Comparisons of OCO-2 satellite derived XCO_(2)with in situ and modeled data over global ocean

Atmospheric CO_(2)is one of key parameters to estimate air-sea CO_(2)flux.The Orbiting Carbon Observatory-2(OCO-2)satellite has observed the column-averaged dry-air mole fractions of global atmospheric carbon dioxide(XCO_(2))since 2014.In this study,the OCO-2 XCO_(2)products were compared between in-situ data from the Total Carbon Column Network(TCCON)and Global Monitoring Division(GMD),and modeling data from CarbonTracker2019 over global ocean and land.Results showed that the OCO-2 XCO_(2)data are consistent with the TCCON and GMD in situ XCO_(2)data,with mean absolute biases of 0.25×10^(-6)and 0.67×10^(-6),respectively.Moreover,the OCO-2 XCO_(2)data are also consistent with the CarbonTracker2019 modeling XCO_(2)data,with mean absolute biases of 0.78×10^(-6)over ocean and 1.02×10^(-6)over land.The results indicated the high accuracy of the OCO-2 XCO_(2)product over global ocean which could be applied to estimate the air-sea CO_(2)flux.

Associations between cardiorespiratory fitness,physical activity, intraindividual variability in behavior, and cingulate cortex in younger adults

Background.Higher levels of cardiorespiratory fitness(CRF)and greater amounts of physical activity have been associated with lower intraindividual variability(IIV)in executive function in children and older adults.In the present study,we examined whether CRF,measured as maximal oxygen uptake(VO2max),and daily volume of moderate-to-vigorous intensity physical activity(MVPA)were associated with IIV of reaction time during performance of the incongruent condition of the Stroop task in younger adults.Further,we examined whether the thickness of the cingulate cortex was associated with regulating variability in reaction time performance in the context of CRF or physical activity.Methods:CRF(measured as VO2max),accelerometry-measured MVPA,Stroop performance,and thickness of the rostral anterior cingulate cortex(rACC)derived from magnetic resonance imaging data were collected in 48 younger adults(age=24.58±4.95 years,mean±SD).Multiple regression was used to test associations between IIV during the Stroop task and CRF,MVPA,and rACC thickness.Mediation was tested using maximum likelihood estimation with bootstrapping.Results:Consistent with our predictions,higher VO2max was associated with greater rACC thickness for the right hemisphere and greater daily amounts of MVPA were associated with greater rACC thickness for both the left and right hemispheres.Greater thickness of the right rACC was associated with lower IIV for the incongruent condition of the Stroop task.CRF and MVPA were not directly associated with IIV.However,we did find that IIV and both CRF and MVPA were indirectly associated via the thickness of the right rACC.Conclusion:These results indicate that higher CRF and greater daily volume of MVPA may be associated with lower IIV during the Stroop task via structural integrity of the rACC.Randomized controlled trials of MVPA would provide crucial information about the causal relations between these variables.

Data fusion in data scarce areas using a back-propagation artificial neural network model： a case study of the South China Sea

The cloud cover for the South China Sea andits coastal area is relatively large throughout the year,which limits the potential application of optical remotesensing. A H J-charge-coupled device （HJ-CCD） has theadvantages of wide field, high temporal resolution, andshort repeat cycle. However, this instrument suffers fromits use of only four relatively low-quality bands whichcan＇t adequately resolve the features of long wavelengths.The Landsat Enhanced Thematic Mapper-plus （ETM＋）provides high-quality data, however, the Scan LineCorrector （SLC） stopped working and caused striping ofremote sensed images, which dramatically reduced thecoverage of the ETM＋ data. In order to combine theadvantages of the HJ-CCD and Landsat ETM＋ data, weadopted a back-propagation artificial neural network （BP-ANN） to fuse these two data types for this study. Theresults showed that the fused output data not only have theadvantage of data intactness for the HJ-CCD, but also havethe advantages of the multi-spectral and high radiometricresolution of the ETM＋ data. Moreover, the fused datawere analyzed qualitatively, quantitatively and from apractical application point of view. Experimental studiesindicated that the fused data have a full spatial distribution,multi-spectral bands, high radiometric resolution, a smalldifference between the observed and fused output data, anda high correlation between the observed and fused data.The excellent performance in its practical application is afurther demonstration that the fused data are of highquality.