On the basis of a previous algorithm of cloud detection, clouds and aerosols are distinguished by analyzing the backscatter signals of a micro pulse lidar. In this way, the content of clouds are classified into ice, water, mixed-phase clouds and horizontal oriented ice flakes. Finally, the supercooled water clouds are distinguished from water clouds by the information of temperature profiles. The monthly changes of the appearance heights and proportions of the various clouds are also calculated with one-year observations over the lidar site. The supercooled clouds are found to appear at 9.84% of all the cloudy time, and 11.99% of all the time for clouds at from 0℃ to − 40℃.

The aerosol optical parameters derived from satellite remote sensing and the related surface PM10 mass concentration data in 2011?2012 over Suzhou and Wuxi Cities were used to assess the location selection of one background monitoring station to be built. The results showed that satellite remote sensing products with 10 km, 5 km and 2 km space average were all significantly correlated to the hourly PM10 concentration. Showing in the annual average regional distribution of satellite remote sensing results, the annual average PM10 mass concentration over the Xishan (the site to be built in Suzhou) will be significantly lower than those over the urban stations in the magnitude up to 14%. Statistical analysis based on an objective weather classification technique showed that the mean concentration of particulate matter over Xishan were lower than that of urban stations in the amplitude range of 7%?21% in various weather patterns. The smaller (7%?9%) concentration difference between the urban stations and the Xishan station could be found at two types of weather conditions, when there were a regional heavy pollution or a regional clean air quality, respectively.

Based on the analysis of wind data measured at one wind measurement tower over Huangang Wind Farm in Jiangsu Province from Dec. 2010 to Nov. 2011, it was calculated that at 10, 50, 70 and 80 m heights the annual average wind speed was 4.0?6.1 m/s, the annual average wind power density was 80.4?238.4 W/m2, the annual effective wind power density was 116.5?262.5 W/m2, the annual effective hours were 5777?7845 h, and the annual effective wind energy density was 679.3?2041.5 (kW?h)/m2. In addition, the dominant wind directions were NNE, N and NE, the sum of them took up nearly 30% of the full year wind directions, the wind energy density of the dominant wind directions accounted for almost 50% of the full year wind energy density, and the wind speed was mainly ranging from 3 to 8 m/s, about 80% of the full year wind speeds. Overall, wind energy resource was abundant in this region. Especially the hub height of the already built wind turbines had the wind power density of more than 250 W/m2, and the effective hours took up nearly 90% of the full year. Therefore, wind energy resource had a great value of development and utilization in this region.

The aerosol optical depth (AOD) products from Moderate Resolution Imaging Spectroradiometer (MODIS), aerosol extinction coefficient profiles from Light Detection and Ranging (LIDAR), surface relative humidity data and particulate matter (PM) mass concentration data over Yuan Long, Hong Kong in 2008 were used in the remote sensing of surface suspended particulate matter mass distribution. LIDAR data were used to get the relationship among surface aerosol extinction coefficient, LIDAR AOD and aerosol scale height, which was further applied in the retrieval of the distribution of surface aerosol extinction coefficients with satellite AOD. After considering relative humidity effect, the correlation between satellite estimated aerosol extinction coefficients and the corresponding surface PM mass was investigated. Finally, the surface PM mass distribution was obtained by synergy usage of satellite and LIDAR measurements. The results show that the correlation coefficients between the estimated aerosol extinction coefficients and the surface PM mass are 0.57?0.86 for PM2.5 and 0.59?0.78 for PM10, respectively. The Root Mean Square Errors (RMSEs) between estimated PM and surface measured PM mass are 11.64?25.34 g/m³ for PM2.5 and 24.64?91.64 g/m³ for PM10. Satellite remote sensing provides a promising way in atmospheric suspended particulate matter monitoring. The 1-km resolution AOD product is more suitable for describing the pollution in the urban areas with complicated topography.

The PM10 mass concentration from 428 ground sites in Eastern China in 2011 were used to investigate the temporal representative of satellites carrying MODIS for air quality monitoring. The daily, monthly, seasonal and yearly averaged ground measurements of PM10 mass concentration at the time when the satellite data is available (SATPM) were compared with the corresponding 24 hours averaged ground measurements (ALLPM). The data with the Aqua-MODIS time are more close to ALLPM than those with Terra-MODIS time, and most relative errors fall into the range of ±20%, indicating a high reliability of temporal representative on Aqua time. Data from both satellites were incorporated together through a linear fitting to get the validated daily and yearly SATPM. The results show a better correlation and own lower root mean square errors (RMSE) with ALLPM. Because PM2.5 is more correlated with optical observations, the results are also of significant implications for the reliability of PM2.5 retrieval from satellite.

