Synoptic Meteorology – Major Air Mass Types From the standard air-mass classification used in meteorology, which combination correctly lists common air masses such as maritime tropical (mT), maritime polar (mP), maritime arctic (mA), and continental polar (cP)?

Introduction / Context:
Air masses are large bodies of air defined by fairly uniform temperature and humidity characteristics acquired over source regions. The common notation pairs moisture type (maritime m, continental c) with thermal origin (tropical T, polar P, arctic A). This question checks your familiarity with widely referenced categories.

Given Data / Assumptions:

• Listed types: mT, mP, mA, cP.
• We must judge whether each listed category is recognized in meteorological literature.
• Roman numerals correspond to the enumerated list in the stem.

Concept / Approach:
Standard air-mass classes include mT (warm, humid), mP (cool, humid), cP (cold, dry), and cA/mA (very cold, dry; sometimes denoted arctic). While some textbooks prefer cA for arctic over continents, maritime arctic (mA) is also used to describe cold, moisture-bearing polar/arctic maritime source regions. Since all four types can appear in classification schemes and forecasting discussions, the most inclusive option is correct.

Step-by-Step Solution:

Verification / Alternative check:
Weather analyses for the North Atlantic/North Pacific regularly reference mT and mP. Arctic variants (cA/mA) and continental polar (cP) are core to cold-season synoptic patterns, validating the set.

Why Other Options Are Wrong:

• I, III, IV or I, II or I, IV: Each omits at least one commonly used category, making the set incomplete.

Common Pitfalls:
Insisting on a single notation (cA only) and rejecting mA. Different curricula use slightly different labels; conceptually, the arctic maritime class exists in practice.

Final Answer:
All of the above