Atmospheric Radiation Measurement Climate Research Facility US Department of Energy

varanal3d > Three-dimensional Constrained Variational AnalysisVAP Type(s) > Baseline • Evaluation

The three-dimensional large-scale forcing data are developed using the three-dimensional constrained variational analysis (3DCVA) approach (Tang and Zhang 2015). This approach is an extension of the original one-dimensional constrained variational analysis (1DCVA or VARANAL). It extends the original method from one atmospheric column into many subcolumns, within a similar size of domain. The constraint equations are satisfied in each subcolumn, and all subcolumns interact with one another through horizontal fluxes. The 3D structure allows for studies of spatial variation of the large-scale forcing fields and tests of physical parameterizations across scales.

Initially, the VARANAL3D products are available from two field campaigns at ARM’s Southern Great Plains atmospheric observatory: the March 2000 Spring Cloud Intensive Operational Period (Xie et al. 2005; Tang and Zhang 2015; Tang et al. 2016) and the Midlatitude Continental Convective Clouds Experiment (Xie et al. 2014). Ensemble products are available for both field campaigns by using multiple reanalyses/analyses data as background data to characterize data uncertainties.

References: Tang, S, and M Zhang. 2015. “Three-dimensional constrained variational analysis: Approach and application to analysis of atmospheric diabatic heating and derivative fields during an ARM SGP intensive observational period.” Journal of Geophysical Research – Atmospheres, 120(15): 7283–7299,

Tang, S, M Zhang, and S Xie. 2016. “An ensemble constrained variational analysis of atmospheric forcing data and its application to evaluate clouds in CAM5.” Journal of Geophysical Research – Atmospheres, 121(1): 33–48,

Xie, S, M Zhang, M Branson, RT Cederwall, AD Del Genio, ZA Eitzen, et al. 2005. “Simulations of midlatitude frontal clouds by single-column and cloud-resolving models during the Atmospheric Radiation Measurement March 2000 cloud intensive operational period.” Journal of Geophysical Research – Atmospheres, 110(D15): D15S03,

Xie, S, Y Zhang, SE Giangrande, MP Jensen, R McCoy, and M Zhang. 2014. “Interactions between cumulus convection and its environment as revealed by the MC3E sounding array.” Journal of Geophysical Research – Atmospheres, 119(20): 11,784–11,808,


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