Understanding Weather Elements and Climate Mechanisms in Spain
Weather in Spain
The Elements of Weather
The elements of weather are a set of indicators that show the basic characteristics of a specific climate. The most significant are rainfall, temperature, atmospheric pressure, wind, humidity, clouds, and fog.
Temperature
Factors influencing temperature are latitude, altitude, and proximity to the sea. On a map, it is represented by isotherms, which are lines that connect points on the Earth’s surface that have the same temperature. Absolute temperatures are the highest (maximum) and lowest (minimum). The thermal oscillation is the difference between the average temperature of the warmest month and the average temperature of the coldest month.
Precipitation
Depending on latitude, precipitation is more abundant near the equator than in temperate zones. Precipitation is also conditioned by altitude and distance from the sea; it is higher on the coast than inland because the sea is a source of humidity. It is represented by isohyets, which are lines that connect points on the land area that record the same amount of precipitation.
Humidity
Humidity is the amount of water vapor in the air. Humidity is measured with the help of a device called a hygrometer and is usually expressed in percentages.
Atmospheric Pressure
Atmospheric pressure is the force exerted by the weight of the air above a certain point on the Earth’s surface. Pressure depends on temperature and decreases with increasing altitude. The air weighs less in hot and humid areas and creates a low pressure, depression, or cyclone. Cool, dry air weighs more and gives rise to an area of high pressure or anticyclone. The equator and temperate zones are areas where low pressures prevail, while in the tropics and the poles, pressures are higher. Pressure is measured with a barometer and is represented by isobars.
Wind
Wind is the displacement of air caused by differences in pressure, blowing from high-pressure areas to low-pressure areas. A wind vane indicates wind direction, and an anemometer measures wind speed.
Mechanisms that Influence Climate
To understand the mechanisms that explain the great diversity of weather and climates, one must take into account atmospheric circulation at high altitude, the movement of surface air, and geographical factors that modify the behavior of air masses. The combination of these variables results in remarkable climatic diversity.
Atmospheric Circulation at High Altitude
In the upper atmosphere, the movement of wind is much stronger than on the surface. These air flows are called jet streams due to their shape and intensity. In winter, currents tend to lose altitude, and in summer, they tend to rise.
Movement of Surface Air
The air circulation that is in contact with the ground is organized into areas of high pressure or anticyclones and areas of low pressure or depressions. The pressure fields are represented by isobars.
Areas of High Pressure
In anticyclones, the air tends to heat up and descend when in contact with the Earth. This air absorbs moisture, resulting in a cloudless sky and strong sunlight. It is a stable weather condition.
Areas of Low Pressure
If the air in a depression tends to rise slightly, it cools, and the moisture condenses, forming clouds that originate rain. It produces unstable weather.