Climatological mean and decadal change in surface ocean pCO2, and net sea-air CO2 flux over the global oceans
Climatological mean and decadal change in surface ocean pCO2, and net sea-air CO2 flux over the global oceans
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DOI：
10.1016/j.dsr2.2008.12.009
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发表时间：
2009-04-01
影响因子：
3
通讯作者：
de Baar, Hein J. W.
中科院分区：
文献类型：
--
作者：
Takahashi, Taro;Sutherland, Stewart C.;de Baar, Hein J. W.
根据1970年至2007年获得的约300万个地表水PCO(2)测量值，建立了非厄尔尼诺条件下全球海洋地表水PCO(2)的气候平均分布，空间分辨率为4度(纬度)×5度(经度)，用于2000年。这项研究使用的数据库大约是我们早期论文使用的94万个数据库的3倍[Takahashi等人，2002年。基于气候表层海洋二氧化碳分压的全球海-气二氧化碳通量(2)，以及季节性生物和温度效应。深海第11、49、1601-1622号决议]。利用北大西洋、北太平洋、南太平洋和南太平洋部分地区(约占全球海洋面积的27%)的非季节性表层水PCO(2)数据进行的时间趋势分析表明，这些海洋地区的表层水PCO(2)平均以1.5亩atm y(-1)的速度增加，流域特定速率在1.2+/-0.5和2.1+/-0.4亩atm y(-1)之间变化。使用这一平均比率汇编了一个2000年单一基准年的全球海洋数据库，以便将不同年份的观测值改正为基准年。该数据库排除了赤道太平洋厄尔尼诺期间的观测和沿海地区的观测。给出了大西洋、太平洋、印度洋和南大洋四个气候带的表层水PCO(2)和海-气PCO(2)差的季节变化。在南大洋季节性冰区，季节性是复杂的。虽然由于观测范围有限而不能完全记录，但PCO(2)的季节变化可以通过使用南半球冬季冰下水域以及边缘冰层和无冰区的数据来近似，利用海-气PCO(2)差和海-气气体转移率来估计海-气净通量，并将其参数化为(风速)2的函数，比例因子为0.26。这是通过使用海洋环流模式和1979-2005年NCEP-DOE AMIP-II再分析(R-2)风速数据反演Bomb C-14数据来估计的。赤道太平洋(北纬14度-S 14度)是大气CO2的主要来源，排放约+0.48pg-Cy(-1)，南北半球14-50度的温带海洋是主要的汇区域，北半球吸收通量为-0.70pg-Cy(-1)，南半球吸收通量为-1.05pg-Cy(-1)。高纬度北大西洋，包括北欧海和北冰洋的一部分，是单位面积上二氧化碳汇最强烈的地区，平均-2.5吨-C月(-1)公里(-2)。这是由于海水中的低PCO(2)和高气体交换率的共同作用。在南大洋无冰区(S 50度-62度)，年平均通量很小(-0.06pg·Cy(-1))，这是由于深水上升流导致夏季吸收通量与冬季CO2释放的抵消而造成的。当代全球海洋的净摄取通量的年平均值估计为-1.6+/-0.9pg-Cy(-1)，其中包括对直接估计的-1.4+/-0.7pg-Cy(-1)的欠采样修正。考虑到工业化前的0.4+/-0.2pg-Cy(-1)的稳态海洋源，2000年包括人为二氧化碳在内的海洋总吸收通量估计为-2.0+/-1.0pg-Cy(-1)。(C)2008爱思唯尔有限公司。保留所有权利。
A climatological mean distribution for the surface water pCO(2) over the global oceans in non-El Nino conditions has been constructed with spatial resolution of 4 degrees (latitude) x 5 degrees (longitude) for a reference year 2000 based upon about 3 million measurements of surface water pCO(2) obtained from 1970 to 2007. The database used for this study is about 3 times larger than the 0.94 million used for our earlier paper [Takahashi et al., 2002. Global sea-air CO2 flux based on climatological surface ocean pCO(2), and seasonal biological and temperature effects. Deep-Sea Res. 11, 49, 1601-1622]. A time-trend analysis using deseasonalized surface water pCO(2) data in portions of the North Atlantic, North and South Pacific and Southern Oceans (which cover about 27% of the global ocean areas) indicates that the surface water pCO(2) over these oceanic areas has increased on average at a mean rate of 1.5 mu atm y(-1) with basin-specific rates varying between 1.2 +/- 0.5 and 2.1 +/- 0.4 mu atm y(-1). A global ocean database for a single reference year 2000 is assembled using this mean rate for correcting observations made in different years to the reference year. The observations made during El Nino periods in the equatorial Pacific and those made in coastal zones are excluded from the database.Seasonal changes in the surface water pCO(2) and the sea-air pCO(2) difference over four climatic zones in the Atlantic, Pacific, Indian and Southern Oceans are presented. Over the Southern Ocean seasonal ice zone, the seasonality is complex. Although it cannot be thoroughly documented due to the limited extent of observations, seasonal changes in pCO(2) are approximated by using the data for under-ice waters during austral winter and those for the marginal ice and ice-free zones.The net air-sea CO2 flux is estimated using the sea-air pCO(2) difference and the air-sea gas transfer rate that is parameterized as a function of (wind speed)2 with a scaling factor of 0.26. This is estimated by inverting the bomb C-14 data using Ocean General Circulation models and the 1979-2005 NCEP-DOE AMIP-II Reanalysis (R-2) wind speed data. The equatorial Pacific (14 degrees N-14 degrees S) is the major source for atmospheric CO2, emitting about +0.48 Pg-C y(-1), and the temperate oceans between 14 degrees and 50 degrees in the both hemispheres are the major sink zones with an uptake flux of -0.70 Pg-C y(-1) for the northern and -1.05 Pg-C y(-1) for the southern zone. The high-latitude North Atlantic, including the Nordic Seas and portion of the Arctic Sea, is the most intense CO2 sink area on the basis of per unit area, with a mean of -2.5 tons-C month(-1) km(-2). This is due to the combination of the low pCO(2) in seawater and high gas exchange rates. In the ice-free zone of the Southern Ocean (50 degrees-62 degrees S), the mean annual flux is small (-0.06 Pg-C y(-1)) because of a cancellation of the summer uptake v flux with the winter release Of CO2 caused by deepwater upwelling. The annual mean for the contemporary net v uptake flux over the global oceans is estimated to be -1.6+/-0.9 Pg-C y(-1), which includes an undersampling correction to the direct estimate of -1.4+/-0.7 Pg-C y(-1). Taking the pre-industrial steady-state ocean source of 0.4+/-0.2 Pg-C y(-1) into account, the total ocean uptake flux including the anthropogenic CO2 is estimated to be -2.0+/- 1.0 Pg-C y(-1) in 2000. (C) 2008 Elsevier Ltd. All rights reserved.