Water in the Atmosphere

WORLD CLIMATE AND CLIMATE CHANGE

Climate refers to the long-term pattern of weather conditions prevailing in a particular area. To study world climate effectively, information and data on temperature, precipitation, and other climatic factors are organized and synthesized into smaller, manageable units for easier understanding, description, and analysis. Three broad approaches have been adopted for classifying climate: empirical, genetic, and applied. The empirical classification is based on observed data, particularly temperature and precipitation. Genetic classification attempts to organize climates according to their causes, such as atmospheric circulation patterns or latitude. Applied classification is designed for specific purposes, such as agricultural planning or urban development. Among these, the empirical classification by V. Koeppen is the most widely used and accepted because it closely relates climate to vegetation distribution, making it practical for understanding climatic zones and their ecological implications.

• Climate is the long-term pattern of weather conditions in a region.
• Three approaches to climate classification: empirical, genetic, and applied.
• Empirical classification uses observed temperature and precipitation data.
• Genetic classification is based on causes of climate.
• Applied classification serves specific practical purposes.
• Koeppen's empirical classification is widely used due to its relation to vegetation.
• 📌 Climate: The long-term average of weather conditions in a region.
• 📌 Empirical classification: Climate classification based on observed data.
• 📌 Genetic classification: Climate classification based on causes.

KOEPPEN'S SCHEME OF CLASSIFICATION OF CLIMATE

Vladimir Koeppen developed an empirical climate classification scheme that is still widely used today. He identified a close relationship between climate and vegetation distribution, which helped him select specific temperature and precipitation values to classify climates. Koeppen's classification is based on mean annual and mean monthly temperature and precipitation data. He used capital letters to denote major climatic groups and small letters to indicate subtypes based on seasonality of precipitation and temperature characteristics. The five major climatic groups he recognized are: A (Tropical), B (Dry), C (Warm Temperate or Mid-Latitude), D (Cold Snow Forest), and E (Polar or Cold). Groups A, C, D, and E are humid climates, while B represents dry climates. Subdivisions within these groups use small letters such as 'f' for no dry season, 'm' for monsoon, 'w' for winter dry season, and 's' for summer dry season. Temperature severity is indicated by letters a, b, c, and d. Dry climates (B) are further subdivided into steppe (S) and desert (W) types, with additional classification based on latitude. This system effectively links climate types with vegetation patterns and geographical distribution, making it practical for understanding global climate zones. **Table on page 1 (6×2)** | Group | Characteristics | | --- | --- | | A - Tropical | Average temperature of the coldest month is 18 C or higher | | B - Dry Climates | Potential evaporation exceeds precipitation | | C - Warm Temperate | The average temperature of the coldest month of the (Mid-latitude) climates years is higher than minus 3 C but below 18 C | | D - Cold Snow Forest Climates | The average temperature of the coldest month is minus 3 C or below | | E - Cold Climates | Average temperature for all months is below 10 C | **Table on page 2 (15×4)** | Group | Type | Letter Code | Characteristics | | --- | --- | --- | --- | | A-Tropical Humid Climate | Tropical wet | Af | No dry season | | | Tropical monsoon | Am | Monsoonal, short dry season | | | Tropical wet and dry | Aw | Winter dry season | | B-Dry Climate | Subtropical steppe | BSh | Low-latitude semi arid or dry | | | Subtropical desert | BWh | Low-latitude arid or dry | | | Mid-latitude steppe | BSk | Mid-latitude semi arid or dry | | | Mid-latitude desert | BWk | Mid-latitude arid or dry | | C-Warm temperate (Mid-latitude) Climates | Humid subtropical | Cfa | No dry season, warm summer | | | Mediterranean | Cs | Dry hot summer | | | Marine west coast | Cfb | No dry season, warm and cool summer | | D-Cold Snow-forest Climates | Humid continental | Df | No dry season, severe winter | | | Subarctic | Dw | Winter dry and very severe | | E-Cold Climates | Tundra | ET | No true summer | | | Polar ice cap | EF | Perennial ice |

• Koeppen's classification is empirical, based on temperature and precipitation data.
• Five major climatic groups: A (Tropical), B (Dry), C (Warm Temperate), D (Cold Snow Forest), E (Polar).
• Capital letters denote major groups; small letters denote subtypes.
• Small letters indicate seasonality of precipitation: f (no dry season), m (monsoon), w (winter dry), s (summer dry).
• Temperature severity indicated by letters a, b, c, d.
• Dry climates subdivided into steppe (S) and desert (W) types.
• 📌 Koeppen's classification: An empirical climate classification system based on temperature and precipitation.
• 📌 Climatic groups: Major categories in Koeppen's system denoted by capital letters.
• 📌 Seasonality letters: Indicators of dry or wet seasons in climate types.