maritime_wind_rose
Analyze Beaufort wind force and wind direction distributions from historical maritime logbooks, with optional period comparisons to differentiate genuine wind shifts from technological changes.
Instructions
Beaufort wind force and wind direction distributions from CLIWOC logbooks.
Counts observations by Beaufort force (0-12) and compass direction (N, NE, E, SE, S, SW, W, NW) with mean speed at each level. Optionally compares distributions between two periods.
Also includes distance calibration: compares logged distances from ship logbooks against haversine-computed distances from lat/lon positions. Ratio near 1.0 indicates good position accuracy.
Key tool for the Kelly and O Grada approach: if recorded Beaufort distributions shift between periods, that indicates genuine wind change. If distributions are stable while speeds increase, that indicates technology improvement (hull, sails, routing).
Wind direction is available for ~97% of observations. Beaufort force is available for ~17%. Returns has_wind_data/has_direction_data flags. Anchored positions are excluded by default.
Args: lat_min/lat_max/lon_min/lon_max: Bounding box nationality: Filter by nationality code year_start/year_end: Filter by year range direction: Filter by "eastbound" or "westbound" month_start/month_end: Month filter (supports wrap-around) period1_years: First period as "YYYY/YYYY" range or "YYYY,YYYY,..." list period2_years: Second period as "YYYY/YYYY" range or "YYYY,YYYY,..." list min_speed_km_day: Minimum speed filter (default: 5.0) max_speed_km_day: Maximum speed filter (default: 400.0) output_mode: Response format - "json" (default) or "text"
Returns: JSON or text with Beaufort + direction distribution, calibration, and optional period splits
Tips for LLMs: - Use period1_years/period2_years to compare distributions - Periods accept "YYYY/YYYY" ranges or "YYYY,YYYY,..." year lists - Wind direction available even without Beaufort force data - direction_counts show prevailing wind patterns by compass sector - distance_calibration compares logged vs computed distances - Combine with group_by="beaufort" on aggregate tool for speed profiles at each wind force
Input Schema
| Name | Required | Description | Default |
|---|---|---|---|
| lat_min | No | ||
| lat_max | No | ||
| lon_min | No | ||
| lon_max | No | ||
| nationality | No | ||
| year_start | No | ||
| year_end | No | ||
| direction | No | ||
| month_start | No | ||
| month_end | No | ||
| period1_years | No | ||
| period2_years | No | ||
| min_speed_km_day | No | ||
| max_speed_km_day | No | ||
| output_mode | No | json |