A 4D-Var Analysis System for the California Current: A Prototype for an Operational Regional Ocean Data Assimilation System

Observing System Impacts on Estimates of California Current Transport

“…Integrated Ocean Observing System (IOOS). Plans are underway to perform such monitoring of observation impacts in the near real-time analysis forecast system for the CCS in support of the Central and Northern California Ocean Observing System (CeNCOOS) described in Moore et al 38 and Kourafalou et al 48,49 …”

“…A secondary quality control check based on departures of the observations from the prior circulation x b was also used to screen observations prior to assimilating them into the model. 38 However, this procedure typically results in less than 0.1% of the observations being rejected. 30 To avoid data redundancy, multiple observations of a single variable type within a single grid cell and within a 6-h window were combined to form super observations.…”

Weak constraint four-dimensional variational data assimilation in a model of the California Current System

“…ROMS strong constraint 4D-Var has been successfully applied to the CCS in a series of studies (Broquet et al, 2009a(Broquet et al, , b, 2011Moore et al, 2011aMoore et al, , 2013 culminating in two long sequences of historical circulation analyses spanning the period 1980-2012. Experience with weak constraint 4D-Var is more limited (Moore et al, 2011a) because of the difficulty in quantifying model error.…”

Quantifying the Amplitude, Structure and Influence of Model Error During Ocean Analysis and Forecast Cycles

“…A key element to advancing these activities has been the development and testing of the tangent linear and adjoint of the Lanczos formulation of the Restricted Preconditioned Conjugate Gradient (RPCG) algorithm for ROMS. As reported last year, the Lanczos form of RPCG was implemented and tested in ROMS as part of this project and is described in Gürol et al (2013).…”

“…The implementation of Lanczos-RPCG in ROMS was described in last year's annual report and is documented by Gürol et al (2013) for the case of a single outer-loop. In the case of multiple outer-loops, the augmented form of the algorithm is required to ensure that the resulting posterior increments lie in the space spanned by the previous outer-loops.…”