Read the contour map of a certain area in China and answer the following questions. (15 points) (1) Briefly describe the main reason why the isotherm at P bends northward. (2 points) (2)

(1) is

Read the contour map of a certain area in China and answer the following questions. (15 points) (1) Briefly describe the main reason why the isotherm at P bends northward. (2 points) (2)

(1) is located in Ningxia plain (or river valley), with low terrain and high temperature (2 points).

(2) There is much precipitation on windward slopes in mountainous areas; The mountainous area has high terrain, low temperature and heavy snowfall (4 points).

(3) The terrain is relatively closed and the surrounding terrain is slightly higher; Less precipitation and vigorous evaporation. (4 points)

(4) Less precipitation and vigorous evaporation (1); There is no inflow of major tributaries (1 min); Severe infiltration (1 min) reduced the flow of this reach (2 points).

Analysis of test questions: the isotherm at (1) P bends to the north, indicating that the temperature is high, which is due to the influence of topography and is located in a valley with low terrain. Question (2) The number of snowfall days in Q year is more than that in the surrounding areas, which is why it is located on the windward slope of the southeast monsoon, with more precipitation, higher terrain, lower temperature and more snowfall. The first (3) inflow area means that the surface water cannot flow out here, that is to say, the terrain of this area is closed, the surrounding terrain is high, there is little precipitation, evaporation is vigorous, and surface runoff is less. Question (4) In the figure, the climate of R reach is dry, with little precipitation and strong evaporation, and there is no large tributary injection, so the river flows downward along the way, so the river flow is decreasing.

Comments: This topic comprehensively investigates the causes of the daily distribution of isotherm and equal snowfall, the causes of the internal flow area and the changes of river runoff. The key to solve the problem is to understand the distribution law of isoline, the concept of internal flow area and the factors affecting river runoff.