NASA Energy and Water Cycle Study Program - Integrated Analysis (NEWS-IA): 
Development and Continuity Project
POC: Brent Roberts (jason.b.roberts@nasa.gov)

Investigators: 
Roberts, Brent (MSFC-ST11) (jason.b.roberts@nasa.gov)
Beaudoing, Hiroko Kato (GSFC-617.0) (hiroko.kato-1@nasa.gov)
Bosilovich, Michael (GSFC-6101) (michael.g.bosilovich@nasa.gov)
Kato, Seiji (LARC-E302) (seiji.kato@nasa.gov)
Olson, William S. (GSFC-612.0) (william.s.olson@nasa.gov)
Robertson, Franklin R. (MSFC-ST11) (pete.robertson@nasa.gov)
Rodell, Matthew (GSFC-6100)  (matthew.rodell@nasa.gov)
Stackhouse, Paul W. (LARC-E302) (paul.w.stackhouse@nasa.gov)

A series of projects conducted over multiple NEWS funding cycles has resulted in the establishment and continued refinement of a water and energy budget optimization methodology. Application of this methodology has resulted in the NEWS climatologies of L’Ecuyer et al. (2015) and Rodell et al. (2015). The existing Version 1 data are available from the GES DISC. An essential benefit of the budget optimization is the ability to close the water and energy budgets objectively and simultaneously, taking into account the uncertainties in the input remote sensing and model-based data products. The latest refinements to the budget optimization approach have enabled three fundamental advances: i) a fully integrated Earth system budget including the atmosphere, ocean, land surface, and cryosphere subsystems, ii) the ability to assess monthly-resolved time variability as opposed to a static climatology and iii) increased flexibility to address regional energy and water variability at finer spatial scales. 

The primary outcome of this ongoing activity is the development and dissemination of the NEWS Integrated Analysis (IA): A historical, objectively optimized analysis of energy and water cycle budget components encompassing the storage and exchanges within and between the atmosphere, ocean, land surface, and cryosphere primarily based on NASA Earth Observations. The preliminary NEWS-IA dataset is now available here in NetCDF format, with documentation here. The approach relies on a consistent treatment of Earth’s energy and water budgets, linked through the latent heat fluxes. The optimization framework is designed to address transports across shared boundaries and to accommodate both random and systematic uncertainty. Table 1 provides a description of the primary data products used as inputs into the NEWS-IA. Numerous alternative products were considered and are used for uncertainty quantification. These products span a common period of 2003-2017 thus establishing the temporal period of coverage (at monthly resolution) for the first version of NEWS-IA. The record begins in 2003, the first full year for which GRACE data and GRACE data assimilation output (GLDAS-2.2) are available. The end of the record coincides with the last publicly available ECCO V4r4 ocean state estimate in 2017. Extensions of the input data products identified in Table 1 regularly occur and the NEWS-IA is planned to be updated on a biannual basis with the goal of extending the record to near present.

The budget optimization approach has been applied to 25 regions (see Figure 1) defined based on the goals and limitations of previous NEWS investigations, with refinements of and additions to the original set of regions. These datasets are appropriate for use in regional to global energy and water budget investigations. Limitations on the scale and number of regions are driven by factors including the effective resolution of observational datasets, uncertainties of the underlying datasets and other model optimization constraints  (e.g., number of parameters, length of datasets, etc.). However, generation of customized budget analyses — e.g., for a large hydrologic basin or regional ocean basin — could be possible with additional refinements; these could be developed in coordination with the NEWS-IA team.

Feedback from the community will drive further improvements to the NEWS-IA approach. This could involve inclusion of novel data products and continued fine-tuning (e.g., uncertainty quantification, treatment of correlated errors, etc.).  Data, documentation, and information on known issues together with answers to frequently asked questions will be made available to the community through the project website. In addition to engagement with the NEWS IA Science Team through routine meetings (e.g., conferences, science team meetings, etc.), we encourage the science community to use the NASA Earthdata Forum to report issues and suggestions for improvement and have open engagement with this activity.

Table 1. Inventory of Input Data Products

¹ GRACE observational data have an effective resolution of 150,000km2 - 200,000km2. This establishes a lower bound on achievable resolution but aggregation over larger areas may be needed to increase signal to noise over regions of interest or ensure stability of the optimization algorithm.

Data Resources:

NEWS-IA Dataset

NEWS-IA Documentation

NEWS (2015) Version 1.0 optimized water and energy balance data

NASA Earth Sciences Hydrology data