Meizhou is the main citrus fruit producing area in China, and its pomelo planting area and output value rank second in China. In this paper, the present situation of prevention and control of citrus HLB(Huanglongbing)...Meizhou is the main citrus fruit producing area in China, and its pomelo planting area and output value rank second in China. In this paper, the present situation of prevention and control of citrus HLB(Huanglongbing) in this city in recent years is introduced, some successful experiences are mentioned, some shortcomings are also analyzed, and combined with the problems existing in the current process of prevention and control of citrus HLB, this paper puts forward some measures, such as timely removal of the diseased individuals, control of planthoppers, establishment of the HLB demonstration site of comprehensive prevention and control and large aseptic seedling breeding base, active introduction of HLB pathogen inspection and quarantine equipment, strengthening supervision and inspection, comprehensive control and other measures, in order to provide scientific basis for the prevention and control of the disease in Meizhou.展开更多
Based on cloud-to-ground lightning data of lightning location system,Doppler radar data,and precipitation data of regional automatic weather stations,the characteristics of cloud-to-ground lightning during a local rai...Based on cloud-to-ground lightning data of lightning location system,Doppler radar data,and precipitation data of regional automatic weather stations,the characteristics of cloud-to-ground lightning during a local rainstorm on June 4,2016 in Meizhou City were analyzed. The results showed that the spatial distribution of cloud-to-ground lightning from 14： 00 to 20： 00 on June 4,2016 in Meizhou City had obvious local characteristics,and the proportion of negative lightning was larger than that of positive lightning（ only 16. 8%）. The concentration period of positive lightning coincided with that of cloud-to-ground lightning. The peak of proportion of positive lightning lagged behind the peak of cloud-to-ground lightning,and appeared in the late period of thunderstorm disappearance. The dense area of cloud-to-ground lightning and the area with heavy rainfall coincided with the area with strong radar echoes. Doppler weather radar data had the feature of the headwind zone,strong combined reflectivity,vertical height of strong echoes,high echo top,and fast radial movement. The peak of cloud-to-ground lightning appeared one hour earlier than that of precipitation. There was no significant correlation between the frequency of cloud-to-ground lightning and precipitation. The peak of negative lightning corresponded to that of positive lightning,and cloud-to-ground lightning ended earlier than rainfall. After the peak of precipitation,convective system rapidly weakened and disappeared. Precipitation and the frequency of cloud-to-ground lightning fluctuated frequently during the whole process. The jumps and peaks of negative lightning were indicative of rainfall changes.展开更多
基金Supported by the Promotion Plan of Higher Education in Guangdong Province(Project of Subject Construction of Agricultural Resources and Environment)the Fourth National Survey of Traditional Chinese Medicine Resources Project(2017/152/013)the Special Fund for Science and Technology of Guangdong Province(2019A103009)
文摘Meizhou is the main citrus fruit producing area in China, and its pomelo planting area and output value rank second in China. In this paper, the present situation of prevention and control of citrus HLB(Huanglongbing) in this city in recent years is introduced, some successful experiences are mentioned, some shortcomings are also analyzed, and combined with the problems existing in the current process of prevention and control of citrus HLB, this paper puts forward some measures, such as timely removal of the diseased individuals, control of planthoppers, establishment of the HLB demonstration site of comprehensive prevention and control and large aseptic seedling breeding base, active introduction of HLB pathogen inspection and quarantine equipment, strengthening supervision and inspection, comprehensive control and other measures, in order to provide scientific basis for the prevention and control of the disease in Meizhou.
基金Supported by Science and Technology Plan Project of Meizhou City(2016B204)
文摘Based on cloud-to-ground lightning data of lightning location system,Doppler radar data,and precipitation data of regional automatic weather stations,the characteristics of cloud-to-ground lightning during a local rainstorm on June 4,2016 in Meizhou City were analyzed. The results showed that the spatial distribution of cloud-to-ground lightning from 14： 00 to 20： 00 on June 4,2016 in Meizhou City had obvious local characteristics,and the proportion of negative lightning was larger than that of positive lightning（ only 16. 8%）. The concentration period of positive lightning coincided with that of cloud-to-ground lightning. The peak of proportion of positive lightning lagged behind the peak of cloud-to-ground lightning,and appeared in the late period of thunderstorm disappearance. The dense area of cloud-to-ground lightning and the area with heavy rainfall coincided with the area with strong radar echoes. Doppler weather radar data had the feature of the headwind zone,strong combined reflectivity,vertical height of strong echoes,high echo top,and fast radial movement. The peak of cloud-to-ground lightning appeared one hour earlier than that of precipitation. There was no significant correlation between the frequency of cloud-to-ground lightning and precipitation. The peak of negative lightning corresponded to that of positive lightning,and cloud-to-ground lightning ended earlier than rainfall. After the peak of precipitation,convective system rapidly weakened and disappeared. Precipitation and the frequency of cloud-to-ground lightning fluctuated frequently during the whole process. The jumps and peaks of negative lightning were indicative of rainfall changes.
