David J. Muraki

# David J. Muraki

## Assistant Professor, Mathematics Department

```Mail Address
251 Mercer St.
New York, NY 10012, U.S.A.
```
```Phones
212.998.3307 (voice)   212.995.4121 (fax)

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```Email
muraki@cims.nyu.edu
```

```Applied Math II (spring 00)
class page

class e-mail

e-mail
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### Revisiting Queney's Flow over Mesoscale Topography

#### The foundations for our understanding of wave generation by topography were established in studies of Queney (1947, 1948) for steady flow past a two-dimensional ridge. In this seminal work, the downstream radiation pattern was inferred from the dispersion characteristics of linear gravity waves. Queney's streamline figures, obtained by approximating a Fourier integral, are frequently reproduced as the canonical illustration of downstream topographic waves. For the case of constant stratification with f-plane rotation, we find there are significant differences in the near-ridge flow pattern upon comparing the original approximation (Queney 1948, Figure 3) with direct computation of the Fourier integral. Flow corrections in the near-field aloft and downslope regions will be presented in updated figures. These new figures are computed using a high-order numerical integration scheme which is especially designed to resolve the near-inertial singular waves. The implementation of these ideas to computing three-dimensional topographic wave flows will be discussed. Finally, a new analytical approximation suggests that an additional by-product of the topographic wave generation is a weak, near-inertial wave that is produced by backscattering from the downslope surface.

##### Equivalent topography: surface plots

topography (topo.pdf) 2.3M

### An sQG Travelling Dipole

##### The figure below shows the surface streamlines (streamfunction in colour) for a steady travelling dipole within a surface QG model. The potential temperature is zero outside the circular streamline, so that this exact surface QG solution is derived in a manner typical of "modon" constructions.

aspen talk (aspen.pdf)