TU BSc Meteorology 1st Year Notes: Complete Guide, Syllabus, Important Questions & Exam Preparation
Introduction
If you are a Tribhuvan University (TU) BSc Meteorology 1st Year student looking for complete notes, syllabus, important questions, and exam preparation resources, this guide is built for you.
Meteorology is one of the most practically relevant science programs in Nepal. The country's geography — from the Terai plains to the Himalayan peaks — creates some of the world's most complex and variable weather systems. Understanding those systems, predicting them, and communicating them accurately has real consequences for agriculture, aviation, disaster preparedness, hydropower planning, and climate adaptation. Nepal needs meteorologists, and TU's BSc Meteorology program is the primary pathway to that career.
This guide covers the official TU 1st Year syllabus for General Meteorology and Climatology, with chapter-wise explanations of every major topic, important exam questions, past paper trends, recommended books, and practical exam tips. Whether you are preparing for regular examinations, back exams, or want a structured revision resource, this is your central reference.
Course Overview
| Field | Information |
|---|---|
| University | Tribhuvan University |
| Faculty | Institute of Science and Technology |
| Program | BSc Meteorology |
| Duration | 4 Years (8 Semesters) |
| Year | First Year |
| Core Subjects | General Meteorology, Climatology |
| Reference Books | Byers, Wallace & Hobbs, Ahrens, Oliver & Hidore |
Career Opportunities After BSc Meteorology
Students sometimes underestimate the career range available after this degree. Meteorology in Nepal and internationally opens paths into:
- Meteorologist / Weather Forecaster — Department of Hydrology and Meteorology (DHM), Nepal
- Aviation Meteorologist — Tribhuvan International Airport and domestic airport weather services
- Climate Researcher — ICIMOD (International Centre for Integrated Mountain Development), CIMMYT, research institutes
- Hydrologist — Water resources departments, dam and hydropower project planning
- Disaster Risk Analyst — UNDP, UN-OCHA, Nepal Disaster Risk Reduction Portal
- Environmental Consultant — Environmental impact assessment firms, NGOs
- Government Weather Officer — DHM, Ministry of Forests and Environment
- Climate Change Specialist — International climate organizations, development agencies
- Remote Sensing and GIS Analyst — Satellite-based weather monitoring
- Academic Researcher — Teaching and research in universities
Nepal's expanding hydropower sector, growing aviation infrastructure, and increasing exposure to climate-related disasters all create sustained demand for trained meteorologists. International organizations working in Nepal on climate adaptation also recruit from this program.
Part 1: General Meteorology
1. Definition and Scope of Meteorology
Meteorology is the scientific study of the atmosphere and its phenomena, with particular emphasis on weather processes and forecasting. The word comes from the Greek meteoron (atmospheric phenomenon) and logos (study).
Meteorology is distinguished from climatology by timescale: meteorology deals with short-term atmospheric behaviour (hours to weeks — weather), while climatology examines long-term atmospheric patterns (months to decades and beyond — climate).
Sub-fields of meteorology:
- Synoptic meteorology: Large-scale weather patterns and forecasting
- Dynamic meteorology: Mathematical and physical laws governing atmospheric motion
- Physical meteorology: Cloud physics, precipitation, radiation processes
- Applied meteorology: Agriculture, aviation, hydrology, pollution applications
2. Composition of the Atmosphere
The Earth's atmosphere is a mixture of gases held by gravity. Its composition by volume (dry air):
| Gas | Chemical Symbol | Percentage by Volume |
|---|---|---|
| Nitrogen | N₂ | 78.09% |
| Oxygen | O₂ | 20.95% |
| Argon | Ar | 0.93% |
| Carbon Dioxide | CO₂ | ~0.042% (rising) |
| Other gases | Neon, Helium, Methane, etc. | Trace amounts |
Water vapour (H₂O) is not listed because it varies from near 0% in desert air to about 4% in warm, humid air. Despite its small percentage, water vapour is the most meteorologically significant variable gas — it drives clouds, precipitation, and much of the energy transport in the atmosphere.
Variable gases (those that change in concentration over time and space): water vapour, carbon dioxide, ozone, methane, nitrous oxide. Several of these are greenhouse gases responsible for trapping heat in the atmosphere.
