A note on an AGU spring meeting discussion of the role of atmospheric water vapour in climate and atmospheric composition (original) (raw)
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Theoretical and Applied Climatology, 1987
The response of the stratosphere and lower mesosphere to the quasi-eleven-year solar activity cycle (indicated by sunspot variations) was studied using temperature data obtained from rockets which are mostly based on a datasonde system throughout the decade 1969-1978. It is suggested that the highest correlation between the long-term stratospheric-lower mesospheric temperature fluctuations and the Zfirich sunspot number is obtained with a time lag of one year (sun leading). A comprehensive insight into the actual process accounting for the observed correlation would be gained from improved observational data, including observations of solar ultraviolet behavior. Zusammenfassung Best~itigung des lljfhrigen Sonnenfleckenzyklus in den stratosph~irischen und niedermesosph §rischen Ozonkonzentrationen und Temperaturen Die Reaktion dee Stratosph/ire und dee niederen Mesosph/ire auf den 1 lj~hrigen-Sonnenzyklus (ausgedriickt durch Sonnenflecken-Variationen) wurde anhand yon Temperaturdaten untersucht, die mit Raketensonden w/ihrend des Jahrzehnts 1969-1978 ermittelt worden waren. Die Ergcbnisse weisen darauf bin, dab die maximale Korrelation zwischen langffistigen stratosph~irischen bzw. niedermesosph/irischen Temperaturfluktuationen und dee Anzahl dee Sonnenflecken in Zfirich mit einer Zeitverz6gerung von einem Jahr zu erhalten ist. Ein besseres Verstfindnis des tatsgchlichen Vorganges, dem die betrachtete Korrelation zugeschrieben wird, kann durch verbesserte Beobachtungsdaten unter Berficksichtigung der Sonnenaktivitiit im Ultravioletten gewonnen werden.
Lower and middle atmosphere and ozone layer responses to solar variation
Proceedings of the International Astronomical Union, 2009
Global 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 extremel...
Atmospheric Chemistry and Physics Discussions, 2008
Three analyses of satellite observations and two sets of model studies are used to estimate changes in the stratospheric ozone distribution from solar minimum to solar maximum and are presented for three different latitudinal bands: Poleward of 30 • north, between 30 • north and 30 • south and poleward of 30 • south. In the model studies the 5 solar cycle impact is limited to changes in UV fluxes. There is a general agreement between satellite observation and model studies, particular at middle and high northern latitudes. Ozone increases at solar maximum with peak values around 40 km. The profiles are used to calculate the radiative forcing (RF) from solar minimum to solar maximum. The ozone RF, calculated with two different radiative transfer schemes is 10 found to be negligible (a magnitude of 0.01 Wm −2 or less), compared to the direct RF due to changes in solar irradiance, since contributions from the longwave and shortwave nearly cancel each other. The largest uncertainties in the estimates come from the lower stratosphere, where there is significant disagreement between the different ozone profiles. 15 25 impact of this change in ozone, however, is uncertain. There are significant differences 4354 Abstract 25 (Houghton et al., 2001). Abstract 25 4359 ACPD 8, 4353-4371, 2008 Abstract the lower stratosphere, where ozone perturbations have the strongest impact on the 4360 ACPD 8,[4353][4354][4355][4356][4357][4358][4359][4360][4361][4362][4363][4364][4365][4366][4367][4368][4369][4370][4371] 2008 Abstract 25 extending the calculations down to 20 km has, as expected, more of an effect on the LW forcing, and causes the net forcing to change in sign from negative to positive ; it, however, remains small. 4363 Abstract References Bian, H. S. and Prather, M. J.: Fast-J2: Accurate simulations of stratospheric photolysis in 25 global chemistry models,
Eleven-year solar cycle variations in the atmosphere: observations, mechanisms and models
The Holocene, 2003
The understanding of natural and anthropogenic climatic change is an important issue in recent studies. The influence of the Sun (11-year solar cycle) as a natural variability factor on the atmosphere is discussed. Statistical studies with observational data (NCEP/NCAR re-analyses) covering four solar cycles show high correlations between the 11 -year solar signal and meteorological parameters, e.g., the geopotential heights and temperatures, in the lower stratosphere and troposphere. Studies with general circulation models (GCM) have discussed the possibility of an indirect dynamical response to direct changes in solar irradiance and ozone in the stratosphere. A physical mechanism explaining the solar influence on the atmosphere is still missing. Part of the mechanism understood so far and ideas from model and observational studies are presented.
