ERA5 Reanalysis Downloader

Download ERA5 single-level reanalysis data from Microsoft Planetary Computer (no API key required).

Quick Start

# List available variables
python era5-download.py variables

# Search for data (note: era5-pds STAC collection currently covers 1979-01 to 2020-12)
python era5-download.py search --variable temperature_2m --start-date 2020-06 --end-date 2020-08

# Download as NetCDF
python era5-download.py download --variable temperature_2m --start-date 2020-06 --end-date 2020-06

# Download with bounding box subset
python era5-download.py download -v precipitation -s 2020-06 -e 2020-06 --bbox -10 35 5 45 -o europe_rain.nc

Available Variables

Variable	Units	Description
temperature_2m	K	Air temperature at 2m (analysis)
precipitation	m	Total precipitation (1-hour accumulation)
wind_u_10m	m/s	U-component of wind at 10m
wind_v_10m	m/s	V-component of wind at 10m
wind_u_100m	m/s	U-component of wind at 100m
wind_v_100m	m/s	V-component of wind at 100m
dewpoint_2m	K	Dewpoint temperature at 2m
surface_pressure	Pa	Surface pressure
sea_level_pressure	Pa	Mean sea level pressure
sea_surface_temperature	K	Sea surface temperature
solar_radiation	J m**-2	Surface solar radiation downwards (1-hour accumulation)

CLI Reference

usage: era5-download [-h] [--version] {search,download,variables} ...

ERA5 Reanalysis Downloader - Download from Planetary Computer

positional arguments:
  {search,download,variables}
    search              Search for ERA5 data
    download            Download ERA5 data as NetCDF
    variables           List available ERA5 variables

options:
  -h, --help            show this help message and exit
  --version             show program's version number and exit

search

python era5-download.py search -v VARIABLE -s START [-e END] [--limit N] [--json]

download

python era5-download.py download -v VARIABLE -s START [-e END] [-o FILE] [--bbox W S E N] [--skip-existing] [--quiet]

Data Source

Uses Microsoft Planetary Computer STAC API:

• Endpoint: https://planetarycomputer.microsoft.com/api/stac/v1
• Collection: era5-pds
• Format: Zarr (cloud-optimized)
• License: Copernicus ERA5 data license (free for research and commercial use)

No authentication or API key is required.

Requirements

• Python 3.8+
• requests
• xarray (optional, for full NetCDF export)
• zarr (optional, for reading cloud-optimized data)

Installation

pip install -r requirements.txt

How It Works

1. Searches Planetary Computer STAC catalog for ERA5 items matching your variable and date range
2. Downloads Zarr-format data chunks
3. Converts and merges into a single NetCDF file
4. Supports spatial subsetting via --bbox
5. Uses .part temp files for safe writes (atomic rename on completion)

Safety

• Safe file writes: downloads to .part temp file, renames on completion
• No API keys or credentials stored or transmitted
• HTTPS-only data source
• Input validation on all parameters

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中文说明

从 Microsoft Planetary Computer 下载 ERA5 单层再分析数据，无需 API 密钥。

快速开始

# 列出可用变量
python era5-download.py variables

# 搜索数据（era5-pds 当前覆盖 1979-01 至 2020-12）
python era5-download.py search --variable temperature_2m --start-date 2020-06 --end-date 2020-08

# 下载为 NetCDF
python era5-download.py download --variable temperature_2m --start-date 2020-06 --end-date 2020-06

# 按边界框裁剪
python era5-download.py download -v precipitation -s 2020-06 -e 2020-06 --bbox -10 35 5 45 -o europe_rain.nc

可用变量

变量	单位	说明
temperature_2m	K	2米气温（分析场）
precipitation	m	总降水量（1小时累积）
wind_u_10m	m/s	10米风场 U 分量
wind_v_10m	m/s	10米风场 V 分量
dewpoint_2m	K	2米露点温度
surface_pressure	Pa	地表气压
sea_surface_temperature	K	海表温度
solar_radiation	J m**-2	向下短波辐射（1小时累积）

数据源

使用 Microsoft Planetary Computer STAC API（era5-pds 集合），数据格式为 Zarr，免费用于研究和商业用途，无需认证。