On November 9th Dr. Trenberth visited our local Fort Lewis College and was the featured speaker at an afternoon climate change symposium.
where he touched on the recent Hurricane Harvey (52:30 video 1/3 embedded below) with its extraordinary longevity and rainfall. Dr. Trenberth went through its vitals, a million people displaced, homes damaged, massive power outage, biblical rainfall.
“(1) an atmosphere with minimal temperature variations, (2) sufficient antecedent soil moisture from rainfall (even swamps or wetlands), and (3) evaporation rates that can provide enough energy to the atmosphere to mimic the ocean.” (source)
“I’d like to bring it back to Hurricane Harvey, can you explain what the Brown Ocean Effect is and how it impacts landfall hurricanes such as Harvey?”
“The ‘Brown Ocean Effect is about land surface areas getting so saturated with hot water that when a hurricane comes over the land it starts sucking up the heat and moisture.”
“So that's presumably the brown ocean effect that if you've dumped a whole lot of water on the land there is a capability for some moisture to reevaporate back into the atmosphere to help refuel the storm if you like.”
“You know having a big dumping of water over land didn't hurt but I don't know just how much it helped either. That's the sort of thing that we can sort out a bit more with experiments with models at some later point.”