A: Elevation is one of the categories under which data can searched. For example, consider the NOAA/NCDC/DAILY/GLOBALSOD dataset:
http://ingrid.ldgo.columbia.edu/SOURCES/.NOAA/.NCDC/.DAILY/.GLOBALSOD/
Click on "Searches" to the right of the map. You will then be able to type in your elevation limits (meters) in the table near the top of the page.