### Spatial Variability in the Primary Drivers of Leading Edge Erosion  
Previous meteorological research has indicated substantial spatial variability in the intensity, frequency and annual accumulation of liquid precipitation and frequency of hail at the global scale. High spatial variability in annual precipitation accumulation has been documented using homogenized records of in situ measurements such as the Global Historical Climatology Network (GCHN) dataset [68] (Figure 2a), blended multi-stream datasets (e.g., Global Precipitation Climatology Centre (GPCC) Full Data Reanalysis Version 7 [69]) Figure 2b), and satellite-derived estimates [70]. Annual precipitation accumulation varies by a factor of 10, even within individual countries (e.g., the US). Further, a recently released data set that merges information from multiple instruments and measurement technologies found that daily precipitation accumulation on the top 1 percent of wet days (i.e., days with daily accumulated precipitation of >1 mm) ranges from <5 mm over large parts of Australia, interior regions of Asia, northern Africa and western North America to >80 mm over large swaths of South America, parts of the eastern US, India and southern China [71]. Hail frequency also varies greatly across different parts of the globe [72]. An analysis of hail observations from the US National Oceanic and Atmospheric Administration (NOAA) Storm Prediction Center's event database, and similar archives from Australia and Europe, found that when the data are conditionally sampled to include only events with maximum hail diameter >25 mm, the annual hail frequency per 100 by 100 km grid cell are over 20 times higher in large parts of the south-central US than either Europe or Australia [73]. Similar spatial patterns in hailstorm frequency are found based on analyses of multi-sensor multi-wavelength brightness temperature data from the GPM mission (Figure 2c). An additional assessment of hail occurrence from Microwave Humidity Sounders onboard a number of different satellites also identifies the Southern Great Plains (SGP, south-central portions of the continental US) as being a global hot-spot for hail occurrence particularly during the Northern Hemisphere (NH) warm months. Secondary maxima are identified in central Eurasia and South America during the NH cold months [74]. It should be noted that these hail climatologies are biased towards detecting large-scale convective events (i.e., those that have long-duration--i.e., last for multiple hours and large spatial scales) [75]. There are also important gradients in the frequency of precipitation and hail at the regional and sub-regional scale. For example, based on data from the Integrated Multi-satellite Retrievals for the Global Precipitation Measurement (GPM) mission (IMERG) [76], the median size of precipitation systems over North America ranges from < 10,000 km\({}^{2}\) in parts of the west to 50,000 km\({}^{2}\) in the US southeast [77]. The mean intensity ranges from below 1 mmhr\({}^{-1}\) in the west to well over 2 mmhr\({}^{-1}\) in the US southeast [71]. Onsub-regional scales there is also high variability. For example, annual precipitation varies by a factor of 10 across Texas and the prevalence of hail events ranges from hundreds of 5 min events per year to nearly zero [78]. Northwestern Texas has high wind turbine installed capacity and a high joint probability of hail and/or heavy precipitation at power-producing wind speeds [78]. Wind speeds and wind resources also vary across a wide range of spatial and temporal scales [80; 81; 82]. This leads to an uneven distribution of wind turbine deployments (Figure 2d), and to large spatial variability in the amount of time wind turbines operate at their maximum rotor rotational speed (Figure 1a). Precipitation frequency and intensity (RR) are highly dependent on the spatial and temporal resolution of observations.