Update some of the documentation around the -drydep, -fire_emis and -…

…-no-megan build-namelist options

bld/namelist_files/namelist_defaults_drydep.xml

@@ -5,23 +5,23 @@
 <namelist_defaults>
 
 <!--
-Values to use by default for creation of CLM model driver namelists.
+Values to use by default for creation of CLM model driver testing namelists.
 The element names are the same as the corresponding namelist
 variables.  Values that depend on the model configuration use
 attributes to express the dependency.  The recognized attributes
 are: RESOLUTION, defaults, mask, ic_ymd, ic_tod, sim_year and all configuration
 attributes from the config_cache.xml file (with keys converted to upper-case).
 -->
 
-<!-- Defaults for drydep_inparm namelist  -->
+<!-- Defaults for drydep_inparm namelist namelists to test standalone CTSM with  -->
 
 <drydep_list>'O3','NO2','HNO3','NO','HO2NO2','CH3OOH','CH2O','CO','H2O2','CH3COOOH','PAN','MPAN','C2H5OOH','ONIT','POOH','C3H7OOH','ROOH','CH3COCHO','CH3COCH3','Pb','ONITR','MACROOH','XOOH','ISOPOOH','CH3OH','C2H5OH','CH3CHO','GLYALD','HYAC','HYDRALD','ALKOOH','MEKOOH','TOLOOH','TERPOOH','CH3COOH','CB1','CB2','OC1','OC2','SOA','SO2','SO4','NH3','NH4NO3'
 </drydep_list>
 
 <!-- effective Henry's coef data for wet and dry deposition -->
 <dep_data_file>atm/cam/chem/trop_mozart/dvel/dep_data_c201019.nc</dep_data_file>
 
-<!-- Defaults for megan_emis_nl -->
+<!-- Defaults for megan_emis_nl namelists to test standalone CTSM with -->
 
 <megan_specifier>'ISOP = isoprene', 'C10H16 = pinene_a + carene_3 + thujene_a', 'CH3OH = methanol', 'C2H5OH = ethanol', 'CH2O = formaldehyde', 'CH3CHO = acetaldehyde', 'CH3COOH = acetic_acid', 'CH3COCH3 = acetone'</megan_specifier>
 

bld/namelist_files/namelist_defaults_fire_emis.xml

@@ -5,15 +5,15 @@
 <namelist_defaults>
 
 <!--
-Values to use by default for creation of CLM model driver namelists.
+Values to use by default for creation of CLM model driver testing namelists.
 The element names are the same as the corresponding namelist
 variables.  Values that depend on the model configuration use
 attributes to express the dependency.  The recognized attributes
 are: RESOLUTION, defaults, mask, ic_ymd, ic_tod, sim_year and all configuration
 attributes from the config_cache.xml file (with keys converted to upper-case).
 -->
 
-<!-- Defaults for fire_emis_nl namelist  -->
+<!-- Defaults for fire_emis_nl namelists for testing -->
 
 <fire_emis_specifier>'bc_a1 = BC','pom_a1 = 1.4*OC','SO2 = SO2'</fire_emis_specifier>
 

bld/namelist_files/namelist_definition_drv_flds.xml

@@ -35,10 +35,14 @@
 	 group="megan_emis_nl"
 	 valid_values="" >
     MEGAN specifier. This is in the form of: Chem-compound = megan_compound(s)
-    where megan_compound(s) can be the sum of megan compounds with a "+" between them.
+    where megan_compound(s) can be an equation with megan compounds added or subtracted together with multiplication
     In each equation, the item to the left of the equal sign is a CAM chemistry compound, the
     items to the right are compounds known to the MEGAN model (single or combinations).
+    Long lines for equations can be split into multiple specifiers
     For example: megan_specifier = 'ISOP = isoprene', 'C10H16 = pinene_a + carene_3 + thujene_a'
+    or...        megan_specifier = 'SOAE = 0.5954*isoprene + 5.1004*(carene_3 + pinene_a + thujene_a + bornene +',
+                                   ' terpineol_4 + terpineol_a + terpinyl_ACT_a + myrtenal + sabinene + pinene_b + camphene +',
+    and etcetera...
   </entry>
 
   <entry id="megan_mapped_emisfctrs"