MetLink Activity 13 (age 14-16)

 

Please note that the study format used in this exercise can be applied to areas of the world other than the UK by using the MetLink resources listed at the end of the activity.

 

Weather Changes in Europe:

This activity is designed for use with students aged 14 to16 years. In England and Wales, these are GCSE students; in Scotland they are young people studying for Standard Grades.

The aims of this activity are:
+ to use ICT skills in finding information
+ to use mapping and graphical skills in presenting information and making use of standard weather mapping symbols
+ to describe how weather conditions change with time and in different locations
+ to interrelate and attempt to explain weather conditions
+ to consider how weather conditions influence human activities.

 

The Activity:

You need the following:
+ Large outline map of Europe.
+ Atlas. If you have access to Microsoft Encarta that would be good. Or you can use an atlas book.

 

1. Go to the MetLink observations database by using the MetLink Home page

+ Click on Data central
+ Click on Search observations
+ Make sure the dates are set correctly
+ Click on Search now

 

This shows you all of the observations made by MetLink participants around the world for the day.

  1. A number of MetLink participants from Europe have logged observations data on both Monday 30 January and Wednesday 1 February.
    Collect their observation data for Monday and today by using the drop-down dates and countries menus. They are in: ES Spain (3); FR France (2); RO Romania (1); SK Slovakia (1).
    Select one participant from each of the countries listed. If the participant has logged at more than one time each day, then pick a common time for both days.
    Also select     three participants from the UK – one from south-east England, one from Wales and one from Scotland – who have logged data on both days.
    This will give you eight sets of data for widely-distributed places across Europe.
  2. Plot the data for each location using the standard Met Office key which you can obtain by clicking here.
    For temperature, use both the maximum and minimum values.
    For cloud types, use the following letters: H for high-level clouds; M for medium-level clouds; L for low-level clouds; V for clouds of great vertical extent.
    High-level clouds: Ci Cirrus; Cc Cirrocumulus; Cs Cirrostratus
    Medium-level clouds: Ac Altocumulus; As Altostratus
    Low-level clouds: Cu Cumulus; Sc Stratocumulus; St Stratus
    Clouds of considerable vertical extent: Ns Nimbostratus; Cb Cumulonimbus.
    To find out more about cloud descriptions, please
    click here.
    c.     Describe the changes that have occurred in the weather at each place in terms of:
    a. Temperature
    b. Precipitation
    c. Wind direction and force
    d. Cloud amount and type
    Overall has there been much change or little change in the weather of each one?

 

2. Compare the satellite images for Europe on the two days by clicking on the days. Remember that on the infra-red image cold cloud which is at high altitude appears white. If it is a rather “thin” white, then this indicates it is only a high-level cloud such as cirrus. If it is a very intense white this means the tops are at high altitude, but there is a considerable vertical extent of cloud below. Low cloud is much warmer and appears grey on the infra-red image.
Important! Double click on each satellite image to increase its size on the screen and to therefore give what is called high resolution (i.e. a lot of fine detail).
Compare the infra-red images for Monday and Wednesday.
Compare the visible images for Monday and Wednesday.
Describe any changes you can see in the cloud types, patterns and distributions. Overall has there been much change or little change?

 

3. Compare the weather overview maps for Monday and Wednesday.
Click here for Monday and click here for Wednesday, but note that Monday’s map was for 12:00UTC, Wednesday’s for 06:00UTC.
Important! Remember to double click for high resolution!.


a. The colours show temperatures. The lowest temperatures are shown in blue and the highest in red. Other temperatures are shown in green or brown or yellow. A scale at the bottom of the picture shows you the temperatures that correspond to each colour. Deep blue, for example, shows temperatures below minus 20 degrees Celsius. Yellow shows temperatures between 0 degrees and plus four degrees Celsius. The colours are shown over both land and sea. Describe any changes you notice in the temperatures across Europe over the two-day period.


b. Look carefully along the title line of each map. What do you notice that could partly explain some of the temperature differences between the two maps?


