CBO makes its estimates of potential output on the basis of data on capital, labor, productivity, and actual GDP; statistical and other modeling methods for assessing cyclical influences and long-term trends in the economy; and analyses of the economic effects of federal tax and spending policies.
The hydrologic cycle is driven primarily by I solar energy II mechanical energy from ECOLOGY 1 at Indiana State University
To understand how water moves in our world, attention must be directed to the hydrologic cycle. The hydrologic cycle is essentially a water continuum, representing the different paths through which water circulates and is transformed in the natural environment (Fig. 1). Being a cycle, it has no specific beginning or ending. Rather, liquid water from the Earth s surface, particularly the oceans, is evaporated into a gaseous form and enters the atmosphere as water vapor (clouds). The atmospheric moisture is eventually returned to the Earth s surface in the form of rain or snow.