WASCAL WRF12km with HadGEM2-ES r1i1p1 forcing from the CMIP5 RCP4.5 experiment

Project: West African Science Service Centre on Climate Change and Adapted Land Use - With climate change being one of the most severe challenges to Africa in the 21st century, West Africa is facing an urgent need to develop effective adaptation and mitigation measures. WASCAL (West African Science Service Centre on Climate Change and Adapted Land Use, http://www.wascal.org) is a large-scale research-focused Climate Service Centre designed to help tackle this challenge and thereby enhance the resilience of human and environmental systems to climate change and increased variability. It does so by strengthening the research infrastructure and capacity in West Africa related to climate change and by pooling the expertise of ten West African countries and Germany. Funded by the German Federal Ministry of Education and Research (BMBF), WASCAL is implemented in a collaborative effort by West African and German partners. An integral part of its climate services is the provisioning of a new set of high resolution, ensemble-based regional climate change scenarios for the region of West Africa. An ensemble approach is chosen to address model uncertainties and provide statistical estimates on possible future climate change scenarios. The ensemble is composed of three regional climate models, WRFV3.5.1, COSMO-CLM 4.18, and REGCM4. Three Earth System Models from the CMIP5 project are downscaled by each of the regional models, MPI-ESM, GFDL-ESM2M, and HadGEM2-ES for the historical period from 1980 to 2010 and for the RCP4.5 scenario from 2020 to 2050 and from 2070 to 2100. Control runs are created by downscaling the European Centre for Medium-Range Weather Forecasts ERA-Interim re-analysis from 1980 to 2014. Two sets of resolutions are made available, 60km and 12km, for a large domain covering the greater region of West Africa from 25W to 25E and 5S to 25N. Summary: This experiment (2006-2100) uses the data from the WRF60_hadgem2_rcp45 experiment as forcing data for downscaling to 12km resolution by the regional model WRFV3.5.1 for the region of West Africa. 'rcp45' is an experiment of the CMIP5 - Coupled Model Intercomparison Project Phase 5 (https://pcmdi.llnl.gov/mips/cmip5). 4.1 rcp45 (4.1 RCP4.5) - future projection (2006-2300) forced by RCP4.5. Experiment design:https://cera-www.dkrz.de/WDCC/ui/Entry.jsp?acronym=Taylor_CMIP5_design.pdf . This experiment is divided into several time slices of 11 years. The first year of each time slice is used as a spin-up phase and should not be used in the analysis. All experiments with HadGEM forcing refer to a calendar with 360 days. The 12 km resolution of this experiment is the second step of the two step downscaling WRF experiment.

项目：西非气候变化与适应土地利用科学服务中心（West African Science Service Centre on Climate Change and Adapted Land Use，简称WASCAL）
气候变化是21世纪非洲面临的最严峻挑战之一，西非地区亟需制定行之有效的适应与减缓措施。WASCAL（http://www.wascal.org）是一家大型以研究为导向的气候服务机构，旨在助力应对这一挑战，进而提升人类与环境系统应对气候变化及气候变率加剧的韧性。该机构通过强化西非地区与气候变化相关的研究基础设施与能力，整合西非十国与德国的专业科研资源以达成目标。WASCAL由德国联邦教育与研究部（BMBF）资助，由西非与德国合作伙伴联合实施。
其气候服务的核心组成内容之一，是为西非地区提供一套全新的高分辨率、基于集合模拟的区域气候变化情景。选取集合模拟方法，旨在解决模型不确定性问题，并为未来潜在的气候变化情景提供统计估算依据。该集合模拟由3个区域气候模型构成，分别为WRFV3.5.1、COSMO-CLM 4.18与REGCM4。每个区域模型均对CMIP5（耦合模式比较计划第五阶段，Coupled Model Intercomparison Project Phase 5）项目下的3个地球系统模型进行降尺度处理，分别为MPI-ESM、GFDL-ESM2M与HadGEM2-ES，处理时段涵盖1980至2010年的历史时期，以及RCP4.5（典型浓度路径4.5）情景下2020至2050年与2070至2100年两个时段。
控制试验通过对1980至2014年的欧洲中期天气预报中心（ECMWF）ERA-Interim再分析资料进行降尺度构建。该数据集提供两种空间分辨率：60km与12km，覆盖的大区域范围为西经25°至东经25°、南纬5°至北纬25°的西非全域。

数据集摘要：
本试验（时段覆盖2006-2100年）以WRF60_hadgem2_rcp45试验的数据作为强迫场数据，通过区域气候模型WRFV3.5.1将其降尺度至12km分辨率，服务于西非地区。“rcp45”是CMIP5中的一类试验（https://pcmdi.llnl.gov/mips/cmip5）。4.1 rcp45（即RCP4.5）是指以RCP4.5为强迫场的未来气候投影试验（2006-2300年）。试验设计详情参见：https://cera-www.dkrz.de/WDCC/ui/Entry.jsp?acronym=Taylor_CMIP5_design.pdf。
本试验被划分为若干个11年的时间切片，每个时间切片的首年作为自旋调整阶段，不应纳入数据分析。所有采用HadGEM强迫场的试验均采用360天历法。本试验的12km分辨率方案是两步降尺度WRF试验的第二步。