Consider the following pairs with reference to world climate types and their characteristics : (Climate) (Characteristic) I. Tropical wet and dry : Winter dry season and dry II. Mid-latitude steppe : Mid-latitude semi-arid or dry III. Humid sub-tropical : No dry season, warm summer IV. Marine west coast : No dry season, severely cold summer How many of the pairs given above is/are correctly matched?

Correct — C, 3. Three of the four pairs reproduce the standard climatic-type table and the fourth does not. Tropical wet and dry (Aw) is the savanna climate of the low latitudes, with rain in the high-sun season and a dry winter, so pair I holds. Mid-latitude steppe (BSk) is the semi-arid grassland belt of the continental interiors — the prairies, the Eurasian steppe, the pampas — and the table describes it in exactly the words the paper prints, mid-latitude semi-arid or dry, so pair II holds. Humid subtropical (Cfa) sits on the eastern side of continents in the lower mid-latitudes, has no dry season and a warm summer, and pair III holds. Pair IV is the false one. Marine west coast climate (Cfb) belongs to the western side of continents between roughly 45 and 55 degrees — north-west Europe and the British Isles, the Pacific North-West, southern Chile, New Zealand — where the ocean and the onshore westerlies keep the annual range small. Its entry reads 'no dry season, warm and cool summer'. The paper gives it a severely cold summer, which is the opposite of what makes a climate maritime, and no C-group climate carries that description at all. Three correct pairs, so the count is 3.

• (a)1 — Undercounts badly. It would need two of the three genuine pairs to be wrong, and pairs II and III are printed exactly as the standard table gives them.
• (b)2 — The likely landing place for anyone who rejects pair I because of the extra words at the end of its description. The core of that entry — a winter dry season for tropical wet and dry climate — is right, and the trailing 'and dry' is a printing slip rather than a change of meaning.
• (d)4 — Requires accepting a severely cold summer for the marine west coast climate. A maritime climate is defined by the sea damping the annual range, so mild summers and mild winters are its signature; the description printed against it is self-contradictory.

Koeppen classified climates by monthly temperature and precipitation, using letters. The capital letter gives the group — A tropical, B dry, C warm temperate, D cold snow forest, E cold — and the letters after it refine it. A second letter f means no dry season, m monsoonal with a short dry season, w a dry winter, s a dry summer, and in the dry B climates S means steppe and W desert. A third letter fixes the temperature detail: a for a hot summer, b for a warm summer, c for a short cool summer, h for hot and k for cold. So Aw is tropical wet and dry, BSk mid-latitude steppe, Cfa humid subtropical and Cfb marine west coast.

Matching items of this kind are won by knowing what each climate is for rather than by memorising the strings. A maritime climate exists because a large body of water refuses to heat or cool quickly, so its whole character is moderation — cool summers, mild winters, rain spread through the year, small annual range. Any description that puts an extreme against 'marine' is suspect on sight, and that is the fastest route to pair IV. The second useful check is against the letters themselves: Cfb has an f, so no dry season, and a b, so a warm rather than a hot summer. Neither letter permits a severely cold summer. One printed oddity is worth naming and setting aside. Pair I's description is given as 'Winter dry season and dry', where the standard table has simply 'Winter dry season'. The extra words add nothing and do not change the match; the paper's wording is reproduced here as printed.

• The table's entries: Tropical wet Af 'no dry season'; Tropical monsoon Am 'monsoonal, short dry season'; Tropical wet and dry Aw 'winter dry season'.
• Subtropical steppe BSh 'low-latitude semi arid or dry'; Mid-latitude steppe BSk 'mid-latitude semi arid or dry'; Mid-latitude desert BWk 'mid-latitude arid or dry'.
• Humid subtropical Cfa 'no dry season, warm summer'; Mediterranean Cs 'dry hot summer'; Marine west coast Cfb 'no dry season, warm and cool summer'.
• Humid continental Df 'no dry season, severe winter'; Subarctic Dw 'winter dry and very severe'; Tundra ET 'no true summer'; Polar ice cap EF 'perennial ice'.
• Marine west coast climate occupies the western margins of continents between about 45 and 55 degrees, where onshore westerlies bring the sea's moderating influence inland.

• Pairing 'marine' with an extreme. Maritime means moderated — small annual range, no dry season, mild in both directions.
• Reading the third letter as though it described winter. In the C and D groups a, b and c describe the summer.
• Rejecting a pair over a printed oddity rather than over its substance, as with the extra words in pair I here.

As a climatic type to characteristic or letter code match, as a name-the-code question for a given region, or in reverse as an identify-the-climate item built from three or four described features.

• practice — not a real PYQ

  In Koeppen's scheme, the letter code Cfb denotes which one of the following climates?

  • (a)Mediterranean climate
  • (b)Marine west coast climate
  • (c)Humid continental climate
  • (d)Tropical monsoon climate

  Answer(b) Marine west coast climate — C for warm temperate, f for no dry season, b for a warm rather than hot summer.

• practice — not a real PYQ

  The second letter 's' in a Koeppen code such as Cs indicates

  • (a)a dry summer
  • (b)a dry winter
  • (c)steppe conditions
  • (d)a severe winter

  Answer(a) a dry summer — Cs is the Mediterranean climate, whose defining feature is summer drought under the migrating sub-tropical high.