南海北部春季非水华期的CO_2分压及其调控

Sea surface partial pressure of CO_2 and its controls in the northern South China Sea in the non-bloom period in spring

针对南海北部和吕宋海峡附近海域的海－气 CO2通量及其调控问题，研究了2009年3月底至4月中旬在这些海域通过走航观测的方法取得的海－气 CO2分压和海表温度、盐度等相关数据。结果表明，在河口、沿岸流以外的南海北部开阔海域，与大气平衡的 CO2分压分布在368380μatm，南低北高，平均值为371μatm；而海表 CO2分压分布在293405μatm，南高北低。南海北部开阔海域的海表 CO2分压主要受温度效应调控，也在一定程度上受水团混合、海－气交换、生物活动等非温度效应的影响。在相同水温条件下，黑潮区的海表 CO2分压比南海北部的海表 CO2分压低。本研究和大多数前人研究的结果都表明，南海北部海盆区域和吕宋海峡西侧海域在春季与大气 CO2接近源汇平衡，而非大气 CO2的显著源区。

To clarify air-sea CO2 flux and the controls in the northern South China Sea （SCS）and the adjacent open sea areas around the Luzon Strait,a new dataset of sea surface and atmospheric partial pressures of CO2 （pCO2 ）as-sociated with underway temperature and salinity obtained from late March to mid-April in 2009 was investigated. In the northern SCS open sea areas other than those estuaries and the coastal current area,atmospheric pCO2 in-creased from 368 μatm at a south site to 380 μatm at a north site,with the average of 371 μatm,while sea surface pCO2 declined from 405 μatm in the south area to 293 μatm in the north area.The northern SCS pCO2 was signifi-cantly influenced by sea surface temperature,although non-temperature effects such as water mixing,air-sea ex-changes,and biological activities also affected the sea surface pCO2 distribution.In the Kuroshio-influenced area a-round the Luzon Strait,however,sea surface pCO2 in given water temperature was generally lower than that in the northern SCS.Based on this dataset,the author suggested that,the springtime CO2 uptake in the northern SCS ba-sin area and the area west of the Luzon Strait from the atmosphere was nearly equal to CO2 release to the atmos-phere at the same time,which is similar to the consensus in relevant literatures based on qualified data.The earlier report published in Haiyang Xuebao in 2014 suggesting that the northeast part of the SCS serves as a significant source of the atmospheric CO2 in spring is questionable.