Yes,

This is my favorite infrastructure project concept: https://www.scientificamerican.com/article/offshore-wind-far...

help with hurricanes, direct DC to the entire country, tons of jobs for maintenance, etc

There's some research that wind farms at scale have a small but non-negligible warming effect:

https://www.sciencedirect.com/science/article/pii/S254243511...!

Wind encounters far more resistance and obstacles when sweeping over land, ex. cities with buildings (tall and small) and other man made structures and then there are various natural ones - trees, hills, etc.

Windmill probably is much less of a drag (pun!) as compared to above.

Yes, research has been done, if only because knowing about that is essential for figuring out at what distance from each other you should place your turbines.

See for example https://energyfollower.com/wind-turbine-spacing, https://ep.liu.se/ecp/057/vol15/014/ecp57vol15_014.pdf

i'm not aware of any comparisons but imagine a sparse forest.

I think offshore wind farms have been proposed to protect the US from hurricanes. So apparently they substantially decrease wind energy.

> offshore wind farms have been proposed to protect the US from hurricanes

No, certainly not seriously.

An estimate of 78,000 turbines is truly a thought experiment, not a realistic solution. There does not exist manufacturing capacity or installation capacity to achieve this (not even remotely close). The offshore wind pipeline, globally, is orders of magnitude fewer WTGs, and procurement & installation pressure is already expected to be very tight in the coming decade.

This is made more difficult in the US due to the complexities of offshore wind installation imposed by the Jones Act.

It’s a neat concept. But it will never be realized.

An interesting thought I've wondered about as well. I imagine the risks outweigh the benefits. I would think the same thing would happen when planting a forest (granted it taking much longer to produce an effect)