@article{147996,
  author = {Zhongshu Li and Junfeng Liu and Denise L. Mauzerall and Xiaoyuan Li and Songmiao Fan and Larry W. Horowitz and Cenlin He and Kan Yi and Shu Tao},
  title = {A potential large and persistent black carbon forcing over Northern Pacific inferred from satellite observations},
  abstract = { Black carbon (BC) aerosol strongly absorbs solar radiation, which warms climate. However, accurate estimation of BC{\textquoteright}s climate effect is limited by the uncertainties of its spatiotemporal distribution, especially over remote oceanic areas. The HIAPER Pole-to-Pole Observation (HIPPO) program from 2009 to 2011 intercepted multiple snapshots of BC profiles over Pacific in various seasons, and revealed a 2 to 5 times overestimate of BC by current global models. In this study, we compared the measurements from aircraft campaigns and satellites, and found a robust association between BC concentrations and satellite-retrieved CO, tropospheric NO2, and aerosol optical depth (AOD) (R2\>0.8). This establishes a basis to construct a satellite-based column BC approximation (sBC*) over remote oceans. The inferred sBC* shows that Asian outflows in spring bring much more BC aerosols to the midPacific than those occurring in other seasons. In addition, inter-annual variability of sBC* is seen over the Northern Pacific, with abundances varying consistently with the springtime Pacific/North American (PNA) index. Our sBC* dataset infers a widespread overestimation of BC loadings and BC Direct Radiative Forcing by current models over North Pacific, which further suggests that large uncertainties exist on aerosol-climate interactions over other remote oceanic areas beyond Pacific. },
  year = {2017},
  journal = {Scientific Reports},
  volume = {7},
  language = {eng},
}