Change Variables and Symbols page into a Glossary of terms

docs/sphinx/source/user_guide/glossary.rst

@@ -0,0 +1,181 @@
+.. glossary:
+
+Glossary
+========
+
+.. glossary::
+
+    airmass
+        Airmass
+
+    airmass_absolute
+        Absolute airmass
+
+    airmass_relative
+        Relative airmass
+
+    albedo
+        Ratio of reflected solar irradiance to global horizontal irradiance
+        [unitless]
+
+    aoi
+        Angle of incidence between :math:`90\deg` and :math:`90\deg`
+
+    aoi_projection
+        cos(aoi)
+
+    ape
+        Average photon energy
+
+    apparent_zenith
+        Refraction-corrected solar zenith angle in degrees
+
+    bhi
+        Beam/direct horizontal irradiance
+
+    dhi
+        Diffuse horizontal irradiance
+
+    dni
+        Direct normal irradiance [Wm⁻²]. Amount of radiation received per unit
+        area by a surface perpendicular (normal) to the sun's rays that
+        propagate in a straight line from the sun.
+
+    dni_clear
+        Clear sky direct normal irradiance
+
+    dni_extra
+        Direct normal irradiance at top of atmosphere (extraterrestrial)
+
+    effective_irradiance
+        Effective irradiance
+
+    eta_inv
+        Inverter efficiency
+
+    eta_inv_nom
+        Nominal inverter efficiency
+
+    eta_inv_ref
+        Reference inverter efficiency
+
+    g_poa_effective
+        Broadband plane of array effective irradiance
+
+    gamma_pdc
+        Module temperature coefficient. Typically in units of 1/C.
+
+    ghi
+        Global horizontal irradiance
+
+    ghi_extra
+        Horizontal irradiance at top of atmosphere (extraterrestrial)
+
+    gri
+        Ground-reflected irradiance
+
+    i_sc
+        Short circuit module current
+
+    i_x, i_xx
+        Sandia Array Performance Model IV curve parameters
+
+    latitude
+        Latitude
+
+    longitude
+        Longitude
+
+    pac, ac
+        AC power
+
+    pdc, dc
+        DC power
+
+    pdc0
+        Nameplate DC rating
+
+    photocurrent
+        Photocurrent
+
+    poa_diffuse
+        Total diffuse irradiation in plane. Sum of ground and sky diffuse.
+
+    poa_direct
+        Direct/beam irradiation in plane
+
+    poa_global
+        Global irradiation in plane. sum of diffuse and beam projection.
+
+    poa_ground_diffuse
+        In plane ground reflected irradiation
+
+    poa_sky_diffuse
+        Diffuse irradiation in plane from scattered light in the atmosphere
+        (without ground reflected irradiation)
+
+    precipitable_water
+        Total precipitable water contained in a column of unit cross section
+        from earth to top of atmosphere
+
+    pressure
+        Atmospheric pressure
+
+    relative_humidity
+        Relative humidity
+
+    resistance_series
+        Series resistance
+
+    resistance_shunt
+        Shunt resistance
+
+    saturation_current
+        Diode saturation current
+
+    solar_azimuth
+        Azimuth angle of the sun in degrees East of North
+
+    solar_zenith
+        Zenith angle of the sun in degrees
+
+    surface_azimuth
+        Azimuth angle of the surface
+
+    surface_tilt
+        Tilt angle of the surface
+
+    surface_tilt
+        Panel tilt from horizontal [°]. For example, a surface facing up = 0°,
+        surface facing horizon = 90°.
+
+    temp_air
+        Temperature of the air
+
+    temp_cell
+        Temperature of the cell
+
+    temp_dew
+        Dewpoint temperature
+
+    temp_module
+        Temperature of the module
+
+    transposition_factor
+        The gain ratio of the radiation on inclined plane to global horizontal
+        irradiation: :math:`\frac{poa\_global}{ghi}`
+
+    tz
+        Timezone
+
+    v_mp, i_mp, p_mp
+        Module voltage, current, power at the maximum power point
+
+    v_oc
+        Open circuit module voltage
+
+    wind_direction
+        Wind direction
+
+    wind_speed
+        Wind speed

docs/sphinx/source/user_guide/index.rst

@@ -16,5 +16,6 @@ User Guide
    bifacial
    weather_data
    variables_style_rules
+   glossary
    singlediode
    faq

pvlib/irradiance.py

@@ -734,9 +734,8 @@ def haydavies(surface_tilt, surface_azimuth, dhi, dni, dni_extra,
     The Hay and Davies model determines the diffuse irradiance from
     the sky (ground reflected irradiance is not included in this
     algorithm) on a tilted surface using the surface tilt angle, surface
-    azimuth angle, diffuse horizontal irradiance, direct normal
-    irradiance, extraterrestrial irradiance, sun zenith angle, and sun
-    azimuth angle.
+    azimuth angle, diffuse horizontal irradiance, direct normal irradiance,
+    extraterrestrial irradiance, sun zenith angle, and sun azimuth angle.
 
     Parameters
     ----------
@@ -745,6 +744,10 @@ def haydavies(surface_tilt, surface_azimuth, dhi, dni, dni_extra,
         defined as degrees from horizontal (e.g. surface facing up = 0,
         surface facing horizon = 90)
 
+    surface_tilt : numeric
+        Panel tilt from the horizontal, in decimal degrees, see
+        :term:`surface_tilt`.
+
     surface_azimuth : numeric
         Surface azimuth angles in decimal degrees. The azimuth
         convention is defined as degrees east of north (e.g. North=0,
@@ -754,7 +757,7 @@ def haydavies(surface_tilt, surface_azimuth, dhi, dni, dni_extra,
         Diffuse horizontal irradiance. [Wm⁻²]
 
     dni : numeric
-        Direct normal irradiance. [Wm⁻²]
+        Direct normal irradiance, see :term:`dni`. [Wm⁻²]
 
     dni_extra : numeric
         Extraterrestrial normal irradiance. [Wm⁻²]