"2" . . "2017-07-24 14:36:59.0" . "false" . . "2" . . "SDN:P07::CFSN0157" . . "SDN:P07::CFSN0157" . "2017-07-24 14:36:59.0" . "" . . "accepted"@en . . . "SDN:P07::CFSN0157" . . . "The surface called \"surface\" means the lower boundary of the atmosphere. \"tendency_of_X\" means derivative of X with respect to time. Air pressure is the force per unit area which would be exerted when the moving gas molecules of which the air is composed strike a theoretical surface of any orientation."@en . "tendency_of_surface_air_pressure"@en . .