Moisture Convergence

[Henrique Barbosa]

Hi Ooi,

You can calculate the moisture convergence like this:

'set t 1 last'
'set z 1 9'
'define es=exp(-2.8603e-1+(tmat-273.15)*5.6664e-2)'
'define q=rhmt*6.22*es/(lev-3.78*es)'
'set z 1'
'qu=vint(tmsp,q*uvmt,300)'
'qv=vint(tmsp,q*vvmt,300)'
'dd=-hdivg(qu,qv)'

Where

dd=vertically integrated moisture flux convercence
qu and qv= componets of vertically integrated moisture flux
tmsp=surface pressure
tmat=layer temperature
uvmt and vvmt=wind components
rhmt=relative humidity
q=specific humidity
es=saturation vapor pressure
300=vertical integration will go from tmsp up to 300mb

Of course, if you already have specific humidity, you don't
need to calculate that (erase the first 4 lines from the code).

You may also set the maximum height of integration
following your humidity data... I mean, if you have humidity
above 300mb, you should change de integration interval.

Cheers
Henrique Barbosa

On 6/11/05, See Hai Ooi <axl419 at yahoo.com> wrote:
> Dear Dr. Charles Seman,
>
>      I used the moisture convergence script written by
> Dr. Michael Maxwell to produce time series of moisture
> convergence at different sectorial points over the
> South China Sea during an early winter monsoon season.
>  It shows interesting result particularly during
> spells of cold surges.  I am pleased to share my work
> as attached herewith.  Hope you can show me how to
> make my script better. Above all, the purpose of this
> email is to seek your kind help in obtaining the
> step-by-step derivation of this moisture convergence
> formula (in particular the numerical quantities and
> their corresponding units) as I fail to get the result
> myself and I do not know how to get in touch with Dr.
> Michael Maxwell on this matter.
>
>     Thanking you in anticipation,
>
> Sincerely,
>
> OOI See-hai
> Malaysia
>
>
> Send instant messages to your online friends http://uk.messenger.yahoo.com
>
>