Intra-seasonal monthly oscillations in stratospheric NCEP data and model results

Mayr H. G., Mengel J. G., Huang F. T., Nash E. R.

JOURNAL OF ATMOSPHERIC AND SOLAR-TERRESTRIAL PHYSICS, vol.71, no.12, pp.1299-1308, 2009 (SCI-Expanded, Scopus) identifier identifier

  • Publication Type: Article / Article
  • Volume: 71 Issue: 12
  • Publication Date: 2009
  • Doi Number: 10.1016/j.jastp.2009.05.003
  • Journal Name: JOURNAL OF ATMOSPHERIC AND SOLAR-TERRESTRIAL PHYSICS
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.1299-1308
  • Keywords: Intra-seasonal oscillations (ISO), Sudden stratospheric warmings (SSW), NCEP data analysis, Stratosphere dynamics, Theoretical modeling, DOPPLER-SPREAD PARAMETERIZATION, WAVE MOMENTUM DEPOSITION, MIDDLE ATMOSPHERE, EQUATORIAL MESOSPHERE, LOWER THERMOSPHERE, INTRASEASONAL OSCILLATIONS, SPECTRAL MODEL, GRAVITY-WAVES, VARIABILITY, SIMULATION
  • Ankara University Affiliated: Yes

Abstract

Intra-seasonal oscillations (ISO) are observed in the zonal-mean of mesospheric wind and temperature measurements-and the numerical spectral model (NSM) generates such oscillations. Relatively large temperature ISO are evident also in stratospheric CPC (NCEP) data at high latitudes, where the NSM produces amplitudes around 3 K at 30 km. Analyzing the NCEP data for the years 1996-2006, we find in Fourier spectra signatures of oscillations with periods between 1.7 and 3 months. With statistical confidence levels exceeding 70%, the spectral features are induced by nonlinear interactions involving the annual and semi-annual variations. The synthesized data show for the 10-year average that the temperature ISO peak in winter, having amplitudes close to 4 K. The synthesized complete spectrum for periods around 2 months produces oscillations, varying from year to year, which can reach peak amplitudes of 15 and 5 K respectively at northern and southern polar latitudes. (C) 2009 Elsevier Ltd. All rights reserved.