Ichiro Fukumori (PI)
Jet Propulsion Laboratory
fukumori@jpl.nasa.gov

Estimating Earth's Climate by Assimilating Satellite Observations of the Ocean and Atmosphere With a Coupled Earth System Model

This proposal aims to 1) develop a next-generation data assimilation system for coupled ocean-atmosphere models, 2) explore means to maximize utilization of satellite observations for climate research and 3) study the workings of the climate system by employing the results.  The study builds on the assimilation system of the Consortium for “Estimating the Circulation and Climate of the Ocean” (ECCO).  ECCO has established a near real-time analysis of global ocean circulation by assimilating satellite and in situ observations with a state-of-the-art ocean general circulation model.  ECCO assimilation is characterized by its advanced methods and its results’ physical consistency.  The objective nature of the assimilation method permits assimilation of virtually any observation that a model equivalent can be defined.  ECCO assimilation incorporates a smoother whereby models are inverted in addition to observations, permitting direct estimation of sources of model error.  The resulting model’s temporal evolution is physically consistent allowing closure of budgets, such as those of heat and mass, which make the solution conducive to diverse scientific investigations.  Existing assimilations focus on separate components of the climate system and are often physically inconsistent; e.g., budgets cannot be closed because of nonzero data increments. Moreover, inter-component flux estimates from these individual assimilations are typically incompatible from one another.  The present proposed investigation will extend the ECCO assimilation system to establish a physically consistent estimate of the coupled climate system’s temporal evolution.  The coupled climate model of NOAA’s Geophysical Fluid Dynamics Laboratory (GFDL), which is used operationally for various climate assessments, will be employed for this study.  Satellite measurements of the ocean and atmosphere will be assimilated to analyze the climate system from 1990 to present spanning the era of the Earth Observing System (EOS).  Mechanisms of the climate system will be studied, in particular, processes underlying its changes.  The assimilation system will also be utilized to assess the relative information content of different observing systems.    This proposal focuses on the development of coupled ocean-atmosphere data assimilation methodologies, and does not include model development per se.  The existing GFDL model will be employed instead.  However, the proposed “divide and conquer” approach to estimation will permit scaling the new assimilation system to next generation ultra-high resolution climate models that are being pursued elsewhere.  In particular, the proposed study is synergistic with the Earth System Modeling effort proposed separately to this NRA by Robert Atlas (GFSC) and will employ their model advancements.  The present investigation is one of two proposals being submitted by ECCO to this NRA.  The other (John Marshall, P.I.) aims to extend ECCO’s ocean model to a high-resolution global model that includes sea-ice.  The present proposal focuses on the ECCO data assimilation system and will extend it from the ocean to a coupled climate system.

+ Back to Participant Listing