The large data set

Question 1

1. the large data set covers data from …
2. where are the weather stations in the UK?
3. where are the weather stations around the world?
4. what weather station collects winter data?
5. when was the UK Great Storm?
6. when were some Florida hurricanes?
7. how may days are there between May and Oct?

Answer 1

1. may - oct in 1987 and 2015
2. Leuchars, Leeming, Heathrow, Hurn, Camborne
3. Beijing, Perth, Jacksonville
4. Perth => Southern Hemisphere
5. 16th Oct 1987 => 100 knot gusts
6. 12th Oct 1987 and 2nd Oct 2015
7. 184

Question 2

how many pieces of data are there for UK weather stations?

Answer 2

14

1. temp
2. rainfall
3. sunshine
4. pressure
5. windspeed in mph
6. windspeed in Beaufort
7. max gust
8. relative humidity
9. cloud cover
10. visibility
11. wind direction (bearings)
12. wind cardinal direction (compass)
13. max gust direction (bearings)
14. max gust cardinal direction (compass)

Question 3

how many pieces of data are there for overseas weather stations?

Answer 3

5

1. temp
2. rainfall
3. pressure
4. windspeed in mph
5. windspeed in Beaufort

Question 4

define daily mean temperature (°C)

OVERSEAS DATA

Answer 4

average of the hourly temp reading in 24hr period

Question 5

1. define total rainfall (mm)
2. what does tr/trace mean?

OVERSEAS DATA

Answer 5

1. includes precipitation, snow + hail => has melted b4 being included in measurements
2. rainfall < 0.05mm

Question 6

define total sunshine (hrs)

Answer 6

recorded to the nearest tenth of an hr (1/10)

• can have 0 hours of sunshine => cloudy
• x more than 15-16hrs of sunshine => gets dark

Question 7

1. define mean windspeed (kn/knots)
2. define mean windspeed (Beaufort scale)
3. define mean wind directions
4. how many mph in 1 knot

OVERSEAS DATA

Answer 7

1. averaged over 24hrs

2. 
0 = calm => <1kn 
1-3 = light => 1-10kn
4 = moderate => 11-16kn
5 = fresh => 17-21kn

3. given as bearing/compass directions
4. 1 kn = 1.15 mph

Question 8

define max gust (kn/knots)

Answer 8

the highest instantaneous windspeed recorded

Question 9

define max relative humidity (%)

Answer 9

% of air saturation w water vapour

• relative humidities above 95% => misty/foggy conditions

Question 10

1. define mean cloud cover (oktas)
2. what does 0 oktas mean?
3. what does 8 oktas mean?

Answer 10

1.

• no. of 1/8ths of the sky covered by cloud
• discrete scale of 9 values

2.
- clear skies

3.
- completely overcast

Question 11

1. define mean visibility (Dm/decametres)

2. how many metres are in a decametre?

Answer 11

1. greatest horizontal dist @ => an object can be seen in daylight
2. 10

Question 12

1. define mean pressure (hPa/hectopascals)
2. how many pascals in a hecto pascal?

OVERSEAS DATA

Answer 12

1. low pressure => bad conditions
   high pressure => settled conditions
2. 100Pa

Question 13

1. what does n/a mean?

2. should extreme values be included?

Answer 13

1.
not available => missing data values
total no. of days = ↓ but only for sunshine, wind + max gust

2.
if genuine
removed if recording errors => total no. of days ↓

Question 14

1. describe conditions in UK weather stations (windier than overseas weather stations)
2. where do the prevailing winds come from?

Answer 14

1. 
Leuchars (coastal) = coolest
Leeming (inland) = 2nd coolest
Heathrow (inland) = highest temp
Camborne (coastal) = windiest 
Hurn (coastal) = least cloud cover

2. SW

Question 15

describe conditions in overseas weather stations

Answer 15

Jacksonville (coastal) = highest min temp

hot summers
less windy than UK
Beijing (inland) = most extreme temp
hot summers
less windy than UK
coldest temp in Oct
Perth (coastal) = similar wind speeds to UK
winter data x summer data