The Study On Characteristics Of Carbon And Water Fluxes And Energy Fluxes In Mixed Evergreen And Deciduous Broad-leaved Forest In Tianmu Mountain

The process of carbon and water cycle in terrestrial ecosystem includes energy and material exchange between land and atmosphere system.This study is based on observations in 2016 full year data,by eddy covariance analysis of variation characteristics at different scales,the meteorological factors and CO₂ fluxes,carbon sequestration capacity of Tianmu Mountain of tropical forest ecosystem;analysis of water vapor flux data to summarize the characteristics,to provide data support for the component research and observation site evapotranspiration hydrological research structure the energy flux balance analysis;process,circulation is of great significance for the research of forest ecosystem water.?1?GEE,NEE and RE monthly mean distribution amount of data were-1602.27 g C·m-2·a-1,-721.62 g C·m-2·a-1,880.65 g C·m-2·a-1,which only one month in February is the carbon source,6.23 g C·m-2·a-1,each of the other months are showing the state of the carbon sink.Full year RE data are positive,the data value is floating in the range of 66.37-121.15 g C·m-2·a-1,the lowest value in February,was 66.37 g C·m-2·a-1;the highest value in the year of July.Except for the negative value of February,all of the remaining 11 months were positive,and the observation site was obvious carbon sink.?2?The maximum range of water vapor flux is 0.024-0.119 g·m-2·s-1,and the minimum range is-0.00097-0.0011 g·m-2·s-1,the maximum value appears in July,the minimum value in January.According to the data of water vapor flux in the daytime,the order from large to small is summer,spring,autumn and winter.Where the summer maximum at around 13:00 in the afternoon,up to0.081 g·m-2·s-1.The total evapotranspiration was 695.96 mm,of which the highest value of evapotranspiration in summer was 255.42 mm,which accounted for 36.7% of the whole year,the lowest value in winter,92.11 mm,the proportion of the whole year was about 13.23%.The water vapor flux values are associated with positive net radiation,summer?R2=0.8901?>autumn?R2=0.6702?> spring?R2=0.5716?> winter?R2=0.3905?,through correlation test?p<0.01?,each quarter of 2016 between the vapor flux and net radiation significantly.?3?The monthly cumulative values of net radiation,latent heat flux,sensible heat flux and soil heat flux were four 1504.25 MJ·m-2,1109.9 MJ·m-2,764.4 MJ·m-2,40.57 MJ·m-2,respectively.On the Bowen ratio,the main output value of net radiation for sensible heat flux.The annual average closure degree was 0.89,and the closure rate was only about 0.11%,which means that the effective energy of 0.11% was underestimated.