The  NASA Ames Format for Data Exchange, often referred to as NASA Ames Format, grew out of NASA aircraft campaigns and was first formalised at the Ames Research Centre, California.  It is still used by the atmospheric observation community although it has largely been replaced by the binary NetCDF format for aircraft data.  

NASA-Ames is an ASCII text file format with a defined header followed by columns of space separated variables.

Which type of data?

Any set of functions of 1 to 4 independent variables can be recorded using the NASA Ames format, however, it is most useful for simple datasets with just one independent variable (eg time series or profiles). Other formats, such as  NetCDF, may be more suitable for more complex data structures, or for very large datasets.

File structure

Each file is made of two parts. At the top of the file, the file header includes information on the data ( metadata). The actual data are recorded in the lines that follow the header. In many cases, some of the independent variables are defined in the header and are not repeated in the data section (e.g. for a regular grid). Below is a brief description, but you can find extra details here  CEDA NASA Ames FFI Summary

Header or Metadata section

The header includes, in a strictly defined order and format, all the information needed to read and understand the data. The image below describes each line of metadata for the most commonly used version (index 1001).

Information on the data and source of the data (instrumentation, model used, data processing, data quality, location, date, revision date, etc.), is usually included in the comment lines. 
Many data files contain the variable  time which can be expressed in several ways, guidelines on the recommended format of the time-variable header lines, units and the data values are available.

Data section

The data section starts directly after the header starting with the independent variable in the first column. The primary variables follow in subsequent columns in the order listed in the header. The columns are separated by spaces (usually 4) and not tabs (see example below).

File names

At CEDA, NASA Ames files generally follow the CEDA file naming convention given below, with the ending .na. This enables quick access to pertinent metadata and avoids the need to open and read the file in order to assess its contents.


For further information please see the  File Names explained documentation.


Examples of NASA Ames formats can be found below;

Examples are also included in the guides to 1D and 2D formats.

Checking your data files

A NASA Ames Format checker is  available at CEDA.  Please contact for your file to be checked. The checker is based on a program written by S. Gaines, NASA Ames Research Center.

Uploading NASA Ames files to CEDA

To upload your data please use our  HTTP: File uploader service. A step by step guide can be found  here.

Further reading

Format Specification for Data Exchange, Version 1.3 ( Gaines and Hipskind, 1998) is the primary reference for NASA Ames formatting. As far as possible, the CEDA documentation keeps the same nomenclature and notation system as in this original document.

Every File Format Index is explained line by line in the  NASA Ames FFI Summary provided by CEDA.

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