Statistics - The Large Dataset Flashcards
What years is the data from?
May-October 1987 and May-October 2015
Where are the eight weather stations?
UK - Camborne, Hurn, Heathrow, Leeming, Leuchars (South —> North)
Overseas - Beijing, Jacksonville (North America), Perth (Australia)
How are air temperatures (the daily mean temperature) recorded?
By thermometers in a louvered screen 1.25 metres above short grass (except at some Weather Centre’s and Climate Data Logger stations where observations are made from a non-standard roof top exposure)
What is the daily mean temperature measured in?
Degrees (celcius) to the nearest tenth
What are unavailable readings recorded as?
n/a
When is the daily mean air temperature recorded from and to?
0900-0900 GMT
When is the daily total rainfall recorded from and to?
0900-0900 GMT
What is recorded for the daily total rainfall?
Rain, any solid precipitation, such as snow or hail, which is melted and measured in the same way as rainfall
What does a ’trace’ or ’tr’ refer to?
Very little rainfall (Less than 0.05mm of rain) - treat as 0 (so still use in calculations)
What is daily total rainfall measured in?
Millimetres (mm)
What is daily total sunshine measured by?
An instrument that measures the amount of solar radiation exceeding a threshold
What is daily total sunshine measured in?
Hours (to the nearest tenth) - (shows the amount of bright sunshine)
What is the daily maximum relative humidity a measure of?
How close the air is to being saturated with water vapour
What are relative humidities above 95% associated with?
Mist and fog
What are daily mean wind speeds measured in?
Knots
What is 1 knot in mph?
1.15mph
When is daily mean wind speed measured from and to?
0000-0000GMT
What is the daily mean wind direction measured in?
Degrees (rounded to the nearest 10) - (also listed as cardinal directions - NESW - in the UK)
Where is the direction of the maximum gust measured from?
From true north (in degrees)
What is the speed of the wind also categorised in?
The Beaufort scale
What is cloud cover measured in?
Oktas (to the nearest eighth) - there are 9 value it can take as it can be 0 as well
What is cloud cover?
The fraction of the celestial dome covered by cloud
How is visibility measured?
Horizontally
What is visibility measured in?
Decametres (Dm)
What indicates visibility data that is unavailable?
A dash (-)
What is pressure measured in?
Hectopascals (hPa)
What is 1 millibar (mb) equal to in hectopascals (hPa)?
1 hPa
How was the mean sea level pressure calculated?
Calculated from a measurement made at station level
What is the descriptive term for a 5 on the Beaufort scale?
Light
What type of variable is daily mean pressure?
A continuous variable
