ERA5 daily data on single levels - atmosphere

This dataset contains daily statistics of atmospheric and land-surface quantities derived from ECMWF’s ERA5 hourly data on single levels. It is produced by the Earth Data Hub Team from the hourly data of the Climate Data Store (CDS), following the conventions of the CDS ERA5 post-processed daily statistics on single levels. It uses the standard UTC day, i.e., the day starts at 00:00 UTC and ends at 23:59 UTC on all pixels irrespective of the latitude and the local time.

For instantaneous variables, e.g. the 2 metre temperature (t2m), each day is the mean of the 24 hourly values from 00:00 to 23:00 UTC. This includes the precipitation type (ptype): as in the CDS daily statistics, its daily value is the mean of the hourly type codes, not itself a type code.

Accumulations, mean rates, minima and maxima refer instead to the hour ending at their timestamp: e.g. the 00:00 UTC value covers 23:00 to 24:00 UTC of the previous day. Each day therefore uses the 24 values from 01:00 UTC of that day to 00:00 UTC of the next day:

• accumulated variables, e.g. the total precipitation (tp), are summed into the day's total;
• mean rates and fluxes, e.g. the mean total precipitation rate (avg_tprate), are averaged;
• the maximum 2 metre temperature (mx2t), the 10 metre wind gust (fg10) and the maximum total precipitation rate (mxtpr) since previous post-processing take the day's maximum; the minimum 2 metre temperature (mn2t) and the minimum total precipitation rate (mntpr) take the day's minimum.

Time-invariant variables, e.g. the geopotential (z) and the land-sea mask (lsm), have no time dimension.

📊 Chunking Specifications

The dataset employs a spatio-temporal chunking scheme of 75 days × 37.5° latitude × 75° longitude. This corresponds to an array chunk shape of 75 (valid_time) × 150 (latitude) × 300 (longitude).