Does line 588 in the 500 HPA weather map represent subtropical high?

Yes, but you can't look at the 588 line too rigidly. Let me explain it to you:

In the process of general weather forecast and analysis, line 588 is the key control range of the subtropical high, or an important reference line for dividing the ridge line and poles of the subtropical high. Generally, the area within the 588 line is within the scope of high-pressure control, and it is sunny and hot.

Sometimes the range of subtropical high control depends on the airflow blowing from the periphery of high pressure along the line 588 or 584, that is, the area controlled by anticyclone airflow affected by high pressure is sometimes within 588 or 584, that is, the area controlled by subtropical high is within 584 or 588.

Whether the 584 or 588 control is specific depends on the potential difference between the subtropical high and other systems, and the external potential is often low, the control range of the subtropical high is within 584, and the external potential is high, within 588 (several).