Some changes in the Earth’s climate system lead to the emergence of new climate patterns that may be for a short period or lasting for long decades and this is related to the Earth’s geological history, and more recently, since the Industrial Revolution, the climate is increasingly affected by human activities that affect climate change.
What is the climate?
Climate is defined as a set of elements such as temperature, amount of precipitation, humidity, atmospheric pressure, wind speed, and the amount of sunlight falling, and every region in the world has its own climatic characteristics that are taken by observing them and recording observations about the aforementioned elements over a period of time. Where, that is, the averages of the weather elements are taken and on its basis the climate for a region is determined according to the results.
The climate of a region is ultimately determined by the radiation energy of the sun, and its distribution and temporal fluctuations.
The long-term state of the atmosphere is a function of a variety of interacting elements. They are:
▪️ Solar radiation.
Solar radiation is the radiation, or energy we get from the sun. It is also known as short-wave radiation. Solar radiation is probably the most important element of climate.
Solar radiation first and foremost heats the Earth’s surface which in turn determines the temperature of the air above. The receipt of solar radiation drives evaporation, so long as there is water available. Heating of the air determines its stability, which affects cloud development and precipitation. Unequal heating of the Earth’s surface creates pressure gradients that result in wind. Every location on Earth receives sunlight at least part of the year.
The amount of solar radiation that reaches any one spot on the Earth’s surface varies according to: Geographic location, Time of day, Season, Local landscape, Local weather. Solar radiation comes in many forms, such as visible light, radio waves, heat (infrared), x-rays, and ultraviolet rays. Measurements for solar radiation are higher on clear, sunny day and usually low on cloudy days. When the sun is down, or there are heavy clouds blocking the sun, solar radiation is measured at zero.
▪️ Air masses.
An air mass is a large body of air with generally uniform temperature and humidity. Air masses control the characteristics of temperature, humidity, and stability. Location relative to source regions of air masses in part determines the variation of the day-to-day weather and long-term climate of a place.
▪️ Pressure systems (and cyclone belts).
•Air pressure is the weight of air resting on the earth’s surface.
•Air has specific weight.
•This weight exerted by the air is atmospheric pressure.
•It is defined as the force per unit area exerted against a surface by the weight of air above that surface in the Earth’s atmosphere.
Pressure systems have a direct impact on the precipitation. In general, places dominated by low pressure tend to be moist, while those dominated by high pressure are dry. The seasonality of precipitation is affected by the seasonal movement of global and regional pressure systems.
▪️ Ocean Currents.
Ocean currents greatly affect the temperature and precipitation of a climate. Those climates bordering cold currents tend to be drier as the cold ocean water helps stabilize the air and inhibit cloud formation and precipitation. Air traveling over cold ocean currents lose energy to the water and thus moderate the temperature of nearby coastal locations.
Air masses traveling over warm ocean currents promote instability and precipitation. Additionally, the warm ocean water keeps air temperatures somewhat warmer than locations just inland from the coast during the winter.
Topography affects climate in a variety of ways. The orientation of mountains to the prevailing wind affects precipitation. Windward slopes, those facing into the wind, experience more precipitation due to orographic uplift of the air. Leeward sides of mountains are in the rain shadow and thus receive less precipitation. Air temperatures are affected by slope and orientation as slopes facing into the Sun will be warmer than those facing away. Temperature also decreases as one moves toward higher elevations.
Climate types are divided into five main types, and each has its own characteristics that are based on the availability of a set of elements and factors:
1. Tropical climate.
Tropical areas are characterized by high temperatures and large amounts of rain, and vital areas that contain a tropical climate, include: rain forests and savannahs, where the average temperature is 18 degrees Celsius, and the winter season tends to be zero.
2. Polar climate.
Polar regions are characterized by sub-zero temperatures and characterized by weak precipitation, and regions with a polar climate cover more than 20% of the land area, most of these areas are far from the equator, and the polar climate consists of a cold summer and very cold winter, which results in glaciers, a permanent layer or Semi-permanent from ice.
3. Dry climate.
Dry areas suffer from lack of rainfall, and are characterized by high daily temperatures significantly, where the temperature can reach 49 degrees Celsius during the day, and at night 37.7 degrees Celsius, and these areas are divided into dry areas and semi-arid regions, and the dry climate mediates between climates. Desert and humid climates in environmental characteristics and agricultural potential.
4. Temperate climate.
is characterized by temperate regions with average temperatures, where the summer is warm with little rain in these areas while the winters are mild and wet, and the temperature of the coldest months in temperate regions ranges between 26.6 and 64.4 degrees Fahrenheit (-3-18 degrees Celsius) and includes Temperate zone climate both; Subtropics, Mediterranean regions, and marine areas.
5. Cold climate.
is also known as microclimates or continental climates (Cold Regions). The climate of cold regions is characterized by moderate rains with high seasonal changes in temperature, with average temperatures ranging between 70 to 90 degrees Fahrenheit (about 21 – 32 degrees Celsius) during Summer is in a cold climate, while the average temperature in the coldest month is less than 26 degrees Fahrenheit (about -3 degrees Celsius), and this type of climate usually prevails in the central regions of land masses, and northern Scandinavia and Siberia are the most prominent Examples of cold regions climate.
Factors affecting climate.
1. The distance from the equator: the farther the area is from the equator, the lower the temperature will be; This is due to the curvature of the earth.
2. Altitude above sea level: The higher the area is, the cooler the temperatures.
3. Distance from the sea: It is known that the oceans heat up more slowly than land, which makes coastal areas cooler in summer and warmer in winter than inland areas that are at the same latitude and altitude, and therefore the farther from the seas and oceans the hotter they are.
4. Human use of land: urban areas are usually warmer than rural areas; This is due to buildings and paved roads that absorb the sun’s heat during the day and release it at night.
5. External influences: There are some external factors that can affect the climate, such as greenhouse gases and changes in the Earth’s orbit, as these factors affect climate change for long periods of time, and this occurs as a result of a change in the balance between incoming and outgoing radiation.
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Prof A. Balasubramanian (1-8-2017), “ELEMENTS OF CLIMATE AND WEATHER”، www.researchgate.net
What Are the Different Climate Types?”, scijinks,