uncertainty in AWS barometer height via JAR 2009 GPS data

[jasonebox]

first, renamed folder from "2010 JAR1 gps" to "2009 JAR1" because the relevant data are from 2009

now, to resolve the offset of the red stars dots in the graphic below, I think we need to know a couple offsets:

1. the offset of the GPS antenna to the ice surface, do we have field notes or photos? J Zwally isn't responding to my last 3 data requests via his Facebook page that I can see he has used
2. the offset of the AWS barometer to the ice surface, photos could do the trick

An offset of -4.0 m would bring the red stars to the best guess magenta line in the figure... I don't believe the GPS antenna would be 4 m above ground.

By the way, GPS equipment is not featured in the photos archive (links below),

https://github.com/GEUS-Glaciology-and-Climate/GCNET_photos_availability/blob/main/photo_archive_of_GC-Net_AWS/JAR%202010%2005%2012%2012%2018%2057%20via%20D%20Houtz.JPG

https://github.com/GEUS-Glaciology-and-Climate/GCNET_photos_availability/blob/main/photo_archive_of_GC-Net_AWS/JAR%202009%2004%2030%2007%2050%2049%20via%20D%20Houtz.JPG

https://github.com/GEUS-Glaciology-and-Climate/GCNET_photos_availability/blob/main/photo_archive_of_GC-Net_AWS/JAR%202009%2005%2002%20post%20via%20D.%20McGrath.jpeg

[jasonebox]

similarly, the intriguing shapefile (GCNet_positions/data/GNSS data/Greenland_GNSS_2011_2012.shp) that contains realistic elevations of AWS sites has an uncertain offset for Summit. Below that is the plotted shapefile info. As in the JAR example above, we need field notes for GPS antenna height relative to surface and barometer height to resolve the actual AWS elevation, i.e., the ortometric height which is equal to the height above mean sea level. We'd also need to know if the heights inthe shapefile are ellipsoidal heights (seems not) and using which geoid, e.g. EGM96