nature, and makes the earth a fit habitation for man! it is the central body of the planetary system; and what renders a knowledge of its nature still more interesting to us is, that the numberless stars which compose the universe, appear, by the strictest analogy, to be similar bodies. Their innate light is so intense, that it reaches the eye of the observer from the remotest regions of space, and forcibly claims his notice. Now, if we are convinced that an inquiry into the nature and properties of the sun is highly worthy of our notice, we may also with great satisfaction reflect on the considerable progress that has already been made in our knowledge of this eminent body. It would require a long detail to enumerate all the various discoveries which have been made on this subject; I shall, therefore, content myself with giving only the most capital of them.

Sign in / Sign up

Export Citation Format

Share Document