*3.2.2.1 The pluviothermal quotient*

The mean annual temperatures, the mean annual precipitation, and the calculated rainfall quotients (Q2) are presented in the following **Table 10**.


#### **Table 9.**

*The thermal continentality of the study stations.*


*Biophysical Effects of Evapotranspiration on Steppe Areas: A Case Study in Naâma… DOI: http://dx.doi.org/10.5772/intechopen.97614*

**Table 10.**

*Values of the rainfall quotient.*

**Figure 4.**

*Variation of the Emberger climagram, of study stations.*

The quotients are inversely proportional to the aridity; this Emberger climagram allows us to determine the bioclimatic stages and the thermal variants (**Figure 4**).

The comparative reading of the pluviothermal climagram (**Table 10** and **Figure 4**) shows a slight change in pluviothermal quotients between the old period and the new period. This type of climate change probably also causes a change in plant formation. For example, the Aïn Sefra station moves from the arid lower level with cold winter in the old period to the upper Saharan level with cool winter in recent times. The Mécheria station is moved from the middle arid stage with cool winter in the old period to the lower arid stage with cool winter in recent times.
