Environmental Science Unit-I Basics

Unit-I: Fundamentals of Environmental Sciences

• The word environment is derived from the French verb "environner," meaning "to encircle" or "surround."
• Environment encompasses physical, chemical, and biological worlds, along with social and cultural conditions affecting individuals or communities.
• Biologist Jacob Van Uerkal defined environment as one's surroundings, encompassing physical and biological habitat.
• Boring defined environment as the sum total of stimulations from conception to death, including physical, intellectual, mental, economic, political, cultural, social, moral, and emotional forces.
• Douglas and Holland defined environment as the aggregate of external forces, influences, and conditions affecting an organism's life, behavior, growth, development, and maturity.
• Environmental science combines scientific methods with various biological disciplines (ecology, environmental studies, etc.).

Importance of Environmental Studies

• Increasing global population, industries, and pollution issues make conservation and protection paramount.
• Global warming, ozone depletion, acid rain, marine pollution, and biodiversity loss require international cooperation and effort.
• Development (urbanization, industries, etc.) creates complex environmental issues, particularly in developing nations.
• Pollution and resource depletion threaten global well-being.

Classification of Environment

• A. Physical Environment: Includes air, water, and land.
• B. Living Environment: Includes plants, animals, and microorganisms.

Hydrosphere, Lithosphere, Atmosphere, Biosphere

• Hydrosphere: Encompasses all water resources (oceans, seas, lakes, rivers, etc.).
• Lithosphere: Earth's crust composed of soil and rocks, including inorganic and organic matter.
• Atmosphere: The gaseous envelope surrounding Earth, including elements like nitrogen, oxygen, and others.
• Biosphere: Where all life forms exist, interacting with lithosphere, hydrosphere, and atmosphere.

Atmospheric Structure

• Four major zones: Troposphere, Stratosphere, Mesosphere, and Thermosphere.
• Troposphere: Lowest layer, temperature drops with altitude. Weather occurs here.
• Stratosphere: Contains ozone layer, temperature increases with altitude.
• Mesosphere: Temperature decreases with altitude.
• Thermosphere: High temperature, low density.

Ionosphere

• Contains D, E, and F regions.
• Regions with varying ionization levels due to solar activity, affecting radio wave propagation.

Laws of Thermodynamics

• Zeroth law: Defines thermal equilibrium.
• First law: Conservation of energy.
• Second law: Entropy of interacting systems never decreases.
• Third law: Entropy of a system approaches zero at absolute zero.

Energy

• Energy is the ability to do work, existing in various forms.
• Energy transfer occurs through mechanisms like mechanical, electrical, and thermal radiation.
• Energy transformation involves converting one form of energy into another.
• The law of conservation of energy states that energy cannot be created or destroyed, only transformed.

Precipitation

• Precipitation is water released from clouds to Earth's surface.
• Different types include rain, drizzle, snow, sleet, hail, and freezing rain.
• Precipitation factors include air temperature and humidity, cloud type, and atmospheric conditions.

Humidity

• Humidity measures the amount of water vapor in air.
• Absolute humidity: mass of water vapor per unit volume of air.
• Specific humidity: mass of water vapor per unit mass of moist air.
• Relative humidity: percentage of water vapor in air at a given temperature compared to the saturation point.

Solar Radiation

• The sun is the primary heat source for Earth.
• Incoming solar radiation (insolation) is essential for weather patterns.
• Solar radiation is critical to earth's climate, affecting temperature and weather systems.

Wind Velocity

• Wind is the movement of air and is a significant atmospheric phenomenon.
• Wind velocity is measured in units of meters per second or kilometers per hour.

Man-Earth Interface

• Human development has considerable effects on the environment.
• Environmental issues include resource depletion and pollution.

Biogeographical Provinces

• Biogeography studies the distribution of species and ecosystems across geographical space and time in various areas.
• Classification considers habitat, elevation, and isolation.
• Important components include Phytogeography, Zoogeography (plant and animal geography respectively).

Agro-Climatic Zones (ACZs)

• ACZs provide areas for agricultural activities based on growing conditions.

Agro-ecological Zones (AEZs)

• AEZs are land divisions categorized based on climate conditions and other soil factors useful for agricultural activities.

Remote Sensing and GIS

• Remote sensing involves receiving energy from objects at a distance.
• GIS involves storing and analyzing geographic information, using spatial analysis techniques.
• These methods are crucial in land use/land cover mapping for planning and management.
• Several aspects about environmental changes can be recorded and analyzed using remote sensing.

Digital Image Processing

• Image interpretation and analysis involves formatting, correcting, and analyzing digital image data.
• Image processing enhances analysis, with applications in numerous fields.
• Includes categorization: Preprocessing, Image Enhancement, Image Transformation, and Image Classification and Analysis.

Thermal Remote Sensing

• Measures emitted thermal radiation.
• Commonly used for agricultural applications, water resources, and forest fires.