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NOAA National Operational Model Archive & Distribution System

NOMADS: User Manual

Table of Contents

Introduction to Distributed Data Access
Functional Overview
Getting Started
Desktop Services ("Clients")
OPeNDAP Servers
Quick Start to Retrieve or Plot Data
Using FTP to Retrieve Data
Using HTTP to Retrieve Data
Using wget to Retrieve Data
Using GDS Clients to Plot Data
Use Our Server to Create Plots
Explanation of "Online"/"Offline" data
Obtaining Offline Data
Offline Order Limitations
Advanced Data Access Methods
Subsetting Parameters and Levels using FTP4u
Obtain ASCII data using GDS
Scripting wget in a Time Loop
Mass GRIB Subsetting: Utilizing Partial-file HTTP Transfers
General Data Structure
Organization of Data Directories
Organization of Data Files
Use of Templates in GrADS Data Descriptor Files
Dataset Templates
Miscellaneous Information
Building Dataset Collections
Working with Timeseries Data
Creating Plots with GrADS
Scheduled Downtime Notification
NOAA's Weather and Climate Toolkit
MD5 Hash Files
GrADS Data Server User Guide (Off-site documentation)
Model Data Access Page

Top of Page Introduction

The model data repository at NCDC contains both deep archived (i.e.,off-line) and online model data. We provide a variety of ways to access our weather and climate model data. You can access the on-line data using traditional access methods (web-based or ftp), or you can use open and distributed access methods promoted under the collaborative approach called the NOAA National Operational Model Archive and Distribution System (NOMADS).

On the Model Data Access page you are presented with a table that contains basic information about each dataset, as well as links to the various services available for each dataset. The Plot/FTP option takes you into the "NOMADS Web Interface" which allows you to browse the inventories, retrieve model data, create plots, download plots, and ftp data. This page describes how to use the the different access methods and features provided by the NOMADS interface.

NCDC maintains a repository of weather model data sets as well as distributed access servers to these data sets. We provide access to weather model forecast data in near real-time as well as access to historical data in the online and offline (tape archive) repositories.

To view more detailed information regarding what datasets we have available, first vist the NCDC Model Data Inventories page to browse our inventories and locate datasets of interest. After you determine which datasets you want to further explore, visit the Model Data Access page to review the methods and features available to access the data. To directly read and analyze model data or retrieve model data, follow the instructions provided there.