CORDEX regional climate model data on single levels

This catalogue entry provides Regional Climate Model (RCM) data on single levels from a number of experiments, models, domains, resolutions, ensemble members, time frequencies and periods computed over several regional domains all over the World in the framework of the Coordinated Regional Climate Downscaling Experiment (CORDEX). The term "single levels" is used to express that the variables are 2D-matrices computed on one vertical level which can be surface (or a level close to the surface) or a dedicated pressure level in the atmosphere. Multiple vertical levels are excluded from this catalogue entry.
High-resolution Regional Climate Models (RCMs) can provide climate change information on regional and local scales in relatively fine detail, which cannot be obtained from coarse scale Global Climate Models (GCMs). This is manifested in better description of small-scale regional climate characteristics and also in more accurate representation of extreme events. Consequently, outputs of such RCMs are indispensable in supporting regional and local climate impact studies and adaptation decisions. RCMs are not independent from the GCMs, since the GCMs provide lateral and lower boundary conditions to the regional models. In that sense RCMs can be viewed as magnifying glasses of the GCMs.
The CORDEX experiments consist of RCM simulations representing different future socio-economic scenarios (forcings), different combinations of GCMs and RCMs and different ensemble members of the same GCM-RCM combinations. This experiment design through the ensemble members allows for studies addressing questions related to the key uncertainties in future climate change. These uncertainties come from differences in the scenarios of future socio-economic development, the imperfection of regional and global models used and the internal (natural) variability of the climate system. This experiment design allows for studies addressing questions related to the key uncertainties in future climate change:

what will future climate forcing be?
what will be the response of the climate system to changes in forcing?
what is the uncertainty related to natural variability of the climate system?

The term "experiment" in the CDS form refers to three main categories:

Evaluation: CORDEX experiment driven by ECMWF ERA-Interim reanalysis for a past period. These experiments can be used to evaluate the quality of the RCMs using perfect boundary conditions as provided by a reanalysis system. The period covered is typically 1980-2010;
Historical: CORDEX experiment which covers a period for which modern climate observations exist. Boundary conditions are provided by GCMs. These experiments, that follow the observed changes in climate forcing, show how the RCMs perform for the past climate when forced by GCMs and can be used as a reference period for comparison with scenario runs for the future. The period covered is typically 1950-2005;
Scenario: Ensemble of CORDEX climate projection experiments using RCP (Representative Concentration Pathways) forcing scenarios. These scenarios are the RCP 2.6, 4.5 and 8.5 scenarios providing different pathways of the future climate forcing. Boundary conditions are provided by GCMs. The period covered is typically 2006-2100.

In CORDEX, the same experiments were done using different RCMs (labelled as “Regional Climate Model” in the CDS form).
In addition, for each RCM, there is a variety of GCMs, which can be used as lateral boundary conditions. The GCMs used are coming from the CMIP5 (5th phase of the Coupled Model Intercomparison Project) archive. These GCM boundary conditions are labelled as “Global Climate Model” in the form and are also available in the CDS.
Additionally, the uncertainty related to internal variability of the climate system is sampled by running several simulations with the same RCM-GCM combination. On the forms, these are indexed as separate ensemble members (the naming convention for ensemble members is available in the documentation). For each GCM, the same experiment was repeatedly done using slightly different conditions (like initial conditions or different physical parameterisations for instance) producing in that way an ensemble of experiments closely related. More details behind these sequential ensemble numbers is available in the detailed documentation.
The data are produced by the institutes and modelling centres participating in the different CORDEX domains with partial support from different international and national contributions including support from COPERNICUS for some of the EURO-CORDEX runs.
The data can be used for commercial purposes (unrestricted use) with the exception of the simulations from the following RCMs: BOUN-RegCM4-3 model (for Central Asia and Middle East and North Africa domains) and RU-CORE-RegCM4-3 model (for South-East Asia domain). Precise terms of use are provided in the CORDEX licence.

本目录条目提供了协调区域气候降尺度实验（CORDEX）框架下，全球多个区域气候模型（RCM）在不同实验、模型、区域、分辨率、集合成员、时间频率和时段内的单层气候模型数据。其中，“单层”一词用以指代在单一垂直层面（如地表或接近地表的层面，或大气中的专用压力层面）计算得到的二维矩阵变量。本目录排除了多个垂直层面的数据。高分辨率区域气候模型（RCMs）能够以相对细致的细节提供区域和地方尺度上的气候变化信息，此类信息无法从粗尺度的全球气候模型（GCMs）中获得。这体现在对小尺度区域气候特征的更好描述以及对极端事件的更准确表征。因此，此类RCMs的输出对于支持区域和地方气候影响研究和适应决策至关重要。RCMs并非独立于GCMs，因为GCMs为区域模型提供横向和下边界条件。从这一意义上讲，RCMs可视作GCMs的放大镜。CORDEX实验包括代表不同未来社会经济情景（强迫）、不同GCMs和RCMs组合以及同一GCM-RCM组合的不同集合成员的RCM模拟。通过集合成员的实验设计，该实验方案允许研究针对未来气候变化关键不确定性的问题。这些不确定性源自未来社会经济情景的差异、区域和全球模型的缺陷以及气候系统的内部（自然）变率。这种实验设计允许研究针对未来气候变化关键不确定性的问题，例如：未来气候强迫将是什么？气候系统对强迫变化的响应将是什么？与气候系统自然变率相关的不确定性是什么？在CDS形式中，“实验”一词涉及三个主要类别：评估、历史和情景。在CORDEX中，使用不同的RCMs（在CDS形式中标记为“区域气候模型”）进行了相同的实验。此外，对于每个RCM，都存在多种GCMs，可用作横向边界条件。所使用的GCMs来自CMIP5（耦合模式比较计划第五阶段）档案。这些GCM边界条件在形式中标记为“全球气候模型”，并在CDS中也可用。此外，通过运行同一RCM-GCM组合的多个模拟来采样与气候系统内部变率相关的不确定性。在形式上，这些被索引为单独的集合成员（集合成员的命名规范可在文档中找到）。对于每个GCM，使用略微不同的条件（如初始条件或不同的物理参数化等）重复进行相同的实验，从而产生一系列与实验密切相关的结果。有关这些连续集合编号的更多详细信息可在详细文档中找到。这些数据由参与不同CORDEX区域的不同研究所和建模中心产生，部分得益于不同国际和国内贡献的支持，包括COPERNICUS对某些EURO-CORDEX运行的支援。这些数据可用于商业目的（不受限制的使用），但以下RCMs的模拟除外：BOUN-RegCM4-3模型（针对中亚和中东及北非区域）和RU-CORE-RegCM4-3模型（针对东南亚区域）。详细的使用条款可在CORDEX许可中找到。