Refactor each constituent into separate files

Author: bkeepers

packages/tide-predictor/src/constituents/2MK3.ts

@@ -0,0 +1,18 @@
+import { defineCompoundConstituent } from "./index.js";
+import M2 from "./M2.js";
+import O1 from "./O1.js";
+
+/**
+ * Shallow-water terdiurnal (2MK3).
+ * Compound constituent: M2 + O1
+ * Speed ~42.93°/h with period ~8.39 hours (terdiurnal).
+ * Lunar-lunar interaction from M2 semi-diurnal and O1 diurnal components.
+ * Nodal factors combine fM2 with fO1.
+ * Generated in shallow-water environments; typical amplitude <1 cm.
+ *
+ * @see https://tidesandcurrents.noaa.gov/ NOAA CO-OPS
+ */
+export default defineCompoundConstituent("2MK3", [
+  { constituent: M2, factor: 1 },
+  { constituent: O1, factor: 1 },
+]);

packages/tide-predictor/src/constituents/2MK5.ts

@@ -0,0 +1,21 @@
+import { defineCompoundConstituent } from "./index.js";
+import M2 from "./M2.js";
+import K1 from "./K1.js";
+
+/**
+ * Shallow-water quinte-diurnal from M2-K1 interaction.
+ * Doodson Number: ~465.555 (estimated; compounded frequency)
+ * Components: 2×M2 (lunar semi-diurnal × 2) + K1 (lunisolar diurnal).
+ * Speed 44.025°/h with period ~8.18 hours.
+ * Nodal factors combine (fM2)² with fK1.
+ *
+ * Note: Found in coastal tide predictions, especially in enclosed bays and harbors.
+ * Amplitude typically 0.1-0.5 cm depending on location and water depth.
+ * Shallow-water constituent only; not present in deep ocean.
+ *
+ * @see NOAA CO-OPS
+ */
+export default defineCompoundConstituent("2MK5", [
+  { constituent: M2, factor: 2 },
+  { constituent: K1, factor: 1 },
+]);

packages/tide-predictor/src/constituents/2MO5.ts

@@ -0,0 +1,21 @@
+import { defineCompoundConstituent } from "./index.js";
+import M2 from "./M2.js";
+import O1 from "./O1.js";
+
+/**
+ * Shallow-water quinte-diurnal from M2-O1 interaction.
+ * Doodson Number: ~445.555 (estimated; compounded frequency)
+ * Components: 2×M2 (lunar semi-diurnal × 2) + O1 (lunar diurnal).
+ * Speed 43.47°/h with period ~8.28 hours.
+ * Nodal factors combine (fM2)² with fO1.
+ *
+ * Note: Primarily shallow-water coastal phenomenon, not present in deep ocean.
+ * Amplitude typically <0.5 cm except in extreme shallow-water or enclosed basins.
+ * Found in coastal tide predictions alongside other shallow-water constituents.
+ *
+ * @see NOAA CO-OPS
+ */
+export default defineCompoundConstituent("2MO5", [
+  { constituent: M2, factor: 2 },
+  { constituent: O1, factor: 1 },
+]);

packages/tide-predictor/src/constituents/2MS6.ts

@@ -0,0 +1,22 @@
+import { defineCompoundConstituent } from "./index.js";
+import M2 from "./M2.js";
+import S2 from "./S2.js";
+
+/**
+ * Quarter-diurnal shallow-water interaction: 2×M2 + S2.
+ * Doodson Number: 473.555
+ * Speed 58.984°/h with period ~6.10 hours.
+ * Nodal factor: f(M2)²(S2) / u(M2)²(S2) = combined M2² and S2 factors.
+ *
+ * Note: Sometimes denoted as MS4 in alternative notation systems.
+ * Generated only in shallow water; typical amplitude 0.01-0.2 meters depending on depth.
+ * Included in IHO shallow-water constituent tables and NOAA analysis (order #37).
+ *
+ * @see https://iho.int/en/standards-and-specifications/standards/s-14 IHO Tidal Constituent Bank
+ * @see https://tidesandcurrents.noaa.gov/ NOAA CO-OPS
+ * @see https://en.wikipedia.org/wiki/Theory_of_tides
+ */
+export default defineCompoundConstituent("2MS6", [
+  { constituent: M2, factor: 2 },
+  { constituent: S2, factor: 1 },
+]);

packages/tide-predictor/src/constituents/2N2.ts

@@ -0,0 +1,15 @@
+import { defineConstituent } from "./index.js";
+import nc from "../node-corrections/index.js";
+
+/**
+ * Lunar semi-diurnal (2N2).
+ * Doodson Number: 2.-2.0.2.0.0.0
+ * Speed 27.895°/h with period ~12.91 hours (lunar semi-diurnal).
+ * Second-order lunar semi-diurnal from Moon's orbital ellipticity.
+ * Uses M2 nodal factors (fM2/uM2) for amplitude and phase modulation.
+ * Nodal factor ranges: f from ~0.4 to ~1.6; u from 0° to ±180°.
+ * Amplitude typically 5-10% of M2; significant in semi-diurnal analysis.
+ *
+ * @see https://tidesandcurrents.noaa.gov/ NOAA CO-OPS
+ */
+export default defineConstituent("2N2", [2, -2, 0, 2, 0, 0, 0], nc.uM2, nc.fM2);

