Atmospheric Dynamics, Radiation, Thermodynamics, and Formation of Air Mass Thunderstorms

• Each student has a different assignment: make sure you have the correct one. This assignment is for student 690750.
• Write your student number at the top of each page in your answer.
• Number your answers according to the questions below. There is no need to copy/paste the questions to your answer sheet.
• Answer all parts of all questions.
• Describe the reasoning behind any calculation or chart work.
• Mathematical expressions, such as equations, should be written as phrases within sentences. Use the correct units used throughout. Aguado and Burt provide a good example when calculating air density at sea level, (page 122 in the 2015 print edition, page 116 in the 2013 e-book edition). There are worked example on Canvas (Week 3, Stefan’s law, see the worksheet, and Week 4, Resource: Pressure, Temperature, Density, Humidity).
• Calculations may be hand-written, photographed, and inserted as images. It is also possible to use the equation editor in your word processing program, but these are time-consuming. Neatly hand-written work is just as good. The same is true for diagrams.
• Text for question 4 should be typed as usual, for checking by Turnitin.

A mid-latitude cyclone is observed over the North Atlantic Ocean. A set of measurements are taken at Kirkwall Airport (latitude 59N). A radiosonde above the airport measures a westerly wind in the free atmosphere with a speed of 26 knots. Mean sea level pressure at Kirkwall is 1010 hPa, and the temperature is 12 JC. The low pressure centre is located 600 km to the north.

1. Show that the air density at Kirkwall is approximately fl = 1.2 kg m?3.
2. Estimate the mean sea level pressure at the low pressure centre.
3. Comment on the approximation you have used.

A student is investigating the urban heat island effect at the Swansea University Bay Campus as part of their dissertation project. They measure average temperatures of 12.6 JC in the centre of the campus and 10.4 JC in the nearby Crymlyn Burrows.

1. Compute the power per unit area of terrestrial radiation emitted at each location.
2. The student thinks that extra evaporation might account for the difference between the two sites.

How much extra water must be evaporated per unit area each year to explain the difference? Is this a plausible figure?

A westerly wind blows over a high mountain range. Weather station 1 on the western side of the range measures a pressure of 1000 hPa, a temperature of 19 JC and a wet bulb temperature of 10 JC. Station 2, located at the summit, measures a pressure of 500 hPa. Station 3, located on the lower slopes to the east, measures a pressure of 900 hPa.

a) Use the tephigram overleaf to estimate the pressure and temperature at the lifting condensation level.

b) Estimate the temperature, the potential temperature and the equivalent potential temperature at station 2.

c) Assuming that all condensation on the windward slope falls as rain, estimate the temperature at station 3.

Explain the physical mechanisms leading to the formation of air mass thunderstorms and radiation fog. Write no more than 600 words