4.7.The2 nd$law$of$thermodynamics$and$Clausius9 … · 2015. 3. 31. · q s ≈ 0.622e s p e s =e o...
Transcript of 4.7.The2 nd$law$of$thermodynamics$and$Clausius9 … · 2015. 3. 31. · q s ≈ 0.622e s p e s =e o...
-
4.7. The 2nd law of thermodynamics and Clausius-‐Clapeyron equa
-
€
qs ≈0.622es
p
es = eo ⋅ expLRv⋅
1To−
1T
%
& '
(
) *
%
& '
(
) *
where qs : saturation mixing ratio; p : air pressurees : saturation vapor pressureeo : saturation vapor pressure at a reference temperature, To,often To = 273.15K = 0
oCL : 2.5 ×106 J deg-1, latent heat of vaporation, Rv = 461 Jdeg
−1 kg−1 : gas constant for water vaporT : temperature;
What control atmospheric water vapor: • The satura
-
Discussion:
• Why do storm intensity and extreme rainfall tend to increase, esp. in tropics, under a warmer climate?
-
Summary: • Most of
-
Exercises-‐Moist thermodynamics
• We oOen experience a cool downdraO air during a summer thunderstorm. – What causes a cool downdraO in the thunderstorm? – Compare air temperatures at 1000 hPa for these two cases. In both cases, air
temperature was 0C at 700 hPa. In the first case, a dry air subsides to 1000 hPa. In the second case: 5 g/kg liquid water evaporated in the air as it subsides to 1000 hPa.
2. Air at 1000 hPa and 25C has a wet bulb temperature at 20C. Using the in
SkewT-‐lnp chart: – Find the dew-‐point, Td, – If this air were expanded un
-
3. Water vapor feedback is the strongest atmospheric feedback to climate change. • Assuming that the rela
-
4. Plot the temperature profile and use the Te (ambient temperature) and Td (dew point) at the surface to determine the pressure level of free convec
-
Te values are measured at various pressure levels. We need to compute Tc for convec
-
Solu%on for 4b: To compute CAPE, we use Te and Tc values in each atmospheric layer between
the LFC and LOC given in the above discussed tables and the formula
• Calculate CAPE uses formulas (2) for Td=20C and 15C, respec
-
Materials covered by Quiz-‐2 (April 7th):
• All materials in the thermodynamics of dry and moist air