scale luminance so that ghi=1

openalea-incubator · Nov 26, 2024 · 1253a56 · 1253a56
1 parent c2ee663
commit 1253a56
Show file tree

Hide file tree

Showing 3 changed files with 24 additions and 39 deletions.
diff --git a/example/notebooks/Sky irradiance.ipynb b/example/notebooks/Sky irradiance.ipynb
@@ -898,9 +898,9 @@
    "name": "python",
    "nbconvert_exporter": "python",
    "pygments_lexer": "ipython3",
-   "version": "3.8.15"
+   "version": "3.12.3"
   }
  },
  "nbformat": 4,
- "nbformat_minor": 1
+ "nbformat_minor": 4
 }
diff --git a/example/notebooks/Sky luminance.ipynb b/example/notebooks/Sky luminance.ipynb
@@ -289,7 +289,7 @@
    "id": "be342dc1",
    "metadata": {},
    "source": [
-    "## Estimate sky luminance"
+    "## Estimate sky relative luminance"
    ]
   },
   {
@@ -299,12 +299,12 @@
    "source": [
     "* Sky luminance is estimated from sky irradiances, using Perez all weather sky model (R. Perez, R. Seals, J. Michalsky, \"All-weather model for sky luminance distribution—Preliminary configuration and validation\", Solar Energy, Volume 50, Issue 3, 1993, Pages 235-245)\n",
     "* Luminance is computed every steradian of the sky hemisphere\n",
-    "* For other strategies, see 'sky_luminance modeling strategies' companion tutorial"
+    "* Luminance are scaled to ensure a global horizontal irradiance of 1"
    ]
   },
   {
    "cell_type": "code",
-   "execution_count": 3,
+   "execution_count": 6,
    "id": "ede65060",
    "metadata": {},
    "outputs": [],
@@ -315,7 +315,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 4,
+   "execution_count": 7,
    "id": "43f643de",
    "metadata": {},
    "outputs": [
@@ -347,13 +347,13 @@
    "id": "dad34005",
    "metadata": {},
    "source": [
-    "Sky discretisation allow to split the sky in a limited number of direction for efficiency of light modelling.\n",
-    "You can use football like dicretisation (sky_turtle) or a latitude/longitude regular grid (sky_dirs)"
+    "* Sky discretisation allow to split the sky in a limited number of direction for efficiency of light modelling.\n",
+    "* other strategies can be found in the companon tutorial"
    ]
   },
   {
    "cell_type": "code",
-   "execution_count": 5,
+   "execution_count": 8,
    "id": "83710a79",
    "metadata": {},
    "outputs": [
@@ -388,16 +388,17 @@
    "id": "f4360e2f",
    "metadata": {},
    "source": [
-    "##### light sources are given as elevation, azimuth, relative_luminance tuples, that can be scaled to \n",
+    "##### light sources are given as elevation, azimuth, relative_luminance tuples, that can be scaled to :\n",
     " * global luminance ('Wm2' [W.m-2.s-1])\n",
     " * PAR luminance ('PPFD', [micromol.m-2.s-1])\n",
-    " * global energy emmited over the time period ('MJ', [MJ.m-2])\n",
-    " * PAR emitted over the time-periode ('molPAR', [mol.m-2]) "
+    " * global luminance integrated over the time period ('MJ', [MJ.m-2])\n",
+    " * PAR luminance integrated over the time-periode ('molPAR', [mol.m-2])\n",
+    " Other Strategies can be found in companion tutorial"
    ]
   },
   {
    "cell_type": "code",
-   "execution_count": 6,
+   "execution_count": 9,
    "id": "5673473a",
    "metadata": {},
    "outputs": [],
@@ -407,7 +408,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 7,
+   "execution_count": 10,
    "id": "b0334e5c-848a-4513-be95-47d6960be33c",
    "metadata": {},
    "outputs": [],
@@ -417,22 +418,22 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 9,
+   "execution_count": 11,
    "id": "c9b5a01a-35d1-4e7f-b259-df097b80d6d2",
    "metadata": {},
    "outputs": [
     {
      "data": {
       "application/vnd.jupyter.widget-view+json": {
-       "model_id": "b0ab6ea2a50f4ecc9f945a2053fa8ac0",
+       "model_id": "b1858ede48954ca69ae87289e0d774f8",
        "version_major": 2,
        "version_minor": 0
       },
       "text/plain": [
        "Plot(antialias=3, axes=['x', 'y', 'z'], axes_helper=1.0, axes_helper_colors=[16711680, 65280, 255], background…"
       ]
      },
-     "execution_count": 9,
+     "execution_count": 11,
      "metadata": {},
      "output_type": "execute_result"
     }

