A high-quality hourly, daily and monthly solar irradiance dataset in China during 1981-2014 based on MERRA-2 Reanalysis productsed Item

<b>A high-quality hourly, daily and monthly solar irradiance dataset in China during 1981-2014</b><b> based on MERRA-2 Reanalysis products</b><br>Wenmin Qin¹, Lunche Wang¹, Ming Zhang¹, Lan Feng¹, Yulong Zhong¹, Qiqi Zhu¹，Hejin Fang¹, Hong Cai¹, Chao Yang²¹Hubei Key Laboratory of Critical Zone Evolution, School of Geography and Information Engineering, China University of Geosciences, Wuhan 430074, China;² Institute of Geodesy and Geophysics, Chinese Academy of Sciences, Wuhan 430077, China;Corresponding author: Wenmin Qin, Hubei Key Laboratory of Critical Zone Evolution, School of Geography and Information Engineering, China University of Geosciences, Lumo road 388, Hongshan District, Wuhan 430074, China; E-mail: [e-mail].<b>Abstract: </b>Solar irradiance (SI) is the main driving factor contributing to climate change and energy balance between the land and atmosphere. High-quality records of global solar irradiance (GHI), direct normal irradiance (DNI) and diffuse solar irradiance (DIF) are of vital importance for solar applications, but the solar radiation observations are sparse around the world. As an alternative, numerous SI reanalysis data in grid format have been developed in regional and global scales. Among them, the MERRA-2 (Modern-Era Retrospective Analysis for Research and Applications, version 2) products could provide high quality SI records with acceptable accuracy and long temporal ranges. This study attempted to improve the accuracy of GHI records derived from MERRA-2 products, and to generate grid DNI and DIF datasets for all-sky conditions over mainland China during 1981-2014, based on the REST2 model and cloud transmittance estimates combining sunshine observations. The results indicate that the estimated GHI values (GHInew) show higher agreements with GHI measurement at 17 CMA (China meteorological administrations) stations than that for the GHI records derived from MERRA-2 products (MERRA-2 GHI). Then, grid GHI, DNI and DIF datasets (0.50° (lat) *0.625° (lon)) throughout China were constructed. The results indicated that the MERRA-2 GHI records may overestimate the GHI values over mainland China. The grid GHI, DNI and DIF dataset generated in this study can assist in numerous solar studies and applications.<br><br>Due to the limitation of data upload quantity and speed, we only upload 10 netcdf files, and pack all the remaining netcdf files into a compressed file, the file name of the compressed file is SWGDN.rar. We apologise that the hourly solar irradiance data was not uploaded, because the data size of hourly solar irradiance data is too big (nearly 13Gb). The hourly and monthly solar irradiance data could be obtain by email ([e-mail]).<br><br>Please cite this article: Qin, W., Wang, L., Zhang, M., Feng, L., Fang, H., Cai, H., Zhong, Y., Zhu, Q., and Yang, C.: A high-quality hourly, daily and monthly solar irradiance dataset in China during 1981–2014 based on MERRA-2 Reanalysis products, Earth Syst. Sci. Data Discuss., https://doi.org/10.5194/essd-2019-204, in review, 2019.<br>

基于MERRA-2再分析产品的1981-2014年中国逐时、逐日、逐月太阳辐射数据集
秦文敏¹，王伦彻¹，张明¹，冯兰¹，钟玉龙¹，朱琪琪¹，方和进¹，蔡虹¹，杨超²
¹中国地质大学地理与信息工程学院，关键带演化湖北省重点实验室，武汉 430074，中国；²中国科学院测地与地球物理研究所，武汉 430077，中国；
通讯作者：秦文敏，中国地质大学地理与信息工程学院关键带演化湖北省重点实验室，武汉市洪山区鲁磨路388号，430074，中国；电子邮箱：[e-mail]。
**摘要：** 太阳辐射（solar irradiance, SI）是引发气候变化以及维持陆-气间能量平衡的核心驱动因子。高质量的总太阳辐射（global solar irradiance, GHI）、直接法向辐射（direct normal irradiance, DNI）与散射太阳辐射（diffuse solar irradiance, DIF）观测数据对太阳能利用至关重要，但全球范围内的太阳辐射观测站点十分匮乏。作为替代方案，学界已在区域和全球尺度上开发了诸多格点化太阳辐射再分析数据。其中，MERRA-2（现代时代研究与应用再分析计划第2版，Modern-Era Retrospective Analysis for Research and Applications, Version 2）产品可提供精度可靠、时间跨度较长的高质量太阳辐射数据。
本研究基于REST2模型与结合日照观测的云透射率估算方法，旨在提升MERRA-2源总辐射数据的精度，并生成1981-2014年中国大陆全域全天空条件下的格点化直接法向辐射与散射辐射数据集。结果显示，本研究估算的总辐射值（GHInew）与中国气象局（China Meteorological Administrations, CMA）17个站点的实测总辐射数据吻合度，优于MERRA-2源总辐射数据（MERRA-2 GHI）。最终构建了覆盖全国的格点化总辐射、直接法向辐射与散射辐射数据集，格距为0.50°（纬度）×0.625°（经度）。研究结果表明，MERRA-2源总辐射数据对中国大陆地区的总辐射存在高估现象。本研究生成的格点化太阳辐射数据集可服务于众多太阳能相关研究与应用场景。

受限于数据上传数量与速度限制，本次仅上传了10个NetCDF文件，其余所有NetCDF文件均打包为压缩文件，压缩包名称为SWGDN.rar。由于逐时太阳辐射数据体量过大（近13Gb），未上传该部分数据，我们对此深表歉意。若需获取逐时与逐月太阳辐射数据，可通过电子邮箱[e-mail]联系。

请引用本文：Qin, W., Wang, L., Zhang, M., Feng, L., Fang, H., Cai, H., Zhong, Y., Zhu, Q., 及 Yang, C.: 基于MERRA-2再分析产品的1981-2014年中国逐时、逐日、逐月太阳辐射数据集，Earth Syst. Sci. Data Discuss., https://doi.org/10.5194/essd-2019-204, 已投稿待审，2019年。

搜集汇总

背景与挑战

背景概述

该数据集是一个基于MERRA-2再分析产品生成的中国1981-2014年太阳辐照度高质量数据集，包含全球水平辐照度、直接法向辐照度和散射水平辐照度的小时、日和月度数据，空间分辨率为0.50°（纬度）*0.625°（经度）。数据集通过REST2模型和云透射率估计提高了准确性，适用于太阳能应用和气候研究，但部分大文件需通过邮件获取。