Topic: Contour

Key Stage 4 Geography Resources

Post date 26 November 2020

Resources for 14-16 Year Old Students

Selected Resources for each GCSE Geography Specification

OCR A geography GCSE
OCR B geography GCSE

Geography

Air Masses

Air masses and fronts – introductory text

Air Masses – an introduction to the major air masses affecting the UK

Case studies of UK air masses (November 2010, November 2011 and the end of September 2010) with answers for teachers and a case study of arctic maritime air (Jan/ Feb 2015) can be found on our case studies page.

Air Masses – worksheet and the Met Office’s air mass video .

AWS data to study air masses and depressions (adapted from LGfL)

An introduction to weather systems

Anticyclones, depressions and fronts

Understanding weather charts – excercises

Weather systems plenary, revision or homework exercise – an investigation into why the forecast showed the temperature rising at night.

What is the weather? Work out what the weather is like at several UK locations based on some simplified weather maps.

Isotherm and Isobar drawing exercise based on a depression: student worksheet. A simpler version of the T/ isotherm map can be found here or the full version including solutions may be found on the A level page.

Using WOW data to investigate a depression passing across the UK with worksheets for students

Use WOW data to track a cold front across the UK and work out its speed.

Weather Maps – basic information on synoptic charts, with Isotherm map excercise and Synoptic chart excercise.

We’ve pulled together some resources about ex-hurricane Ophelia, bringing together information about tropical cyclones, depressions, anticyclones and air masses to explore the extremely unusual weather we experienced in October 2017 Ophelia.pptx.

Shipping forecast

Tropical Weather

Using GIS to study hurricane tracks and tropical storm risk (developed by Bob Lang, teacher and GA consultant)

Some useful links about Super typhoon Haiyan/ Yolanda

Monsoons

Other Weather

Microclimates

Urban Heat Island Fieldwork and a simple and effective lesson plan which uses WOW data to identify Urban Heat Islands. The supporting PowerPoint presentations can be found here.

Weather Project Ideas

Other recommended resources:

A wide range of animations from the Met Office suitable for geography and science topics.

Resources looking at change of state, latent heat, data handling and the Electromagnetic Spectrum from the NCAS/ DIAMET project (scroll down to the bottom of the page).

An excellent resource (first published by the GA) investigating weather conditions needed for the various Olympic sporting events using weather station or WOW data.

AS/ A level Resources

Key Stage 3 Resources

Contour Drawing

Post date 26 November 2020

If you’ve ever looked at an Ordnance Survey Map, you’ll have seen the contours – lines joining places which are the same height above sea level. You can spot high places, low places and places where the slopes are steep. The contours are drawn at equal intervals – there might be one every 5m or 10m.

But contour maps are useful for many things other than height. In meteorology, isobars link places where the atmospheric pressure is the same, we use isotherms for temperature, isotachs for wind speed and isohyets for rainfall.

How do you go about creating a contour map from a set of observations?

Here are a few practise resources:

Isotherm and Isobar drawing exercise based on a depression: student worksheet. A simpler version of the T/ isotherm map can be found here or a complete depression based exercise where students draw contours of temperature, pressure and precipitation to work out what the system looks like: Student worksheets and
notes for teachers.

Urban heat island isotherm drawing exercise:notes for teachers, idealised weather station data for isotherm drawing, satellite image of Birmingham and solution for teachers.

Interpreting isotherms

Drawing isolines on WOW data from depression EVA

Isoline mapping Exercise

Isotherm – Notes for Teachers

Drawing Pressure and Temperature Contours (Intermediate)

Post date 19 November 2020

Drawing Temperature and Pressure Contours

Lines of equal temperature – temperature contours, are called isotherms.

In this exercise, the task is to draw the 8.5°C, 6.5°C and 2.5°C isotherms. The 10.5°C and 4.5°C isotherms have already been drawn to help.

Start with the 8.5°C isotherm. This is the line which has everything warmer than 8.5°C on one side of it, and everything colder than 8.5°C on the other side. You could use a coloured pencil to colour in the dots for everywhere that is warmer than 8.5°C. Your isotherm is then the line which separates your coloured dots from the uncoloured ones.

