juliensimon/forbush-decreases

---
license: cc-by-4.0
pretty_name: "Forbush Decrease Events (IZMIRAN FEID)"
language:
- en
description: "Forbush decrease events from IZMIRAN FEID catalog (7,097 events, 1957-2016). Solar wind, IMF, CME, and geomagnetic parameters."
task_categories:
- tabular-regression
- time-series-forecasting
tags:
- space
- space-weather
- forbush-decrease
- cosmic-rays
- solar-wind
- cme
- geomagnetic
- izmiran
- open-data
- tabular-data
- parquet
size_categories:
- 1K<n<10K
configs:
- config_name: default
data_files:
- split: train
path: data/forbush_decreases.parquet
default: true
---

# Forbush Decrease Events (IZMIRAN FEID)

<div align="center">
<img src="banner.jpg" alt="Aurora borealis blankets the Earth, seen from the ISS" width="400">
<p><em>Credit: NASA</em></p>
</div>

*Part of the [Space Weather Datasets](https://huggingface.co/collections/juliensimon/space-weather-datasets-69c24cae98f1666f2101ca70) collection on Hugging Face.*

A comprehensive catalog of **7,097** Forbush decrease events spanning **1957--2016**, from the Forbush Effects and Interplanetary Disturbances (FEID) database maintained by IZMIRAN (Pushkov Institute of Terrestrial Magnetism, Ionosphere and Radio Wave Propagation). Each event includes solar wind parameters, interplanetary magnetic field measurements, Forbush decrease magnitudes, geomagnetic indices, and associated CME data.

## Dataset description

A **Forbush decrease** is a rapid reduction in the galactic cosmic ray intensity observed at Earth, caused by the passage of an interplanetary coronal mass ejection (ICME) or co-rotating interaction region (CIR) through the heliosphere. The enhanced magnetic field within these structures acts as a shield, temporarily deflecting galactic cosmic rays away from the inner solar system. Typical decreases range from 1--10% of the ambient cosmic ray flux, with the largest events (associated with extreme CMEs) exceeding 15%.

Forbush decreases are measured by the worldwide network of ground-based neutron monitors at ~10 GV rigidity. The FEID catalog cross-references each cosmic ray decrease with its solar source (flare, CME), the interplanetary disturbance parameters (solar wind speed, IMF magnitude, Bz component), and the geomagnetic response (Kp, Ap, Dst indices). This multi-parameter approach makes the FEID one of the most richly annotated Forbush decrease catalogs available.

These events are important for: (1) understanding cosmic ray modulation by solar activity, (2) forecasting radiation environment changes relevant to aviation and spaceflight, and (3) studying the propagation and geo-effectiveness of CMEs and ICMEs through the heliosphere.

## Schema

| Column | Type | Description |
|--------|------|-------------|
| `datetime_utc` | datetime | Event onset time (UTC) |
| `onset_type` | float64 | Onset type: 1=shock+SSC, 2=interplanetary shock, 3=weak SSC, 9=no shock |
| `quality` | float64 | Data quality (1-5, higher = better) |
| `solar_source_datetime_utc` | datetime | Solar source event time |
| `solar_source_type` | float64 | Solar source type code |
| `solar_wind_speed_onset_km_s` | float64 | Solar wind speed at onset (km/s) |
| `solar_wind_speed_mean_km_s` | float64 | Mean solar wind speed during event (km/s) |
| `solar_wind_speed_max_km_s` | float64 | Maximum solar wind speed (km/s) |
| `imf_b_max_nt` | float64 | Maximum IMF magnitude (nT) |
| `imf_bz_min_nt` | float64 | Minimum IMF Bz component (nT, southward = negative) |
| `fd_magnitude_pct` | float64 | Forbush decrease magnitude at 10 GV (%) |
| `fd_magnitude_corrected_pct` | float64 | Magnetosphere-corrected FD magnitude (%) |
| `fd_min_time_hours` | float64 | Time to minimum cosmic ray flux (hours) |
| `fd_min_depth_pct` | float64 | Minimum depth of cosmic ray decrease (%) |
| `spectral_index_max` | float64 | Maximum spectral index of the decrease |
| `spectral_index_min` | float64 | Minimum spectral index (during recovery) |
| `kp_max` | float64 | Maximum Kp index during event |
| `ap_max` | float64 | Maximum Ap index during event |
| `dst_min_nt` | float64 | Minimum Dst index during event (nT) |
| `cme_datetime_utc` | datetime | Associated CME observation time |
| `cme_width_deg` | float64 | CME angular width (degrees) |
| `cme_angle_deg` | float64 | CME position angle (degrees) |
| `ground_level_enhancement` | float64 | GLE flag (>0 if ground-level enhancement observed) |
| `sunspot_number` | float64 | Daily sunspot number at event time |

