University allocations

Large requests | Small requests | Data access requests
Classroom allocations | Preparing requests | Eligibility

Reminder: Yellowstone will not be available after December 31, 2017

To add a Cheyenne allocation to your existing project, request a supplemental allocation of up to 400,000 core-hours.

  • Go to
  • Log in with your YubiKey authentication token.
  • Click My Allocation Requests near the top of the page.
  • Select Supplement from the drop-down menu.
  • Fill in the form to request the Cheyenne allocation and click Submit.

To convert your Yellowstone allocation into a Cheyenne allocation, email your request to

Researchers at U.S. universities have several allocation opportunities, each with distinct eligibility rules.

For full eligibility policies, see Eligibility below.

Large Allocation Requests

Requests for more than 400,000 core-hours on Cheyenne or more than 200,000 core-hours on Yellowstone are considered large requests. CISL accepts requests for large allocations of NCAR resources every six months, in March and September.

The panel recommends awards on the basis of the computational experimental design, computational effectiveness, and availability of computing resources. More than 160 million Cheyenne system core-hours are allocated during each allocation cycle.

Check the submission instructions for the next submission deadline and instructions for preparing the required Request Summary document.

If your Request Summary is ready, click here to submit your Large Allocation Request.

If your work needs to begin immediately and your request meets support requirements, a modest advance of computational resources can be made after you submit your online request. Contact

Small Allocation Requests

Requests for up to 400,000 core-hours on the Cheyenne system, and 200,000 core-hours on Yellowstone, are considered small requests

U.S. university researchers who are supported by NSF awards can request a small allocation for each NSF award. Small allocations are also available to graduate students and post-docs at U.S. universities; no NSF award or panel review is required. University researchers also can request allocations for the use of the Geyser and Caldera clusters as well as the CMIP Analysis Platform.

Small requests typically receive a partial allocation within a few business days. Once the initial allocation is consumed, you can email to request additional core-hours up to a total allowed.

Click here to submit a Small Allocation Request.

Click here to submit a Graduate Student / Postdoc Request.

Small Data Access Requests

Faculty and research staff at U.S. universities, U.S. non-profit research organizations, and UCAR affiliates can request read-only access to NCAR-housed data at no charge.

These accounts are granted sufficient access to read data from GLADE and HPSS for up to three years. They may be renewed by sending email to and stating the additional time period needed.

The allocation request form is temporarily unavailable. Please contact if you need to request data access.

Classroom Allocations

CISL offers opportunities to undergraduate and graduate faculty to use high-performance computers in their college courses. Accounts are provided to individual students and the professor for assignments in numerical simulations, modeling, and studies of recently introduced computing architectures. CISL can provide consulting assistance to the professor or teaching assistant.

To request a classroom allocation, use the Graduate Student / Postdoc Request form. While most fields on the form are self-explanatory, review these instructions for information that pertains specifically to classroom allocation requests. 

Preparing allocation requests

This presentation includes tips for writing successful allocation requests. While it also includes a brief description of the Yellowstone system, the same general approach applies to preparing Cheyenne allocation requests.


University use of CISL resources is intended to support research in the atmospheric and related sciences by scientists and graduate students at U.S. universities. The emphasis is on extensive projects that are beyond the scope of university computing centers. There are three primary eligibility criteria.

1. Atmospheric and related sciences

Atmospheric science attempts to understand the total behavior of the earth's fluid envelope on all scales ranging from microscopic processes to global motions. Since this system is bounded by the oceans and solid earth and driven primarily by solar radiation, some areas of ocean science, solid earth science, solar physics, and astrophysics are included.

2. Affiliation

A prime mission of CISL is to support atmospheric science at U.S. universities. Eligibility has been extended to include certain other U.S. educational institutions and non-profit research organizations. Eligible researchers incur no costs for the use of CISL resources. CISL normally does not support research groups in federal agencies.

3. Sponsorship


NSF grants

Researchers can apply for an allocation of NCAR computing time under an associated NSF grant as long as their proposed computing lies appropriately within the scope of the grant. The NSF is kept informed to ensure appropriate use of CISL resources.

Resources for unsponsored graduate students, postdocs, and new faculty

Qualifying graduate students, postdocs, and new faculty can request a one-time NCAR computing allocation. This is to allow access to modeling with a supercomputer in support of their graduate student research and to provide seed grants for postdocs and new faculty in support of work leading to funded and sponsored research.

The funding supporting these allocations must be from an NSF fellowship (not a standard grant) or a non-government source such as a university or non-profit. The work must be the individual's own research project rather than a project assigned by the institution that is hosting the postdoc or grad student.

Other requirements for graduate student, postdoc, or faculty allocations are:

  • The applicants must work in the atmospheric sciences;
  • Their work does not lie within the scope of an associated NSF grant; and
  • They do not have funding to pay for computer time.

Each request must be accompanied by a letter from the advisor or department head commenting on the importance and quality of the proposed research and affirming that funds are not available to support the work.

Non-NSF funding

Due to high demand for CISL resources at this time, CISL is unable to provide computing support to atmospheric scientists who have funding solely from non-NSF sources. The University of Wyoming allocation opportunity has eligibility criteria that permit funding by sources other than NSF.