c. The symbols on the maps show precipitation and various other features of the weather. The asterisks (stars) show where snow was falling. Black dots show where rain was falling and commas show where drizzle was falling. Upside-down triangles show where showers were falling. Showers fall from cumulonimbus clouds. Rain falls from nimbostratus cloud. An upside-down triangle with an asterisk above it shows where snow showers were falling. An upside-down triangle with a dot above it shows where rain showers were falling. Various other symbols are shown on the picture. To find out what they all mean, click here. Describe any changes you notice in the precipitation and other weather features across Europe over the two day period.


d. Wind direction and strength are also shown on the map. Strong winds are shown by red arrows. The barbs show the strength of the wind. A short barb equals 5 knots and a long one 10 knots (1 knot = 1.15 miles per hour = 1.85 kilometres per hour). If you stand with your back to the wind, the barbs are on the left. For a key to all wind speeds, click here. A wind blowing from the west is a westerly wind and a wind blowing from the east is an easterly wind. Describe any changes you notice in wind direction and strength over the two-day period.

 

4. Influences on the weather: The weather is influenced to a large extent by the distribution of areas of high atmospheric pressure (called anticyclones) and areas of low atmospheric pressure (called depressions).


+ Anticyclones are shown on weather maps with the letter H. The pressure values (mb = millibars) are shown on isobars (lines of equal pressure) which form roughly circular patterns around a high. The values increase towards the centre of the system. Winds blow clockwise round highs in the northern hemisphere and anticlockwise round highs in the southern hemisphere.
The air descends in the middle and lower troposphere in an anticyclone and flows outwards from central areas of the high towards its edges. Usually the outward flow is fairly gentle. As the air descends, it is warmed (at 9.8°C/km) and therefore produces no precipitation. Where the descending air meets the air which is flowing over the ground, an inversion of temperature forms, with the descending air warmer than the air beneath. The air beneath the inversion can be quite cold in winter and the air just above the inversion can be several degrees warmer.
Anticyclones sometimes produce fine weather with clear skies. On other occasions, however, low-level cloud and pollutants become trapped below the temperature inversion. When that happens, the high produces overcast, dull and gloomy weather.


+ Depressions are shown on weather maps with the letter L. Their characteristics are the opposite of those of anticyclones. Complete this simple table to show this:

Features

Anticyclones

Depressions

Pressure
 towards
centre

Increases

 

In N Hemisphere
winds circulate

Clockwise

 

In S Hemisphere
winds circulate

Anti-
clockwise

 

Vertical
Movement
of air is

Downwards

 

Surface winds
move

Outwards

 

Force of surface
wind is

Gentle

 

The vertical
movement
of the air causes

Warming

 

Condensation
and
precipitation

Little or none

 

The other features in the atmosphere which greatly affect the weather are fronts. They are shown by solid lines with either semi-circles or triangles or a combination of both drawn on one side of the line in the direction in which the front is moving. Fronts form the boundaries between air masses of contrasting temperature and humidity; and along their lines the warmer less-dense air rises over the colder more-dense air. The rising air is cooled, which results in condensation of water vapour within the air and, therefore, the formation of cloud and precipitation.


For further information on depressions and fronts, please click here.


Study the weather maps for Europe for Monday 30 January (click here) and Wednesday 1 February (click here).


a. Describe the positions of anticyclones, depressions and fronts on the map for Monday 30 January and explain how this seems to be influencing the weather.


b. What changes have taken place in the positions of the anticyclones, depressions and fronts by the time of the map on Wednesday 1 February? How does this seem to have influenced the weather?


c. Overall, has there been little or much change between the two days in terms of: (i) the weather and (ii) the pressure maps?


5. a. Look at these two maps which show temperatures in Europe yesterday and today (31 January and 1 February). Click here for maximum temperatures and click here for minimum temperatures. Carry out a web search of news to find out how the weather has been affecting people’s lives across Europe in the past few days.

Adaptation for use in other areas of the world:

This study format can be applied to areas of the world other than Europe by using MetLink resources:

Please select the resources you wish to use from the selection obtained by clicking on these links:
Monday 30 January – click here
Wednesday 1 February – click here
Unfortunately no weather overview map is available for other world areas, although you may find useful materials by carrying out a web search of your own country’s weather service.