建國中學
暑假地球科學讀書會
斜溫圖
Presenter: 122527 Brine
Index
INtroduction
commonly used thermodynamic diagrams
general purposed ones
- P-V diagram
- T-S(specific entropy) diagram
- H(enthalpy)-S diagram
- Psychrometrics chart
- cooling curve
You guys are smart and know these already right?
weather bois
- Emagram
- Stüve diagram
- Tephigram
- Skew T Log P diagram
weather bois
- Emagram
- Stüve diagram
- Tephigram
- Skew T Log P diagram
Emagram
- Devised by Heinrich Hertz
- P-T diagram based
- European
- First of the kind
Stüve diagram
- Used in the US
- P-T based
- No Clausius–Clapeyron relation
- No CAPE
- T-S(phi) based
I don't actually know
SKew T
- We'll talk about this later
"Preview"
things to know
what you will need to understand the following(maybe not)
Physical quantities - bar
1 bar=100,000 Pa↔1 mb=1 hPa
1\ bar = 100,000\ Pa \leftrightarrow 1\ mb = 1\ hPa
why switch?
SI units→1 Pa=1mN
SI\ units \rightarrow 1\ Pa = 1\frac{N}{m}
Entropy
ΔS=TΔQ
\Delta S = \frac{\Delta Q}{T}
a reversible process should have an entropy of 0
a\ reversible\ process\ should\ have\ an\ entropy\ of\ 0
"possibility"
"possibility"
First law of thermodynamics
ΔQ=ΔU+W
\Delta Q = \Delta U + W
dH=TdS+vdp
dH = TdS + vdp
Potential Temperature
how?
Potential Temperature
- We move air parcels to a certain height to compare their temperature at such altitude
θ=T0(P0Pr)CpRd
\theta = T_0(\frac{P_r}{P_0})^\frac{R_d}{C_p}
∂z∂θ>0
\frac{\partial \theta}{\partial z} > 0
Basics of Skew-T
Introduction to what made me suffered
What a skew-T looks like
base element
log where
Back to the graph
Adiabats
Saturation mixing ratio
Review
Before jumping into application
full picture
IsoBars
Isotherms
adiabats
Saturation ratio
Other given info
The rest of the things that make this even more messy
Wind
Dewpoint and temperature
what′s this
what's\ this
Dewpoint and temperature
what′s this
what's\ this
The rest of the info
- this is too much.
The rest of the info
- this is too much.
Condensation
that′s a lot of names!
that's\ a\ lot\ of\ names!
Lifting condensation level
level an air parcel would need to be raised to to become saturated
convective condensation level
a parcel, if heated to the “convective temperature,” would freely rise and form a cumulus cloud
LeVel of free condensation
self-explanatory
Equilibrium level
It's time to stop.
CAPE
Convective Available Potential Energy
Vmax=2CAPE
V_{max} = \sqrt{2CAPE}
1500, 2500
1500,\ 2500
Convective Inhibition
cout cin
\sout{cout}\ cin
Quantitative precipitation forecast
yes.
INdices
Some other tools to make forecasts
Total totals index
- yes
VT=T850mb−T500mb
VT = T_{850 mb} - T_{500 mb}
CT=Tdew 850mb−T500mb
CT = T_{dew\ 850 mb} - T_{500 mb}
TT=VT+CT
TT = VT + CT
45, 50, 55(K)
45,\ 50,\ 55(K)
K Index
K=T850mb+Tdew 850mb−T500mb−(T700mb−Tdew 700mb)
K = T_{850 mb} + T_{dew\ 850 mb} - T_{500 mb}\\
- (T_{700mb} - T_{dew\ 700 mb})
around 30(K) ↓ less rain possibility
LIFTED Index
LI=T500mb env−T500mb parcel
LI=T_{500 mb\ env} - T_{500 mb\ parcel}
−3, −6, −9
-3,\ -6,\ -9
Showalter index
- I am not actually sure how this is calculated
SI=T500mb env−T850→500mb parcel
SI=T_{500 mb\ env} - T_{850\rightarrow 500 mb\ parcel}
−3, −4, −6
-3,\ -4,\ -6
SWEAT
- Severe WEAther Threat Index
- The fomula is too complicated
- It's meaningless to remember / know at this point
150, 300, 400
150,\ 300,\ 400
that's the end of introduction
- or is it?
- there are actually plenty more of them
- our brain is going to explode
How to use Skew-T
This is an important skill, I suppose.
Use the pre-calculated info
so simple!
so\ simple!
some skew-ts
SOME SKEW-TS
Some Skew-Ts
taiwan's skew t
8 a.m., 8 p.m.
8\ a.m.,\ 8\ p.m.
0:00 UTC, 12:00 UTC
0:00\ UTC,\ 12:00\ UTC
That's IT
Thank you for listening.
建國中學 暑假地球科學讀書會 斜溫圖 Presenter: 1 22527 Brine