UKCP18 21st century time-mean sea level projections around the UK for 2007-2100

The UKCP18 21st century sea level projections are provided as spatially a continuous dataset around the UK coastline. The projections are rooted in CMIP5 climate model simulations and the process-based methods described in IPCC AR5 (Church et al, 2013). The data consist of annual time series of the projected change in the time-mean coastal water level relative to the average value for the period 1981-2000. Projections are available for the RCP2.6, RCP4.5 and RCP8.5 climate change scenarios (Meinshausen et al, 2011). Nine percentiles are provided to characterise the projection uncertainty. The 5th, 50th and 95th percentiles are equivalent to the IPCC AR5 lower, central, and upper estimate of projected sea level change, based on underlying modelling uncertainty.

This dataset was updated in March 2023 to correct a minor processing error in the earlier version of the UKCP18 site-specific sea level projections relating to the adjustment applied to convert from the IPCC AR5 baseline of 1986-2005 to the baseline period of 1981-2000. The update results in about a 1 cm increase compared to the original data release for all UKCP18 site-specific sea level projections at all timescales. Further details can be found in the accompanying technical note.

英国气候预测中心（UKCP18）21世纪的海洋水平面预测数据集以空间连续形式围绕英国海岸线提供。该预测基于CMIP5气候模型模拟以及《政府间气候变化专门委员会第五次评估报告》（IPCC AR5）中描述的基于过程的预测方法（Church et al., 2013）。数据包括相对于1981-2000年期间平均值的时间平均海岸水位的年际变化系列。预测数据适用于RCP2.6、RCP4.5和RCP8.5气候变化情景（Meinshausen et al., 2011）。提供了九个百分位数以表征预测的不确定性。第5、50和95个百分位数分别等同于基于潜在模型不确定性的IPCC AR5对预测海平面变化的低、中、高估计。该数据集于2023年3月更新，以纠正UKCP18针对特定站点的早期海洋水平面预测版本中关于将IPCC AR5基线1986-2005调整为1981-2000基线所应用调整的微小处理错误。更新导致所有时间尺度的UKCP18针对特定站点的海洋水平面预测数据相对于原始数据发布均上升约1厘米。更多详细信息可在附带的技术说明中找到。