Earth Science — The Global Water Cycle

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    {
      "id": "wc-sun",
      "type": "sun",
      "label": "Solar radiation — supplies the 2.26 MJ kg⁻¹ latent heat of vaporisation",
      "x": 60,
      "y": 60,
      "width": 240,
      "height": 117,
      "fill": "#dcfce7",
      "stroke": "#15803d"
    },
    {
      "id": "wc-atmos",
      "type": "cloud",
      "label": "Atmosphere — 12 900 km³ of vapour, 0.001 % of all water",
      "x": 340,
      "y": 60,
      "width": 240,
      "height": 117,
      "fill": "#dbeafe",
      "stroke": "#1d4ed8"
    },
    {
      "id": "wc-advect",
      "type": "arrow-right",
      "label": "Advection — winds carry the net 40 from ocean to land",
      "x": 620,
      "y": 60,
      "width": 240,
      "height": 117,
      "fill": "#fef3c7",
      "stroke": "#b45309"
    },
    {
      "id": "wc-condense",
      "type": "rain-cloud",
      "label": "Condensation — cooling to the dew point on aerosol nuclei forms droplets",
      "x": 900,
      "y": 60,
      "width": 240,
      "height": 117,
      "fill": "#fef3c7",
      "stroke": "#b45309"
    },
    {
      "id": "wc-precipland",
      "type": "rain-cloud",
      "label": "Precipitation over land — 113 × 10³ km³ yr⁻¹",
      "x": 1180,
      "y": 60,
      "width": 240,
      "height": 117,
      "fill": "#dcfce7",
      "stroke": "#15803d"
    },
    {
      "id": "wc-oevap",
      "type": "water-drop",
      "label": "Ocean evaporation — 413 × 10³ km³ yr⁻¹, 86 % of the global total",
      "x": 60,
      "y": 235,
      "width": 240,
      "height": 117,
      "fill": "#fef3c7",
      "stroke": "#b45309"
    },
    {
      "id": "wc-precipocean",
      "type": "rain-cloud",
      "label": "Precipitation over the ocean — 373 × 10³ km³ yr⁻¹",
      "x": 340,
      "y": 235,
      "width": 240,
      "height": 117,
      "fill": "#dcfce7",
      "stroke": "#15803d"
    },
    {
      "id": "wc-et",
      "type": "leaf",
      "label": "Evapotranspiration from land — 73 × 10³ km³ yr⁻¹",
      "x": 620,
      "y": 235,
      "width": 240,
      "height": 117,
      "fill": "#fef3c7",
      "stroke": "#b45309"
    },
    {
      "id": "wc-snowice",
      "type": "snowflake",
      "label": "Snow & ice — 68.7 % of all fresh water; glaciers turn over in 20–100 yr",
      "x": 900,
      "y": 235,
      "width": 240,
      "height": 117,
      "fill": "#dbeafe",
      "stroke": "#1d4ed8"
    },
    {
      "id": "wc-runoff",
      "type": "arrow-left",
      "label": "Surface runoff & rivers — 40 × 10³ km³ yr⁻¹ back to the ocean",
      "x": 1180,
      "y": 235,
      "width": 240,
      "height": 117,
      "fill": "#fce7f3",
      "stroke": "#be185d"
    },
    {
      "id": "wc-ocean",
      "type": "ocean-wave",
      "label": "Ocean — 97 % of Earth's water; residence time ≈ 3 200 years",
      "x": 60,
      "y": 410,
      "width": 240,
      "height": 117,
      "fill": "#dbeafe",
      "stroke": "#1d4ed8"
    },
    {
      "id": "wc-baseflow",
      "type": "arrow-left",
      "label": "Baseflow — groundwater discharge keeps rivers running between storms",
      "x": 620,
      "y": 410,
      "width": 240,
      "height": 117,
      "fill": "#fef3c7",
      "stroke": "#b45309"
    },
    {
      "id": "wc-ground",
      "type": "cylinder",
      "label": "Groundwater — 30 % of fresh water; deep aquifers reside 10³–10⁴ years",
      "x": 900,
      "y": 410,
      "width": 240,
      "height": 117,
