## 3 Theories and Methodology
### The Methods of Locating Strong Electromagnetic Pulses  
The technique of synchronizing events across multiple detection systems in both space and time, based on the distinctiveness of physical processes or the occurrence of events, is frequently employed. This method serves to validate system capabilities or to enrich the detection data from various systems to deepen the comprehension of the underlying physical processes and the mechanisms of detection events. In this study, the spatial and temporal information from the WEMPD detection events are matched in synchronization with a ground-based lightning location network. The precise locational data from this network are utilized to compensate for the inherent limitations of single-satellite detection. In a previous study, [27] demonstrated that the FORTE satellite detected the effective radiated power of the most potent lightning in the order of 100 kW( corresponding to on-orbit \(E_{dec}^{2}\) in the order of 1 mV\({}^{2}\)/m\({}^{2}\)). Subsequently, in a pivotal investigation conducted by [10], the WEMPD was employed to discern signals emanating from an electromagnetic pulse pulser (EMPP) with an effective radiated power of about 1 MW, corresponding to the strongest lightning radiations. This study revealed that the WEMPD exhibited the sensitivity to capture the EMPP signals within an 800 km radius of the subsatellite point. Furthermore, it was observed that the propagation time for these emissions to traverse  
Figure 1: Schematic of the space-borne WEMPD signal detection. the spatial expanse to the SY15 satellite is approximately 2 to 3 ms. Drawing on the outcomes of these two studies, the times of arrival and the subsatellite points of the events documented by the SY15 satellite are cross-referenced with the events detected by ground-based lightning locating networks. If two events in two systems exhibit a time difference of less than +3 milliseconds (satellite time minus ground time), a two-dimensional spatial deviation within 800 km, and a one-to-one correlation, it is hypothesized that they may originate from an identical radiation source. Furthermore, utilizing the geographic coordinate information from the ground-based lightning location network, the temporal difference, denoted as \(\Delta t\), is ascertained between the 'occurrence' time of the WEMPD-detected events, post-adjustment for the effects of distance and the ionosphere, and the timestamp ascribed to the events by the ground-based lightning location network. [PERSON] et al. (2018) conducted an analysis concluding that when the temporal difference \(|\Delta t|\) between the satellite-borne and ground-based detection systems is less than 300 us, the probability that the radiation source pertains to the same event is 97.5%. To augment the reliability of the synchronous matching process for locating the WEMPD-detected events, this study adopts the geographic coordinate information from the ground-based lightning location network, focusing on events with a temporal difference \(|\Delta t|\) of less than 100 us, which corresponds to a spatial error of 30 km. The aforementioned process for ascertaining the geographic locations of single satellite-detected events constitutes the SCL method. However, discrepancies in detection frequency bands and capabilities between space-borne and ground-based systems limit the SCL method's ability to accurately pinpoint the geographic coordinates for a limited portion of events captured by a single satellite, typically no more than 10%, according to [PERSON] et al. (2018). To address this limitation, the following refined strategies are implemented to enhance the determination of geographic locations for the WEMPD-detected events:  
1. Retaining the aforementioned spatial matching conditions, an additional temporal window is introduced for alignment with the WWLLN observations, thereby yielding a dataset denoted as \(S\) under these specified conditions. 2.