The Hadley circulation describes the large-scale tropical atmospheric circulation, where air rises at the equator and sinks around 30° latitude.
- Option (A) is correct because the ascending branch of the Hadley cell is typically narrower than the descending branch, due to the concentrated updrafts near the equator.
- Option (D) is also correct because latent heat is released during the condensation of water vapor in the ascending region and is transported to the descending region of the Hadley cell.
- Option (B) is incorrect because thunderstorms are more frequent in the ascending region where warm, moist air rises and condenses.
- Option (C) is false because the lower level winds between the ascending and descending branches of the Hadley cell are generally south-easterly in the northern hemisphere, not north-westerly.
Thus, the correct answers are (A) and (D).
Final Answer:
\[
\boxed{(A), (D) \, \text{The ascending branch is narrower than its descending branch, and latent heat is transported from the subsiding to the ascending region of the Hadley cell.}}
\]