Next, try the 2.5°C isotherm. For this, you could use a different colour to shade the dots for everywhere that is colder than 2.5°C.

Lastly, draw the 6.5°C isotherm. This will be very close to the 4.5°C isotherm in places, so be careful! To help with this, you could use a 3rd colour to shade the places where the temperature is 7 or 8°C, and a 4th colour to shade the places where the temperature is 5 or 6°C. Your line will divide the two.

Remember, contours can never touch or cross each other (it can’t be 8.5°C and 6.5°C at the same place!). The line should start and finish at an edge of the page.

Lines of equal pressure – pressure contours, are called isobars.

In this exercise, the task is to draw the 1016, 1012, 1008 and 1004mb isobars. However, to save space on the map, the pressure values have been recorded in shorthand – so 9 or 09 is short for 1009, 11 is short for 1011 etc.

On this map, we have some extra clues – these weather observations indicate the wind speed by the tail on the symbol. The wind is blowing from the tail of the arrow to the centre (the bars on the tail of the arrow tell you the wind speed) so –o is a wind blowing from the west to the east, or o—is a wind blowing from the east to the west. The wind tends to blow along the pressure contours, so your contours need to be roughly parallel to the tails on the closest weather symbols.

Start with the 1016mb contour. Where on the map are there places where the pressure is higher than that? If it helps, colour in those symbols where the value is greater than 16. Your pressure contour needs to divide those symbols from the others.

Now use a different colour to shade the symbols where the pressure value is 13, 14 or 15. Can you now draw the 1012mb isobar?

Again, use a different colour to shade the symbols where the pressure value is 9, 10 or 11. Can you now draw the 1008mbar contour?

Lastly, is there anywhere where the pressure is under 1004mb? If so, draw the 1004mb contour to separate off that observation from the others.

These two maps both correspond to the same weather situation. Can you work out what is going on?

Clues:

– Where is the pressure lowest?

– How is the wind direction changing across the map?

– In general, where is the temperature lower and where is it higher?

– Where is the temperature changing most rapidly? Remember that a front is where cold and warm air meets. You can use the wind information on the second map to see where the cold air is pushing into the warm air (a cold front) or whether the warm air is pushing into cold air (a warm front).

Drawing Pressure and Temperature Contours (Harder)

Post date 19 November 2020

Drawing Isobars

Isobars are lines of constant pressure. Drawing the isobars reveals features (eg highs, lows, ridges and troughs) which help us understand the weather.

When trying to draw isobars, remember the following

– You are trying to draw the isobars of pressure for the values below the
graph

– The symbols on the map give the observed pressure and wind speed and
direction. Remember that the wind is blowing from the tail of the arrow
to the centre. The bars on the tail of the arrow tell you the wind speed:

– The wind blows almost parallel to the isobars (they are usually blow
slightly more towards the centre of the low pressure area). If you stand
with your back to the wind in the northern hemisphere the pressure is
lower on your left than on your right.

– Isobars tend to be parallel to each other, don’t wiggle and never cross.

– The closer the isobars are to each other, the stronger the wind. You can
use the bars on the tail of the weather station symbol to give you the
Beaufort force of the wind. Look at the scale at the top of the map (this is
called the ‘geostrophic scale’). The distance from the left hand edge of
the scale to the force at the symbol gives you the spacing between 2mbar
isobars at that point.

Draw the 1004, 1008, 1012 and 1016 isobars (noting that they have been recorded in shorthand, such that 1004 becomes 04 etc.) remembering that the wind tends to blow parallel to the isobars. Can they see what sort of a weather system it is, and where the fronts might be?

Draw the 2.5, 4.5, 6.5, 8.5 and 10.5 isotherms (lines of equal temperature), remembering that sometimes, if there isn’t any data in a particular place, you have to make an educated guess about what the contour might look like. Is it more obvious now what the structure of the weather system is?

Shade the areas of rain, heavy rain and drizzle in the map below. Is it more obvious now what the structure of the weather system is?

