Large data set (copy)

Daily mean temperature: Units and Accuracy

˚C, 1 d.p.

Large data set overseas locations

Beijing (China, Northern hemisphere, inland)

Jacksonville (USA, Northern hemisphere, coastal)

Perth (Australia, Southern hemisphere, coastal)

During which months is data collected for the large data set?

May to October

From which years has data been used for the large data set?

1987 and 2015

Daily total rainfall: units and accuracy

mm, 1 d.p.

Daily total rainfall: what does tr mean?

Trace, less than 0.05 mm

Daily total rainfall: Max rainfall UK/overseas

UK: 51.6mm (Heathrow 26/8/15)

overseas: 102mm (Perth 17/5/15)

Daily total sunshine: units and accuracy

Hours, 1 d.p.

Daily total sunshine: Maximum and minimum (only measured in UK)

Max = 15 hrs, min = 0 hrs (Heathrow 2015)

Daily maximum relative humidity: How is it measured?

As a percentage of maximum air saturation with water vapour

Wind: What is measured and how? (4 types)

• Daily mean windspeed (knots/beaufort)

• Daily mean wind direction (degrees, NSEW)

• Daily maximum gust (instantaneous windspeed) (knots)

• Daily maximum gust direction (degrees, NSEW)

Daily mean wind speed: Maximum and minimum UK

Max = 23 kns (Leuchars 6/6/15), min = 2 kns (Hurn 3/10/15)

Daily mean wind speed: Maximum and minimum overseas

Max = 14.1 kns (Perth), min = 0.9 kns (Jacksonville)

Visibility: What is it?

Greatest horizontal distance at which an object can be seen in daylight.

Visibility: How is it measured?

Decametres, Dm (1Dm = 10m)

Pressure: How is it measured?

Hectopascals, hPa (1hPa = 100Pa)

Pressure: Maximum and minimum

Maximum = 1036 hPa, minimum = 989 hPa (Heathrow 2015)

Daily mean cloud cover: What is it?

How many eighths of the sky is covered (uniform distribution of 0-8 oktas - each with 1/9 probability)

Daily mean cloud cover: What unit are used to measure it?

Oktas (0-8)

Which months have the highest average temperature in the UK?

July and August

Which UK location is the warmest on average, and why?

Heathrow - It is inland

Which UK location is the coldest on average, and why?

Leuchars - It is coastal (and furthest from equator)

Which overseas location is the warmest on average, and why?

Jacksonville - It is close to the equator, and in the Northern hemisphere (so it is summer during the May-October period)

Which overseas location is the coldest on average, and why?

Perth - It is far from the equator, coastal and in the Southern hemisphere (so it is winter during the May-October period)

Is there a difference between average temperatures in 1987 and 2015 in the UK?

Slight increase (<1°C)

Which UK location has the most rainfall on average, and why?

Camborne (2.8mm) - It is coastal

Which UK location has the least rainfall on average, and why?

Heathrow (1.8mm) - It is inland

Which UK location has the highest average wind speed, and why?

Camborne (9.4 kns) - It is coastal

Which month is the wind speeds highest in the UK?

May

What factors can explain the trends in each location?

• Distance from the equator (Hotter near equator)

• Coastal or inland (Higher wind speed at coast)

• Northern or Southern hemisphere (Opposite seasons)

Which overseas location has the most rainfall on average, and why?

Jacksonville (5.9mm) - It is coastal

Which overseas location has the least rainfall on average, and why?

Beijing (2.1mm) - It is inland

Which UK location has the lowest average wind speed, and why?

Leeming (7.4 kns) - it is inland

Large data set UK locations

Leuchars (most northern, coastal)

Leeming (central England, inland)

Heathrow (London, inland)

Hurn (southern England, coastal)

Camborne (most southern, coastal)

How are daily average variables measured?

Readings taken every hour for 24 hours, starting at 9:00 GMT (or 0:00 GMT for windspeed)

What does a humidity greater than 95% suggest?

Misty and foggy conditions

Knots to mph conversion

1kn = 1.15mph

What is the Beaufort scale?

A scale used to describe conditions based on windspeed:

0 = less than 1 knot = ‘calm’

1-3 = 1-10 knots = ‘light’

4 = 11-16 knots = ‘moderate’

5 = 17-21 knots = ‘fresh’

If the data is incomplete, what is shown?

‘n/a’ or ‘-‘ (not available)

When was the great storm of 1987?

15-16th October 1987

What effect did the great storm of 1987 have in the UK?

• High wind speeds

• Affected the south of England

• Skewed some variables (wind, gust, rainfall)