## question on Vstretching

Discussions, suggestions and corrections to ROMS/TOMS documentation currently under developement.

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tony1230
Posts: 87
Joined: Wed Mar 31, 2010 3:29 pm
Location: SKLEC,ECNU,Shanghai,China

### question on Vstretching

Hi roms's friends

Simplified: How to give the values for theta_s and theta_b according to different kinds of Vstretching = 1,2,3,4? Here and follows i would use 1,2,3,4 to represent.

Narrate: Now there are four schemes for we to choose on vertical stretching, and as i know the 2 and 4 were hingly recommended either on the forum or in some documents/literatures. Frankly, i have no idea that which one was suitable to a particular case, and how to choose one from the four,especially how to specify the values related to them.

Here,viewtopic.php?f=13&t=1233&hilit=Vstretching, Hernan told we to use 3 in very shallow sediment applications(<200m). If we have more shallow than that, say 5~50 m, the 3? Do we have any thumb rule to follow to use the formular which tells the most reasonable under that particular situation?

With regard to theta_s and friend, i have saw so many different values gaven to them within the range given by https://www.myroms.org/wiki/index.php/V ... coordinate.

What i want to clarify:

1. How to choose the stretching scheme if i take the followings into account: surface boundary layer(SBL)/bottom boundary layer(BBL)/water depth(topography)(or any other condition which might affected by different stretching formular).

2. How to specify the values for theta_s,theta_b when one of the stretching schemes was used. I have tested the values within the range of meaningful given by the roms's manual(P121) and have found significant difference based on what values i choosed for them, say theta_s = 10.0(0.00001) and theta_b = 0.00001(4.0).

3. Something related to Tcline.