Update citation keywords

Author: RobertPincus

CITATION.cff

@@ -26,7 +26,10 @@ identifiers:
     value: 10.5281/zenodo.7988261
 keywords:
   - netCDF
-  -
+  - "RTE+RRTMGP"
+  - "atmospheric radiation"
+  - "radiative transfer"
+  - "climate model"
   - research
 license: BSD-3-Clause
 message: "If you use this software, please cite it using these metadata."