Weather, Rainfall, and Map Analysis

Rainfall and Wind Conditions in Different Australian Cities

a) Which state capital city is most likely to experience the heaviest rain, and why? (3 marks).

Hobart, Tasmania. Area of low pressure, with cold from just passing through. Low pressure troughs extending from Southeastern mainland Australia to Tasmania. 

b) Describe the weather experienced at Perth, Western Australia, and explain your reasoning (3 marks).

Sunny, low wind speeds, generally cloudless day. Given the time of the year, temperatures will be low, but will be a mild winter day.

c) Describe the weather experienced at Melbourne, Victoria, and explain your reasoning (3 marks).

Melbourne will likely be cold, gusty and windy. A cold front has just passed the region, and there is a low pressure trough extending through the city. This is also a winter month, so temperatures would already be low to begin with.

d) Describe the wind conditions at Townsville (1 mark).
The weather in Townsville is likely to be clear and sunny. Southeast Tradewinds coming in from Coral Sea at low speeds. Temperatures are likely to be in the low 20s.
The table above documents Annual Rainfall Totals for Townsville from 2000-2019.

From these data:

a)Calculate the mean annual total rainfall for the period and the standard deviation (5 marks).
Mean = 1148.5mm, sd = 564.4mm

b) What is the co-efficient of variation for this data sample? (1 mark).

49.15%

c) Construct a histogram depicting the frequency of rainfall totals in classes of 400 mm each (i.e. rainfall totals of 0-399 mm, 400-799 mm, etc). There is no need to show the histogram here. However, from your histogram answer the following:

i) The modal rainfall class is 400 – 799mm (2 marks).

ii) Are the data normally distributed, negatively skewed or positively skewed? Based on your answer is it valid to calculate the standard deviation and co-efficient of variation? Why or why not ? (2 marks).

Positive skew. Not valid to calculate sd and cv because these analyses assume a normal distribution. 

The above map is of the eastern end of the Strand. It is drawn at 1: 10,000 scale. Note that the grid reference co-ordinates are not real ones.

a) Using the map above give the grid references Eastings northings for the locations marked A and B (6 marks).

GRID REFERENCE for location A (Strand Jetty):

402538

GRID REFERENCE for location B (Tobruk Pool):

410549

b) What distance would you cover if you swam from the jetty to the seawall behind the Tobruk Pool? (2 marks).

Rainfall Analysis in Townsville

1280m

c) What approximate bearing would you be swimming at? (2 marks).

135 degrees
4. In less than 100 words explain the reason why the Bureau of Meteorology expresses rainfall variability using the variability index.
Rainfall in Australia varies throughout the year. By taking into account three annual rainfall percentiles, they can measure annual rainfall reliability.
5. On a weather map, what conditions usually indicate fine conditions and why?
High pressure systems – dry weather, cloudless, descending air subsides slowly
Wide isobars -  low wind speeds 
6. When drawing topographic cross sections, why do we sometimes use vertical exaggeration?
This is to exaggerate heights of features which would be otherwise too small to pick up on the horizontal scale
7. What two rainfall statistics (such as the mean etc) would be most important to understand if you were designing a dam for Cairns? Why?
Mean and standard deviation 
8. Convert the following to scales expressed as representative fractions (e.g. 1: 1000): (1 mark each).

 a) 1 cm represents 25 km.

25km = 2500000cm
Scale = 1:2,500,000

b)1 cm represents 50 m.
50m = 5000 cm
Scale = 1:5,000

c)2 cm represents 1600 m.
1600m = 160000cm
Scale = 2:160,000
          = 1:80,000

a) Based on the contour in the map above, does the stream to the south of Swamp Lake drain into or out of the lake? Why? (1 mark).

Out, elevation of landscape is higher north and gets lower moving south.

b) Describe the terrain you would traverse walking from the shelter to the south of Swamp Lake to the shore of the lake in the top right corner of the map. (2 Marks)

Gentle upward climb, followed by steep slope up towards a peak, the, a steep descent to the lake.
10
The southeast trade winds typical for FNQ are caused by what type of global air circulation?

During an El Nino...
Sea surface temperatures warm above average in the Eastern Pacific but are cooler than normal in the Western Pacific.
12.

The statistic best used to compare the standard deviations calculated for different data sets is:
the co-efficient of variation

13.

When navigating using a topographic map and a compass, in order to safely arrive at your destination you must know:
the date the map was published, the magnetic declination rate, and when the bearing you have been given was measured.

14.
Select the most correct answer. The relatively low rainfall experienced at Townsville is a function of:

its position in the rain shadow of Mount Elliot, its orientation parallel to the prevailing SE tradewinds, and thus limited topographic uplift of the onshore wind flow.
its latitudinal position under the descending limb of the Hadley Cell.

15.

If a tropical cyclone crossed the coast at Townsville after approaching from the northeast, the winds 20km north of Townsville would be

strong westerly or southerly depending on the size and intensity of the system.