Meteo 003: Lab 6Chapter 8: 1abc, 2abcd, 7ab, 9a, 11ab

Chapter 9: 2, 6ab

8.1ab pg. 345

a)• Lapse rate defined as rate of temperature decrease with altitude

*(+ when temp. decreases w/ altitude)

b)• Stable: < 6ᵒC/km • Conditionally Unstable: 6ᵒC/km < < 10ᵒC/km• Unstable: > 10ᵒC/km • Be sure to reference lapse rates in your response

8.1 Example

Height Above Ground (m) Temperature (C)

0 20

500 21

1000 15.5

• Calculate the lapse rates for the two layers and determine the stability of each layer

8.1c

• Only need to do lowest 3 layers• Need to calculate temperature of parcel from dry and moist adiabatic

ascent• Use 10ᵒC/km and 6ᵒC/km• Is parcel positively buoyant for both ascents? (unstable) negatively buoyant for both ascents? (stable)

positive/negative for one of each? (conditionally unstable)Positively Buoyant: parcel is warmer than environmentNegatively Buoyant: parcel is cooler than environment

8.2 pg. 345

a)• Parcel will initially cool at dry adiabatic lapse rate• What will the temperature need to be for a cloud to

form?• At what level does the parcel reach this temperature?b)• Parcel cools at moist adiabatic lapse rate the rest of the

way• Find the temperature of the parcel at the peak (2500

m)

8.2 cntd…

c)• Is the parcel warmer or cooler than the environment?• If: Warmer -> Positively Buoyant -> Continue rising Colder -> Negatively Buoyant -> Sink back downd)• Parcel is unsaturated now and descends 2500 m• Warms at the dry adiabatic lapse rate (10ᵒC/km) during descent• What processes occurred during ascent/descent that could have

affected the temp. of the parcel?

8.2 Example• Assume a parcel starts at sea level and is forced to rise up Mt.

Washington (~2000 m). The initial temperature and dew point of the parcel at sea level is 15ᵒC and 10ᵒC respectively. The environmental temperature at the summit is -4ᵒC. Assume dew point remains constant during initial ascent. Remember that once the parcel is saturated both temperature and dewpoint will decrease together.• Find the level you’d expect a cloud to form, the temperature of the

parcel at the peak of the mountain, and determine if the parcel will continue to rise (unstable) or sink back down (stable).

8.7ab pg. 349a)• Think of an air parcel descending from 9500 m to 1800 m • Parcel will warm at dry adiabatic lapse rate• Calculate the temperature change in that descentb)• Is the temperature calculated from part (a) a comfortable room temperature?• Convert Celsius to Fahrenheit to help

8.9a pg. 351

• Parcels rise in unstable layers, whereas in stable layers they remain trapped close to the ground• Is fog and haze more likely to form in

unstable or stable layers?• Reference figure 8.63a in your answer

8.11ab pg. 352

a)• Clouds show up as white blobs on visible imagery• Add in your response what the wind direction is. Look

at cloud-free areas near the lakes to help figure it out.

b)• Winter/Summer? Morning/Afternoon/Evening/Overnight?• Clouds shown are convective cumulus clouds• What season and time of day are these most likely to form where they are?• Think about the temperature of water and land at these times

9.2 pg. 401

• First need to convert temperature to Kelvins

*this is an approximate equation, so units do not work out

• Units for speed here are m/s

Example)-Estimate the elapsed time between seeing lightning and hearing thunder if the strike is 2 km away and the air temperature is 68ᵒF

9.6ab pg. 405

a)• Parcels will cool at dry adiabatic lapse rate

initially• Determine the temperature parcels need to

cool to for it to reach saturation at each location

b)• High-based thunderstorms lead to evaporation

of the rain before it reaches the ground, which leads to fires

Chapter 8: 1abc, 2abcd, 7ab, 9a, 11abChapter 9: 2, 6ab

Astrid (ais5396@psu.edu): 10-11 AM in 511 WalkerJosh (jig5374@psu.edu): 2-3 PM in 6th Floor Walker Wx CenterZach (zmg5025@psu.edu): 4-5 PM in 6th Floor Walker Wx Center