问什么是潮汐? 答潮汐是发生在沿海岸或大海中的海平面连续周期性的升降或涨落运动。一般每日升降或涨落两次,通常把白天的一次升降叫做潮,晚上的一次叫做汐,合称为潮汐。问潮汐有哪些周期变化特征? 答潮汐具有半日、全日、半月、一月、一年周期和8.85年、18.61年长周期变化特征等。在一月内,上半月某日与大约相距半个月后的下 What is a tidal wave? A tidal wave is a series of periodic, periodic movements of the sea that occur along the sea or in the sea. Generally daily movements or fluctuations twice, usually during the day called a tide rise and fall, at night once called the tidal, collectively known as the tide. Q. What are the periodic variations of tides? There are half-day, full-day, half-moon, January, one-year and eight-year periods and troughs of 18.61 years. In January, one day in the first half of the month was about half a month behind