A study of processes controlling convection over complex terrain (UK-COPS)

强对流雨引发的洪水在英国是一个严重的问题。丘陵地带的山洪暴发可能会造成特别严重的破坏。对流对流诱发降水研究(COPS)是一个国际项目，旨在解决这一问题并改进对强对流降水的预报。这项提案是《公约》的联合王国部分，增加了补充其他《公约》伙伴的具体目标。它将使人们了解控制丘陵地区对流降水形成和发展的过程，气象局中尺度模型组的科学家将利用统一模式减少复杂地形对流预测的不确定性。这将通过综合缔约方会议数据以及侧重于解释数据的建模活动来实现。这个问题涉及五个需要共同解决的整体部分。(1)复杂地形中的热驱动流动在很大程度上取决于地表的热交换和水交换。(2)气溶胶粒子的组成和粒度分布对对流云的微物理和动力学，特别是对流云的降水量有重要影响。(3)边界层中向对流云输送热量、水汽和气溶胶的热力和其他特征。(4)降水的发展在很大程度上取决于对流云的微观物理和动力学特征。(5)最后，减少UM对丘陵地区对流风暴位置和时间的可预测性的不确定性，取决于从这四个部分获得的知识。特别是，将量化不同来源的不确定性对丘陵地区对流风暴可预报性的相对贡献，从而为集合预报系统提供基础。

Flooding caused by heavy convective rain is a serious problem in the UK. Flash floods in hilly terrain can be particularly damaging. The Convective Orographically-induced Precipitation Study (COPS) is an international project designed to address this problem and to improve predictions of heavy convective precipitation. This proposal is the UK component of COPS which adds specific objectives complementary to those of other COPS partners. It will produce an understanding of the processes that control the formation and development of convective precipitation over hilly terrain which will be used by scientists within the Mesoscale Modelling group of the Met Office in reducing uncertainty in predictability of convection over complex terrain with the Unified Model (UM). This will be achieved by synthesising COPS data alongside modelling activities focussed on interpreting the data. The problem involves five integrated parts that need to be tackled together. (1) The thermally driven flows in complex terrain depends critically on the surface exchanges of heat and water. (2) The composition and size distribution of the aerosol particles have a crucial influence on the microphysics and dynamics of the convective clouds and particularly the amount of precipitation. (3) The thermals and other features in the boundary layer that transport heat, moisture and aerosols to the convective clouds. (4) The development of precipitation depends critically on the detailed microphysics and dynamics of the convective clouds. (5) Finally, reducing uncertainty in predictability of the location and timing of convective storms in hilly terrain with the UM, depends on the knowledge gained from these four parts. In particular the relative contributions of different sources of uncertainty in predictability of convective storms in hilly terrain will be quantified, thus providing the basis for an ensemble forecast system.