Graham McIntire
604140220a
Add Propagation.Region module with 8 CONUS climate zones (gulf_coast, southeast, southern_plains, corn_belt, northeast, desert_southwest, pacific_northwest, mountain_west) and per-region monthly seasonal adjustment multipliers. The scorer's score_season now takes lat/lon and applies a regional multiplier from Region.seasonal_adjustment on top of the band's seasonal_base + seasonal_adj. Gulf coast August gets a 1.15x boost (drier, better for ducting) while Corn Belt August gets a 0.80x penalty (corn evapotranspiration = miserable dewpoints). Adjustments are hand-tuned starting points from the meteorologist's qualitative guidance. Phase 9 recalibration will refine them from backtest data.
111 lines
3.6 KiB
Elixir
111 lines
3.6 KiB
Elixir
defmodule Microwaveprop.Propagation.Region do
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@moduledoc """
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Classifies CONUS grid points into climatological regions for
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band-specific seasonal scoring adjustments.
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The meteorologist's April 2026 review noted that the existing
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uniform seasonal scoring is wrong: Gulf coast August is drier and
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better for propagation than June/July, while Iowa August is peak
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corn evapotranspiration with brutally high dewpoints. Same month,
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opposite effect.
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This module provides:
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- `for_point/2` — classifies a lat/lon into one of ~8 regions
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- `seasonal_adjustment/2` — returns a multiplier (0.7-1.3) that
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the scorer applies on top of the band's `seasonal_base` score.
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Region boundaries are deliberately simple bounding boxes rather
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than precise climate zone shapefiles. The scoring impact of getting
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a boundary pixel wrong is a few points out of 100; the impact of
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having no regional adjustment at all is the entire seasonal factor
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being wrong for half the country.
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"""
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@regions [
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{:gulf_coast, {25.0, 32.0}, {-100.0, -80.0}},
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{:southeast, {30.0, 37.0}, {-90.0, -75.0}},
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{:southern_plains, {32.0, 38.0}, {-105.0, -93.0}},
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{:corn_belt, {38.0, 48.0}, {-100.0, -82.0}},
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{:northeast, {38.0, 48.0}, {-82.0, -67.0}},
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{:desert_southwest, {30.0, 38.0}, {-120.0, -105.0}},
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{:pacific_northwest, {42.0, 50.0}, {-125.0, -115.0}},
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{:mountain_west, {38.0, 48.0}, {-115.0, -100.0}}
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]
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@doc """
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Classify a lat/lon point into a climatological region.
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Returns an atom like `:gulf_coast`, `:corn_belt`, etc.
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Returns `:other` for points outside any defined region (including
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non-CONUS).
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"""
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@spec for_point(float, float) :: atom
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def for_point(lat, lon) do
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Enum.find_value(@regions, :other, fn {name, {lat_min, lat_max}, {lon_min, lon_max}} ->
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if lat >= lat_min and lat < lat_max and lon >= lon_min and lon < lon_max do
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name
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end
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end)
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end
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# Regional seasonal adjustments: multipliers on the band's seasonal_base
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# score by month. 1.0 = no change; > 1.0 = better than the base suggests;
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# < 1.0 = worse. Only months/regions where the uniform base is known to
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# be wrong get non-1.0 values.
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#
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# These are hand-tuned starting points based on the meteorologist's
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# qualitative guidance. Phase 9 recalibration will refine them from
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# backtest data.
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@seasonal_adjustments %{
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gulf_coast: %{
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# Gulf August is drier than June/July → better propagation
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6 => 0.95,
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7 => 0.95,
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8 => 1.15,
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9 => 1.10
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},
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corn_belt: %{
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# Iowa July/August: corn evapotranspiration → high dewpoints → worse
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6 => 1.05,
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7 => 0.85,
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8 => 0.80,
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9 => 0.95
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},
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southeast: %{
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# Similar to Gulf but less extreme
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7 => 0.97,
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8 => 1.08
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},
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southern_plains: %{
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# TX panhandle drier than Gulf but wetter than desert
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8 => 1.05
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},
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desert_southwest: %{
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# Monsoon July/Aug brings moisture → briefly good ducting
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7 => 1.10,
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8 => 1.10,
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9 => 1.05
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},
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pacific_northwest: %{
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# Marine layer summer inversions
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6 => 1.15,
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7 => 1.20,
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8 => 1.20,
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9 => 1.10
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}
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}
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@doc """
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Seasonal score multiplier for a given region and month (1-12).
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Returns a float in [0.7, 1.3]. The scorer multiplies the band's
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`seasonal_base[month]` by this value. Unknown regions or months
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without an adjustment return 1.0.
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"""
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@spec seasonal_adjustment(atom, integer) :: float
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def seasonal_adjustment(region, month) do
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@seasonal_adjustments
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|> Map.get(region, %{})
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|> Map.get(month, 1.0)
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end
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end
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