Seasonal variations of the tropical intraseasonal oscillation （ISO） and relationship to seasonal variation of the climate background are studied by using NCEP/NCAR reanalysis data and output of SAMIL-R42L9. Analysis...Seasonal variations of the tropical intraseasonal oscillation （ISO） and relationship to seasonal variation of the climate background are studied by using NCEP/NCAR reanalysis data and output of SAMIL-R42L9. Analysis of NCEP data shows that spatial distribution of the tropical ISO has obvious seasonal variations, which are well consistent with the seasonal variation of climate background. The activity of the tropical ISO is, to a great extent, dependent on warm SST, strong convection, zonal western wind, strong precipitation and low-level moisture convergence. Main characteristics of the seasonal variations of the tropical ISO are captured by SAMIL-R42L9. Simulations of seasonal variation of climate background vary greatly with different variables. Results of SAMIL-R42L9 indicate that the seasonal variations of the tropical ISO in dynamical fields are more dependent on climate background than in heating fields and SAMIL-R42L9 canllot represent well the strong dependence of the ISO on the climate background present in NCEP/NCAR reanalysis data. It also suggests that seasonal variations of the ISO do not completely depend on that of climate background.展开更多
An adiabatic bin-sized cloud parcel model is developed by incorporating the multi-chemical-component (MCC) aerosol effects into the UWyo single-chemical-component (SCC) parcel model. The effects of MCC aerosols on the...An adiabatic bin-sized cloud parcel model is developed by incorporating the multi-chemical-component (MCC) aerosol effects into the UWyo single-chemical-component (SCC) parcel model. The effects of MCC aerosols on the warm cloud microphysics in North China are investigated with the model. The simulations are initialized using the data on chemical components and number size distribution of aerosols measured during the IPAC (Influence of Pollution on Aerosols and Cloud Microphysics in North China) campaign in spring 2006. It is found that the MCC aerosols in North China increase the cloud droplet number concentration (CDNC) and decrease the effective radius more efficiently than pure ammonium-sulfate aerosols. It is also shown that the MCC aerosols in North China can narrow the cloud droplet spectra (CDS) by increasing CDNC in small size and decreasing CDNC in large size. Our results indicate that aerosol chemical components and their size distributions can influence the microphysics of warm clouds, and thus affect atmospheric radiation and precipitation. This should attract more attentions in weather and climate change research in the future.展开更多
基金Natural Science Foundation of China (4057502740675051)Innovative Project for ChineseAcademy of Sciences (KZCX3-sw-226)
文摘Seasonal variations of the tropical intraseasonal oscillation （ISO） and relationship to seasonal variation of the climate background are studied by using NCEP/NCAR reanalysis data and output of SAMIL-R42L9. Analysis of NCEP data shows that spatial distribution of the tropical ISO has obvious seasonal variations, which are well consistent with the seasonal variation of climate background. The activity of the tropical ISO is, to a great extent, dependent on warm SST, strong convection, zonal western wind, strong precipitation and low-level moisture convergence. Main characteristics of the seasonal variations of the tropical ISO are captured by SAMIL-R42L9. Simulations of seasonal variation of climate background vary greatly with different variables. Results of SAMIL-R42L9 indicate that the seasonal variations of the tropical ISO in dynamical fields are more dependent on climate background than in heating fields and SAMIL-R42L9 canllot represent well the strong dependence of the ISO on the climate background present in NCEP/NCAR reanalysis data. It also suggests that seasonal variations of the ISO do not completely depend on that of climate background.
基金supported by National Natural Science Foundation of China (Grant No. 40433008)Research and Development Special Fund for Public Welfare Industry (Meteorology) of China Meteorological Administration (Grant Nos. GYHY(QX)-2007-6-36, GYHY(QX)-2007-6-5)Foundation of Nanjing University of Information Science & Technology (Grant No. NUIST-20090218#)
文摘An adiabatic bin-sized cloud parcel model is developed by incorporating the multi-chemical-component (MCC) aerosol effects into the UWyo single-chemical-component (SCC) parcel model. The effects of MCC aerosols on the warm cloud microphysics in North China are investigated with the model. The simulations are initialized using the data on chemical components and number size distribution of aerosols measured during the IPAC (Influence of Pollution on Aerosols and Cloud Microphysics in North China) campaign in spring 2006. It is found that the MCC aerosols in North China increase the cloud droplet number concentration (CDNC) and decrease the effective radius more efficiently than pure ammonium-sulfate aerosols. It is also shown that the MCC aerosols in North China can narrow the cloud droplet spectra (CDS) by increasing CDNC in small size and decreasing CDNC in large size. Our results indicate that aerosol chemical components and their size distributions can influence the microphysics of warm clouds, and thus affect atmospheric radiation and precipitation. This should attract more attentions in weather and climate change research in the future.
