How to detect a sporadic time series?

Could someone give me some suggestions as to how I can go about trying to detect if a time series is sporadic or not? Are there any tests for the same? Also, I think sporadic series are quite different from random or white noise series and therefore the tests like Ljung box tests do not work.

Could someone help me with some ideas to test for sporadic series?

• How are you defining "sporadic"? Aug 16, 2021 at 17:23
• I mean something like an Intermittent time series where the peaks occur occasionally. Aug 17, 2021 at 7:31

$$H_0: \text{The series is not stationary (series values are time dependent)}$$
$$H_A: \text{The series is stationary, evidence of no trend (series values are not time dependent)}$$