采用静态暗箱-气相色谱法,研究了南京市郊区集约化生产管理下,芹菜-空心菜-小白菜-苋菜轮作菜地与休闲裸地的N2O排放通量的动态变化,及其与土壤温度、湿度以及NO3--N和NH4+-N含量的关系.结果表明:轮作菜地的N2O累积排放量达137.2kg N.hm...采用静态暗箱-气相色谱法,研究了南京市郊区集约化生产管理下,芹菜-空心菜-小白菜-苋菜轮作菜地与休闲裸地的N2O排放通量的动态变化,及其与土壤温度、湿度以及NO3--N和NH4+-N含量的关系.结果表明:轮作菜地的N2O累积排放量达137.2kg N.hm-2,显著大于休闲裸地(29.2 kg N.hm-2);轮作菜地生态系统N2O-N的排放系数高达4.6%.4种蔬菜地中,空心菜地对轮作菜地的周年累积排放量贡献最大,为53.5%,小白菜地次之,为31.9%,芹菜地和苋菜地最小,分别为4.5%和4.8%.轮作菜地的N2O排放通量与土壤温度呈显著正相关,Q10为2.80;土壤湿度以及NO3--N和NH4+-N含量与轮作菜地的N2O排放通量之间的相关性不显著.展开更多
The estimation of the quality factor Q plays a fundamental role in enhancing seismic resolution via absorption compensation in the near-surface layer.We present a new geometry that can be used to acquire field data by...The estimation of the quality factor Q plays a fundamental role in enhancing seismic resolution via absorption compensation in the near-surface layer.We present a new geometry that can be used to acquire field data by combining surface and cross-hole surveys to decrease the effect of geophone coupling on Q estimation.In this study,we drilled number of receiver holes around the source hole,each hole has different depth and each geophone is placed geophones into the bottom of each receiver hole to avoid the effect of geophone coupling with the borehole wall on Q estimation in conventional cross-hole seismic surveys.We also propose a novel tomographic inversion of the Q factor without the effect of the source signature,and examine its stability and reliability using synthetic data.We estimate the Q factors of the near-surface layer in two different frequency bands using field data acquired in the Dagang Oilfield.The results show that seismic absorption in the nearsurface layer is much greater than that in the subsurface strata.Thus,it is of critical practical importance to enhance the seismic solution by compensating for near-surface absorption.In addition,we derive different Q factors from two frequency bands,which can be treated,to some extent,as evidence of a frequency-dependent Q.展开更多
文摘采用静态暗箱-气相色谱法,研究了南京市郊区集约化生产管理下,芹菜-空心菜-小白菜-苋菜轮作菜地与休闲裸地的N2O排放通量的动态变化,及其与土壤温度、湿度以及NO3--N和NH4+-N含量的关系.结果表明:轮作菜地的N2O累积排放量达137.2kg N.hm-2,显著大于休闲裸地(29.2 kg N.hm-2);轮作菜地生态系统N2O-N的排放系数高达4.6%.4种蔬菜地中,空心菜地对轮作菜地的周年累积排放量贡献最大,为53.5%,小白菜地次之,为31.9%,芹菜地和苋菜地最小,分别为4.5%和4.8%.轮作菜地的N2O排放通量与土壤温度呈显著正相关,Q10为2.80;土壤湿度以及NO3--N和NH4+-N含量与轮作菜地的N2O排放通量之间的相关性不显著.
基金supported by the National Natural Science Foundation of China(Grant No.41174117 and 41474109)the National Key Basic Research Development Program of China(Grant No.2013CB228606)
文摘The estimation of the quality factor Q plays a fundamental role in enhancing seismic resolution via absorption compensation in the near-surface layer.We present a new geometry that can be used to acquire field data by combining surface and cross-hole surveys to decrease the effect of geophone coupling on Q estimation.In this study,we drilled number of receiver holes around the source hole,each hole has different depth and each geophone is placed geophones into the bottom of each receiver hole to avoid the effect of geophone coupling with the borehole wall on Q estimation in conventional cross-hole seismic surveys.We also propose a novel tomographic inversion of the Q factor without the effect of the source signature,and examine its stability and reliability using synthetic data.We estimate the Q factors of the near-surface layer in two different frequency bands using field data acquired in the Dagang Oilfield.The results show that seismic absorption in the nearsurface layer is much greater than that in the subsurface strata.Thus,it is of critical practical importance to enhance the seismic solution by compensating for near-surface absorption.In addition,we derive different Q factors from two frequency bands,which can be treated,to some extent,as evidence of a frequency-dependent Q.
