Greater Future UK Winter Precipitation Increase in New Convection-Permitting Scenarios
Greater Future UK Winter Precipitation Increase in New Convection-Permitting Scenarios
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DOI：
10.1175/jcli-d-20-0089.1
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发表时间：
2020-09-01
影响因子：
4.9
通讯作者：
Tucker, Simon O.
中科院分区：
文献类型：
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作者：
Kendon, Elizabeth J.;Roberts, Nigel M.;Tucker, Simon O.
这是第一次在国家气候情景中使用分辨率与业务天气预报模型相当的模型。作为联合王国气候预测项目的一部分，对联合王国进行了对流允许范围（2.2公里）的12个气候变化预测的集合。与以往的研究相反，这些显示出更大的未来增加冬季平均降水的对流允许模型相比，粗糙（12公里）的驾驶模型。未来陆地冬季降水增加的大部分（60%）来自2.2公里模型中对流阵雨的增加，这很可能是在海上触发的，并有可能进一步发展。在12公里的模式，降水发生在海上增加，主要是由于对流阵雨的增加，不延伸到陆地。这部分是由于已知的对流参数化方案的局限性，在传统的粗分辨率气候模式中使用，它的行为没有直接的记忆，因此没有能力平流诊断对流的土地或触发新的阵雨沿着对流流出边界。这项研究表明，准确地代表对流的重要性超出了短期降水极端和夏季预测未来的变化，在冬季平均降水。
For the first time, a model at a resolution on par with operational weather forecast models has been used for national climate scenarios. An ensemble of 12 climate change projections at convection-permitting (2.2 km) scale has been run for the United Kingdom, as part of the UK Climate Projections (UKCP) project. Contrary to previous studies, these show greater future increases in winter mean precipitation in the convection-permitting model compared with the coarser (12 km) driving model. Alarge part (60%) of the future increase in winter precipitation occurrence over land comes from an increase in convective showers in the 2.2 km model, which are most likely triggered over the sea and advected inland with potentially further development. In the 12 km model, increases in precipitation occurrence over the sea, largely due to an increase in convective showers, do not extend over the land. This is partly due to known limitations of the convection parameterization scheme, used in conventional coarse-resolution climate models, which acts locally without direct memory and so has no ability to advect diagnosed convection over the land or trigger new showers along convective outflow boundaries. This study shows that the importance of accurately representing convection extends beyond short-duration precipitation extremes and the summer season to projecting future changes in mean precipitation in winter.