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Calculated and observed climate change in the thermosphere, and a prediction for solar cycle 24
Author(s) -
Qian Liying,
Roble Raymond G.,
Solomon Stanley C.,
Kane Timothy J.
Publication year - 2006
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2006gl027185
Subject(s) - thermosphere , atmospheric sciences , solar minimum , environmental science , solar cycle , solar irradiance , solar maximum , climate change , solar cycle 24 , secular variation , atmosphere (unit) , solar cycle 22 , climatology , physics , meteorology , ionosphere , solar wind , geology , oceanography , geophysics , quantum mechanics , astronomy , magnetic field
The long‐term change of thermospheric neutral density has been investigated using satellite drag measurements and through sensitivity studies using upper atmosphere general circulation models. The magnitude of the change has been quantified in both approaches, and the source of the secular change attributed to the concentration changes of greenhouse gases. In this study, we use CO 2 concentration measured at Mauna Loa Observatory and solar variation based on a proxy model to calculate the secular change of thermosphere neutral density for the last three decades, using a global mean upper atmosphere model. Our results show that the average density decrease at 400 km from 1970 to 2000 is 1.7% per decade. To quantify the impact of solar activity on the secular change of neutral density, we also calculated the long‐term density change under solar minimum and solar maximum conditions for the same time period. The average trends at 350 km and 450 km are 2.2% per decade and 2.9% per decade for solar minimum conditions, while at solar maximum, they are 0.7% per decade and 0.8% per decade, respectively. These model results are compared to estimates of thermosphere density change derived from satellite drag observations, showing good agreement. In addition, based on a recent forecast of the intensity of solar cycle 24, we predict that the long‐term change of thermospheric neutral density from 2006 to the end of solar cycle 24 will be ∼2.7% per decade at 400 km.