      "fill": "#dbeafe",
      "stroke": "#1d4ed8"
    },
    {
      "id": "wc-infil",
      "type": "layers",
      "label": "Infiltration & percolation through soil and fractured rock",
      "x": 1180,
      "y": 410,
      "width": 240,
      "height": 117,
      "fill": "#fef3c7",
      "stroke": "#b45309"
    },
    {
      "id": "wc-balance",
      "type": "note",
      "label": "The budget closes: the ocean loses 413 and gains 373, a net −40; land gains 113 and loses 73, a net +40; runoff returns exactly that 40 × 10³ km³ yr⁻¹.",
      "x": 340,
      "y": 410,
      "width": 240,
      "height": 117,
      "fill": "#fef9c3",
      "stroke": "#ca8a04"
    },
    {
      "id": "wc-sublime",
      "type": "note",
      "label": "Sublimation turns snow and ice straight into vapour and deposition reverses it — small globally, but the dominant term in polar and high-alpine budgets.",
      "x": 60,
      "y": 585,
      "width": 520,
      "height": 117,
      "fill": "#fef9c3",
      "stroke": "#ca8a04"
    },
    {
      "id": "wc-residence",
      "type": "note",
      "label": "Residence time = store ÷ flux. Nine days in the atmosphere is why weather changes within a week; 3 200 years in the ocean is why sea level responds over centuries.",
      "x": 620,
      "y": 585,
      "width": 520,
      "height": 117,
      "fill": "#fef9c3",
      "stroke": "#ca8a04"
    }
  ],
  "edges": [
    {
      "id": "wc-e1",
      "source": "wc-sun",
      "target": "wc-oevap",
      "label": "latent heat input"
    },
    {
      "id": "wc-e2",
      "source": "wc-ocean",
      "target": "wc-oevap",
      "label": "413"
    },
    {
      "id": "wc-e3",
      "source": "wc-oevap",
      "target": "wc-atmos"
    },
    {
      "id": "wc-e4",
      "source": "wc-atmos",
      "target": "wc-advect"
    },
    {
      "id": "wc-e5",
      "source": "wc-advect",
      "target": "wc-condense",
      "label": "net 40 crosses the coast"
    },
    {
      "id": "wc-e6",
      "source": "wc-condense",
      "target": "wc-precipland",
      "label": "113"
    },
    {
      "id": "wc-e7",
      "source": "wc-condense",
      "target": "wc-precipocean",
      "label": "373"
    },
    {
      "id": "wc-e8",
      "source": "wc-precipocean",
      "target": "wc-ocean"
    },
    {
      "id": "wc-e9",
      "source": "wc-precipland",
      "target": "wc-et",
      "label": "73 returns straight to the air"
    },
    {
      "id": "wc-e10",
      "source": "wc-et",
      "target": "wc-atmos"
    },
    {
      "id": "wc-e11",
      "source": "wc-precipland",
      "target": "wc-snowice",
      "label": "as snow above the freezing level"
    },
    {
      "id": "wc-e12",
      "source": "wc-precipland",
      "target": "wc-infil"
    },
    {
      "id": "wc-e13",
      "source": "wc-precipland",
      "target": "wc-runoff",
      "label": "overland flow"
    },
    {
      "id": "wc-e14",
      "source": "wc-infil",
      "target": "wc-ground"
    },
    {
      "id": "wc-e15",
      "source": "wc-ground",
      "target": "wc-baseflow"
    },
    {
      "id": "wc-e16",
      "source": "wc-baseflow",
      "target": "wc-runoff"
    },
    {
      "id": "wc-e17",
      "source": "wc-snowice",
      "target": "wc-runoff",
      "label": "seasonal melt"
    },
    {
      "id": "wc-e18",
      "source": "wc-runoff",
      "target": "wc-ocean",
      "label": "40 closes the budget"
    },
    {
      "id": "wc-e19",
      "source": "wc-sun",
      "target": "wc-et"
    }
  ]
}