Temeraire opened his jaws and what emerged was a roar that was less a sound than a force, a terrible wave of noise so vast it seemed to distort the air before him. (HMD, 330)
The Divine Wind is the most mysterious of dragon abilities-- a sort of 'sonic roar' capable of doing great destruction, especially to objects made of wood. It only presents itself in one breed in all the world, the Celestial. There are few Celestials in the world, and few of them ever venture outside of China, so very little is known of this ability in the western world. Sir Edward Howe suggests in his book Observations on the Order Draconia in Europe, with Notes on the Oriental Breeds (excerpted in HMD) that since the divine wind is known only by "heresay" and that some experts dismiss it as "phantasy."
The Divine Wind is able to destroy wood, stone and bones (humen, dragons), to cause a tsunami and to send a ship to the bottom, the greater the distance is the less destructive the Divine Wind is. With closed jaws it can be used to model stone/wood etc. Even when a Celestial roars a nuance of the Divine Wind is in it to intimidate others. The roaring of other breeds can be nearly as impressive as the roaring of Celestials (see Kulingile or the Regal Coppers). The Divine Wind uses the same muscles as speaking, roaring and breathing but it is more exhausting and strains the throat what prevents the dragon from using it too often or too much. Obviously it develops when the dragon is nearly fully grown and it can be trained. Other dragons don't recognize it as quickly as they recognize acid-spitters or fire-breathers but it is very very impressive for the surviving dragons and aviators of a divine wind attack. It does heavy damage to organic material, it seems that the whole body explodes of his inner side and the victims immediately start to bleed much. But it is a short death. The noise starts by getting reflected in the Celestial's body (lungs, belly, air sacks) and boosts with every reflection. The skin stretches, the dragon's whole body is under tension and he trembles.
Howe is naturally delighted to come into contact with Temeraire and confirm the divine wind's existence to other draconic scholars.
When Kublai Khan, the grandson of Genghis Khan, invaded Japan in 1274, his and the korean fleet were defeated by a taifun which destroyed most of the ships. Later the Japanese called this storm the "divine wind" because they thought it had been send by a deity to save Japan. During his second invasion 7 years later, the Khan burned the Hakozaki shrein but this invasion didn't succeed either. What if it wasn't a storm that destroyed the ships but a dragon? A japanese Celestial. Raiden, one of Temeraire's favourite heroes, fought against the Khan's armada so he could possibly have been a Celestial. We have seen the destructive force of the Divine Wind in the Battle of Shoeburyness performed by Lien. Of course it could have been a Sui-Riu too but a Celstial is more likely. In Naomi Novik's universe the Khan stole the last Celestial eggs from the shrein and extinguished the rest of this breed. Lord Jinai says that he has seen japanese Celestials but he was born around 1400 only, 100 years after Kublai Khan's invasion. This indicates that some individuals survived but obviously they weren't enough to reproduce. And this whole story shows that both countries, China and Japan, had the same breeding success in the same time (the Yellow Emperor was a chinese Celestial, maybe derived from a gift from Japan or a mutation) and that the japanese Celestials were much more individuals than the chinese ones and not too close related to each other to not breed among themselves. Whether Naomi Novik took the name of her special ability from this event as inspiration or the japanese and chinese people in her books invented this name for the Celestial's special ability because of this event.