Multi-decadal CESM2-Large Ensemble direct downscaled reference and mid 21st century hydroclimate simulations Alaska and the Yukon at 4 kilometer (km) resolution

### Access
Files be accessed and downloaded from the directory via: [http://arcticdata.io/data/10.18739/A2HX15S78](http://arcticdata.io/data/10.18739/A2HX15S78).
### Overview
We present a novel, high-resolution land-atmosphere regional climate model (RCM) configuration for Alaska and Yukon River basin. The Regional Arctic System Model (RASM) was reconfigured from its 50 kilometer (km) grid-spacing to 4 km and coupled to the Community Terrestrial Systems Model (CTSM) with hydrology specific optimization providing improved treatment of orographic precipitation, spatial heterogeneity of the landscape, and improved surface and sub-surface processes particularly tailored to cold regions. The new RASM configuration was used to dynamically downscale four Community Earth System Model version 2-Large Ensemble (CESM2-LE) climate model members for reference (model timestamp water year (WY) 1991-2021) and mid-century (WY2035-2065) time-slices. We performed a simple bias correction to the CESM2-LE specific humidity, with vertical variations, to reduce a high precipitation bias when using the CESM2-LE data directly. The simulations have resulted in a unique high-resolution small ensemble of the hydroclimate over Alaska and the Yukon that can be used for studying atmospheric and hydrologic processes, and assessing impacts related to climate variability and change across the region. Hourly, three-hourly, daily, and monthly outputs are available for surface precipitation, temperature, streamflow, and snowpack, among many other variables. A companion dataset (https://doi.org/10.5065/ZPSB-PS82) is available that provides an ERA5 forced historical (WY1991-2021) and two future pseudo global warming simulations with the same outputs and future time slices.
### Model Scripts and Example Run
An example of model inputs, scripts, and outputs are available through the Arctic Data Center at [https://doi.org/10.18739/A2RN3094N](https://doi.org/10.18739/A2RN3094N).
### Citation
The corresponding description paper is Newman et al. (2026) and we appreciate it if users cite both this dataset and the description paper when basing outcomes or analysis on this work.

### 访问方式
用户可通过以下链接从对应目录获取并下载本数据集的全部文件：[http://arcticdata.io/data/10.18739/A2HX15S78](http://arcticdata.io/data/10.18739/A2HX15S78)。
### 概况
本数据集针对阿拉斯加与育空河流域，提出了一套全新的高分辨率陆-气区域气候模型（Regional Climate Model, RCM）配置方案。我们将区域北极系统模型（Regional Arctic System Model, RASM）从原50千米（km）的网格间距重构为4千米（km），并将其与经过水文专项优化的社区陆地系统模型（Community Terrestrial Systems Model, CTSM）进行耦合。该优化方案可更好地处理地形降水、景观空间异质性，且针对寒区量身优化了地表与地下过程。
我们采用该新型RASM配置方案，对4个社区地球系统模型第二版大集合（Community Earth System Model version 2-Large Ensemble, CESM2-LE）气候模型成员开展动力降尺度试验，分别设置参考时段（模型时间戳对应水文年（Water Year, WY）1991-2021）与本世纪中期时段（WY2035-2065）。为降低直接使用CESM2-LE数据时出现的降水高估偏差，我们针对CESM2-LE比湿的垂直变化特征进行了简单的偏差校正。
本模拟试验生成了一套独特的阿拉斯加与育空河流域高分辨率小集合水文气候数据集，可用于研究该区域的大气与水文过程，以及评估气候变化与气候变率带来的相关影响。数据集提供逐小时、每3小时、每日及月度的多变量输出结果，涵盖地表降水、气温、径流与积雪等核心变量，以及其他诸多辅助变量。
另有配套数据集（https://doi.org/10.5065/ZPSB-PS82）可供使用，该数据集包含ERA5强迫的历史时段（WY1991-2021）模拟结果，以及两场未来伪全球变暖模拟试验，其输出变量与本数据集一致，且覆盖未来指定时段。
### 模型脚本与示例运行
模型输入文件、运行脚本及输出示例可通过北极数据中心获取，链接为：[https://doi.org/10.18739/A2RN3094N](https://doi.org/10.18739/A2RN3094N)。
### 引用说明
本数据集对应的描述性论文为Newman等人（2026）的研究成果。若您的研究成果或分析基于本数据集，请同时引用本数据集与该描述性论文，我们深表感谢。