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8.1.2 Generic Integral Function

The functionality described in this section is operated by cost_gencost_boxmean.F. It is primarily aimed at obtaining a mechanistic understanding of a chosen physical variable via adjoint sensitivity computations (see Chapter 5) as done for example in Fukumori et al. [2015]; Marotzke et al. [1999]; Heimbach et al. [2011]. Thus the quadratic term in Eq. 8.1 ( $ \vec{d}_i^T R_i^{-1} \vec{d}_i$ ) is by default replaced with a $ d_i$ scalar8.2 that derives from model fields through a generic integral formula (Eq. 8.3). The specification of gencost_barfile again selects the physical variable type. Current valid options to use cost_gencost_boxmean.F are reported in table 8.5. A suffix starting with `_' can again be appended to gencost_barfile.

The integral formula is defined by masks provided via binary files which names are specified via gencost_mask. There are two cases: (1) if gencost_mask = `foo_mask' and gencost_barfile is of the `m_boxmean*' type then the model will search for horizontal, vertical, and temporal mask files named foo_maskC, foo_maskK, and foo_maskT; (2) if instead gencost_barfile is of the `m_horflux_*' type then the model will search for foo_maskW, foo_maskS, foo_maskK, and foo_maskT.

The `C' mask or the `W' / `S' masks are expected to be two-dimensional fields. The `K' and `T' masks (both optional; all 1 by default) are expected to be one-dimensional vectors. The `K' vector length should match Nr. The `T' vector length should match the # of records that the specification of gencost_avgperiod implies but there is no restriction on its values. In case #1 (`m_boxmean*') the `C' and `K' masks should consists of +1 and 0 values and a volume average will be computed accordingly. In case #2 (`m_horflux*') the `W', `S', and `K' masks should consists of +1, -1, and 0 values and an integrated horizontal transport (or overturn) will be computed accordingly.


Table 8.5: Implemented gencost_barfile options (as of checkpoint 65z) that can be used via cost_gencost_boxmean.F (section 8.1.2).
variable name description remarks
m_boxmean_theta mean of theta over box specify box
m_boxmean_salt mean of salt over box specify box
m_boxmean_eta mean of SSH over box specify box
m_horflux_vol volume transport through section specify transect



next up previous contents
Next: 8.1.3 Custom Cost Functions Up: 8.1 ECCO: model-data comparisons Previous: 8.1.1 Generic Cost Function   Contents
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