Caravan MultiMet (Part 1, Nowcasts): Extending Caravan with Multiple Weather Nowcasts and Forecasts

Caravan MultiMet is a novel extension to Caravan, focusing on enriching the meteorological forcing data. Our extension adds three precipitation nowcast products (CPC, IMERG v07 Early, and CHIRPS) and three weather forecast products (ECMWF IFS HRES, GraphCast, and CHIRPS-GEFS). Since all data is kept in it's original time zone (UTC+0) and the ERA5-Land data in the original Caravan data set is shifted to local time of each gauge, we also include ERA5-Land reanalysis data in this extension, matching the UTC-0 timezone for all gauges of the other forcings. This part of the extension includes the nowcast products. The inclusion of diverse data sources, particularly weather forecasts, enables more robust evaluation and benchmarking of hydrological models, especially for real-time forecasting scenarios. To the best of our knowledge, this extension makes Caravan the first open large-sample hydrology dataset to incorporate weather forecast data. The data is also publicly available on Google Cloud Platform (GCP), and we provide below a colab with an example of how to access it which does not require downloading the entire dataset. Additional resources: The Caravan GitHub repository includes further information and links to other extensions. The original Caravan paper ------ Channel log: 21 November 2024: Version 1.1 - Fixed bug in the FAO Penman-Monteith potential evaporation - values are now clipped to 0 (previously, some values were negative). Only the ERA5-Land dataset was changed.Caravan MultiMet 是 Caravan 的全新扩展版本，核心目标为丰富气象强迫（meteorological forcing）数据。本次扩展新增了三类降水临近预报产品（CPC、IMERG v07 Early、CHIRPS）与三类数值天气预报产品（ECMWF IFS HRES、GraphCast、CHIRPS-GEFS）。由于本次扩展中所有数据均保留原始时区（UTC+0），而原始Caravan数据集中的ERA5-Land数据已被调整至各雨量站的本地时区，因此我们在本次扩展中补充了ERA5-Land再分析数据，并将其时区统一调整为与其他强迫数据一致的UTC+0。本次扩展涵盖了上述三类降水临近预报产品。 多源数据的纳入，尤其是数值天气预报数据，可为水文模型提供更稳健的评估与基准测试框架，尤其适配实时预报场景。据我们所知，本次扩展使Caravan成为首个纳入数值天气预报数据的开源大样本水文数据集。 本数据集已在谷歌云平台（Google Cloud Platform, GCP）公开，我们下文将提供一个Colab示例，演示如何无需下载完整数据集即可访问该数据。 附加资源： - Caravan的GitHub仓库包含更多信息及其他扩展的相关链接。 - 原始Caravan论文 --- 更新日志： 2024年11月21日：版本1.1 - 修复了FAO彭曼-蒙特斯（FAO Penman-Monteith）潜在蒸发量计算中的错误：现有数据已被裁剪至非负值（此前部分数值为负）。仅对ERA5-Land数据集进行了修改。