Continuous forcing at SGP
The continuous forcing at SGP is a major VARANAL product with long-term, high-density surface measurements providing accurate constraints. In this approach, the atmospheric state variables from numerical weather prediction (NWP) analyses are adjusted to balance the observed column budgets of mass, heat, moisture, and momentum, rather than the model-produced budgets (Xie et al., 2004).
Currently, two versions of continuous forcing data are available at SGP: version 1 (Xie et al., 2004) available from 1999 to 2011, version 2 (Tang et al., 2019) available from 2004 to October 2018. The major version update is that version 1 only uses EBBR measured surface turbulence fluxes while version 2 uses merged fluxes from EBBR and ECOR to better represent various surface types within the analysis domain. There are some other updates such as fixing bugs, updating input data version and optimizing workflow.
The structure of VARANAL for continuous forcing consists of four steps (Figure 1): (1) preparation of the required raw input data, (2) preprocessing, (3) variational analysis, and (4) postprocessing and output of final products.