3. Structure of the Atmosphere — Layers
The atmosphere is divided into layers based on temperature profile:
EXOSPHERE (500+ km)
↑
THERMOSPHERE (80–500 km)
Temperature increases with height
↑
MESOSPHERE (50–80 km)
Temperature decreases with height
(Coldest layer: –90°C at top)
↑
STRATOSPHERE (12–50 km)
Temperature increases with height
Contains ozone layer (~20–30 km)
↑
TROPOSPHERE (0–12 km)
Temperature decreases with height
Weather occurs here
----------------------
EARTH'S SURFACE
Troposphere: Contains approximately 75–80% of the total atmosphere's mass and virtually all of its water vapour and weather. Temperature decreases with altitude at an average rate of 6.5°C per km (the environmental lapse rate). The top boundary is the tropopause.
Stratosphere: Temperature increases with altitude because ozone absorbs ultraviolet radiation. The absence of vertical mixing makes this layer very stable — ideal for jet aircraft cruising and the reason volcanic eruptions that inject material here can affect climate for years.
Mesosphere: Temperature again decreases with altitude. The coldest place on Earth (–90°C) is at the mesopause. Meteors burn up in this layer.
Thermosphere: Temperature rises sharply because of absorption of high-energy solar radiation. The International Space Station orbits in this layer. Temperatures can reach 2,000°C but the air is so thin that the "heat" has little practical meaning.
4. Lapse Rate
The lapse rate is the rate at which temperature decreases with increasing altitude.
Environmental Lapse Rate (ELR): The actual measured rate of temperature decrease in a specific atmospheric column at a specific time. Average value: approximately 6.5°C per 1,000 m. This varies considerably with weather conditions.
Dry Adiabatic Lapse Rate (DALR): The rate at which a parcel of unsaturated (dry) air cools as it rises: approximately 10°C per 1,000 m. This is fixed by thermodynamics, not variable.
Saturated (Wet) Adiabatic Lapse Rate (SALR/WALR): The rate at which a saturated air parcel (one that is condensing water vapour to form cloud) cools as it rises. Because condensation releases latent heat, this rate is lower than the DALR: approximately 5–6°C per 1,000 m (varies with temperature and pressure).
Stability and Lapse Rate:
- If ELR < SALR: absolutely stable atmosphere (parcels resist vertical movement)
- If SALR < ELR < DALR: conditionally unstable (stable for dry parcels, unstable for saturated ones)
- If ELR > DALR: absolutely unstable (parcels accelerate vertically — convection, thunderstorms)
5. Atmospheric Pressure
Atmospheric pressure is the weight per unit area of the air column above a point. At sea level, standard atmospheric pressure is 1013.25 hPa (hectopascals), also expressed as 760 mm Hg or 1 atmosphere.
Pressure decreases with altitude because there is less air above. The rate of decrease is approximately 10 hPa per 100 m near sea level.
Measuring instruments:
- Mercury barometer: Standard laboratory instrument
- Aneroid barometer: Portable, uses a sealed metal chamber
- Barograph: Records pressure continuously over time
Pressure systems:
- Cyclone (Low pressure): Converging winds spiralling inward. In the Northern Hemisphere, this is anticlockwise. Associated with cloudy, rainy, stormy weather.
- Anticyclone (High pressure): Diverging winds spiralling outward. In the Northern Hemisphere, clockwise. Associated with clear, stable, dry weather.
6. Temperature
Temperature is the measure of the kinetic energy of atmospheric molecules. It is the most commonly measured meteorological variable.
Factors affecting temperature:
- Latitude (solar angle and insolation)
- Altitude (temperature decreases ~6.5°C per 1,000 m)
- Distance from ocean (maritime moderation vs. continental extremes)
- Prevailing winds (warm or cold origin)
- Ocean currents
- Land cover (forests, deserts, urban heat islands)
- Aspect (which direction a slope faces)
Instruments: Thermometer (mercury or alcohol), maximum-minimum thermometer, thermograph (continuous record), radiosonde (upper-air measurement via weather balloon).
7. Wind
Wind is the horizontal movement of air from areas of high pressure to areas of low pressure. It is described by direction (where it comes from) and speed.