packages/tide-predictor/src/constituents/2Q1.ts

@@ -0,0 +1,19 @@
+import { defineCompoundConstituent } from "./index.js";
+import N2 from "./N2.js";
+import J1 from "./J1.js";
+
+/**
+ * Shallow-water diurnal (2Q1).
+ * Compound constituent: N2-J1
+ * Speed ~12.854°/h with period ~27.93 hours (diurnal).
+ * Derived from interaction of semi-diurnal N2 and diurnal J1 constituents.
+ * Nodal factor combines effects from both parent constituents: fN2/fJ1 with phase uN2-uJ1.
+ * Amplitude typically very small; rarely significant.
+ * Found only in shallow-water regions with strong tidal distortion.
+ *
+ * @see https://tidesandcurrents.noaa.gov/ NOAA CO-OPS
+ */
+export default defineCompoundConstituent("2Q1", [
+  { constituent: N2, factor: 1 },
+  { constituent: J1, factor: -1 },
+]);

packages/tide-predictor/src/constituents/2SM2.ts

@@ -0,0 +1,18 @@
+import { defineCompoundConstituent } from "./index.js";
+import S2 from "./S2.js";
+import M2 from "./M2.js";
+
+/**
+ * Shallow-water semi-diurnal (2SM2).
+ * Compound constituent: 2×S2 - M2
+ * Speed ~31.02°/h with period ~11.61 hours.
+ * Solar-lunar interaction constituent generated in shallow-water environments.
+ * Nodal factors combine (fS2)² with inverse M2 effects.
+ * Amplitude typically <2% of M2; complementary to MU2.
+ *
+ * @see https://tidesandcurrents.noaa.gov/ NOAA CO-OPS
+ */
+export default defineCompoundConstituent("2SM2", [
+  { constituent: S2, factor: 2 },
+  { constituent: M2, factor: -1 },
+]);

packages/tide-predictor/src/constituents/3L2.ts

@@ -0,0 +1,16 @@
+import { defineCompoundConstituent } from "./index.js";
+import L2 from "./L2.js";
+
+/**
+ * Triple lunar elliptic; 3 times L2 interaction.
+ * Doodson Number: ~265 (estimated; not standard Doodson notation)
+ * Speed ~88.5°/h (≈ 3 × 29.5°/h) with period ~4.14 hours.
+ * Nodal factor: (fL2)³ / (uL2)³ = cubic L2 nodal modulation (very small).
+ *
+ * Warning: Not in standard IHO constituent bank. Mainly historical/theoretical interest.
+ * Very small amplitude (<0.1 cm); found only in extreme shallow water or enclosed basins.
+ * Often ignored in routine tide predictions.
+ *
+ * @see Schureman, P. (1958). Manual of Harmonic Analysis and Prediction of Tides
+ */
+export default defineCompoundConstituent("3L2", [{ constituent: L2, factor: 3 }]);

packages/tide-predictor/src/constituents/3N2.ts

@@ -0,0 +1,16 @@
+import { defineCompoundConstituent } from "./index.js";
+import N2 from "./N2.js";
+
+/**
+ * Triple N2 shallow-water harmonic (3 × N2).
+ * Doodson Number: ~336 (estimated; not standard Doodson notation)
+ * Speed 85.32°/h (≈ 3 × 28.44°/h) with period ~4.23 hours.
+ * Nodal factor: (fN2)³ / (uN2)³ = cubic N2 nodal modulation.
+ *
+ * Note: Shallow-water constituent with definition based on compound frequency estimates.
+ * Typical amplitude <0.5 cm; often <0.1 cm except in extreme shallow-water or enclosed basins.
+ * Rarely significant in routine tide predictions.
+ *
+ * @see NOAA CO-OPS shallow-water constituents
+ */
+export default defineCompoundConstituent("3N2", [{ constituent: N2, factor: 3 }]);

packages/tide-predictor/src/constituents/EP2.ts

@@ -0,0 +1,16 @@
+import { defineConstituent } from "./index.js";
+import nc from "../node-corrections/index.js";
+
+/**
+ * Lunar elliptic semi-diurnal constituent (ε2).
+ * Doodson Number: 256.555
+ * From Moon's elliptical orbit; speed 29.6°/h with period of ~12.0 hours.
+ * Uses M2 nodal factors (fM2/uM2) for amplitude and phase modulation.
+ *
+ * Note: Sometimes called ν2 variant in some sources, but IHO designation is definitive.
+ *
+ * @see https://iho.int/en/standards-and-specifications/standards/s-14 IHO Tidal Constituent Bank
+ * @see https://tidesandcurrents.noaa.gov/ NOAA CO-OPS constituent tables
+ * @see https://en.wikipedia.org/wiki/Theory_of_tides Theory of Tides
+ */
+export default defineConstituent("EP2", [2, 0, 1, 0, 0, 0, 0], nc.uM2, nc.fM2);