<html><head><meta http-equiv="Content-Type" content="text/html; charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class="">I agree but maybe call it “linear dependence” instead of “double counting”. Although this linear dependence may be stronger between atmospheric variables that are used as input for bulk formulae, there is also non-zero linear dependence between surface fluxes.<div class=""><div class=""><div class=""><br class=""><div class=""><div class=""><div><blockquote type="cite" class=""><div class="">On Apr 3, 2020, at 6:53 AM, Dan Jones <<a href="mailto:dcjones.work@gmail.com" class="">dcjones.work@gmail.com</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><meta http-equiv="Content-Type" content="text/html; charset=utf-8" class=""><div dir="ltr" class=""><div class="">Hi Dimitris,</div><div class=""><br class="">Although I could be wrong, I do not think that the potential double counting issue matters much for the adjoint optimization process. As long as the control adjustments reduce the cost function, then I suppose that the optimization process will still work. Do you agree?<br class=""><br class="">However, if we are attempting to reconstruct an objective function using adjoint sensitivities and anomalies (e.g. Helen Pillar's work on RAPID time series reconstructions, see her 2016 J. Climate paper), then the potential double-counting could be an issue. I'm hoping that by avoiding the bulk formulae I can more cleanly separate the effects of wind stress anomalies from those of heat flux anomalies. </div><div class=""></div><div class=""><br class=""></div>Best,<br class="">Dan<br class=""><br clear="all" class=""><div class=""><div dir="ltr" class="gmail_signature" data-smartmail="gmail_signature"><div dir="ltr" class=""><div class=""><div dir="ltr" class=""><div class=""><div dir="ltr" class=""><div dir="ltr" class=""><div dir="ltr" class=""><div dir="ltr" class=""><div dir="ltr" class=""><div dir="ltr" class=""><div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: small;" class=""><div class="">--------------------------------------------------------------<br class="">Dr Dan Jones / British Antarctic Survey</div><div class=""><a href="http://www.danjonesocean.com/" target="_blank" class="">danjonesocean.com</a> / @DanJonesOcean</div><div class="">--------------------------------------------------------------</div></div></div></div></div></div></div></div></div></div></div></div></div></div></div>
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