Analyze the reasons for the large daily temperature difference in Lhasa.

(26 points) (1)( 10 points) The altitude is high, the air is thin, and there are relatively few water vapor and impurities (2 points). During the day, the atmosphere has a weak weakening effect on solar radiation, and the amount of solar radiation reaching the ground is large and the temperature is high (2 points); At night, the atmospheric inverse radiation is weak, the temperature is low (2 o'clock) and the daily temperature difference is large. The valley terrain is not easy to dissipate heat during the day (2 points), and cold air (mountain wind) sinks down the slope at night (2 points), which increases the daily temperature difference. (2)(8 points) There is relatively little precipitation during the day and sufficient sunshine (2 points), which is beneficial to photosynthesis, increases the accumulation of organic matter in crops, and can improve their yield and quality (2 points); There is more precipitation at night, the temperature is lower than during the day, and the part consumed by rainwater evaporation is less (2 points). More water permeates into the soil, which is beneficial to water conservation and increases crop root absorption (2 points). (3)(8 points) Advantages: high altitude, cool in summer; Near the Lhasa River, there is a lot of rain and moderate humidity in summer and evening; The air is fresh; There are many sunny days and plenty of sunshine. (Answer two points at any time, 2 points for each point ***4 points) Disadvantages: high altitude, thin air and insufficient oxygen; Solar ultraviolet radiation is strong; The daily temperature difference is large. (Just answer two points, 2 points for each point ***4 points)