# **IMPMCT: A Dataset of Integrated Multi-source Polar Meso-Cyclone Tracks**
This README file was generated on March 20, 2025 by Runzhuo Fang
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## **Dataset Overview**  
	IMPMCT combines vortices tracking algorithms from ERA5 reanalysis with deep learning-based detection of cyclonic cloud features in Advanced Very High-Resolution Radiometer (AVHRR) infrared imagery, while incorporating near-surface wind matching by Advanced Scatterometer (ASCAT) and Quick Scatterometer (QUIKSCAT) measurements. The dataset contains 1,184 vortices tracks, 16,630 cyclonic cloud features, and 4,373 wind speed records, with multi-dimensional attributes such as cloud morphology, core wind speed, and environmental advection wind speed. 
  - Temporal Coverage**: February 2001 – April 2024.  
  - Spatial Coverage**: 50–85°N, 40°W–80°E.  

## **Dataset Structure**  
- **`cyclone_IR_images/`**:  
  - Contains 1,185 subfolders named by cyclone IDs (matching track IDs).  
  - Each subfolder stores infrared images of cyclonic cloud features.  
  - These images are generated in the same way as the VCI image (see text),but are centered on cyclone centers, with wind vectors overlaid when available.  
  - Naming convention: `{ID}_{step}.png` (e.g., `11_3.png`), where `step` denotes the temporal sequence.  
  - **Brightness temperature** mapped to grayscale (210–280 K), **wind speed** mapped to 0–25 m/s (examples in auxiliary folder).  

- **`auxiliary_information/`**:  
  - **Color mapping examples**:  
    - `Mapping_of_brightness_temperature_to_grayscale.png`  
    - `Wind_speed_mapping.png`  
  - **Vortex evolution logs**:  
    - `split_IDs.txt`: IDs of vortices formed via splitting.  
    - `merge_IDs.txt`: IDs of vortices terminated via merging.  
  - **Visual examples**:  
    - `merge_example.png`, `split_example.png` (illustrating merging/splitting processes).  

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## **Data Tables**  

### **1. `ERA5_tracks.xlsx`**  
- **Temporal Resolution**: 1 hour.  
- **Variables**:  

| Variables | Abbreviations | Units | Notes |
| --- | --- | --- | --- |
| ID | ID | - | Track  identifier |
| Longitude | lon | °E /°W| Vortex center longitude |
| Latitude | lat | °N | Vortex center latitude |
| Time | time | UTC | Timestamp of track point |
| Smoothed relative vorticity at 850hPa | ζ_smth850 | 10^-4 s^-1 | 850 hPa relative vorticity uniformly smoothed over a 60 km radius at the vortex center |
| Vorticity equivalent radius | r | km | Equivalent circular radius of the vortex area |
| Sea level pressure center value | slp | hPa | Minimum sea-level pressure within 150km of the vort center |
| Sea level pressure center longitude | slp_lon | °E /°W | Longitude of the matched SLP minimum center |
| Sea level pressure center latitude | slp_lat | °N | Latitude of the matched SLP minimum center |

note:The track with ID 399 differs by 3 time steps, which is connected in the cloud image but disconnected in ERA5 data
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### **2. `cyclone_infos.xlsx`**  
- **Variables**:  

| Variables | Abbreviations | Units | Notes |
| --- | --- | --- | --- |
| ID | ID | - | Cyclone track number (corresponds to vortex track) |
| Sequence number | step | - | Cyclone image step at temporal sequence |
| Longitude | lon |  °E/°W | Cyclone center longitude |
| Latitude | lat | °N | Cyclone center latitude |
| AVHRR scanning time | time | UTC | Average time of AVHRR scanning within 50km of the cyclone center |
| Width of bounding box | width | km | Shorter side of the oriented bounding box circumscribing the cyclone |
| Length of bounding box | length | km | Longer side of the oriented bounding box circumscribing the cyclone |
| AVHRR satellite | AVHRR_satellite | - | Satellite used to draw the AVHRR infrared image |
| Scatterometer scanning time | wind_time | UTC | Average time of wind scatterometer scanning within 50km of the cyclone center |
| Maximum near-surface wind speed associated with the cyclone | max_wind | m/s | Maximum near-surface wind speed within a short search radius of the cyclone center |
| Environmental advection near-surface wind speed | env_wind | m/s | 75th percentile of near-surface wind speed within a long search radius of the cyclone center |
| Effective ratio of wind speed | valid_fraction | - | Proportion of available wind speed data within a short search radius |

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**License**: CC BY 4.0  
**Contact**: fang8464@foxmail.com 
**Citation**: