Extensive studies have illustrated the importance of obtaining exact vertical structures of clouds
and aerosols for satellite and relevant climate simulations. However, challenging exists, for example, in
distinguishing clouds from aerosols at times. Accurate cloud vertical profiles are mainly determined by cloud
bases and heights. Based on the ground-based lidar observations in Hefei Radiation Observatory (HeRO), the
vertical structures of clouds and aerosols in Hefei area(31.89°N,117.17°E) during May 2012-May 2014
have been investigated. The results show that the cloud fraction in the autumn and winter is less than that in
the summer and spring, and is largest in the spring followed by the summer. The cloud fractions in the autumn
and winter are comparable. The low cloud accounts for the most portion of the total. Compared with the cloud
of the other heights, the high cloud is the least in the winter. Nearly 50% of the total vertical profiles can be
detected by lidar as clouds and the proportion of the cloud of different heights seems to be stable annually.
The fraction of low cloud is nearly 45%, medium cloud is nearly 35%, and high cloud is nearly 20%. In
comparison with the results derived from CALIPSO, it is found that high cloud is usually missed for the
ground-based lidar, while low cloud is usually omitted for the satellite observations. A combination of
ground-based and space-borne lidar could lead to more reliable results. Further analysis will be performed in
future studies.
An algorithm to retrieve the optically thick ice cloud microphysical property profiles is developed by using the GSFC 9.6 GHz ER-2 Doppler Radar (EDOP) and the 94 GHz Cloud Radar System (CRS) measurements aboard the high-altitude ER-2 aircraft. In situ size distribution and total water content data from the CRYSTAL-FACE field campaign are used for algorithm development. To reduce uncertainty in calculated radar reflectivity factors (Ze) at these wavelengths, coincident radar measurements and size distribution data are used to guide the selection of mass-length relationship and to deal with the density and non-spherical effects of ice crystals on Ze. The algorithm is able to retrieve microphysical property profiles of optically thick ice clouds, such as, deep convective and anvil clouds, which are very challenge for single frequency radar and lidar. An example of retrieved microphysical properties of a deep convective cloud is presented.
This paper systematically discussed the three-wavelength dual differential absorption lidar (dual-DIAL) method for measuring the stratospheric and tropospheric ozone profiles in the presence of high loading or inhomogeneous aerosols along the measurement path. Results of theoretical analysis and comparisons with DIAL and aerosol correction method show that the three-wavelength dual-DIAL method not only can greatly reduce the effect of aerosols on tropospheric and stratospheric ozone measurements, but also can get more accurate ozone profiles than DIAL after aerosol correction. The system error of three-wavelength dual-DIAL due to aerosols is kept in a low level. As the system error in the three-wavelength dual-DIAL is almost insensitive to the spatial inhomogeneity of aerosol loading and aerosol optical properties, this method does not need to known the detailed information about the spatial distribution of aerosol loading and aerosol optical properties. In the regions contained high loading or inhomogeneous aerosols, accurate ozone profile can be obtained directly from the lidar return signals with three wavelengths dual-DIAL method. Experimental results indicate the three wavelengths dual- DIAL method is effective.
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