The MPL observation data in Beijing is used to develop two new algorithms which will not need to refer to the low SNR signal in high altitude. In the first algorithm, the boundary in mixing layer is chosen in the Fernald’s theory. Then the lidar constant can be retrieved by combining AOD. Compared with the data from the automatic meteorological station locates in the same place, this algorithm seems viable for lidar’s extinction coefficient retrieval. In the second algorithm, since the range corrected lidar data near the surface is linear relate to the surface extinction coefficient, the visibility data in the surface could be used to calculate the lidar constant. The result of the lidar constant and the average extinction-to-backscatter ratio during the experiment period are similar to the first algorithm. In these two algorithms, the lidar constant is retrieved without using the high altitude signal. In the end, the lidar observation of a classic aerosol case when a Siberian High passes through Beijing is analyzed. By comparing the lidar observation with the Nanjiao Observation Station data, the lidar retrieval and the new algorithm are considered to be reliable.

How to use the measurement from the visible channel of Chinese Fengyun-2C geostationary satellite to retrieve aerosol optical depth (AOD) is discussed. By calculating mean surface reflectance at the same local time of each day in one month, the randomicity of the estimated surface reflectance can be reduced. The influence of different values of AOD assumed in the cleanest days on the quality of final AOD product is analyzed. In addition, the data in May 2008 was used to test the proposed algorithm and the results were compared with the AOD product from six AERONET sites in East Asian and MODIS AOD product respectively. Last, the error sources were analyzed in the retrieval of AOD from FY2C satellite, and the corresponding possible schemes to decrease the error influence and improve the quality of FY2C AOD product were investigated. The comparison indicates that in East Asian the AOD product can display the pattern of aerosol distribution, but overestimates the values of AOD in southwest of China and low latitude areas, and underestimates the values of AOD in east of China.

SAGEⅡ( stratospheric aerosol and gas experiment Ⅱ) data extending as long as 20 years was used to study both the spatial and temporal distributions and the trend of column aerosol between 5.0 and 15.0 km over East Asia. The transport of aerosol to the upper level and downstream areas by dust activities was also studied. It's found that there are three different kinds of horizontal distributions. In the low level of 5.0 -8.5 km, the high-value area is just above the dust source of aerosol, e.g. Tibetan Plateau, deserts in the northwest of China; in the middle level of 9.0-10.0 km, the high-value area is consistent with the area with high extratropical cyclone frequency; in the high level of 10.5 - 15.0 km, the value in low-latitude is significantly higher than that in high-latitude. Upper level aerosol distributions in all the three levels significantly vary seasonally resulting from different synoptic systems. A downward trend of upper air aerosol is found in recent ten years over East Asia and the aerosol optical depth (AOD) between 5.0 and 15.0 km has decreased by 0.016. It is also found that aerosol between 5. 0 and 11. 5 km has significant positive correlation with the dust storm activity, which infers the injection of surface dust to all the altitude in troposphere. Upper-air-effect-index of dust storm was defined to study the impact of dust storms in East Asia on the downstream areas. The movement of dust towards the east was observed; and the dust could reach the Atlantic Ocean in about 12 days.

Seasonal changes of aerosol optical depth over the Central and Eastern China, the Sichuan Basin, the Yangtze River Delta and the Pearl River Delta from MODIS data from March 2000 to February 2009 are analyzed and compared. It is found that in the 9 years the mean AOD over every region in all seasons has significant increasing trends, except for Sichuan Basin in autumn. The highest AOD occurs over the Yangtze River Delta in both annual and seasonal averages, and the increasing rate of annual mean is up to 1.82% per year. The AOD over Sichuan basin ranks second, and then is North China, the Pearl River Delta has the lowest annual average AOD. The fastest increase of AOD is in summer, the difference between spring and summer becomes smaller, and some areas, such as North China, AOD in summer is higher than that in spring. AOD data are the least and their growth rate are the lowest in winter. Thus, the gap between winter and other seasons becomes larger. The AOD over some regions in some seasons, such as over the North China in summer and autumn, the Sichuan Basin in spring, summer and autumn, and the Pear River Delta in autumn, over the period of 2006 to 2008 have continuous decreasing trends. These results will benefit the studies of regional climate change and air pollution variation.

This study was based on two-year MODIS aerosol optical depth (AOD) product and PM₁₀ mass concentrations calculated from Air Pollutant Index (API) in Beijing and the hourly averaged measurements at Peking University in Beijing and Yuen Long station in Hong Kong. The direct correlation between AOD and PM₁₀ mass concentration was found relatively low. The correlation coefficient between aerosol surface extinction ( achieved from dividing AOD by seasonal aerosol scalar heights) and PM₁₀ mass concentration increased to some extent. The correlation further improved after considering the influence of relative hfumidity (RH) on aerosol optical properties. This comparison verified that the MODIS AOD can be applied in the evaluation of surface PM₁₀ mass concentration after taking aerosol vertical distribution and influence of RH into consideration.

Based on the radiation transfer equation and a optimized retrieval method proposed by Dennis Chesters et al., this paper describes the general formula of retrieving precipitable water(PW) by the different absorption in the split channel. The feasibility of using radiosonde observations or ground based water vapor radiometer to calibrate the absorption coefficients is researched, and the field of PW is retrieved with the coefficients.