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

8.1ab pg. 345 *(+ when temp. decreases w/ increasing altitude) a) Lapse rate defined as rate of temperature decrease with increasing altitude *(+ when temp. decreases w/ increasing altitude) b) Stable: Environmental Lapse Rate < 6ᵒC/km Conditionally Unstable: 6ᵒC/km < < 10ᵒC/km Unstable: > 10ᵒC/km Be sure to reference lapse rates in your response!

Height Above Ground (m) 8.1 Example Calculate the lapse rates for the two layers and determine the stability of each layer Height Above Ground (m) Temperature (C) 20 500 21 1000 15.5

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 environment Negatively 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 (saturation)? 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 Cooler -> Negatively Buoyant -> Sink back down d) 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 dew-point 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). First part cools dry adiabatic lapse rate. To cool from 15 to 10 (to saturation point) we cool 5 degrees. 10 degrees/km  so 5 degrees is 500 m until saturated. After this point we raise parcel 1500m to the top, cooling at 6 degrees per km  will cool 9 degrees in 1500 m to 1 degree celsius. Parcel will be warmer than enviro  will continue to rise.

8.7ab pg. 349 a) 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 descent b) Is the temperature calculated from part (a) a comfortable room temperature? Convert Celsius to Fahrenheit to help

8.9a pg. 351 Cloud appearance gives clues to stability: Bubbly (cumulus) = ? Flat (stratus) = ? Rising parcels near the ground continue to 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: in which seasons would you expect afternoon water temperatures to be lower than those over land?

9.2 pg. 401 First need to convert temperature to Kelvins 𝑆𝑝𝑒𝑒𝑑 𝑜𝑓 𝑆𝑜𝑢𝑛𝑑=20∗ 𝑇 *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 m/s = 20*T (plug in temperature and distance and solve for time (seconds)).

9.6ab pg. 405 a) Parcels will initially cool at dry adiabatic lapse rate Determine the temperature parcels need to cool to for them to reach saturation at each location b) The relative humidity below the cloud base is <100%, so what will happen to the raindrops as they fall? If they fall a long way through dry (unsaturated) air, what do you think will happen to the raindrops?

Chapter 8: (1abc), (2abcd), (7ab), (9a), (11ab) Chapter 9: (2), (6ab) Lab #6 – Due Friday October 14th Please do your own work. No used labs from prior years (make sure everything is erased). Ann (arr221@psu.edu): 12-1 PM 6th floor Walker Weather Center (room 606) Dalton (dss5330@psu.edu): 2-3 PM 6th floor Walker Weather Center Kerry (kvm5478@psu.edu): 3-4 PM 6th floor Walker Weather Center Chapter 8: (1abc), (2abcd), (7ab), (9a), (11ab) Chapter 9: (2), (6ab)