add band_wavelength variable and timeline_id

himawari/ahi2cmi.py

@@ -357,7 +357,7 @@ class HimawariAHIasCMIP(object):
             cdm_data_type="Image",
             time_coverage_start=start.strftime(UTCFMT),
             time_coverage_end=stop.strftime(UTCFMT),
-            timeline_id=None,
+            timeline_id='AXI Mode 1',
             production_data_source=None,
             id=None,
         )
@@ -488,6 +488,9 @@ class HimawariAHIasCMIP(object):
         # nav structure
         yield self.p(self._projection_name), np.int32(0), {}, self.nav
 
+        # band_wavelength in µm
+        yield self.p('band_wavelength'), np.float64(self.central_wavelength), {}, {}
+
         # y and x variables and friends
         for each in self.pvda_yx():
             yield each