maritime_wind_direction_by_year
Extract year-by-year wind direction data from CLIWOC logbooks to detect ENSO signals and changes in trade wind patterns across 1662-1854.
Instructions
Year-by-year wind direction distributions from CLIWOC logbooks.
Returns 8-compass-sector wind direction distributions for each year, with ~97.5% coverage across the full 1662-1854 period. This makes it a powerful tool for detecting long-term atmospheric circulation shifts, including ENSO phases and Walker circulation changes.
Args: lat_min/lat_max/lon_min/lon_max: Bounding box filter nationality: Filter by nationality code year_start/year_end: Year range filter direction: "eastbound" or "westbound" month_start/month_end: Month filter (1-12, supports wrap-around) 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 per-year sector distributions
Tips for LLMs: - Wind direction has 97.5% coverage (vs 17% for Beaufort force) - Covers full 1662-1854 period — ideal for ENSO detection - In trade wind belt (lat -30 to 30): expect E/SE dominance - During El Nino: trades weaken, may shift toward variable/W - During La Nina: trades strengthen, E/SE percentages increase - Compare sector percentages across known ENSO/neutral years - Use month_start=11, month_end=2 for peak ENSO season
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 | ||
| min_speed_km_day | No | ||
| max_speed_km_day | No | ||
| output_mode | No | json |