# Meteo Module¶

The METEO module was initially developed for simulations of meteotsnamis. It now includes subroutines for simulating the wind effects on waves, storm surges, landslide-generated tsunamis and processes related to atmospheric pressure effects.

- Wind effect on waves

Wind effects are modeled using the wind stress forcing proposed by Chen et al. (2004). The wind stress is expressed by

where \(\rho_a\) and \(\rho\) represent air density and water density, respectively, \(\bf C\) is wave celerity. The wind stress is only applied on wave crests. A free parameter representing a ratio of the forced crest height to maximum surface elevation is implemented in the model.

- Holland model

Holland model is an analytic model of wind and pressure profiles described based on Hurricanes. The pressure distribution can be expressed by

where \(p\) is the pressure at radius \(r\), \(p_c\) and \(p_n\) are the central pressure and the ambient pressure, respectively. \(A\) and \(B\) are scaling paramters from the model input. The velocity distribution can be described by

Based on the formulations above, it is easy to obtain the following storm parameters

The radius of maximum winds (RMW) is

The maximum wind speed

where

- Storm surge

To calculate storm surges, wind stress is applied

Note that \(\bf C\) is not used, compared to the formula for ‘Wind effect on waves’.

- Meteotsunami

Meteotsunami is modeled using a pressure source of two-dimensional Gausian distribution:

where \(dP\) is the pressure anomaly in mb, \((x^\prime,y^\prime)\) are the coordinates rotated to the pressure moving direction (angle is \(\theta\) as indicated in the figure). \(\sigma_x\) and \(\sigma_y\) are paramters representing the length of the width of the pressure source.

- Landslide-generated tsunami

Landslide-generated tsunami can be calculated using the same approach as the meteotsunami. Details will be reported by Woodruff (2017).