## Quick stats

- **7,097** Forbush decrease events (1957--2016)
- Median FD magnitude: **1.0%**, maximum: **28.1%**
- **656** events with associated CME data
- **7097** events with Dst index measurements
- **91** events coinciding with ground-level enhancements (GLEs)

## Usage

```python
from datasets import load_dataset

ds = load_dataset("juliensimon/forbush-decreases", split="train")
df = ds.to_pandas()

# FD magnitude distribution
import matplotlib.pyplot as plt
df["fd_magnitude_pct"].dropna().hist(bins=50)
plt.xlabel("Forbush Decrease Magnitude (%)")
plt.ylabel("Count")
plt.title("Distribution of Forbush Decrease Magnitudes")
plt.show()

# FD magnitude vs solar wind speed
valid = df.dropna(subset=["fd_magnitude_pct", "solar_wind_speed_max_km_s"])
plt.scatter(valid["solar_wind_speed_max_km_s"], valid["fd_magnitude_pct"], alpha=0.3, s=10)
plt.xlabel("Max Solar Wind Speed (km/s)")
plt.ylabel("FD Magnitude (%)")
plt.title("Forbush Decrease vs Solar Wind Speed")
plt.show()

# Annual event count (tracks solar cycle)
df["year"] = df["datetime_utc"].dt.year
df.groupby("year").size().plot(kind="bar", figsize=(14, 4))
plt.ylabel("Events per year")
plt.title("Forbush Decrease Events by Year")
plt.show()
```

## Data source

IZMIRAN Forbush Effects and Interplanetary Disturbances (FEID) database, maintained by the
Pushkov Institute of Terrestrial Magnetism, Ionosphere and Radio Wave Propagation, Russian Academy of Sciences.
[spaceweather.izmiran.ru](http://spaceweather.izmiran.ru/eng/dbs.html)

## Related datasets

- [Neutron Monitor](https://huggingface.co/datasets/juliensimon/neutron-monitor) — Cosmic ray count rates
- [DONKI Space Weather](https://huggingface.co/datasets/juliensimon/donki) — CMEs, flares, geomagnetic storms
- [Solar Wind (OMNI)](https://huggingface.co/datasets/juliensimon/omni) — Hourly solar wind parameters
- [Dst Index](https://huggingface.co/datasets/juliensimon/dst-index) — Geomagnetic storm index
- [Substorm Onsets](https://huggingface.co/datasets/juliensimon/substorm-onsets) — Magnetospheric substorm events

## Pipeline

Source code: [juliensimon/space-datasets](https://github.com/juliensimon/space-datasets)

## Support

If you find this dataset useful, please give it a ❤️ on the [dataset page](https://huggingface.co/datasets/juliensimon/forbush-decreases) and share feedback in the Community tab! Also consider giving a ⭐ to the [space-datasets](https://github.com/juliensimon/space-datasets) repo.

## Citation

```bibtex
@dataset{forbush_decreases,
author = {Simon, Julien},
title = {Forbush Decrease Events (IZMIRAN FEID)},
year = {2026},
publisher = {Hugging Face},
url = {https://huggingface.co/datasets/juliensimon/forbush-decreases},
note = {Based on IZMIRAN FEID catalog (spaceweather.izmiran.ru)}
}
```

## License

[CC-BY-4.0](https://creativecommons.org/licenses/by/4.0/)