Food & Climate 

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3. Drought in the Mediterranean - more

Worksheet 1: Climate diagrams

Climate diagrams are important sources of information on precipitation amounts and temperatures at a particular location.

1. Diagram by Julia Heres.

Explanation of the diagram:

1. name of place / city
2. height above sea level
3. average annual temperature
4. average annual percipitation
5. precipitation in mm
6. month
7. temperature in °C

The climate is the average weather conditions seen at a particular location.  The climate, therefore, can't be observed directly.  We need at least 30 years of data to determine the average climate.

A climate diagram is the best way to visualise climate data.  The climate diagram shown above is called a Walter Lieth diagram.

On Walter Lieth diagrams 10°C on the temperature scale always correspond to 20 mm of rain on the precipitation scale. In the diagram precipitation (rainfall) is also often shown using one line instead of 12 columns. Arid and humid months can be directly read off. 

Arid months are months when the temperature line is higher than the precipitation line. These months are dry. The diagram above has no arid months.

Humid months are months when the precipitation line is higher than the temperature line.  All the months on the diagram above are humid.

Climate diagrams can also be shown in different formats, for example, as circle diagrams.

Using the following data, draw your own climate diagram for Barcelona.

Instructions:

- Use graph paper
- First draw the months on the x-axis.  Use a scale so that 5 mm represents 1 month.
- Then draw each of the two y-axes: 
         put temperature on the first y-axis and make 1 cm represent 10°C.
         put precipitation on the second y-axis and make 1 cm represent 20 mm rain fall.
- Mark on the temperature data and connect the data together with one red line.
- Mark on the precipitation data and connect the data with one blue line or draw 12 separate  blue columns.

Barcelona (175 m / 574 feet above sea level)

Jan Feb Mar Apr May Jun Jul Aug Sept Oct Nov Dec year °C 9.1 10.3 11.8 14.1 17.4 21.2 24.2 24.1 21.6 17.5 13.1 9.9 16.2 mm 38.0 37.5 47.0 47.2 43.8 37.7 27.5 43.8 76.3 96.2 51.2 43.7 590   °F 48.4 50.5 53.2 57.4 63.3 70.2 75.6 75.4 70.9 63.5 55.6 49.8 61.2 inch 1.5 1.5 1.9 1.9 1.7 1.5 1.1 1.7 3.0 3.8 2.0 1.7 23.2

Have a look at the site: www.worldclimate.com

Find your home town or somewhere close to it and use the data on the web page to draw a climate diagram for where you live.

Collect your own data and draw a simple climate diagram

What you will need:
- thermometer
- rain meter

Measure the temperature and the amount of precipitation once a day at the same time each day (e.g. 13.00 hours) for one week and record the data in the table.

Remember:
This "climate diagram" only shows one weeks worth of data.  A proper climate diagram shows the average weather conditions over at least 30 years.

Comparison of two climate diagrams.

Print out the worksheet and try to answer the questions on it.

2. Climate diagrams for Ny Alesund and Jerez de la Frontera.  Author: Dipl. Met. Bernhard Mühr, Institute for Meteorology and Climate Science, University of Karlsruhe.  Source: www.klimadiagramme.de

About this page:

author: Sarah Ancot - University of Nürnberg, Nürnberg, Germany
educational reviewing: Dr. Helmut Schrettenbrunner and Julia Heres - University of Nürnberg, Nürnberg, Germany
last update: 2003-09-16