第四篇 气温影响
【机经回忆】
太阳加热土地，而土地则加热与大地接触的空气，这样旅行者会觉得上层的空气会比脚部的空气要凉爽。气流的对流和空气的改变也很大的。最热的时候不是日当正午，而是出现在下午，但具体是什么时候要根据当地的条件和当天的天气情况来定。
【重点词汇解析】
heat 加热
accessible 可接触到的
air 空气
traveler 旅行者
cooler 凉爽
convection 对流
at noon 正当午
local condition 当地条件
weather 天气
【机经解析】
气流对流：午后是一天当中最热的时光
The highest temperature, particularly on a cloudless day in Summer occurs somewhere between 3 pm and 7 pm, with the most common time being around 5 pm, Daylight time. This is somewhat later than in Winter when the time of maximum temperature is somewhere between 1 and 3 pm.
You can think of it almost like baking something in an oven or warming something in a microwave. Even though the oven or microwave is putting a constant amount of energy into whatever you are cooking, it takes time for the food to warm up from the lower temperature that it started out at.
In the same way, it takes time for the Sun to heat the ground and therefore for the ground to heat the air above it. Since the maximum intensity of Sunlight occurs at local solar noon (which might be as much as an hour different from the Daylight time, depending on where you live in a time zone), the ground is warming throughout the morning, but its temperature can not catch up to the increasingly greater amount of energy that the Sun is providing (unlike the constant heat in the oven or microwave). After noon, the Sun continues to raise the ground and air temperature until more energy is lost to space than the ground can take in from the Sun. Therefore, there is a long lag between noon and the time of maximum air temperature. Having more than 12 hours of daylight in the Summer also contributes to pushing the maximum temperature time to the late afternoon
Daily Temperature Lag日常温度差
The lag is due to the fact that heating of the air occurs, not from the sun's rays passing though, but from heating of the ground and infrared radiation leaving the ground in the form of heat. This process takes some time, and it is also the reason it does not get chilly immediately after sunset.....there is residual warmth in the ground being radiated into the air producing some residual heating even after the sun has set.
If the warmth of the air resulted from the sun's rays passing through, then you would observe highest air temp. when the sun's rays were at their daily peak.
以上就是1月12日托福阅读机经整理，希望各位考友合理利用机经，认真备考，获得一个自己理想的成绩。
