Boundary-Layer Meteorology

, Volume 99, Issue 3, pp 349–378

Improvement Of The Mellor–Yamada Turbulence Closure Model Based On Large-Eddy Simulation Data

  • Mikio Nakanish

DOI: 10.1023/A:1018915827400

Cite this article as:
Nakanish, M. Boundary-Layer Meteorology (2001) 99: 349. doi:10.1023/A:1018915827400


On the basis of data constructed with large-eddy simulation (LES), an attempt is made to improve the Mellor–Yamada (M–Y) turbulence closure model. Firstly, stably-stratified and convective planetary boundary layers without moisture are simulated by a LES model to obtain a database for the improvement. Secondly, based on the LES data, closure constants are re-evaluated and a new diagnostic equation for the master length scale L is proposed. The new equation is characterized by allowing L in the surface layer to vary with stability instead of constant kz, where k is the von Kármán constant, and z is height.

The non-dimensional eddy-diffusivity coefficients calculated from the modifiedM–Y model are in satisfactory agreement with those from the LES data. It isfound that the modified M–Y model improves the original one largely, and thatthe improvement is achieved by considering buoyancy effects on the pressurecovariances andby using the newly proposed equation for L.

Closure constantEddy-diffusivity coefficientLarge-eddy simulationLength scaleLevel 3 modelTurbulence closure model

Copyright information

© Kluwer Academic Publishers 2001

Authors and Affiliations

  • Mikio Nakanish
    • 1
  1. 1.Japan Weather AssociationToshima, TokyoJapan