ALMA Memo No. 517 Turbulence simulations of dry and wet phase fluctuations at Chajnantor. Part I: The daytime convective boundary layer
نویسندگان
چکیده
We have performed numerical simulations of the atmosphere for typical daytime convective conditions at Chajnantor, and derived the resulting wet and dry contributions to the atmospheric phase fluctuations. The simulations show that: ◦ Dry phase fluctuations are concentrated in two layers – near to the ground, and at the temperature inversion. The wet fluctuations are concentrated at the inversion, while the total phase fluctuations are more uniformly distributed within the convective layer. This is because of significant positive and negative correlations between the dry and wet refractive index fluctuations. ◦ The phase structure function is well described by a Kolmogorov turbulence spectrum on small scales, with a turn over on a scale of order the depth of the boundary layer. ◦ The variation of total r.m.s. phase with elevation shows a dependence on the square root of air mass for the total phase, but the dry component shows a linear variation with air mass, and the wet component varies as air mass to the power 0.75.
منابع مشابه
ALMA MEMO 459 Investigation of Anomalous Fast Phase Fluctuations in the Site-Test Interferometer Data from Chajnantor May 14, 2003
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