Causes of wind:
- Pressure gradient force: Drives wind from high to low pressure. The steeper the gradient, the faster the wind.
- Coriolis effect: Deflects wind to the right in the Northern Hemisphere and to the left in the Southern Hemisphere due to Earth's rotation.
- Friction: Slows wind near the surface.
Global wind belts:
- Trade Winds: 0–30° latitude, blowing from subtropical highs toward the equatorial low
- Westerlies: 30–60° latitude, dominant in Nepal's weather
- Polar Easterlies: 60–90° latitude
Local winds:
- Valley/Mountain winds: Anabatic (upslope, daytime) and katabatic (downslope, nighttime) winds in Nepal's terrain
- Sea/Land breeze: Coastal areas — sea breeze by day, land breeze by night
Measuring instruments: Anemometer (speed), wind vane (direction).
8. Humidity and Moisture
Water exists in the atmosphere as gas (water vapour), liquid (cloud droplets, rain), and solid (ice crystals, snow). Humidity describes the amount of water vapour present.
Types of humidity:
- Absolute humidity: Mass of water vapour per unit volume of air (g/m³)
- Specific humidity: Mass of water vapour per unit mass of moist air (g/kg)
- Relative humidity (RH): Ratio of actual water vapour to the maximum possible at that temperature, expressed as percentage. 100% RH = saturation.
Dew point: The temperature to which air must be cooled (at constant pressure and moisture content) for saturation to occur. If air is cooled below the dew point, condensation begins — forming dew, frost, fog, or cloud.
Measuring instruments: Hygrometer, psychrometer (wet-bulb/dry-bulb thermometer pair).
9. Clouds and Precipitation
Cloud formation: When moist air rises, it cools. When it cools to the dew point, water vapour condenses on tiny particles called condensation nuclei (dust, sea salt, pollen) to form cloud droplets.
Cloud classification (by height):
| Family | Height (Nepal) | Types |
|---|---|---|
| High Clouds | Above 6,000 m | Cirrus, Cirrocumulus, Cirrostratus |
| Middle Clouds | 2,000–6,000 m | Altocumulus, Altostratus |
| Low Clouds | Below 2,000 m | Stratus, Stratocumulus, Nimbostratus |
| Vertical Development | All heights | Cumulus, Cumulonimbus |
Precipitation types:
- Rain: Liquid water drops >0.5 mm diameter
- Drizzle: Fine liquid drops <0.5 mm
- Snow: Ice crystals forming below 0°C
- Hail: Ice pellets formed in strong updrafts in cumulonimbus clouds
- Sleet: Partially melted snowflakes
- Fog: Cloud at ground level (visibility < 1 km)
10. Greenhouse Effect and Global Warming
The greenhouse effect is the process by which certain atmospheric gases (greenhouse gases) absorb outgoing infrared radiation from Earth's surface and re-emit it in all directions, warming the lower atmosphere.
Natural greenhouse gases: Water vapour (H₂O), carbon dioxide (CO₂), methane (CH₄), nitrous oxide (N₂O), ozone (O₃).
The enhanced greenhouse effect: Human activities — burning fossil fuels, deforestation, agriculture, industrial processes — have increased concentrations of greenhouse gases beyond natural levels, intensifying the warming effect. Atmospheric CO₂ has risen from approximately 280 ppm (pre-industrial) to over 420 ppm (2026).
Consequences: Global average temperature increase, sea level rise (thermal expansion + glacier melt), extreme weather intensification, ecosystem disruption, shifts in monsoon patterns.
Relevance for Nepal: Himalayan glaciers are retreating rapidly (documented by ICIMOD). Glacial Lake Outburst Floods (GLOFs) are increasing. Monsoon variability is intensifying. Nepal contributes negligibly to global emissions but bears disproportionate climate impacts.
Part 2: Climatology
1. Climatology — Definition and Scope
Climatology is the scientific study of climate — the long-term average atmospheric conditions (temperature, precipitation, humidity, wind) of a place, typically calculated over a 30-year reference period. It asks: "What is the normal weather for this place and this time of year?"