diff --git a/src/alinea/astk/meteorology/sky_luminance.py b/src/alinea/astk/meteorology/sky_luminance.py
@@ -215,11 +215,11 @@ def all_weather_relative_luminance(grid, sun_zenith, sun_azimuth, clearness, bri
 
 
 def sky_luminance(grid, sky_type='soc', sky_irradiance=None):
-    """Normalised sky luminance map for different conditions, periods and sky types
-       Luminance are normalised so that sum(luminance) = 1.
+    """Relative sky luminance map for different conditions, periods and sky types
+       Luminance are scaled so that total sky horizontal irradiance equals one.
 
     Args:
-        sky_type (str): sky type, one of ('soc', 'uoc', 'clear_sky', 'sun_soc', 'blended', 'all_weather')
+        sky_type (str): sky type, one of ('soc', 'uoc', 'clear_sky', 'blended', 'all_weather')
         sky_irradiance: a datetime indexed dataframe specifying sky irradiances for the period, such as returned by
         astk.sky_irradiance.sky_irradiance. Needed for all sky_types except 'uoc' and 'soc'
     """
@@ -232,17 +232,14 @@ def sky_luminance(grid, sky_type='soc', sky_irradiance=None):
 
     if sky_type in ('soc', 'uoc'):
         lum = w_c * cie_relative_luminance(grid=grid, type=sky_type)
-        lum /= lum.sum()
     elif sky_type == 'clear_sky':
         for row in irrad.itertuples():
             _lum = w_c * cie_relative_luminance(grid=grid,
                                           sun_zenith=row.sun_zenith,
                                           sun_azimuth=row.sun_azimuth,
                                           type='clear_sky')
-            _lum /= _lum.sum()
             _hi = sky_hi(grid, _lum)
             lum += (row.ghi / _hi * _lum)
-        lum /= lum.sum()
     elif sky_type == 'all_weather':
         for row in irrad.itertuples():
             brightness = all_weather_sky_brightness(row.dates, row.dhi, row.sun_zenith)
@@ -252,21 +249,8 @@ def sky_luminance(grid, sky_type='soc', sky_irradiance=None):
                                                   sun_azimuth=row.sun_azimuth,
                                                   brightness=brightness,
                                                   clearness=clearness)
-            _lum /= _lum.sum()
             _hi = sky_hi(grid, _lum)
             lum += (row.ghi / _hi * _lum)
-        lum /= lum.sum()
-    elif sky_type == 'sun_soc':
-        lum = w_c * cie_relative_luminance(grid=grid, type='soc')
-        # scale to total luminance of sky
-        lum /= lum.sum()
-        hi = sky_hi(grid, lum)
-        lum *= (irrad.dhi.sum() / hi)
-        for row in irrad.itertuples():
-            daz, dz = map(lambda x: numpy.diff(x)[0], (azimuth, zenith))
-            i, j = int(row.sun_zenith // dz), int(row.sun_azimuth // daz)
-            lum[i, j] += row.dni
-        lum /= lum.sum()
     elif sky_type == 'blended':
         soc = w_c * cie_relative_luminance(grid=grid, type='soc')
         for row in irrad.itertuples():
@@ -277,14 +261,14 @@ def sky_luminance(grid, sky_type='soc', sky_irradiance=None):
             epsilon = all_weather_sky_clearness(row.dni, row.dhi, row.sun_zenith)
             f_clear = f_clear_sky(epsilon)
             _lum = f_clear * cs + (1 - f_clear) * soc
-            _lum /= _lum.sum()
             _hi = sky_hi(grid, _lum)
             lum += (row.ghi / _hi * _lum)
-        lum /= lum.sum()
     else:
         raise ValueError('undefined sky type: ' + sky_type)
 
-    return lum
+    # scale so that ghi = 1
+    hi = sky_hi(grid, lum)
+    return lum / hi
 
 
 def scale_sky_sources(sky_sources, sky_irradiance, scale='Wm2', diffuse_only=False):