Climate of Ethiopia and the Horn PDF
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This document provides an overview of the climate of Ethiopia and the Horn of Africa, discussing the elements and controls of weather and climate such as temperature, precipitation, and wind. It also explains concepts like lapse rates and equinoxes, and how they impact the climate in the area.
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Climate of Ethiopia and the Horn: An Easy Guide Introduction Ethiopia, located in the Horn of Africa, experiences diverse altitudinal ranges and climatic conditions. The country's proximity to the equator and the Indian Ocean leads to significant temporal and spatial variations in weather and cli...
Climate of Ethiopia and the Horn: An Easy Guide Introduction Ethiopia, located in the Horn of Africa, experiences diverse altitudinal ranges and climatic conditions. The country's proximity to the equator and the Indian Ocean leads to significant temporal and spatial variations in weather and climate. Elements and Controls of Weather and Climate Weather: The current state of the atmosphere, including temperature, pressure, humidity, wind, cloudiness, and precipitation. Climate: The long-term state of the atmosphere, a composite of daily weather conditions recorded over extended periods. Table 5.1. Elements and Controls of Weather and Climate Elements Controls 1. Temperature 1. Latitude/angle of the Sun 2. Precipitation and humidity 2. Land and water distribution 3. Winds and air pressure 3. Winds and air pressure 4. Altitude and mountain barriers 5. Ocean currents Controls of Weather and Climate Latitude ○ The distance from the equator affects solar insolation and temperature. Ethiopia's latitude results in: ▪ High average temperatures. ▪ High daily and small annual temperature ranges. ▪ No significant variation in day and night length between seasons. ○ 1. Inclination of the Earth's Axis ○ The Earth's rotation axis is tilted at about 66.5° to the plane of its orbit. ○ This inclination leads to changes in the directness of the sun's rays, causing seasonal changes and variations in day length. 2. Equinoxes and Solstices Equinox: When the sun's rays strike the Earth's equator directly, resulting in equal day and night length. ○ Vernal (Spring) Equinox: Around March 21, marks the beginning of spring in the Northern Hemisphere. ○ Autumn Equinox: Around September 23, marks the beginning of autumn. Solstice: When the sun's rays are furthest from the equator, causing the longest or shortest days. ○ Summer Solstice: Around June 21, longest day in the Northern Hemisphere. ○ Winter Solstice: Around December 22, shortest day in the Northern Hemisphere. Altitude and Lapse Rates: An Easy Guide Altitude Definition: Altitude is the height of a location above sea level. Temperature Change: Generally, temperature decreases with increasing elevation. ○ Lapse Rate: The rate of temperature change per unit of altitude change. ○ Normal Lapse Rate: 6.5°C per kilometer rise in altitude (applies in the troposphere). Types of Lapse Rates Dry Adiabatic Lapse Rate Definition: The rate at which the temperature of an air parcel changes due to expansion or compression without heat exchange from external sources. ○ Process: Occurs in unsaturated air (relative humidity < 100%). 1. Geo unit 5 Friday, January 17, 2025 2:09 PM New Section 1 Page 1 ○ Process: Occurs in unsaturated air (relative humidity < 100%). ○ Rate: 10°C per 1,000 meters change in elevation. Example: A dry air parcel rising from sea level to 5,486 meters will expand and cool, its temperature dropping at the dry adiabatic rate. ○ Wet Adiabatic Lapse Rate Definition: The rate at which the temperature of saturated air changes due to expansion or compression, influenced by the release or absorption of latent heat from water vapor. ○ ○ Process: Occurs in saturated air, cooling more slowly than dry air. ○ Rate: Approximately 5°C per 1,000 meters ascent. Example: Rising saturated air containing water droplets will cool more slowly due to latent heat released during condensation. ○ 2. Environmental Lapse Rate (Atmospheric Lapse Rate) ○ Definition: The actual observed change in temperature with altitude in the atmosphere. ○ Normal Behavior: Temperature is highest near the Earth's surface and decreases with altitude. Factors: The lower atmosphere (troposphere) is warmer due to higher density, more water vapor, and dust, making it more efficient at absorbing Earth radiation. ○ ○ Rate: Generally 6.5°C per 1,000 meters but can vary due to temperature inversions.
