1 / 9

Some GOTM Physics

Learn about the implemented physics equations and processes in the GOTM model at the SOPRAN.GOTM School in Warnemünde, Germany.

murphyedward
Download Presentation

Some GOTM Physics

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. SOPRAN GOTM School Warnemünde: 10.-11.09.07 Hans Burchard Baltic Sea Research Institute Warnemünde, Germany Some GOTM Physics

  2. 1D equations which are explicitly implemented into GOTM: • momentum equations (x- and y-directions) • potential temperature • salinity • turbulence equations (zero-, one-, or two-equation model) • Processes included: • Earth rotation (depending on latitude) • external pressure gradients • internal pressure gradients • vertical advection • equation of state (fully non-linear)

  3. Options for these processes: External pressure gradient: prescription of surface slopes prescription of depth-mean velocity presciption of velocity time series in one point GOTM will then calculate the surface slope, which goes into the momentum equations as external pressure gradient Internal pressure gradient: prescribe horizontal gradients of T & S GOTM will then calculate the horizontal density gradient, which goes into the momentum equations as internal pressure gradient Advection of T & S may be calculated from the gradients and the velocity profile (restoring avoids run-away stratification). Variable water depth This may be relevant when the surface elevation amplitude is high compared to mean water depth

  4. Example for internal pressure gradient & advection of S r / x < 0 u<0 u>0 tidal phase

  5. Nudging (same as restoring): For u, v, T and S, GOTM users may chose simulations to be nudged to observations at a certain time constant t : For large t, nudging is small, for small t nudging is strong, for infinite t, there is no nudging.

  6. Vertical advection: If effects of vertical advection (e.g. internal tides) should be reproduced, then a vertical velocity profile of triangular shape (zero at surface and bottom) may be prescribed. This vertical advection will affect temperature and salinity profiles.

  7. Example of vertical advection: Observations and simulations in the Northern North Sea.

  8. Observations of u, v, T, S, and e may be included into GOTM: The observations of u, v, T, S may be used for initial conditions, nudging, analysis. The observations of e may be used for analysis only.

  9. For the air-sea fluxes (see modelling talk), the Kondo 1975 bulk formulae are included, the more advanced Fairall et al. (1996) formulae are about to be implemented. For the short-wave radiation Jerlov classes may be prescribed or parameters given user-defined. Spectral models will be included within the SOPRAN project. For the turbulence closure models (see modelling talk), many formulations are included, such that GOTM is a state-of-the-art library for turbulence models. So far, counter-gradient fluxes are not included, but this may change during the next years. So far for the GOTM physics.

More Related