# Capability Analysis of Earth Observation Data for Integrated Emergency Management
## 4 R2-D2 Case Study Results
### Pilot Studies Investigating Satellite Imagery in Support of Emergency Management
#### 4.3.3 Electricity Transmission Faults  
Following Storm Arwen in November 2021, a considerable number of rural villages in the counties of Northumberland and Durham (both in North East England) suffered several days without electricity [78]. NASA's Black Marble Nighttime Lights product VNP46A2, a VIIRS supporting a Day/Night Band (DNB) sensor, provides global daily nighttime light data at a 500 m resolution. VNP46A2 is corrected based on clouds, atmospheric conditions and lunar illumination [66] and can help detect the nighttime impact of low light and indicate potential power outages resulting from storms. Including corrections for bidirectional reflectance distribution function (BRDF) and considering noise reduction, VNP46A2 can produce cleaner images than VNP46A1, a daily uncorrected product of the nighttime radiance at the top of atmosphere (TOA).  
For example purposes, we demonstrated the applicability of the VNP46A2 datasets available through the GEE data catalogue for four sites in North East England that suffered reported power cuts resulting from Storm Arwen: two rural areas (Wooler and Rothbury) and one market town (Alnwick) in Northumberland, and the city of Newcastle upon Tyne. Figure 9 shows the radiance level for all four areas. As the VNP46A2 product contains quality flags to identify and mask pixels affected by clouds, the affected areas are excluded in the output graphic, leaving blank values in the time-series graph.  
As reported by the local operator, Northern Powergrid, numerous households suffered from power cuts on the night of Storm Arwen (26-27 November 2021): Alnwick (c. 260 households), Wooler (c. 70) and Newcastle (c. 250) [78]. Following the night of the storm, different households in these areas also reported power cuts. Unfortunately, the night of Storm Arwen had cloud coverage of 100% over both Alnwick and Newcastle, obscuring nighttime data. The nights of 27 November through to 08 December also all presented a high level of cloud coverage (92-100%) for the Alnwick area, with the exceptions of 1-2 December and 6-7 December. Little nighttime light is recorded in the mean radiance data for the nights of 28-30 November and 3-4 December. On 4 December, Northumberland areas (such as Wooler) and Newcastle reported further power cuts, leading to missing recorded nighttime data from 4 to 7 December. From the night of 7-8 December, we see the activity of nighttime radiance for the rural areas, indicating that power was restored, which also correlates with the date Northern Powergrid estimated for power restoration.  
Figure 9: Time series of nighttime light radiance levels for four locations in North East England.  
Figure 10 presents map outputs for two different nights upon which data were acquired, and which are relatively important to the storm and its associated impacts for the study areas. VNP46A2 quality flags are used to mask pixels affected by clouds, excluding them from the output graphic. Figure 10a visualises Northumberland two nights after the storm (28-29 November 2021) displaying restored power in the county, and (b) represents the same night in Newcastle; (c) visualises the night following further reported power cuts (4-5 December 2021) in Northumberland, and (d) the corresponding night in Newcastle. As the households affected were estimated from available online sources, we suggest obtaining historical data from Northern Powergrid during Storm Arwen and overlaying the nighttime imagery to understand the correlation between definitively known power cuts and remotely sensed irradiance patterns as future work.