Diurnal Variation of TRMM/LIS Lightning Flash Radiances

AbstractThis study provides, for the first time, an analysis of the climatological diurnal variations in the lightning flash radiance data product e from the Tropical Rainfall Measuring Mission Lightning Imaging Sensor (TRMM/LIS). The e values over 13 years (2002–14), and over a global scale (∼38°S–38°N), reveal novel and remarkably consistent regional and seasonal patterns as a function of the local solar time (LST). In particular, the diurnal variation of e (over both continental and oceanic regions) is characterized by a monotonic increase from late afternoon (∼2000 LST), attaining a maximum around 0900 LST, followed by a decreasing trend. The continental (oceanic) e values reach a broader minimum spanning from ∼1500 to 1900 LST (∼1800 to 2000). The relative diurnal amplitude variation in continental e is about 45%, compared to about 15% for oceanic e. This study confirms that the results are not affected by diurnal biases associated with instrument detection or other statistical artifacts. Notable agr...