Long-term trends and the effect of solar cycle variations on mesospheric winter temperatures over Longyearbyen, Svalbard (78°N) (original) (raw)
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Polar OH-airglow temperature variations in the 87/88 winter
Physics and Chemistry of the Earth, Part C: Solar, Terrestrial & Planetary Science, 2001
Measurements of OH-airglow spectra from Nordlysstasjonen in Adventdalen, Svalbard (15¡ E, 78¡ N) from the period 1980-2000 have been done. The temperature at 87 km height was iterated by fitting synthetic spectra to the measured spectra using the vibrational band (6-2). As a first result of the analysis of the time series mesospheric coolings, strong diurnal and semidiurnal tides and a planetary wave have been found in the temperatures in the winter of 1987/1988. At the time of the extraordinarily early stratospheric warming in December a cooling of 30 K was observed. The strength of the diurnal and semidiurnal tides were 30 K and 15 K respectively. The observation of the planetary wave confirms various models that have shown that mesospheric planetary waves can be generated indirectly by planetary waves in the stratosphere, due to an uneven distribution of the propagation of orographic planetary waves into the mesosphere.
Solar Activity and Svalbard Temperatures
Advances in Meteorology, 2011
The long temperature series at Svalbard (Longyearbyen) show large variations and a positive trend since its start in 1912. During this period solar activity has increased, as indicated by shorter solar cycles. The temperature at Svalbard is negatively correlated with the length of the solar cycle. The strongest negative correlation is found with lags 10-12 years. The relations between the length of a solar cycle and the mean temperature in the following cycle are used to model Svalbard annual mean temperature and seasonal temperature variations. Residuals from the annual and winter models show no autocorrelations on the 5 per cent level, which indicates that no additional parameters are needed to explain the temperature variations with 95 per cent significance. These models show that 60 per cent of the annual and winter temperature variations are explained by solar activity. For the spring, summer, and fall temperatures autocorrelations in the residuals exist, and additional variables may contribute to the variations. These models can be applied as forecasting models. We predict an annual mean temperature decrease for Svalbard of 3.5 ± 2 • C from solar cycle 23 to solar cycle 24 (2009-20) and a decrease in the winter temperature of ≈ 6 • C.
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
Spectral Analysis of the Svalbard Temperature Record 1912–2010
Advances in Meteorology, 2011
Climate development with possible anthropogenic effects occurs on a background of natural climatic variations, which may be considerable, and especially in the Arctic. Natural climate variations however remain poorly understood, although they remain important for discriminating between natural and anthropogenic influences on current climate change. Using the Svalbard (78 • N) surface air temperature record 1912-2010 as an example, we here suggest a road ahead to identify and describe such natural climate variations. By means of Fourier and wavelet analysis the record is decomposed into time-frequency space, to extract information on periodic signals and their amplitude and variation over time. By this we identify several cyclic variations on the time scale investigated. These oscillations are present in the annual record, as well as in seasonal subsets of the record. Using only three oscillations it is possible to hindcast the Svalbard temperature record well. We suggest that such persistent oscillations may be used for forecasting the overall features of future temperature changes for a limited period, about 10-25% of the record length. Our main focus is on identifying the character of recurrent natural temperature variations, but we also comment briefly on possible physical explanations for some of the identified cyclic variations.
2016
The mesopause region can be considered a “boundary region” between the neutral atmosphere, where atmospheric constituents and momentum are transported mainly by winds and turbulent eddies, and the ionosphere, where the main transport mechanism is molecular diffusion. In the mesopause, complex interactions between dynamics and photochemistry occur, and we are far from a complete understanding of these interactions. This thesis aims to better understand the processes responsible for the large temperature fluctuations we observe in the polar mesopause region, especially the effects of atmospheric circulation and wave activity from lower atmospheric layers. Investigations of trends have also been conducted. To carry out these investigations, we have derived and examined mesopause temperatures from two high-latitude locations: Tromsø (70◦N, 19◦E) and Longyearbyen (78◦N, 16◦E), and turbopause height only from Tromsø. A long-term change in turbopause height may be important for understandi...
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Earth System Science Data Discussions, 2012
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Radiation climate variability in Svalbard: surface and satellite observations
Polar Research, 1999
This paper performs a climatological investigation of the surface radiation budget (SRB) in Svalbard. on the basis of the Norwegian Polar Institute's radiation measurements from Ny-Alesund ( 198 1-1 997) and the NASA/Langley Surface Radiation Budget Dataset (1983)(1984)(1985)(1986)(1987)(1988)(1989)(1990)(1991). The radiation climate is related to meteorological conditions and surface properties, and compared to surface radiation fluxes measured from space. The natural variability of the short-wave and long-wave radiation fluxes in Ny-Alesund is generally governed by the large annual variation in the incoming light with polar night and polar day conditions, the large changes of surface albedoespecially during springand the atmospheric circulation with frequent cyclone passages during winter with alternating periods of warm, humid maritime air from the south and cold, dry Arctic air from the north.
Seasonal variation in the correlation of airglow temperature and emission rate
Geophysical Research Letters, 2007
1] The hydroxyl (OH) rotational temperature and band emission rate have been derived using year-round, groundbased measurements of the infrared OH nightglow from Sweden from 1991 to 2002. Recent work has suggested that, during the winter, all scales of dynamical variations of radiance and temperature arise from vertical motions, implying that the effective source concentrations of atomic oxygen are constant. The present data show correlations between temperature and radiance both during winter and summer that are consistent with those observed in that previous work. However, during the transition to summer there is a rapid decrease in the temperature and its variation that is not reflected in the band radiance, suggesting that only the shorter-scale variations are accompanied by significant vertical motion. This indicates that the shorter-scale dynamical variations occur against an independent, seasonally changing background temperature profile in a way that is consistent with that predicted by gravity-wave models. Citation: Espy, P. J., J. Stegman, P. Forkman, and D. Murtagh , Seasonal variation in the correlation of airglow temperature and emission rate, Geophys.