滨江潮汐型水体水下光场时空分布模拟

Temporal and Spatial Distribution of Underwater Light Field for a Waterfront Tide-Influenced Water Body

建立内江水下光场分布预测模型,选择洪季、枯季两个典型全日潮,研究内江水下光场分布特征.结果表明:洪季内江水下光照条件明显优于枯季,枯季悬沙浓度较低,光强垂向衰减速度略慢于洪季;洪、枯两季水下0.3 m处光强分别比表面光强削减了89.1%和83.5%.受水量交换及水动力条件影响,洪季内江东部水域光照强度比西部水域平均增加59.2%;枯季内江南北两岸滩地水下光强平均约为主流区的2.63倍.洪季潮汐作用对内江水下光场分布影响较小;枯季潮差大于洪季,落潮期间,悬沙的落淤,水下光照强度平均较涨潮过程增加47.2%.

The underwater light model for Neijiang was established. Two typical tidal cycles in flood season and dry season were selected to demonstrate the underwater light field characters in Neijiang. The results were as follows： The underwater light condition in flood season was distinctly better than that in dry season. The light intensity at 0.3 m depth decreased by 89.1%, 83.5% than that at the water surface in flood and dry season respectively. Light intensity in the east region of Neijiang in flood season was in average increased by 59.2% than that in the west region, and in dry season the light intensity in the north and south bottomland of Neijiang was about 2.63 times than that in the mainstream. The impact of tide on underwater light distribution in flood season was not evident, but in dry season, as a result of the greater tidal gap suspended sediment began to settle down during the ebb tide, and the underwater light intensity increased by 47.2% than that during the spring tide in average.