Understanding Temperature
Introduction
Temperature is a fundamental aspect of our environment, affecting everything from our daily activities to global climate patterns. It is a measure of the heat present in the atmosphere and Earth’s surface, resulting from the interaction of solar radiation (sunlight) with these surfaces.
Definition
Temperature is usually measured in degrees Celsius, Fahrenheit or Kelvin. It is measured using an instrument called a thermometer, and areas of equal temperature are connected by lines called isotherms.
Isotherm
Isotherms are lines that connect places of equal temperature. They are important for understanding how temperature changes at the Earth’s surface. When drawing isotherms, we adjust the temperature to sea level to negate altitude effects. Isotherms exhibit several characteristics:
1. Directionality: Isotherms generally trend in the east-west direction due to the distribution of solar radiation.
2. Land-Water Contrast: They bend sharply at the boundary between land and water due to differences in heating and cooling rates.
3. Spacing: The spacing between isotherms indicates the rate of temperature change with latitude. Closely spaced isotherms indicate rapid temperature changes, while widely spaced isotherms indicate more stable weather conditions.
Temperature Measurement
The maximum and minimum temperatures are determined using special thermometers filled with alcohol. The average daily temperature is the average of these extremes. Specifically, Al-Azizia in Libya holds the record for the highest temperature, while Vostok in Antarctica is the coldest place on Earth.
Temperature Distribution:
The temperature distribution is represented in different ways:
1. Horizontal Distribution: Isotherms show how temperature changes over the Earth’s surface. Closely spaced isotherms indicate rapid temperature changes, while widely spaced isotherms indicate more stable weather conditions.
2. Vertical Distribution: Temperature decreases by about 6.5°C per kilometer upward in the atmosphere, a phenomenon known as the normalized loss rate. The rate of depletion is affected by surface characteristics such as land or water.
3. Spatial or Zonal Distribution: Temperature distribution is closely related to insolation. Generally, temperatures decrease from the equator toward the poles, dividing the Earth into warm, temperate, and temperate zones.
Regional Distribution of Geographical Zones
Different geographic regions experience unique temperature patterns:
1. Equatorial Linear Region: Located near the equator, this region experiences consistently high temperatures and minimal temperature variation throughout the year due to the almost vertical incidence of sunlight.
2. Inter-tropical Region: Found between 5 and 12 latitudes, this zone sees significant temperature differences between seasons due to the changing angle of sunlight.
3. Tropical Region: Extending from 12 to 25 latitudes, with varying durations of day and night, temperatures fall from low to high latitudes.
4. Sub-tropical zone: Located between 25° to 45° latitudes, this region experiences relatively low temperatures, sometimes dropping below zero.
5. Temperate zone: Falling between 45° and 66.5° latitude, this region shows significant temperature fluctuations between seasons.
6. Tundra Region: Characterized by lack of trees and long periods of snow cover, this region experiences very low temperatures due to the oblique rays of the sun.
7. Polar Region: Located around the poles, this region receives minimal insolation, resulting in consistently cool temperatures and negligible diurnal variations.
Inversion of Temperature
Temperature inversion refers to an unusual atmospheric condition where a layer of warm air traps cold air beneath it. This phenomenon occurs under specific conditions such as clear skies and calm winds.
Ranges of Temperature
Temperature range refers to the difference between the maximum and minimum temperatures. Annual ranges vary in different regions due to factors such as latitude and proximity to large water bodies.
Diurnal and Seasonal Cycle
The daily temperature cycle sees a gradual increase from sunrise to noon, followed by a decline until evening. Seasonal temperature changes are mainly influenced by the angle of the sun’s rays and the duration of sunlight.
Heat Island
Factors such as concrete structures and low vegetation may cause urban areas to experience higher temperatures than surrounding areas, leading to the formation of local heat islands.
Temperature Change
Temperature change can occur through two processes: diabatic and adiabatic. Diabatic changes involve heat exchange, whereas adiabatic changes occur without heat exchange with the surroundings.
Temperature Anomaly
Temperature anomaly refers to a deviation from the normal temperature at a specific location. Positive anomalies indicate warmer temperatures, while negative anomalies indicate colder temperatures. Isotherms help to visualize these anomalies, showing irregularities in the Northern Hemisphere due to the extensive landmass.
BRIEF SUMMARY
What is the Temperature?
• Temperature measures the heat in the air and on the Earth’s surface.
• Measured with a thermometer in Celsius, Fahrenheit or Kelvin.
• Isotherms are lines connecting places of equal temperature.
Isotherm:
• Directionality: Due to solar radiation the direction is mostly towards east-west.
• Land-Water Paradox: Bending of land-water boundaries due to temperature difference.
• Spacing: Closely spaced isotherms mean rapid temperature changes.
Temperature Measurement
• Special thermometers determine the maximum, minimum and average daily temperatures.
• Al-Azizia, Libya holds the record for the highest temperature; Vostok, Antarctica is the coldest.
Temperature Distribution
• Horizontal Distribution: Isotherms show changes in temperature on the Earth’s surface.
• Vertical distribution: Temperature decreases upward in the atmosphere.
• Spatial distribution: Temperature decreases from the equator to the poles.
Regional Distribution of Geographical Areas
• Different regions experience different temperature patterns depending on latitude.
• Equatorial to polar regions show different temperature characteristics.
Inversion of Temperature
• Warm air traps cold air beneath it under certain conditions.
Ranges of Temperature
• The difference between maximum and minimum temperatures.
• Varies due to latitude and proximity to water bodies.
Diurnal and Seasonal Cycle
• Diurnal cycle: increase from sunrise to noon, decrease until evening.
• Seasonal changes are affected by the angle of the sun and the duration of sunlight.
Heat Island
• Urban areas may experience higher temperatures due to structures and vegetation.
Temperature Change
• Diabetes: Heat Exchange; Adiabatic: Without heat exchange.
Temperature Anomaly
• Deviation from normal temperature; Positive means hot, negative means cold.
• Isotherms show discrepancies, especially in the Northern Hemisphere due to terrain.