## Abstract

After removing annual variability, power spectral analyses of local atmospheric temperature from hundreds of stations and ice core records have been carried out from time scales of 10^{-2} to 10^{6} yr. A clear sequence of power-law behaviors is found as follows: 1) from 40 ka to 1 Ma a flat spectrum is observed; 2) from 2 ka to 40 ka the spectrum is proportional to f^{-2} where f is the frequency; and 3) below time scales of 2 ka the power spectrum is proportional to f^{-1/2}. At time scales less than 1 month we observe that the power spectra of continental stations become proportional to f^{-3/2} while maritime stations continue to have power spectra proportional to f^{-1/2} down to time scales of 1 day. To explain these observations, we model the vertical transport of heat in the atmosphere as a stochastic diffusion process. The power spectrum of temperature fluctuations at the earth's surface expected from this model equation in a two-layer geometry with thermal and eddy diffusion properties appropriate to the atmosphere and the ocean and a radiation condition at the top of the atmosphere agrees with the observed spectrum. The difference in power spectra between continental and marine stations can be understood with this approach as a consequence of the air mass above a maritime station exchanging heat with both the atmosphere above and the ocean below while a continental station exchanges heat mostly with the atmosphere above.

Original language | English (US) |
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Pages (from-to) | 157-164 |

Number of pages | 8 |

Journal | Earth and Planetary Science Letters |

Volume | 158 |

Issue number | 3-4 |

DOIs | |

State | Published - May 30 1998 |

## ASJC Scopus subject areas

- Geophysics
- Geochemistry and Petrology
- Earth and Planetary Sciences (miscellaneous)
- Space and Planetary Science

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