Surface Water Flood Maps (FRM_FH_SURFACE_WATER_VELOCITY_H)

The following probabilities are available for surface water flooding: - High - 10 year return period - Medium - 200 year return period - Low - 200 year return period plus climate change using the UKCP09 high emissions scenario for the 2080s.The surface water hazard maps show (where available): - Flood extent - Flood depth - Flood velocities where appropriate. Velocity is presented, where appropriate; this is determined by considering the confidence in input data, modelling method and impact. It is currently represented as one of four bandsThe climate change scenario has been defined by United Kingdom Climate Projection 2009 (UKCP09) predictions for 2080 high emissions 95%ile predictions. Medium and low probability flood events were selected for consistency with return periods used in Scottish Planning Policy, whereas the high probability was chosen as it is reflective of observed events experienced over the last few decades.本数据集可提供的地表水漫溢（surface water flooding）概率分级及对应条件如下： - 高概率：10年一遇重现期 - 中概率：200年一遇重现期 - 低概率：200年一遇重现期叠加气候变化影响，采用英国气候预测2009（UKCP09）2080年代高排放情景 地表水灾害风险图（如可获取）将展示以下内容： - 淹没范围 - 淹没水深 - 适宜场景下的洪水流速。洪水流速仅在对输入数据、建模方法及影响的可信度评估达标时才会展示，目前将流速划分为四个等级。 本数据集采用的气候变化情景，基于英国气候预测2009（UKCP09）针对2080年高排放情景的95%分位预测结果。中等及低概率洪涝事件的选取标准与苏格兰规划政策中采用的重现期保持一致，而高概率事件的选取则参考了近数十年间实际观测到的洪涝事件特征。