What Is an Air Current?

Airflow is an academic term in meteorology. Especially the vertical movement of air. Air flow (wind). Its speed is expressed in meters per second (m / s). The cause of air flow is the temperature difference caused by uneven heating. The hot air rises lightly, and the cold air flow supplements it to form convection. The air at the production site is heated by the heat source in the workshop to expand its volume and reduce its density. It will be discharged from the upper air outlet to the outside, and the cold air outside will enter the room through the side window or door to form an air flow. The impact of atmospheric wind pressure on the plant can also cause indoor airflow.

1. airflow

The flowing air is called airflow. Like the wind.

2.

1. Reversibility principle

An object moves in a stationary air or an air current flows over a stationary object.

One: What is airflow?

Simply put, airflow is the up-and-down movement of air. Air moving up is called updraft, and air moving down is called downdraft. The updraft is divided into power flow, heat flow, mountain wave and other types.

Using 10 layers of NCEP / NCAR's global 1000 hPa, 850 hPa, 700 hPa, 600 hPa, 500 hPa, 400 hPa, 300 hPa, 200 hPa, 150 hPa, and 100 hPa from January 1948 to December 2004 To the grid wind, the global equatorial airflow and its annual variation were calculated, and the temporal and spatial characteristics of the global 850 hPa transequatorial airflow channel were analyzed. It is pointed out that during the study period, the global 850 hPa transequatorial airflow has obvious long-term trends and interdecadal changes. In recent 57 years, 45 to 50 ° E in June to August, 105 to 115 ° E in May to September, 130 to 140 ° E in May to September and May to November, and 20 to 25 in February to April The cross-equatorial airflow at ° E has strengthened significantly, and the cross-equatorial airflow at 50-35 ° W from June to August has weakened. In summer, the cross-equatorial airflow of Somalia increases by 0.25 m / s every 10 years, and 130-140 ° E. The cross-equatorial airflow of May-September increases by 0.32 m / s on average every 10 years. Singular spectrum analysis shows that the variance contribution of the interdecadal change and trend change of the 850 hPa cross-equatorial airflow reaches 35% to 45%. The variance contribution of interannual variation does not exceed 30%. It is also pointed out that the change of the intensity of the transequatorial air current in the Pacific in summer has a clear relationship with the Southern Oscillation. When the weak South Oscillation has a strong transequatorial current. The Somali jet strength has a weak positive correlation with the North Atlantic Oscillation. ^[3]