Annual precipitations and average temperatures recorded in a location over several years are recorded in climates and inform the type of climate of a region.
What is climograma
The climogram is a graph representing the mean temperatures and total precipitation that occurred in one place during the 12 months of the year. In the chart, temperatures are indicated with a line, and precipitations, with bars. As the data are usually the means of several years, the climate chart visually reveals the climate of that place.
How to make a climograma
To create a climogram. meteorological data are required first .
Many official sources (national meteorological institutes) provide tables with these data. The two most important for each month of the year are: the average temperature in degrees centigrade and the amount of precipitation , totaled in millimeters or liters per square meter.
The data are presented by means of a coordinate system. Graphite or graph paper should be used to trace the coordinate axis with two vertical axes.
1. Plot the horizontal axis with the months of the year and assign the same space to each one. Write the initials.
2. Make the vertical axis of the temperatures on the left. Divide the space proportionally.
3. Write the temperature numbers and indicate in the “Temperature in ° C” axis.
4. Draw the vertical axis of the precipitations to the right. Divide the space proportionally, but remember that rainfall always doubles the value of temperatures. That is to say, when it is 10 ° C, it should be 20 mm.
5. Write the numbers of precipitations and write down on the “Precipitations” axis.
6. Place a point at the height of the average temperatures of each month.
7.Merge all points with a red line to get the temperature curve.
8. Mark the height of the total rainfall and draw a blue bar for each month.
How to analyze a climogram
The following steps should be considered when interpreting a climogram:
- Observe general information: title and location, units of measurement, etc.
- Analyze the composition of the diagram.
Note the variation of monthly average temperatures, as well as the existence or absence of significant contrasts between the coldest and warmest month (amplitude or thermal oscillation). All this allows to determine if the climate is hot, temperate or cold. When the temperature curve is above precipitation, it means a dry month.
It is possible to know if the climate is humid by observing the values between which the monthly precipitations oscillate, as well as their distribution throughout the year (sum the data of every month to know the annual precipitations). It should be noted whether rainfall is distributed evenly throughout the year or if it is concentrated in a few specific months.
- To identify the type of climate , that is, to relate the thermopluviometric information with the Koppen classification.
- Finally, to make the commentary itself, in which the climatic identification is justified, the general characteristics of the place, the causes of the climate, the location of the climate type and the biogeographical features (relation to the vegetation) are exposed.
In the above example average temperatures are high throughout the year. In six months, they exceed 20 ° C. Therefore, a hot climate is observed . There are few precipitation records. Therefore, among the types of hot climate, it is considered desert , since, in the sum of the precipitations of every month, the total is below 250 mm.