Climate Classification Systems Questions and Answers

Answer: A

Correct answer: temperature and rainfall thresholds

Koppen defined his classes by numerical limits on monthly and annual temperature and precipitation - the coldest month above or below a stated value, the driest month against a rainfall threshold, and so on. Those two variables were chosen because they were widely measured and because they governed the vegetation he was really classifying.

Answer: B

Correct answer: Both A and R are true, and R is the correct explanation of A

Both are true and the reason gives the sense in which the system is empirical. Koppen was a botanist, and he set his thresholds where the observed vegetation changed - the 10 degree isotherm of the warmest month at the tree line, the 18 degree coldest-month limit for tropical vegetation. The boundaries therefore describe what is there rather than following from any theory of why, which is exactly what distinguishes an empirical classification from a genetic one.

Answer: C

The fifth group, E, covers polar climates where no month is warm. The first letter fixes the broad type and the following letters refine the seasonality of precipitation and the summer temperature. Five groups cover the world.

Answer: D

Correct answer: aridity, on a variable threshold

Group B is the dry group, and its threshold is not a fixed rainfall figure: it depends on the mean annual temperature, because warmer air evaporates more, and on the seasonality of the rain, because summer rain is less effective than winter rain. A place can therefore be arid at 500 mm and humid at 300 mm depending on where and when the rain falls.

Answer: A

Both are true and the reason gives the logic, and it is why a place with four hundred millimetres may be arid in the tropics and humid in a cold climate. Demand as well as supply enters the test. Warm climates need more rain to stay humid.

Answer: B

Correct answer: 1 and 2 only

Statements 1 and 2 describe the coding correctly - the first letter gives the broad group, the second the precipitation pattern and the third the temperature detail. Statement 3 is wrong, and it is the standing contrast in this topic: Koppen is empirical, built on observed thresholds, while a genetic classification derives its types from the general circulation that causes them.

Answer: C

Correct answer: temperate, with no dry season

Reading the three letters in turn: C is the temperate group, f means no dry season - precipitation in every month - and b means a warm rather than hot summer, the warmest month below 22 degrees. It is the climate of north-western Europe, New Zealand and the Pacific north-west of North America.

Answer: D

Learning a representative place for each code fixes the system far better than memorising the thresholds. The s in the third denotes a dry summer, which is the Mediterranean signature. A place fixes a code better than a threshold.

Answer: A

Correct answer: potential evapotranspiration

Thornthwaite computes how much water the atmosphere could evaporate given the temperature and day length, compares it with the precipitation, and classifies on the resulting moisture surplus or deficit. That makes it a water balance approach, better suited to agriculture and hydrology than Koppen’s thresholds, at the cost of needing a calculation rather than a look-up.

Answer: B

Both are true and the reason gives the advantage, since the surplus and deficit it computes are directly what an irrigation or drainage decision requires. Surplus and deficit are computed monthly. Data demands are heavier than for Koppen.