Climatology differs from meteorology in timescale and approach. Meteorology forecasts what the weather will do in the next hours to days. Climatology describes what weather typically does and how that long-term pattern is changing.
2. Factors Affecting Climate
- Latitude: Determines the angle of incoming solar radiation and thus the intensity of insolation.
- Altitude: Higher elevations are colder (lapse rate). Nepal's climate varies from subtropical in the Terai to alpine and arctic in the Himalayas over a horizontal distance of only ~200 km.
- Distance from ocean: Maritime climates are mild and moist. Continental climates have extreme temperature ranges.
- Prevailing winds and ocean currents: The South Asian Monsoon, driven by differential heating between the Indian Ocean and Asian landmass, is the dominant climate driver for Nepal.
- Relief and aspect: Mountains block or funnel air masses; south-facing slopes are warmer than north-facing ones in the Northern Hemisphere.
- Human modification: Urbanization (urban heat islands), deforestation, land use change.
3. Air Masses
An air mass is a large body of air (thousands of kilometres across) that is relatively homogeneous in temperature and humidity, having acquired these properties by sitting over a source region for days to weeks.
Classification:
- By temperature: Arctic (A), Polar (P), Tropical (T)
- By moisture: Continental (c — dry), Maritime (m — moist)
Types affecting South Asia:
- Continental Polar (cP): Cold, dry air from Central Asia — source of winter cold waves in Nepal
- Maritime Tropical (mT): Warm, moist air from the Indian Ocean — source of monsoon moisture
- Continental Tropical (cT): Hot, dry air from the Thar Desert — influences pre-monsoon weather
4. Fronts
A front is the boundary between two contrasting air masses. Weather changes rapidly across fronts.
| Front Type | Description | Associated Weather |
|---|---|---|
| Cold Front | Cold air advancing, pushing under warm air | Sudden storms, heavy rain, rapid temperature drop |
| Warm Front | Warm air advancing, rising over cold air | Gradual cloud thickening, steady rain, slow temperature rise |
| Stationary Front | Neither air mass advancing | Prolonged cloud and precipitation |
| Occluded Front | Cold front catches warm front | Complex precipitation patterns |
5. Climate of Nepal
Nepal has exceptional climatic diversity due to its extreme topographic range — from 60 m (Terai) to 8,849 m (Everest summit) — and its position at the intersection of the South Asian Monsoon and the mid-latitude westerlies.
Four main climatic zones:
- Tropical/Subtropical (Terai, <300 m): Hot summers, mild winters, heavy monsoon rainfall (1,500–2,000 mm/year)
- Warm Temperate (Hills, 300–2,000 m): Warm summers, cool winters, significant rainfall
- Cool Temperate (Middle Mountains, 2,000–3,000 m): Mild summers, cold winters, snow possible
- Alpine/Arctic (High Himalaya, >3,000 m): Short cool summers, very cold winters, snowfall
Nepal's four seasons:
- Pre-monsoon (March–May): Rising temperatures, thunderstorms, hailstorms
- Monsoon (June–September): ~80% of Nepal's annual rainfall. SW monsoon drives moisture from the Bay of Bengal. Flooding, landslides.
- Post-monsoon (October–November): Clear skies, excellent visibility, trekking season
- Winter (December–February): Western disturbances bring snowfall to hills and mountains. Terai has cold nights with occasional fog.
6. Monsoon
The South Asian Monsoon is the most important weather system for Nepal. It is driven by the seasonal reversal of wind direction caused by differential heating between the ocean (heats slowly) and the Asian landmass (heats rapidly in summer).
Summer (SW) Monsoon — June to September:
- Intense heating of Asia creates a deep low pressure over the subcontinent
- Moist air flows from the high pressure over the Indian Ocean northward into this low
- The flow is deflected by the Coriolis effect to become southwesterly
- Moisture-laden air rises over the Himalayas, cools, and produces heavy rainfall
Winter (NE) Monsoon — December to February:
- Asia cools rapidly, creating high pressure over the continent
- Dry, cold air flows outward from this high as northeasterly winds
- Brings dry conditions to Nepal except where western disturbances override it
7. Western Disturbances
Western disturbances are extratropical cyclones originating over the Mediterranean Sea and Caspian Sea that travel eastward along the mid-latitude westerly belt. They bring winter precipitation to northern South Asia, including Nepal's hills and mountains, in the form of rain at lower elevations and snow at higher elevations.
