Surface Water Flood Maps (FRM_FH_SURFACE_WATER_VELOCITY_M)

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.本次公开的地表洪水（surface water flooding）概率等级如下： - 高概率：重现期10年 - 中概率：重现期200年 - 低概率：叠加2080年代英国2009年气候预测（UKCP09）高排放情景下气候变化影响的200年一遇事件。 地表洪涝灾害地图（surface water hazard maps）的展示内容（如有）包括： - 洪水淹没范围 - 洪水水深 - 适宜场景下的洪水流速。 流速的展示与否需结合输入数据可信度、建模方法与影响评估综合判定，当前流速被划分为四个等级之一。 本数据集采用的气候变化情景，基于英国2009年气候预测（UKCP09）中2080年代高排放情景下95%分位数预测结果设定。 本次选取中、低概率洪水事件，是为与苏格兰规划政策（Scottish Planning Policy）中采用的重现期标准保持一致；而高概率洪水事件的选取，则因其能够反映近数十年来实际观测到的洪涝事件特征。