ERA5-Land hourly data from 1950 to present

ERA5-Land (European Centre for Medium-Range Weather Forecasts (ECMWF) Re-Analysis) is a reanalysis dataset providing a consistent view of the evolution of land variables over several decades at an enhanced resolution compared to ERA5. ERA5-Land has been produced by replaying the land component of the ECMWF ERA5 climate reanalysis. Reanalysis combines model data with observations from across the world into a globally complete and consistent dataset using the laws of physics. Reanalysis produces data that goes several decades back in time, providing an accurate description of the climate of the past.
ERA5-Land uses as input to control the simulated land fields ERA5 atmospheric variables, such as air temperature and air humidity. This is called the atmospheric forcing. Without the constraint of the atmospheric forcing, the model-based estimates can rapidly deviate from reality. Therefore, while observations are not directly used in the production of ERA5-Land, they have an indirect influence through the atmospheric forcing used to run the simulation. In addition, the input air temperature, air humidity and pressure used to run ERA5-Land are corrected to account for the altitude difference between the grid of the forcing and the higher resolution grid of ERA5-Land. This correction is called 'lapse rate correction'.
The ERA5-Land dataset, as any other simulation, provides estimates which have some degree of uncertainty. Numerical models can only provide a more or less accurate representation of the real physical processes governing different components of the Earth System. In general, the uncertainty of model estimates grows as we go back in time, because the number of observations available to create a good quality atmospheric forcing is lower. ERA5-land parameter fields can currently be used in combination with the uncertainty of the equivalent ERA5 fields.

ERA5-Land（欧洲中期天气预报中心再分析数据集，European Centre for Medium-Range Weather Forecasts (ECMWF) Re-Analysis）是一款再分析数据集，相较ERA5，其以更高分辨率提供了近数十年间陆面变量演变的一致性刻画。该数据集通过对ECMWF ERA5气候再分析的陆面分量进行再驱动模拟而生成。再分析借助物理定律，将全球各地的观测数据与模式模拟数据融合，构建出一套全球完整且一致的数据集。再分析可回溯近数十年的历史数据，精准刻画过去的气候状态。
ERA5-Land以ERA5大气变量（如气温、空气湿度）作为输入，用以约束模拟陆面场，这一过程被称为大气强迫（atmospheric forcing）。若缺乏大气强迫的约束，基于模式的估算结果会快速偏离真实物理状态。因此，尽管观测数据并未直接用于ERA5-Land的生成流程，但其会通过驱动模拟所用的大气强迫产生间接影响。此外，ERA5-Land运行所需的输入气温、空气湿度与气压数据，会针对强迫场网格与ERA5-Land更高分辨率网格之间的高程差异进行校正，该校正方法被称为递减率校正（lapse rate correction）。
与其他模拟产品一样，ERA5-Land数据集所提供的估算结果存在一定程度的不确定性。数值模式仅能近似准确地刻画支配地球系统各组分的真实物理过程。总体而言，模式估算的不确定性会随时间回溯而增大，这是因为用于生成高质量大气强迫的可用观测数据数量会随之减少。目前，ERA5-Land参数场可与对应ERA5数据集的不确定性信息结合使用。

搜集汇总

背景与挑战

背景概述

ERA5-Land是由欧洲中期天气预报中心提供的全球陆地再分析数据集，包含1950年至今每小时的高分辨率(0.1°×0.1°)陆地变量数据。该数据集通过结合模型和观测数据，为陆地应用研究提供长期一致的全球气候数据记录。