Middle atmosphere temperature changes and the duration of summer

Offermann, D.; Donner, M.; Knieling, Peter; Naujokat, B.

doi:10.1016/j.jastp.2004.01.028

Cited by 41 publications

(55 citation statements)

References 13 publications

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“…It may explain some of the diverse results reported so far. Offermann et al (2004) show a systematic variation in the long-term temperature trends from month to month in the mesopause region. French and Burns (2004) have recently found a dramatic seasonality in the trends in the mesopause region temperature at higher latitudes of the Southern Hemisphere.…”

Section: Consistent Pattern Of Long-term Trendsmentioning

confidence: 93%

Emerging pattern of global change in the upper atmosphere and ionosphere

et al. 2008

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Abstract. In the upper atmosphere, greenhouse gases produce a cooling effect, instead of a warming effect. Increases in greenhouse gas concentrations are expected to induce substantial changes in the mesosphere, thermosphere, and ionosphere, including a thermal contraction of these layers. In this article we construct for the first time a pattern of the observed long-term global change in the upper atmosphere, based on trend studies of various parameters. The picture we obtain is qualitative, and contains several gaps and a few discrepancies, but the overall pattern of observed long-term changes throughout the upper atmosphere is consistent with model predictions of the effect of greenhouse gas increases. Together with the large body of lower atmospheric trend research, our synthesis indicates that anthropogenic emissions of greenhouse gases are affecting the atmosphere at nearly all altitudes between ground and space.

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Section: Consistent Pattern Of Long-term Trendsmentioning

confidence: 93%

Emerging pattern of global change in the upper atmosphere and ionosphere

et al. 2008

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“…We follow the method used before in several analyses (e.g. Bittner et al, 2002;Offermann et al, 2004Offermann et al, , 2006Offermann et al, , 2010Perminov et al, 2014) and perform a harmonic analysis based on least-square fits for each year separately. As described in Bittner et al (2000) the seasonal variation is characterised by an annual, a semi-annual, and a ter-annual cycle.…”

Section: Data Processingmentioning

confidence: 99%

Long-term dynamics of OH * temperatures over central Europe: trends and solar correlations

et al. 2016

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Abstract. We present the analysis of annual average OH * temperatures in the mesopause region derived from measurements of the Ground-based Infrared P-branch Spectrometer (GRIPS) at Wuppertal (51 • N, 7 • E) in the time interval 1988 to 2015. The new study uses a temperature time series which is 7 years longer than that used for the latest analysis regarding the long-term dynamics. This additional observation time leads to a change in characterisation of the observed longterm dynamics.We perform a multiple linear regression using the solar radio flux F10.7 cm (11-year cycle of solar activity) and time to describe the temperature evolution. The analysis leads to a linear trend of (−0.089 ± 0.055) K year −1 and a sensitivity to the solar activity of (4.2 ± 0.9) K (100 SFU) −1 (r 2 of fit 0.6). However, one linear trend in combination with the 11-year solar cycle is not sufficient to explain all observed long-term dynamics. In fact, we find a clear trend break in the temperature time series in the middle of 2008. Before this break point there is an explicit negative linear trend of (−0.24 ± 0.07) K year −1 , and after 2008 the linear trend turns positive with a value of (0.64 ± 0.33) K year −1 . This apparent trend break can also be described using a long periodic oscillation. One possibility is to use the 22-year solar cycle that describes the reversal of the solar magnetic field (Hale cycle). A multiple linear regression using the solar radio flux and the solar polar magnetic field as parameters leads to the regression coefficients C solar = (5.0 ± 0.7) K (100 SFU) −1 and C hale = (1.8 ± 0.5) K (100 µT) −1 (r 2 = 0.71). The second way of describing the OH * temperature time series is to use the solar radio flux and an oscillation. A leastsquare fit leads to a sensitivity to the solar activity of (4.1 ± 0.8) K (100 SFU) −1 , a period P = (24.8 ± 3.3) years, and an amplitude C sin = (1.95 ± 0.44) K of the oscillation (r 2 = 0.78). The most important finding here is that using this description an additional linear trend is no longer needed. Moreover, with the knowledge of this 25-year oscillation the linear trends derived in this and in a former study of the Wuppertal data series can be reproduced by just fitting a line to the corresponding part (time interval) of the oscillation. This actually means that, depending on the analysed time interval, completely different linear trends with respect to magnitude and sign can be observed. This fact is of essential importance for any comparison between different observations and model simulations.

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“…An additional parameter which is reportedly influenced by long-term changes of solar activity is the duration of the stratospheric summer circulation at northern mid-and high latitudes (Offermann et al, 2004). They showed on the basis of meteorological analyses (e.g.…”

Section: The Solar Cyclementioning

confidence: 99%

Long-term changes and variability in a transient simulation with a chemistry-climate model employing realistic forcing

Dameris¹,

Grewe²,

Ponater³

et al. 2005

Atmos. Chem. Phys.

116

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Abstract.A transient simulation with the interactively coupled chemistry-climate model (CCM) E39/C has been carried out which covers the 40-year period between 1960 and 1999. Forcing of natural and anthropogenic origin is prescribed where the characteristics are sufficiently well known and the typical timescales are slow compared to synoptic timescale so that the simulated atmospheric chemistry and climate evolve under a "slowly" varying external forcing. Based on observations, sea surface temperature (SST) and ice cover are prescribed. The increase of greenhouse gas and chlorofluorocarbon concentrations, as well as nitrogen oxide emissions are taken into account. The 11-year solar cycle is considered in the calculation of heating rates and photolysis of chemical species. The three major volcanic eruptions during that time (Agung, 1963; El Chichon, 1982; Pinatubo, 1991) are considered. The quasi-biennial oscillation (QBO) is forced by linear relaxation, also known as nudging, of the equatorial zonal wind in the lower stratosphere towards observed zonal wind profiles. Beyond a reasonable reproduction of mean parameters and long-term variability characteristics there are many apparent features of episodic similarities between simulation and observation: In the years 1986 and 1988 the Antarctic ozone holes are smaller than in the other years of that decade. In mid-latitudes of the Southern Hemisphere ozone anomalies resemble the corresponding observations, especially in 1985, 1989, 1991/1992, and 1996. In the Northern Hemisphere, the episode between the late 1980s and the first half of the 1990s is dynamically quiet, in particular, no stratospheric warming is found between 1988 and 1993. As observed, volcanic eruptions strongly influence dynamics and chemistry, though only for Correspondence to: M. Dameris (Martin.Dameris@dlr.de) few years. Obviously, planetary wave activity is strongly driven by the prescribed SST and modulated by the QBO. Preliminary evidence of realistic cause and effect relationships strongly suggests that detailed process-oriented studies will be a worthwhile endeavour.

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Middle atmosphere temperature changes and the duration of summer

Cited by 41 publications

References 13 publications

Emerging pattern of global change in the upper atmosphere and ionosphere

Emerging pattern of global change in the upper atmosphere and ionosphere

Long-term dynamics of OH * temperatures over central Europe: trends and solar correlations

Long-term changes and variability in a transient simulation with a chemistry-climate model employing realistic forcing

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