English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Zendy Plus

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Zendy Tools

Zendy Open

In this study, the effect of CO2 observations on an analysis of surfaceCO2 flux was calculated using an influence matrix in theCarbonTracker, which is an inverse modeling system for estimating surfaceCO2 flux based on an ensemble Kalman filter. The influence matrixrepresents a sensitivity of the analysis to observations. The experimentalperiod was from January 2000 to December 2009. The diagonal element of theinfluence matrix (i.e., analysis sensitivity) is globally 4.8% onaverage, which implies that the analysis extracts 4.8% of the informationfrom the observations and 95.2% from the background each assimilationcycle. Because the surface CO2 flux in each week is optimized by 5weeks of observations, the cumulative impact over 5 weeks is 19.1%,much greater than 4.8%. The analysis sensitivity is inverselyproportional to the number of observations used in the assimilation, whichis distinctly apparent in continuous observation categories with asufficient number of observations. The time series of the globally averagedanalysis sensitivities shows seasonal variations, with greater sensitivitiesin summer and lower sensitivities in winter, which is attributed to thesurface CO2 flux uncertainty. The time-averaged analysis sensitivitiesin the Northern Hemisphere are greater than those in the tropics and theSouthern Hemisphere. The trace of the influence matrix (i.e., informationcontent) is a measure of the total information extracted from theobservations. The information content indicates an imbalance between theobservation coverage in North America and that in other regions.Approximately half of the total observational information is provided bycontinuous observations, mainly from North America, which indicates thatcontinuous observations are the most informative and that comprehensivecoverage of additional observations in other regions is necessary toestimate the surface CO2 flux in these areas as accurately as in NorthAmerica

atmospheric chemistry and physics

Influence of CO&amp;lt;sub&amp;gt;2&amp;lt;/sub&amp;gt; observations on the optimized CO&amp;lt;sub&amp;gt;2&amp;lt;/sub&amp;gt; flux in an ensemble Kalman filter