Eva – A Case Study of a Depression

Post date 19 November 2020

A Case Study of a Weather System using WOW data

Go to the WOW website wow.metoffice.gov.uk

Use the pop up calendar to select 24th December 2015 and the drop down box to choose 0600 to 0659 in the morning.

Use the Layers menu on the right to select wind speed/ direction.

Use the Filters menu to select only official observations.

Where is the wind coming from?

Is the wind weak or strong?

Change the time to 0800-0859. How does the wind look now?

Change the time to 1200-1259. How does the wind look now?

Capture the image, stick it into a work book

NOW USE THE LAYERS MENU TO LOOK AT TEMPERATURE.

At 0600-0659, what are the temperatures across the U.K.? (You may need to click on some dots to work out exactly what the temperature is)

Capture the image, stick it into a work book at draw a line roughly dividing colder and warmer temperatures. What is a line dividing cold and warm temperatures called?

Now look at the temperature between 0800-0859. What is the pattern of temperatures?

Now look at the temperature between 1200-1259. What is the pattern of temperatures?

Capture the image, stick it into a work book at draw a line dividing colder and warmer temperatures.

Now compare this image and the line you have drawn on it with the wind image you captured earlier. What do you notice?

CHALLENGE YOURSELF:

Find the Met Office Weather Station in Glasgow/ Bishopton, and click on it. Click on ‘View Full Observation’ and use the Graph view and the calendars to select from
23/12/15 to 25/12/15. How does the air temperature change?

NOW USE THE LAYERS MENU TO SELECT RAINFALL RATE AT 0600-0659

You’ll also need to add ‘WOW observations’ from the Filter menu because the official observations don’t include rainfall. Where is it raining?

Go back in time, hour by hour, what happens to where the rain is?

NOW USE THE LAYERS MENU TO SELECT ‘PRESSURE’.

Investigate how that changes through the day.

CHALLENGE YOURSELF:

Find the Met Office Weather Station in Glasgow/ Bishopton again, and click on it. Click on ‘View Full Observation’ and use the Graph view and the calendars to select from 23/12/15 to 25/12/15. How does the mean sea level pressure change?

CHALLENGE YOURSELF:

Capture the pressure image from 1200-1259 on 24th December 2015.
Can you sketch pressure contours for 992, 996, 1000, 1004, 1008 and 1012hPa?

Summarise what you think is going on with the weather on the 24th December 2015.

Interpreting Isotherms

Post date 19 November 2020

Isotherms

The figure below is a map of isotherms, showing the average mean temperatures for January over the UK, based on average values for 1961–90.

1. Explain the reasons why Newquay is warmer than Ayr in January.

2. With reference to the Environmental Lapse Rate, outline why temperatures at Okehampton are lower than at Newquay.

3. In northern England, temperatures on the west coast near Keswick are similar to those at Middlesbrough on the east coast. Explain how the föhn effect might influence these temperature patterns.

4. (a) Outline how physical factors affect the shape of the 4 °C isotherm in the River Severn estuary and valley north of Gloucester.
(b) How does this pattern affect agriculture?

5. The 4 °C isotherm also bulges around cities such as London and Bristol. Explain the human factors which have caused these cities to be milder in January than rural areas with a similar latitude, such as Marlborough.

Web page reproduced with the kind permission of the Met Office.

Resources for 14-16 Year Old Students

Air Masses

Past Climate Change

Rainfall

Weather Systems and Synoptic Charts

Tropical Weather

Other Weather

Other recommended resources:

Isoline mapping Exercise

Other Useful Links

Drawing Temperature and Pressure Contours

Drawing Isobars

A Case Study of a Weather System using WOW data

NOW USE THE LAYERS MENU TO LOOK AT TEMPERATURE.

CHALLENGE YOURSELF:

NOW USE THE LAYERS MENU TO SELECT RAINFALL RATE AT 0600-0659

NOW USE THE LAYERS MENU TO SELECT ‘PRESSURE’.

CHALLENGE YOURSELF:

CHALLENGE YOURSELF:

Isotherms

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