## 1 Introduction  
Sufficiently accurate measurements of precipitation are indispensable for a large spectrum of socio-economic human activities [1]. Such precipitation measurements are essential over a wide range of spatiotemporal scales. However, over several regions around the world, precipitation measurements from rain gauges or other in situ rainfall measuring instruments are limited by the scarcity of observations from a locally coarse network [2, 3, 4]. Data from other ground-based platforms (e.g., ground-based weather radars) cannot fill in the gap. The Sinai Peninsula in Egypt is an example of a region with insufficient ground-based measurements from rain gauges. Nevertheless, satellitescan provide estimations of precipitation at broader geographical scales [5; 6; 7] and, thus, satellite-derived rainfall estimations offer a potential source for obtaining higher-quality spatiotemporal precipitation distributions over the Sinai Peninsula. This is particularly important in cases where socio-economic activities greatly rely on aquifers for water resources, as in the geographical area referred to in this case study. However, monitoring precipitation by the spaceborne sensors in arid areas is a challenging task because such areas are characterized by low precipitation intensities and large spatial heterogeneities [8]. In arid and semi-arid areas, replenishment of aquifers by precipitation is influenced by the recharge rate and general water cycle equilibrium [9]. Increased precipitation, especially during monsoons, reduces stress on aquifers, either by a direct recharge or indirectly by the reduction of abstraction [10]. Consequently, precipitation is the most prominently analyzed factor in most hydrological studies, particularly those on flash flood risk assessment, groundwater location, climate change, and forecasting [11]. Precipitation intensity is determined by the storm extent, strength, and movement, which varies over small-scale areas in arid and semi-arid regions [12; 13]. Low precipitation rates negatively affect the continuity of land reclamation [14]. However, the significance of light-intensity events lies in their frequency. These are the most frequent event types in most arid regions of the world, when compared to more rare heavy-intensity rain events [15; 16]. The contribution of the most frequent light rainfall events to infiltration and aquifer recharge rates is, therefore, greater than that of the heavy-intensity events. Event intensity was previously determined primarily by a combination of rain gauge and radar data [17; 18]. However, rain gauge data on its own produces the most accurate measurement of precipitation rates both in terms of spatial resolution and rainfall accumulation depth [11; 19]. Several types of rain gauges exist, including accumulation gauges, tipping bucket gauges, weighing gauges, and optical gauges. Each carries its own advantages and disadvantages [11; 19; 20]. Although rain gauges have been ranked as the most accurate tool for rainfall detection, they are sparsely distributed or even non-existent in most developing countries, particularly those in mountainous regions [17; 21; 22]. However, there exist numerous, freely available sets of satellite-based rainfall estimates and reanalysis products, which enable users to bridge gaps in data derived from rain gauge networks. The El-Qaa Plain in the Sinai Peninsula was selected as a test site. This region was chosen for its standing as one of the most promising areas in the Sinai Peninsula for further development and, in particular, tourism. These prospects have already led to a gradual increase in the number of inhabitants and expansion of land exploitation. As a result, local water consumption is gradually increasing in an area where the main source of groundwater is the regional quaternary aquifer [23; 24]. This aquifer extends from Wadi Feiran to the head of Ras-Mohamed and is mainly recharged by rainfall [25].