Ipcc color update

RELEASE_NOTES.md

@@ -1,5 +1,7 @@
 # Next Release
 
+- [#314](https://github.com/IAMconsortium/pyam/pull/314) Update IPCC color scheme colors and add SSP-only colors
+
 ## API changes
 
 PR [#305](https://github.com/IAMconsortium/pyam/pull/305) changed the default

pyam/plotting.py

@@ -35,19 +35,30 @@
 }
 
 PYAM_COLORS = {
-    'AR6-SSP1-1.9': "#00AAD0",
-    'AR6-SSP1-2.6': "#003466",
-    'AR6-SSP2-4.5': "#EF550F",
-    'AR6-SSP3-7.0': "#E00000",
-    'AR6-SSP3-LowNTCF': "#E00000",
-    'AR6-SSP4-3.4': "#FFA900",
-    'AR6-SSP4-6.0': "#C47900",
-    'AR6-SSP5-3.4-OS': "#7F006E",
-    'AR6-SSP5-8.5': "#990002",
-    'AR6-RCP-2.6': "#003466",
-    'AR6-RCP-4.5': "#5492CD",
-    'AR6-RCP-6.0': "#C47900",
-    'AR6-RCP-8.5': "#990002",
+    # AR6 colours from https://github.com/IPCC-WG1/colormaps
+    # where each file is processed to generate hex values, e.g.:
+    # for liwith open('rcp_cat.txt') as f:
+    #   for l in f.readlines():
+    #     rgb = np.array([int(x) for x in l.strip().split()]) / 256
+    #     print(matplotlib.colors.rgb2hex(rgb))
+    'AR6-SSP1': "#1e9583",
+    'AR6-SSP2': "#4576be",
+    'AR6-SSP3': "#f11111",
+    'AR6-SSP4': "#e78731",
+    'AR6-SSP5': "#8036a7",
+    'AR6-SSP1-1.9': "#1e9583",
+    'AR6-SSP1-2.6': "#1d3354",
+    'AR6-SSP2-4.5': "#e9dc3d",
+    'AR6-SSP3-7.0': "#f11111",
+    'AR6-SSP3-LowNTCF': "#f11111",
+    'AR6-SSP4-3.4': "#63bce4",
+    'AR6-SSP4-6.0': "#e78731",
+    'AR6-SSP5-3.4-OS': "#996dc8",
+    'AR6-SSP5-8.5': "#830b22",
+    'AR6-RCP-2.6': "#980002",
+    'AR6-RCP-4.5': "#c37900",
+    'AR6-RCP-6.0': "#709fcc",
+    'AR6-RCP-8.5': "#003466",
     # AR5 colours from
     # https://tdaviesbarnard.co.uk/1202/ipcc-official-colors-rcp/
     'AR5-RCP-2.6': "#0000FF",