How fast is the Earth spin
From: http://www.gsfc.nasa.gov/gsfc/newsroom/tv%20page/G02-023_space.htm
We can caculate easily how fast earth is spinning by 2¥ğR(radius of the earth)/24 hours. but that is just speed of the equator of the earth. We have different spinning speed every different latitude.
As we could see from above picture every latidtude have different speed of spinning per hour. And speed of the earth spinning could effect on such as water reservoirs.We don't feel that because everything else is moving with us and because the motion is very, very smooth.
Changes in the Earth's spin are measured in terms of length of days. A faster spin shortens the length of daylight. "Due to the reservoir effect," (Chao). "the day 40 years ago was longer than today by about 8 millionths of a second." More significant, he said, is the fact that the sporadic spacing of water reservoirs has changed the Earth's axis. Since 1940, water impoundment has pushed the axis of rotation about 60 centimeters away from the North Pole toward western Canada, said by Chao
Also it effect on the direction of the wind and movement of the clouds.