从气象原理来看，三伏天期间，我国大部地区被副热带高压或大陆高压控制，一般高压系统比较稳定少动，容易长时间控制一个地区，且控制区域内盛行下沉气流，不利于热量扩散，此时太阳仍然直射北半球，热量累积，容易出现高温天气。

“大暑”是中国传统二十四节气之一，通常出现在每年的7月22日前后，是一年中最炎热的时节。在这段时间里，人们会吃一些清凉消暑的食物，尽量待在室内，并采用各种传统方法来对抗酷热天气。

SINGAPORE, July 19 (Xinhua) -- Tian Muran fell just one place short of advancing to the semifinals of the 3km open water knockout sprint at the World Aquatics Championships, but she walked away with a ...

According to the Tobacco Industry and Marketing Board (TIMB), the sector is witnessing record-breaking sales this year, with farmers already delivering more than 340 million kg of the golden leaf to ...