Strong coupling between convection, radiation, turbulent fluxes and dynamics is a fundamental characteristic of tropical climate. While spectra of these various processes are red, significant peaks at intraseasonal (e.g. Madden-Julian Oscillation) and interannual (El Nino-Southern Oscillation) time scales testify to significant modes of variability that are important for various reasons: (1) they may embody coupling or feedbacks that are relevant at some level to understanding climate sensitivity to radiative forcing; (2) pragmatically speaking, they are accessible to study with the wealth of state variable and energy flux data flowing from the evolving satellite data record; (3) the rather poor ability of coupled global climate models to simulate intraseasonal variability and ENSO is widely acknowledged. This potentially raises concerns about how uncertainties in moist physical processes in climate models influence their climate change projections.

However, there are complexities in using coupling relationships observed on these short scales to reduce uncertainties on climate change resulting from external forcing. First, these events are by nature departures from equilibrium generated internally by the climate system itself (e.g. chaotic dynamics), not by external forcing. This makes traditional forcing-feedback interpretation difficult at best. Furthermore, observational uncertainty and energetic consistency between different observed quantities (e.g. precipitation with latent heat flux and radiation) is an issue. The latest reanalysis efforts (e.g. MERRA, the NASA Modern-Era analysis for Research and Applications and CFSR, the NOAA Climate Forecast System Reanalysis) have substantially improved in quality, even in their energy fluxes, and help mitigate some observational uncertainties. They do this, however, at the expense of additional forcing terms that systematically correct model physical biases. With the changing satellite record, some spurious trends or step functions in fluxes appear.

In this paper we will present observational and reanalysis diagnostics of energy and water balance scaling relationships for intraseasonal and ENSO events and compare / contrast the results to those argued heuristically and diagnostically recovered from climate change modeling experiments. For example, the adherence of low-tropospheric moisture to Clausius-Clapeyron scaling as well as the hydrologic response (precipitation associated with system temperature change) are examined. Lag relationships between Sea-surface temperature (SST) anomaly forcing, turbulent and radiative fluxes and subsequent feedback on the SST are also evaluated. These analyses are performed both with direct retrievals of fluxes from satellites (e.g. CERES and GEWEX SRB radiative fluxes, TRMM precipitation, OAFlux turbulent fluxes) as well as reanalyses (MERRA and CFSR). The assumptions typically made (either explicitly or implicitly) by investigations seeking inferences on feedbacks relevant to climate change are illuminated and their implications for the interpretation of behavior on intraseasonal and interannual time scales are discussed.