Journal of Atmospheric and Solar-Terrestrial Physics, 2005
Three independent temperature datasets have been analyzed for quantifying the influence of the 11-year solar cycle modulation of the UV radiation. The datasets used include: US rocketsondes, the OHP lidar, and the global temperature database made by the successive SSU on the NOAA satellites, adjusted and provided by the UK Meteorological Office. These measurements cover the upper stratosphere and the mesosphere, where the direct photochemical effect is expected. The improvement of the analysis compared to previous ones was possible because the overall quality and the continuity of many data series have been checked more carefully during the last decade in order to look for anthropogenic fingerprints and the one used here have been recognized as the best series according to their temporal continuity. The analysis of the different data set is based on the same regression linear model. The 11-year solar temperature response observed presents a variable behavior, depending on the location. However, an overall adequate agreement among the results has been obtained, and thus the global picture of the solar impact in the upper stratosphere and lower mesosphere has been obtained and is presented here. In the tropics, a 1-2 K positive response in the mid and upper stratophere has been found, in agreement with photochemical theory and previous analyses. On the opposite, at mid-latitudes, negative responses of several Kelvin have been observed, during winters, in the analyses of the datasets analyzed here. In the mesosphere, at sub-tropic and mid-latitude regions, we observe a positive response all the year round increasing by a factor of two during winter. r
Geophysical Research Letters, 2005
The impact of 11‐year solar cycle variations on stratospheric ozone (O3) is studied with the Freie Universität Berlin Climate Middle Atmosphere Model with interactive chemistry (FUB‐CMAM‐CHEM). To consider the effect of variations in charged particle precipitation we included an idealized NOx source in the upper mesosphere representing relativistic electron precipitation (REP). Our results suggest that the NOx source by particles and its transport from the mesosphere to the stratosphere in the polar vortex are important for the solar signal in stratospheric O3. We find a positive dipole O3 signal in the annual mean, peaking at 40–45 km at high latitudes and a negative O3 signal in the tropical lower stratosphere. This is similar to observations, but enhanced due to the idealized NOx source and at a lower altitude compared to the observed minimum. Our results imply that this negative O3 signal arises partly via chemical effects.
The direct solar influence on climate: modeling the lower atmosphere
2005
A set of ensemble experiments has been run focusing on the Dalton minimum to identify the individual contributions of solar variability, volcanism, greenhouse gas concentration changes and the combination of these forcing on climate. Additionally an idealized experiment has been carried out, where a sinusoidal forcing corresponding to the period of the Gleissberg-cycle, which led to the Dalton minimum, has been prescribed. Both, the volcanic and the solar forcing contribute to the global cooling during the Dalton minimum. The volcanic forcing, however, plays the major role for the global mean temperature. The temperature rise due to the greenhouse gases concentration increase counteracts this cooling only marginally. For the European region significant reduction of the solar constant (in the range of the imposed volcanic forcing) shift the NAO into the negative phase, thus enhancing the cooling over Europe. The experimental setup, which does not allow to take the volcanic aerosol fo...
The Middle Atmospheric Ozone Response to the 11-Year Solar Cycle
Space Science Reviews, 2007
Because of its chemical and radiative properties, atmospheric ozone constitutes a key element of the Earth's climate system. Absorption of sunlight by ozone in the ultraviolet wavelength range is responsible for stratospheric heating, and determines the temperature structure of the middle atmosphere. Changes in middle atmospheric ozone concentrations result in an altered radiative input to the troposphere and to the Earth's surface, with implications on the energy balance and the chemical composition of the lower atmosphere. Although a wide range of ground-and satellite-based measurements of its integrated content and of its vertical distribution have been performed since several decades, a number of uncertainties still remain as to the response of middle atmospheric ozone to changes in solar irradiance over decadal time scales. This paper presents an overview of achieved findings, including a discussion of commonly applied data analysis methods and of their implication for the obtained results. We suggest that because it does not imply least-squares fitting of prescribed periodic or proxy data functions into the considered times series, time-domain analysis provides a more reliable method than multiple regression analysis for extracting decadal-scale signals from observational ozone datasets. Applied to decadal ground-based observations, time-domain analysis indicates an average middle atmospheric ozone increase of the order of 2% from solar minimum to solar maximum, which is in reasonable agreement with model results.
Solar variability, coupling between atmospheric layers and climate change
Philosophical Transactions of the Royal Society of London. Series A: Mathematical, Physical and Engineering Sciences, 2002
One of the enduring puzzles of atmospheric physics is the extent to which changes in the Sun can in®uence the behaviour of the climate system. While solar-®ux changes tend to be relatively modest, a number of observations of atmospheric parameters indicates a disproportionately large response. Global-scale models of the coupled middle and upper atmosphere have provided new insights into some of the mechanisms that may be responsible for the ampli cation of the solar signal. In particular, modi cation of the transport of heat and chemicals such as ozone by waves during periods of solar activity has been shown to make an important contribution to the climate of the stratosphere and mesosphere. In this paper, a review of some of the recent advances in understanding the coupling between atmospheric layers and how this work relates to Sun{weather relations and climate change in the troposphere will be presented, along with a discussion of some of the challenges that remain.