The flow of Energy through the Earth's Climate System: Land and Ocean Exchanges

two. Incoming radiant energy may be scattered and reflected by clouds and aerosols or absorbed in the atmosphere. The transmitted radiation is then either absorbed or reflected at the Earth’s surface. Radiant solar or shortwave energy is transformed into sensible heat, latent energy (involving different water states), potential energy and kinetic energy before being emitted as longwave radiant energy. Energy may be stored for some time, transported in various forms, and converted among the different types, giving rise to a rich variety of weather or turbulent phenomena in the atmosphere and ocean. Moreover, the energy balance can be upset in various ways, changing the climate and associated weather. In this paper, the mean and annual cycle of energy flowing into the climate system and its storage, release, and transport in the atmosphere, ocean, and land surface are estimated with recent observations. The variability is also considered. An emphasis is placed on establishing internally consistent quantitative estimates with discussion and assessment of uncertainty. At the top-of-atmosphere (TOA), adjusted radiances from Earth Radiation Budget Experiment (ERBE) and Clouds and the Earth’s Radiant Energy System (CERES) are used. In the atmosphere, reanalyses from the National Centers for Environmental Prediction/NCAR reanalysis (NRA) (Kalnay et al. 1996) and the second generation European Centre for Medium Range Weather Forecasts (ECMWF) Reanalysis (ERA-40) (Uppala et al. 2005) and recent Japanese Reanalysis (JRA) (Onogi et al. 2007) are used as they contain the most comprehensive estimates of global atmospheric temperature and moisture fields. Vertically-integrated quantities for energy components, the transports, and divergences have been computed and archived. The net upward surface flux (FS) over ocean is derived as the residual of TOA and atmospheric energy budgets, and is compared with direct calculations of ocean heat content (OE) and its tendency (δOE/δt) from several ocean temperature datasets. The ocean datasets used to diagnose T include the World Ocean Atlas 2005 (WOA, Locarini et al. 2006), the ocean analysis of the Japanese Meteorological Agency Version 6.2 (JMA, Ishii et al. 2006), and the recently corrected Global Ocean Data Assimilation System (GODAS, Behringer 2006), along with some consideration of the ECCO (Estimating the Circulation and Climate of the Ocean) analyses (Stammer et al. 2004). Over land FS from a stand-alone simulation of the Community Land Model forced by observed fields is used. Comprehensive depiction of the energy budget during the ERBE (February 1985 to April 1989) and CERES (Mar. 2000 to May 2004) periods are constructed that match estimates of the global, global-ocean, and global-land imbalances. In addition, the annual cycle of the energy budget during both periods is examined and compared with δOE/δt. The near balance between net TOA radiation (RT) and FS over ocean and thus with OE, and between RT and atmospheric total energy divergence over land, are documented both in the mean and for the annual cycle. However, there is an annual mean transport of energy by the atmosphere from ocean to land regions of 2.2±0.1 PW (10 15 watts) primarily in the northern winter when the transport exceeds 5 PW. The global albedo is dominated by a semiannual