Graham McIntire
864a91fc5c
Inversion detection module (Propagation.Inversion): - find_inversion_top/1 walks the native profile to locate the first temperature inversion (surface-based or elevated) - bulk_richardson/3 computes the Richardson number across the inversion layer (Ri < 0.25 = turbulent, > 1 = laminar/good) - shear_magnitude/3 computes the wind shear vector magnitude - potential_temperature/2 for θ = T*(P0/P)^0.286 Theta-e module (Weather.ThetaE): - Bolton (1980) equivalent potential temperature - dewpoint_from_spfh/2 via Magnus-Tetens inversion - theta_e_jump/3 for the thermodynamic decoupling metric mix hrrr_native_derive_fields populates inversion_top_m, bulk_richardson, theta_e_jump_k, and shear_at_top_ms on existing hrrr_native_profiles rows. First real data: 2022-08-20 12Z TX profile shows inversion at 186 m, Ri = 0.16 (turbulent), θ_e jump = 0.33 K — consistent with marginal propagation conditions at that hour.
144 lines
4.9 KiB
Elixir
144 lines
4.9 KiB
Elixir
defmodule Microwaveprop.Propagation.InversionTest do
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use ExUnit.Case, async: true
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alias Microwaveprop.Propagation.Inversion
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# Helper: build a profile struct-like map from level tuples.
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# Each level is {height_m, temp_k, spfh, pressure_pa, u_ms, v_ms, tke}
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defp profile(levels) do
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%{
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level_count: length(levels),
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heights_m: Enum.map(levels, &elem(&1, 0)),
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temp_k: Enum.map(levels, &elem(&1, 1)),
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spfh: Enum.map(levels, &elem(&1, 2)),
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pressure_pa: Enum.map(levels, &elem(&1, 3)),
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u_wind_ms: Enum.map(levels, &elem(&1, 4)),
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v_wind_ms: Enum.map(levels, &elem(&1, 5)),
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tke_m2s2: Enum.map(levels, &elem(&1, 6))
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}
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end
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describe "find_inversion_top/1" do
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test "returns :none for a monotonically cooling profile (no inversion)" do
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# Standard atmosphere: T decreases with height, no inversion
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p =
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profile([
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{10.0, 295.0, 0.010, 101_000.0, 2.0, 1.0, 0.5},
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{100.0, 294.0, 0.009, 100_000.0, 2.5, 1.0, 0.4},
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{300.0, 292.0, 0.007, 97_000.0, 3.0, 1.5, 0.3},
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{500.0, 289.0, 0.005, 95_000.0, 4.0, 2.0, 0.2},
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{1000.0, 283.0, 0.003, 90_000.0, 5.0, 2.5, 0.1}
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])
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assert Inversion.find_inversion_top(p) == :none
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end
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test "detects a surface-based temperature inversion" do
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# Cool at surface, warm layer at 100-300m (classic radiation inversion)
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p =
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profile([
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{10.0, 288.0, 0.008, 101_000.0, 1.0, 0.5, 0.1},
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{50.0, 289.0, 0.008, 100_500.0, 1.0, 0.5, 0.1},
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{100.0, 291.0, 0.007, 100_000.0, 1.5, 0.5, 0.1},
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{200.0, 293.0, 0.006, 99_000.0, 2.0, 1.0, 0.2},
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{300.0, 292.0, 0.006, 98_000.0, 3.0, 1.5, 0.3},
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{500.0, 289.0, 0.005, 95_000.0, 4.0, 2.0, 0.5}
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])
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{:ok, top} = Inversion.find_inversion_top(p)
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# The inversion top is where temperature stops increasing and starts decreasing
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# Between 200m (293K) and 300m (292K) — so the top is at the 200m level
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assert top.height_m == 200.0
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assert top.level_idx == 3
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assert top.strength_k > 0
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end
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test "detects an elevated inversion" do
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# Normal lapse below 500m, inversion between 500-1000m
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p =
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profile([
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{10.0, 295.0, 0.010, 101_000.0, 2.0, 1.0, 0.5},
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{100.0, 294.0, 0.009, 100_000.0, 2.5, 1.0, 0.4},
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{300.0, 292.0, 0.007, 97_000.0, 3.0, 1.5, 0.3},
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{500.0, 290.0, 0.005, 95_000.0, 4.0, 2.0, 0.2},
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{700.0, 292.0, 0.004, 93_000.0, 5.0, 3.0, 0.1},
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{1000.0, 294.0, 0.003, 90_000.0, 6.0, 3.5, 0.1},
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{1500.0, 291.0, 0.002, 85_000.0, 8.0, 4.0, 0.2}
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])
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{:ok, top} = Inversion.find_inversion_top(p)
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# T increases from 500m to 1000m then drops — top at 1000m
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assert top.height_m == 1000.0
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assert top.level_idx == 5
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end
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test "returns :none for a profile with too few levels" do
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p = profile([{10.0, 295.0, 0.010, 101_000.0, 2.0, 1.0, 0.5}])
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assert Inversion.find_inversion_top(p) == :none
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end
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end
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describe "bulk_richardson/3" do
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test "returns large Ri for a strong inversion with weak shear (laminar)" do
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# Strong warming (5 K) with minimal wind change → Ri >> 1
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p =
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profile([
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{10.0, 288.0, 0.008, 101_000.0, 2.0, 1.0, 0.1},
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{200.0, 293.0, 0.006, 99_000.0, 2.1, 1.1, 0.1}
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])
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ri = Inversion.bulk_richardson(p, 0, 1)
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assert ri > 1.0
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end
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test "returns small Ri for an inversion with strong shear (turbulent)" do
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# Mild warming (1 K) with strong wind change (20 m/s) → Ri < 0.25
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p =
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profile([
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{10.0, 290.0, 0.008, 101_000.0, 2.0, 1.0, 0.1},
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{200.0, 291.0, 0.006, 99_000.0, 22.0, 1.0, 0.5}
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])
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ri = Inversion.bulk_richardson(p, 0, 1)
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assert ri < 0.25
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end
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test "clamps at 100.0 when shear is near zero" do
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p =
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profile([
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{10.0, 290.0, 0.008, 101_000.0, 2.0, 1.0, 0.1},
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{200.0, 295.0, 0.006, 99_000.0, 2.0, 1.0, 0.1}
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])
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ri = Inversion.bulk_richardson(p, 0, 1)
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assert ri == 100.0
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end
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end
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describe "shear_magnitude/3" do
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test "computes the vector magnitude of wind difference" do
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p =
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profile([
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{10.0, 290.0, 0.008, 101_000.0, 0.0, 0.0, 0.1},
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{200.0, 290.0, 0.008, 101_000.0, 3.0, 4.0, 0.1}
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])
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shear = Inversion.shear_magnitude(p, 0, 1)
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assert_in_delta shear, 5.0, 0.001
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end
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end
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describe "potential_temperature/2" do
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test "computes theta correctly at standard sea-level conditions" do
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# At P = 100000 Pa (exactly), theta should equal T
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theta = Inversion.potential_temperature(300.0, 100_000.0)
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assert_in_delta theta, 300.0, 0.01
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end
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test "theta > T when pressure is above 1000 hPa" do
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# At P = 101325 Pa, theta should be slightly less than T
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theta = Inversion.potential_temperature(300.0, 101_325.0)
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assert theta < 300.0
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end
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end
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end
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