Control of Climate

  Climatic controls


Climatic controls are those factors of the atmosphere that causes different weathers and climates over the surface of the Earth

  Latitude


Latitude is a geographic coordinate that specifies the north-south position of a point on the Earth's surface. Latitude is an angle which ranges from 0° at the Equator to 90° (North or South) at the poles. Latitude is the distance of a location from the equator

The hottest temperatures on Earth are found near the equator. This is because the sun shines directly on it for more hours during the year than anywhere else. As you move further away from the equator towards the poles, less sun is received during the year and the temperature become colder

Depending on the latitude of a location determines the amount of sunlight that a location receives. The higher your latitude the less sunlight you will receive throughout the year, and the cooler will be your climate

There is great imbalance between latitude and heat balance

 

Longitude is a geographic coordinate that specifies the east-west position of a point on the Earth's surface. It is an angular measurement, usually expressed in degrees and denoted by the λ.

By convention, one of these, the Prime Meridian, which passes through the Royal Observatory, Greenwich, England, was allocated the position of zero degrees longitude. The longitude of other places is measured as the angle east or west from the Prime Meridian, ranging from 0° at the Prime Meridian to +180° eastward and −180° westward

 

  Altitude


Altitude is the difference in the vertical height of the atmosphere. Altitude is the height you are above sea level

Altitude controls temperature and pressure density. The higher up you are the lower the temperature will be. The temperature decreases with altitude and this temperature phenomena is known as the Lapse Rate. The air that is higher altitudes is less dense than it is at lower altitudes and air temperature depends on its density

 The normal lapse rate is 6.5°C per km (Memory test : what is the value of DALR ?? (Air Pollution))

The rate of decrease of pressure with altitude is not constant

Different types of clouds are found at different altitudes which controls different types of precipitation

The pressure at any level in the atmosphere may be interpreted as the total weight of the air above a unit area at any elevation. At higher elevations, there are fewer air molecules above a given surface than a similar surface at lower levels.

Since most of the atmosphere's molecules are held close to the earth's surface by the force of gravity, air pressure decreases rapidly at first, then more slowly at higher levels.

Since more than half of the atmosphere's molecules are located below an altitude of 5.5 km, atmospheric pressure decreases roughly 50% (to around 500 mb) within the lowest 5.5 km. Above 5.5 km, the pressure continues to decrease but at an increasingly slower rate

Measurement of Latitude/Longitude and Altitude

GPS is a satellite navigation system used to determine the ground position of an object. GPS technology was first used by the United States military in the 1960s and expanded into civilian use over the next few decades. 

The GPS system includes 24 satellites deployed in space about 12,000 miles (19,300 kilometers) above the earth's surface

A GPS receiver combines the broadcasts from multiple satellites to calculate its exact position using a process called triangulation. Three satellites are required in order to determine a receiver's location, though a connection to four satellites is ideal since it provides greater accuracy.

GPS receivers require a relatively unobstructed path to space, GPS technology is not ideal for indoor use

  Land and water


The distribution of water and land across the surface of the Earth is another important control that regulates climate

Water responds to temperature change much more slowly than does land. It takes longer to heat water, and longer for it to cool down. As a result, locations near the oceans experience milder changes in climate than location near the land

Variations in air temperature are much greater over land than over water

It is the differential heating of land and water that effects for the distinct types of marine and continental types of climate

  Distance from Sea


Sea temperature changes slower than land temperature. If the temperature on land drops then the area next to the sea will be kept warmer for longer than areas inland

Islands have a less dramatic climate than continents. Continents have extreme weather conditions (Continentality)

Continentality, a measure of the difference between continental and marine climates characterized by the increased range of temperatures that occurs over land compared with water

Areas located near the water bodies will have mild climates and the areas located in the interior of the continent will have severe climatic conditions

Different seas have different temperatures therefore allowing one side of an island to be having different temperatures than the other side

  Pressure and wind System


Pressure systems have a direct impact on the precipitation characteristics of different climate regions

 

Places dominated by low pressure tend to be moist, while those dominated by high pressure are dry

Pressure dominance also affects the receipt of solar radiation

Places dominated by high pressure tend to lack cloud cover and hence receive significant amounts of sunshine, especially in the low latitudes

 

  Mountains barriers/Relief


In geography, "relief" refers to the highest and lowest elevation points in an area. Mountains and ridges are typically the highest elevation points, while valleys and other low-lying areas are the lowest. Also referred as Topography, it 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 while 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

Mountains can often act as barriers, diverting wind and moisture, effecting the climate in the areas around it

Often mountains create a vast shadow, where rain can seldom fall, with rainfall being blocked by vast mountain ranges, these areas become deserts

  Ocean Currents


Surface Ocean Currents

Water flows in a circular pattern – clockwise in the Northern Hemisphere and counterclockwise in the Southern Hemisphere. Warm surface currents flow from the tropics to the higher latitudes, driven mainly by atmospheric winds, as well as the Earth's rotation. Cold surface currents come from polar and temperate latitudes. These currents tend to flow toward the equator

Deep Ocean Currents

Currents flow in complex patterns affected by wind, salinity and water temperature, bottom topography, and the Earth's rotation. The density of ocean water causes deep ocean currents. Sea water that flows in polar regions will cool or freeze, becoming saltier and denser. Cold or salt water tends to sink.

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 do not favour 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. The warm ocean currents raise the temperature of the near by coastal regions slightly above the mean values during the winter season.

 

Currents are driven by the prevailing winds passing over the surface of the ocean.  Therefore winds blowing from tropical areas bring warm currents and vice versa

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