Western disturbances are responsible for snowfall at Himalayan trekking destinations in winter and spring, and occasional severe cold waves in the Terai.
8. Climate Change and Nepal
Nepal is recognized internationally as a climate change hotspot despite contributing less than 0.1% of global greenhouse gas emissions.
Observed changes in Nepal:
- Himalayan glaciers retreating at accelerating rates (ICIMOD data)
- Increase in frequency and intensity of extreme events (floods, droughts, GLOF events)
- Changes in monsoon onset timing and rainfall distribution
- Declining snowfall in some regions, paradoxically increased avalanche risk in others
- Shifts in agricultural growing seasons
Nepal's economy depends heavily on agriculture (climate-sensitive), hydropower (dependent on river flow from snow/glacier melt), and tourism (affected by changing mountain conditions). These dependencies make climate change a development issue, not only an environmental one.
Important Questions for Exam
General Meteorology — Long Questions
- Define meteorology. Explain its scope and applications.
- Describe the composition of the atmosphere. What are the variable gases and why are they meteorologically significant?
- Explain the structure of the atmosphere with a labelled diagram showing each layer.
- What is lapse rate? Explain dry adiabatic, saturated adiabatic, and environmental lapse rates with their significance for atmospheric stability.
- Explain the greenhouse effect. How does the enhanced greenhouse effect contribute to global warming?
- Describe the classification of clouds by altitude with examples of each type.
- Explain the causes and types of wind. What is the Coriolis effect and how does it influence wind direction?
- Define atmospheric pressure. Explain cyclones and anticyclones and their associated weather.
General Meteorology — Short Questions
- Define meteorology. How does it differ from climatology?
- State the composition of the dry atmosphere.
- What is the tropopause?
- Define relative humidity and dew point.
- What is an anemometer? What does it measure?
- Differentiate between weather and climate.
- Define precipitation. List four types.
- What is the greenhouse effect?
- What is atmospheric pressure? What is its standard sea-level value?
- Define lapse rate.
Climatology — Long Questions
- Define climatology. Explain the major factors that affect the climate of a region.
- What is an air mass? Explain the types of air masses and their influence on Nepal's weather.
- Explain the South Asian Monsoon. How does it bring rainfall to Nepal?
- Describe the climate of Nepal. Explain how altitude influences its climatic diversity.
- What are fronts? Explain the types of fronts and their associated weather.
- Explain western disturbances. What is their significance for Nepal?
- Write a note on climate change in Nepal. What are the observed impacts on the Himalayas?
Climatology — Short Questions
- Define climatology.
- What is the 30-year reference period in climatology?
- Name the four seasons of Nepal.
- What is a western disturbance?
- Define air mass.
- What is a GLOF?
- Name two greenhouse gases.
- Explain the urban heat island effect.
Past Exam Question Trend Analysis
Based on the structure of TU BSc Meteorology past papers, these topics appear most consistently:
Appears almost every year:
- Atmospheric layers with diagram
- Composition of atmosphere
- Greenhouse effect and global warming
- Lapse rate (three types)
- Climate of Nepal
- Monsoon — mechanism and significance for Nepal
- Weather vs climate differentiation
Appears frequently:
- Air masses and their types
- Fronts (types and weather)
- Atmospheric pressure (cyclone vs anticyclone)
- Cloud classification
- Precipitation types
- Western disturbances
- Himalayan glacier retreat and climate change
Occasionally appears:
- Specific humidity calculations
- Urban heat island
- Climate classification systems (Köppen)
- Coriolis effect explained mathematically
Recommended Books
| Book | Author | Use |
|---|---|---|
| General Meteorology | H.R. Byers | Comprehensive theory reference |
| Atmospheric Science: An Introductory Survey | Wallace & Hobbs | Modern, university-level |
| Essentials of Meteorology | C. Donald Ahrens | Very accessible, well-illustrated |
| Climatology | Oliver & Hidore | Climatology specific |
| Meteorology and Climatology for the UGC NET | Singh & Singh | Exam-focused |
For Nepal-specific climate data and reports: the Department of Hydrology and Meteorology (DHM) website publishes annual climate summaries, and ICIMOD publishes research on Himalayan climate.
