CLIMATE - THE ELEMENTS

The authors present an analytical climate model, which has the feature s that (i) the atmosphere is a simple oscillator for all periods great er than or equal to I year, (ii) the ocean stores heat, (iii) the ocea n exchanges momentum with the atmosphere, and (iv) random forcing exis ts due to atmospheric thermodynamics and oceanic dynamics. The piecewi se analytical integration of coupled linear equations for sea temperat ure, air-sea temperature difference, and air-sea velocity difference g enerates experimental climates. The exchange parameters of the algorit hm. except for the exchange coefficient for heat with the deep ocean, are calibrated to the observed climate using the annual cycle, and ran dom forcing is applied over intervals of one year, The atmospheric ran dom forcing leads to bounded random walks, the extent of which increas es as the exchange coefficient with the deep ocean decreases, and the oceanic random forcing generates a stationary response. It is found th at the observed statistics of the global temperature series can be rep roduced by either a relatively large heat exchange coefficient with th e deep ocean and little oceanic variability or a smaller exchange coef ficient with a larger oceanic variability. Plausible exchange coeffici ent values imply random walk lengths of at least a century-long timesc ale.