Given ambient raster, extend metrics #10
Description
For the United States, there are existing rasters that estimate summer daytime L50:
Mennitt D, Sherrill K, Fristrup K. A geospatial model of ambient sound pressure levels in the contiguous United States. J Acoust Soc Am. 2014 May;135(5):2746-64. doi: 10.1121/1.4870481. PMID: 24815258.
However, they are very inaccurate (read: ±12 dB) at the spatial scale a noise model is concerned with. Too inaccurate to be of use, unfortunately.
Still, it stands that if a user could supply a meaningful source of (ideally spectral) sound levels across the landscape it would be very interesting and useful to extend the functions in NMSIM grid results (.tig) to raster (.TIF). The following metrics could then be easily added:
- Time Audible (i.e., Duration)
- Increase above natural sound levels