Exam Tips
Draw diagrams for every atmospheric structure question. The atmospheric layers diagram, cloud classification diagram, and front diagrams are expected as part of long answers. A labelled diagram with incorrect prose will still earn diagram marks. Missing the diagram from an answer that calls for one will lose marks.
Learn the three lapse rates and their values. DALR = 10°C/1,000 m, SALR ≈ 5–6°C/1,000 m, ELR (average) = 6.5°C/1,000 m. These values are frequently asked as short-answer items and are prerequisite for stability questions.
For climate of Nepal questions: Structure your answer around the four topographic zones (Terai, Hills, Middle Mountains, High Himalaya) and the four seasons. Include at least one example of typical precipitation and temperature for each zone.
For monsoon questions: Explain the mechanism (differential heating, pressure gradient, Coriolis deflection) before describing the effects on Nepal. Mechanism earns more marks than description alone.
Use SI units: Temperature in °C, pressure in hPa, wind speed in m/s or km/h, altitude in m or km, precipitation in mm.
Frequently Asked Questions
What is meteorology? Meteorology is the scientific study of the atmosphere, particularly its short-term behaviour — weather. It uses physics, chemistry, and mathematics to understand and predict atmospheric phenomena from individual thunderstorms to large-scale wind systems.
What is the scope of BSc Meteorology in Nepal? Strong. Nepal's dependence on agriculture, hydropower, and tourism — all highly sensitive to weather and climate — creates sustained demand for trained meteorologists. The Department of Hydrology and Meteorology, aviation weather services, international organizations working in Nepal (ICIMOD, UNDP, WFP), and development agencies all recruit from this field.
Is BSc Meteorology difficult? It requires solid understanding of physics (thermodynamics, fluid dynamics), mathematics (calculus, statistics), and chemistry (atmospheric composition). Students with strong science backgrounds typically find the first year challenging but manageable. The practical aspects — weather observation, data analysis, map reading — make it more engaging than purely theoretical courses.
What jobs can I get after BSc Meteorology in Nepal? Government positions in the Department of Hydrology and Meteorology are the primary pathway. International organizations, aviation weather services, research institutions (ICIMOD, NARC), NGOs working on disaster risk reduction, and the growing climate consultancy sector also recruit meteorology graduates. A master's degree significantly expands research and international opportunities.
Which books are best for TU BSc Meteorology 1st Year? Start with Ahrens' Essentials of Meteorology for accessible explanations with diagrams. Wallace & Hobbs' Atmospheric Science is the standard rigorous reference. For exam practice, past TU question papers combined with DHM's published reports on Nepal's climate are particularly useful.
How is climate different from weather? Weather is the short-term state of the atmosphere at a specific place and time — today's temperature, tonight's rain, tomorrow's wind. Climate is the long-term average of weather conditions over decades (typically 30 years). "Climate is what you expect; weather is what you get."
Why is Nepal particularly vulnerable to climate change? Nepal's geography places it directly in the path of the most significant climate impacts: Himalayan glacier retreat (affecting river flows, water availability, and GLOF risk), changing monsoon patterns (affecting agriculture), and increasing extreme weather events (flooding, drought). Nepal contributes negligibly to global greenhouse gas emissions but faces disproportionate consequences because of its geography and economic structure.
Conclusion
Meteorology and climatology are sciences with immediate, tangible relevance in Nepal. The concepts introduced in first year — atmospheric structure, pressure systems, moisture and clouds, lapse rates, air masses, monsoon dynamics, and climate change — form the foundation for every advanced topic in the program and for professional practice in weather forecasting, climate research, and disaster risk management.
Approach this material as practical knowledge, not abstract theory. Nepal's weather — the monsoon that fills the rivers, the western disturbances that bring winter snowfall to the hills, the warming that is retreating Himalayan glaciers — is the real-world expression of every concept in this course.
For related subjects: BSc CSIT Physics (PHY118) Complete Guide, Newton's Laws of Motion — Complete Guide, and Mathematics-I (MTH117) Complete Guide.
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