Data from the World Wide Lightning Location Network （WWLLN） for the period 2005-2011 and data composite of the Lightning Imaging Sensor/Optical Transient Detector （LIS/OTD） for 1995-2010 are used to analyze the li...Data from the World Wide Lightning Location Network （WWLLN） for the period 2005-2011 and data composite of the Lightning Imaging Sensor/Optical Transient Detector （LIS/OTD） for 1995-2010 are used to analyze the lightning activity and its diurnal variation over land and ocean of the globe. The Congo basin shows a peak mean annual flash density of 160.7 fl km-2 yr-1 according to the LIS/OTD. The annual mean land to ocean flash ratio is 9.6：1, which confirms the result from Christian et al. in 2003 based on only 5-yr OTD data. The lightning density detected by the WWLLN is in general one order of magnitude lower than that of the LIS/OTD. The diurnal cycle of the lightning activity over land shows a single peak, with the maximum activity occurring around 1400-1900 LT （Local Time） and a minimum in the morning from both datasets. The oceanic diurnal variation has two peaks： the early morning peak between 0100 and 0300 LT and the afternoon peak with a stronger intensity between 1100 and 1400 LT over the Pacific Ocean, as revealed from the WWLLN dataset; whereas the diurnal variation over ocean in the LIS/OTD dataset shows a large fluctuation.展开更多
基金Supported by the National Natural Science Foundation of China (41005004 and 40930949)
文摘Data from the World Wide Lightning Location Network （WWLLN） for the period 2005-2011 and data composite of the Lightning Imaging Sensor/Optical Transient Detector （LIS/OTD） for 1995-2010 are used to analyze the lightning activity and its diurnal variation over land and ocean of the globe. The Congo basin shows a peak mean annual flash density of 160.7 fl km-2 yr-1 according to the LIS/OTD. The annual mean land to ocean flash ratio is 9.6：1, which confirms the result from Christian et al. in 2003 based on only 5-yr OTD data. The lightning density detected by the WWLLN is in general one order of magnitude lower than that of the LIS/OTD. The diurnal cycle of the lightning activity over land shows a single peak, with the maximum activity occurring around 1400-1900 LT （Local Time） and a minimum in the morning from both datasets. The oceanic diurnal variation has two peaks： the early morning peak between 0100 and 0300 LT and the afternoon peak with a stronger intensity between 1100 and 1400 LT over the Pacific Ocean, as revealed from the WWLLN dataset; whereas the diurnal variation over ocean in the LIS/OTD dataset shows a large fluctuation.
