Dry Convection

[bas]

Hi everyone,

 

I am new to the forum. I have a  question about convection. We can identify moist convection by cloud formation and rardar reflectivity; I  wonder how could i capture/indentify dry convection especially in the model output?

 

Regards,

bas:)

 

[isohume]

You would identify dry convection the same way as moist convection. Convection is the transfer of heat energy through a fluid (gas, liquid) and it requires a sigfnt thermal difference in order to occur deeply. Thermal lows across the SW CONUS sometimes remain dry through the column and they are generated by large temperature differences with height (lapse rates). So, one good tool to access the degree of natural convection is lapse rates, mid-level and low-level. You can use model soundings or SPC's mesoanalysis page, to name a couple sources, to evaluate the convective potential. 

 

http://www.spc.noaa.gov/exper/mesoanalysis/new/viewsector.php?sector=12&parm=laps&underlay=1&source=1#

 

[bas]

 

You would identify dry convection the same way as moist convection. Convection is the transfer of heat energy through a fluid (gas, liquid) and it requires a sigfnt thermal difference in order to occur deeply. Thermal lows across the SW CONUS sometimes remain dry through the column and they are generated by large temperature differences with height (lapse rates). So, one good tool to access the degree of natural convection is lapse rates, mid-level and low-level. You can use model soundings or SPC's mesoanalysis page, to name a couple sources, to evaluate the convective potential. 

 

http://www.spc.noaa.gov/exper/mesoanalysis/new/viewsector.php?sector=12&parm=laps&underlay=1&source=1#

 

Thanks for this. Ok, i will try this and plot delta T over the vertical layers.  I have simulated sea breeze over the red sea and trying to see if  convection initiated along the front over the dry desert boundary layer. I could not very well understand the  plot on the SPC's mesoanalysis page though. Would appreciate if you could explain it in a bit detail.

 

cheers,

bas:)

[isohume]

Thanks for this. Ok, i will try this and plot delta T over the vertical layers.  I have simulated sea breeze over the red sea and trying to see if  convection initiated along the front over the dry desert boundary layer. I could not very well understand the  plot on the SPC's mesoanalysis page though. Would appreciate if you could explain it in a bit detail.

 

cheers,

bas:)

 

 

Np. The plot I posted shows mid-level lapse rates between 700 mb and 500 mb (~12Kft-25Kft). It's the difference in temperature C with height (a rate of change). Generally, anything above 7 C/km is highly unstable and capable of supporting deep convection. Of course, other factors need to be in play for strong convection to initiate and/or become maintained, like the lack of a mid-level inversion, shear, upper forcing, low-level lift (boundary), etc.   

[bas]

Thanks. I am now clear on this. I have few more questions but first want to complete some analysis. 

 

Cheers,

bas:)