In order to evaluate the climatological variables of the region and the atmospheric processes ocurring a this level, were considered as a quantative basis for the climatological data at the Fundão weather station which is found at an altitude of 495 m, 40º 08’ latitude and 7º 30’ longitude, corresponding to the 29 year period of observation records for 1961-1990 furnished by the National Institute of Meterology and Geophysics (INMG, 1999).

 

Temperature

For the 29 year  period the mean annual temperature of the Fundão municipalty was 14.1ºC, the mean maximum temperature being 19.8 ºC and the mean minimum temperature was 8.5 ºC.

 

The highest temperatre for the same period was registered in the month of September with 40ºC and a the lowest temperature was registered in February with 8.1ºC.

 

The maximum mean temperature was registered in the months of July and August with 30.3 ºC and the mean minimum temperature of 2.7 ºC was registered in the month of January.

 

The mean annual number of days with maximum air temperature >25ºC was 104.9 days, the greatest number of days were registered in July and August with 27.2 and 27.7 respectively.

 

The mean number of days annually with a minimum air temperature <0ºC was 23.1 days and it was verified that in the months of December and January its 7.9 and 8.2 days respectively (INMG, 1999).

 

According to Medeiros (2005), as the altidude increases, the temperature decreases and consequently the humidity increases.  Despite the inexistence of records for the  summit of the mountain, it is known that the values recorded at the weather station are slightly higher than those verified at the top of the mountains, that is at 1227m.

 

 

Precipitation

This factor is responsible for the regularization of the hydric equilibrium of the vegetation and soil.  More than any other  environmental factor, water affects the internal morphology of certain vegetatve organs which together determine the physiognomy of the vegetation.  To a certain extent, the structure and composition of the communities of vegetation are regulated by hydric requirements. The influence of pluviosity also extends to alterations that can be caused in the soil(Santos, 1993).

 

The mean annual pluviometric values are 943.7mm for the 29 year recorded period varying between 10.4 mm in the month of July and 136. 3mm in the month of February for the same period of time.

 

The months in which the greatest volume of precipitation was registered were November (132.2mm), December (132.1mm), January (134.8mm) and February (136.3mm).

 

The annual mean number of days with precipitation ≥1mm is 79.0 days with the greatest values registered in the months of January (10.6mm) and February (10.3mm).

 

The mean annual number of days with a volume of precipitation less than ≥10mm was 27.9 days, with amounts of 4.1 recorded for the month of January and 4.2mm for the month of February.

 

Precipitation

Regarding this parametre, it was verified that the wind in the Fundão municipaliy for the period 1961-1990 were predominantly in the East-Southeast quadrants with values of 12.7% and 12.6% respectively, and Northwest-West with values of 15.% and 26.3% respectively.

 

In relation to the mean average speed of the wind (km/h), the winds are considered weak during the entire year, however, they gust with more intensity in the West quadrant, with the mean annual velocity being 11.9 km/h for a total of 26.3% of the mean annual occurrences.

 

Relative Air Humidity

With regard to this parameter,  and for the period 1967-1990, measurements were taken twice a day at 9:00 am and 18:00 pm.

 

It was verified the mean annual values for 9:00 am and 18:00 pm were 65% and 62% respectiely, with monthly variations between 46% (July and August) and 82% (January) at 9:00 am;and at 18:00 pm the monthly variations were fom 45% (August) and 76% (December and January) (Figure 4)

Generally speakng it was verified that values are lower during the summer months which is justified due to the weak summer pluviosty.

 

 

Sunshine

Solar radiation is the principal source of atmospheric energy. Large climatic diversity is principally due to the fact that the quantity of solar energy that occurs varies with altitude(Santos, 1993).

 

Sunshine is described as the number of hours the sun is out in a given location during a determined period of time. Evidentally it depends on the period of time the sun is above the horizon and the cloud. (Santos, 1993).

 

The value of mean annual sunlight for the municipality of Fundão was 2697.5 hours corresponding to 60% of the number of annual hours of sunlight.

It is noted that the highest mean level of sunlight is 358.0 hours in the month of July while the lowest mean value for sunlight was 138.7 hours corresponding to the month of December (Figure 6).  These values correspond to the period 1961-1983.

The southern hillside represents the greatest number of hours of solar exposure, while the opposite is true of the Northern hillside which has more sheltered and deeper valleys, which are in turn darker and more humid, diminishing the number of hours of sunlight.

 

The type of vegetation varies according to the exposure of the hillside, as is illustrated further along in this report.

 

Evaporation

The evaporation rate depends fundamentally on the hygrometric state of the air and the wind velocity, diminshing with the increase of the first and increasing as wind velocity increases. (Santos, 1993).

 

The mean evaporation rates were obtained through observation in the morning period and refer to the following 24 hours.

The highest evaporation rate is recorded in the month of August (258.5 mm), while the lowest rate occurs in the month of December with 59.9 mm.

Frost

Frost is always prejudical for vegetation and can even compromise its survival. Frequently it affects plants that are in the floral and folial development phase, which can cause the destruction of new shoots and can burn the flower buds. (Santos, 1993).

 

In the municipality the occurence of frost starts at the beginning of October with 0.4 days and lasts until May with 0.1 days of frost  The months in which the greatest number of days with frost occurred were January (9.3 days) followed by the month of December (9.1 days).

 

The annual mean recorded for frost was 33.4 days.

The analysis of all the aforementioned climatic elements permit the climate of Fundão to be classified as a temperate climate, slightly humid with a water deficit in the summer((PDM, 1993).