-->Is there any way to publish 16 bit raster image in geoserver 2.7.2? Then i tried to publish 16 bit raster image,but i got different color variations in different zoom levels,If any solutions for this issue?
To be short, this effect is due to the fact that the geotiff is stretched to 8 bits before rendering ( I am guessing you are using JPEG as an output format).
The easiest thing to do is to apply a contrast stretch upfront to bring the image to 8 bit and then publish to GeoServer. This is also going to be more performant.
FYI in GeoServer 2.8 we are going to give the possibility to perform controllable contrast stretch on the fly, up to 2.7 you can use contrast stretch but it is applied on a per request basis, hence the tesselated effect (i.e. we use local statistics for the image).