1. TS2.png
    Title
    Effects of sulfate aerosol forcing on East Asian summer monsoon for 1985–2010
    Authors
    Minjoong J. Kim, Sang-Wook Yeh, and Rokjin J. Park
    Picture caption
    Time series of the EASM index from (a) the NCEP DOE RA2, (b) the control run, (c) the SST run, and (d) the SO2 run.
    Summary
    We examine the effect of anthropogenic aerosol forcing on the East Asian summer monsoon (EASM) using the model. One control and two sensitivity model experiments were conducted in order to diagnose the separate roles played by sea surface temperature (SST) variations and anthropogenic sulfate aerosol forcing changes in East Asia. We find that the SST variation has been a major driver for the observed weakening of the EASM, whereas the effect of the anthropogenic aerosol forcing has been opposite and has slightly intensified the EASM over the recent decades. This result indicates that the increase in anthropogenic emissions over East Asia may play a role in compensating for the weakening of the EASM caused by the SST forcing.
    1. Figure6A.JPG
    Title
    Winter monsoon variability and its impact on aerosol concentrations in East Asia
    Authors
    Jaein I. Jeong, Rokjin J. Park
    Picture caption
    Composite differences in (a) simulated wintertime surface aerosol concentrations (contours) and accumulated aerosol mass flux from transport (vectors), and (b) SLP (contours) and 850 hPa winds (vectors) between the ten strong and ten weak EAWM years
    Summary
    In strong winter monsoon years, compared to weak winter monsoon years, lower and higher surface PM2.5 concentrations by up to 25% are shown over northern and southern East Asia, respectively. Analysis of the simulated results indicates that the southward transport of aerosols is a key process controlling changes in aerosol concentrations over Ewintertimeast Asia associated with the EAWM. Variability in the EAWM is found to play a major role in interannual variations in aerosol concentrations; consequently, changes in the EAWM will be important for understanding future changes in air quality over East Asia.
    1. Fig5. Aero_Jaco_effect_new2.png
    Title
    Sensitivity of HCHO column measurements to temporal variation of AMF
    Authors
    Kwon et al. (2017)
    Picture caption
    (a) Differences between AMFh and AMFm values and relative contributions to them by the temporal changes of (b) HCHO profiles, (c) aerosol optical properties, and (d) aerosol vertical distributions.
    Summary
    AMFh (hourly AMF) is smaller than AMFm (monthly AMF) over northeastern China (blue box), whereas the former is higher than the latter in the middle of eastern China (red box). Pronounced differences shown over China appear to correlate significantly with the effect of aerosols, whose optical properties (Fig. (c)) and vertical distributions (Fig. (d)) change with time. In particular, the decrease of AMF in the north results from decreased HCHO absorption within and below aerosol layers (a shielding effect). Aerosol profile effects are evident over the red box where the increment of AMF occurs. The resulting change of AMF is owing to HCHO above aerosol layers (an enhancement effect).