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. 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).
    1. 그림1.jpg
    Title
    Efficacy of dust aerosol forecasts for East Asia using the adjoint of GEOS-Chem with observations
    Authors
    Jaein I. Jeong, Rokjin J. Park
    Picture caption
    (top) Flowchart of the proposed adjoint framework, (bottom) Observed versus simulated hourly surface PM10 concentrations over the Korea Peninsula on May 24–27, 2007.
    Summary
    Based on our adjoint model constrained by observations for the whole period of each event, the reproduction of the spatial and temporal distributions of observations over East Asia was substantially improved. We then examine the efficacy of the data assimilation system for daily dust storm forecasts based on the adjoint model including previous day observations to update the initial condition of the forward model simulation for the next day. The forecast results successfully captured the spatial and temporal variations of ground-based observations in downwind regions, indicating that the data assimilation system with ground-based observations effectively forecasts dust storms, especially in downwind regions.