Update to ensure that mesh resolution is constant in northern high latitudes

FESOM2_Mesh_Generation_{{cookiecutter.mesh_name}}/mesh_CORE2_{{cookiecutter.mesh_name}}/triangle_refine_global.c

@@ -2153,13 +2153,16 @@ int triunsuitable(triorg, tridest, triapex, area)
   //****************************************************************************
   
+  // PG: Adds new code to ensure that the transition north of 48 remains constant
+  //
   res_max = 83000.;		  // 50km //80000.;
   
   //res_satl = 120000.;             // 20dg S -- 50dg N in Atlantic
   //res_natl = 40000.;              // Around Greenland
   //res_pac = 100000.;              // 50dg N of pacific
   
-  //res_arc = 40000.;               // Arctic  
+  // PG: Uncomment this line for transition North of 48 to remain constant
+  res_arc = 40000.;               // Arctic  
   //res_arc2= 15200.;
   
   res_hud = 41000.;               // FS (old:Hudson Bay)
@@ -2187,14 +2190,17 @@ int triunsuitable(triorg, tridest, triapex, area)
   
   //res_bg = (250000.0*cos(triorg_ll[1]*PI/180.0) > res_max) ? (250000.0*cos(triorg_ll[1]*PI/180.0)) : res_max;
   
+  // PG: This line can stay the same based on Qiang's email
   res_bg = (185000.0*cos(triorg_ll[1]*PI/180.0) > res_max) ? (185000.0*cos(triorg_ll[1]*PI/180.0)) : res_max;
   if  ( 
+        // PG: Here you can specify rules for the MESH resolution
         ( le>res_bg ) ||
         ( dist_cst<2.0 && le>res_bg/((4.0-dist_cst)/2.0)) ||  // coastline
-        
+        // PG: Add this from Qiang's email
+        ( le>res_arc && triorg_ll[1]>50) ||     //  north of 50 degree (both Pacific and Atlantic)
 	//( inpoly_satl && le>res_satl ) ||     // south atlantic
         //( inpoly_satl==0 && dist_satl<12. && le>(res_satl+(res_bg-res_satl)*dist_satl/12)) ||
 	
@@ -2212,7 +2218,8 @@ int triunsuitable(triorg, tridest, triapex, area)
         //( le>res_arc && triorg_ll[1]>50 && triorg_ll[0]<50 && triorg_ll[0]>-100 && inpoly_hud==0) || 
         
 	//( le>res_arc && triorg_ll[1]>50 && inpoly_hud==0) ||  //  north of 50 degree (both Pacific and Atlantic)
-	//( triorg_ll[1]<50 && le>(res_arc+(res_bg-res_arc)*(50.-triorg_ll[1])/8.) )  || // transition from big-arctic region (50dgN) to the south to b.g. res.
+        // PG: Turn on the next line from Qiang's email
+	( triorg_ll[1]<50 && le>(res_arc+(res_bg-res_arc)*(50.-triorg_ll[1])/8.) )  || // transition from big-arctic region (50dgN) to the south to b.g. res.
 		
 	//( le>res_arc2 && triorg_ll[1]>52) ||  //  north of 52 degree (both Pacific and Atlantic)
 	//( triorg_ll[1]<52 && le>(res_arc2+( (res_arc+(res_bg-res_arc)*(50.-triorg_ll[1])/8.) -res_arc2)*(52.-triorg_ll[1])/4.) )  || 
@@ -2247,7 +2254,14 @@ int triunsuitable(triorg, tridest, triapex, area)
         ( inpoly_hud && le>res_hud ) || // FS (old:hudson bay)
         ( inpoly_hud==0 && dist_hud<2 && le>(res_hud+(res_bg-res_hud)*dist_hud/2) )  ||
-        
+        // PG: Next two checks are from Qiangs email also
+         // equator
+	(abs(triorg_ll[1])<=15. &&
+	  le>(185000.0-(185000.0-62000.0)*(15.0-abs(triorg_ll[1]))/15.)*cos(triorg_ll[1]*PI/180.0))   || 
+
+        //coastline
+        ( dist_cst<2.0 && le>res_bg/((4.0-dist_cst)/2.0)) ||  // coastline
+       // PG END
 	//( triorg_ll[0]<50 && triorg_ll[0]>-100 && triorg_ll[1]>40 && triorg_ll[1]<50 && 
 	// le>(res_arc+(res_satl-res_arc)*(50-triorg_ll[1])/10) )   // || // transition atlantic