Kopparthi, I assume you meant to upload only the meta data in the text file. I am not familiar with ADCP so I am not sure how your raw data is organized. Please add more information to your question (eg - what are the data dimensions? (not file size), what are the dimension variables? how is the data organized in the text file? (row-major or col-major?) what type is it? (integer, double?) etc.
Note - The meta data can be written using ncwriteatt.
You mentioned you tried using nccreate and ncwrite, what did you try and how was it not the required file you wanted?
The help for ncwrite has an example which shows you how to 2D data.