Development and application of high-resolution regional climate models

区域气候模式（RCMs）目前通常以每个网格框约50公里的分辨率运行。 该应用程序的主要目标是启动RCM物理参数化领域的工作，以开发下一代RCM，这些RCM将在更高的分辨率（~ 10 km）下表现最佳。在这一规模上，区域协调机制应开始提供气候变化和长期（季节性）预测领域的规划者和影响评估者所需的详细信息。大部分的工作将致力于开发一个更好的代表性的大气水循环在高模式分辨率。特别是，将采用统一和基于物理的方法来确定湍流、对流、云的形成和降水的参数。这项工作的大部分将使用GEM（全球环境多尺度）模型作为基本建模工具，并将其应用于区域气候模式和云解析分辨率。后者的分辨率（每个格点约1- 2公里）允许许多关键的对流和湍流环流得到明确的解决。沿着非常详细的云方案，这使得云解析模型能够提供关键云尺度过程的非常准确的模拟，尽管计算成本非常高。该模型版本将作为参照，据此制定和评价参数化方法。特别是，湿过程参数化方案中的许多条款不能观察到，因此必须从这些显式模式模拟。与此同时，将在撒哈拉以南非洲应用高分辨率区域气候模型，模拟控制这一气候敏感区域降雨时间、分布和数量的关键区域气候过程。其目的是调查全球季节性预测和撒哈拉以南非洲气候变化情景的高分辨率区域降尺度的潜力。我们的进一步目标是将这些区域预测与该地区的影响评估和规划机构联系起来。

Regional Climate Models (RCMs) are presently routinely run at resolutions of around 50km per grid box.  The major thrust of this application is to initiate work in the area of RCM physical parameterisations to develop the next generation of RCMs that will perform optimally at significantly higher resolution (~10km). At this scale, RCMs should begin to provide the detailed information required by planners and impact assessors in the areas of climate change and longer-range (seasonal) forecasting. Much of the work will be devoted to developing a better representation of the atmospheric water cycle at high model resolutions. In particular, a unified and physically based approach to the parameterisation of turbulence, convection, cloud formation and precipitation will be pursued. Most of this work will use the GEM (Global Environmental Multiscale) model as the basic modelling tool and apply this in both Regional Climate mode and at Cloud Resolving resolutions. The latter resolutions (~1-2km per grid box) allow many of the key convective and turbulent circulations to be explicitly resolved. Along with a very detailed cloud scheme, this allows the Cloud Resolving Model to provide very accurate simulations of key cloud scale processes, albeit at a very high computational cost. This model version will act as a reference against which parameterisation approaches will be developed and evaluated. In particular, many terms in moist process parameterisation schemes cannot be observed and therefore must be derived from these explicit model simulations. Parallel to this effort, the high-resolution RCM will be applied over sub-Saharan Africa to simulate key regional climate processes controlling the timing, distribution and amount of rainfall over this climate sensitive region. The aim will be to investigate the potential for high-resolution regional downscaling of Global seasonal predictions and climate change scenarios for sub-Saharan Africa. We further aim to link these regional predictions to impact assessment and planning bodies in the region.