Yep, that's coordinated
To answer your question: in CIV the attacker ALWAYS has the advantage if he brings a mixed stack, unless you have more catapults than him. The reason is the very powerful collateral damage and the city attack boni for catapults. Thus, either you can weather the attack - but be prepared for ridiculous losses if he has enough units to mop up your wounded after using his catapults. Or you must pre-attack the SOD in open terrain.
I guess you do NOT have 20 or more catapults ready for the NE stack? And roughly the same of the second one?