earth science

The discussion activity this week is designed to give you a chance to see how the unusual properties of water – the high specific heat and high latent heat of vaporization/condensation – influences our weather and climate. In part 2 we will be dealing with VERY large numbers so this is a good opportunity to practice using scientific notation (e.g. 2 x106 rather than 2,000,000) in calculations.

1. Specific heat and monsoons

a) Draw two fully labelled diagrams below explaining why we get dry winters and wet summers in monsoon climates. Make sure that your explanatory labels include why land/ocean heat and cool at different rates, how this results in high and low pressure over land/ocean, whether clouds and rainfall develop and why. (Tip – drawing labeled diagrams is a very good way of studying for the final.)

b) What is the difference between Santa Ana winds and katabatic winds? How are Santa Ana winds similar to the Monsoon/dry seasons described above? How are they different?

2. Latent heat and hurricanes

Hurricanes are very damaging storms that form in areas where there are very high sea surface temperatures and so large amounts of atmospheric moisture. The energy that creates these enormously powerful storms comes entirely from the condensation of water vapor into water droplets. (Remember that the latent heat of vaporization (and condensation) of H2O is the largest of any substance). Using the amount of rainfall that occurs during a hurricane we can get a very rough estimate of how much energy was released during the storm. Use scientific notation for your answers below.

a) A typical hurricane produces 1.5 cm/day of rain over a circular area with a radius of 665 km. What is the total volume of rain produced by this hurricane per day in cm3? (Note the different units below.)

Volume = ______________cm3

b) A cm3 of rain weighs 1g. What is the total mass of rain produced by this hurricane per day in kg?

Mass = _________________kg

c) If the latent heat of condensation is 2,500,000 J/kg how much energy would be released by the condensation of rainfall in this hurricane per day?

Energy=___________________

d) The total amount of electrical energy (i.e. electricity) produced globally each day is about 2.5 x1017 Joules. How does the amount of energy produced by a typical hurricane per day compare to the amount of global electricity produced each day? Does this surprise you?