Positive End Point Rates (meters/year)

Shorelines are continuously moving in response to winds, waves, tides, sediment supply, changes in relative sea level, and human activities. Shoreline changes are generally not constant through time and frequently switch from negative (erosion) to positive (accretion) and vice versa. Cyclic and non-cyclic processes change the position of the shoreline over a variety of timescales, from the daily and seasonal effects of winds and waves, to changes in sea level over a century to thousands of years. The shoreline "rate of change" statistic thus reflects a cumulative summary of the processes that altered the shoreline for the time period analyzed.

海岸线始终处于动态变化之中，其位置偏移受风力、波浪、潮汐、沉积物供给、相对海平面变化以及人类活动等多重因素共同调控。海岸线的变化通常并非恒定不变，而是频繁在负向（侵蚀）与正向（淤积）状态间往复切换，反之亦然。从风力与波浪带来的日度、季节性影响，到百年乃至千年尺度的海平面变化，各类周期性与非周期性过程均会在不同时间尺度上改变海岸线的位置。因此，海岸线“变化速率”这一统计量，实则为分析时段内所有塑造海岸线的过程所做的累积性总结。