Meso Exam 2 Flashcards
What KI indexes indicate thunderstorm probability?
15-19 : 10-20%
40 : 90-100%
What is the KI formula and what is it?
A thunderstorm probability index
KI = T850+Td850+Td700-T700-T500
What is LI measure and it’s formula?
It is a conditional severe weather index.
LI = T500 - Tp500
LCL at surface then moist to 500 for Tp
What do the LI values indicate?
> -3 : weak
-3 to -5 : moderate
<-5 : strong
What does SSI measure and the formula?
It is an index for the type of event of a storm.
SSI = T500 - Tp500
LCL at 850 lift moist to 500 for Tp
What do the SSI values stand for?
1 to 3 : rain
0 to -2 : some thunderstorms
-3 to -6 : severe thunderstorms
<-6 : possible tornadoes
What does TT stand for and the formula?
It is an event index.
TT = (T850+Td850)-(2*T500)
What do the TT values stand for?
44-48 : non-severe storms
49-55 : some severe storms
>55 : severe storms possible tornadoes
What are the two ways to calculate CAPE or CIN?
1cm = 0.0280 CAPE = -Rd((Tvp-Tvenv)+(Tvp-Tvenv)/2)*ln(Pup/Plow)
What is the surface energy budget equation?
Rn = Qh+Qe+Qg+Sn
What is Qh and Qe?
Qh is sensible heat flux. Deals with conduction
Qe is latent heat flux. Deals with phase changes (evaporation)
What is the Bowen ratio formula?
Qh/Qe
What do d(flux)/dz lead to when they are greater than or less than zero?
d(flux)/dz > 0: flux divergence, boundary layer warming, positive slope
d(flux)/dz < 0: flux convergence, boundary layer cooling,drying, negative slope
What are the lapse rate values?
GammaD = 10C/km GammaM = 6C/km
What are parcels AU,AS,CU,DN,and MN in terms of potential temp?
AU: dtheta/dz0
CU: dthetaE/dz<dtheta/dz
DN: dtheta/dz=0
MN: dthetaE/dz=0
How does vegetation affect Bowen ratios and convective properties of the boundary layer?
Areas of large vegetation lead to small Bowen ratios(lots of latent heat exchange between plants and atmosphere) and not convective. Small or no vegetation leads to no latent hear flux and therefore convection and large Bowen ratios
What p’ is used for hydrostatic systems? Non-hydrostatic?
Pd’ or dynamic for non-hydrostatic
Pb’ or buoyancy for hydrostatic
