CLAD Call for U.S. Critical Loads and Supporting Data

CLAD accepts data submissions at any time, and submissions can be made using the information provided under the Data Submission section. The last official Call for Data occurred in 2014-2015, and much of the description on this page refers back to that official call.


The Critical Load of Atmospheric Deposition Science Committee (CLAD) welcomes the announcement of 2014-2015 U. S. Critical Load Call for Data and asks you to submit new or updated critical load data and supporting information to the National Critical Load Database (NCLD). We also ask that you share this announcement with new scientists working in the field of critical loads who may not be members of CLAD.

Types of Critical Loads

The current national database contains

  • surface water critical loads of acidity
  • critical loads of acidity for forested ecosystems
  • empirical critical loads of nitrogen

This 2014-15 U.S. Call for Data seeks to update and add to the existing data for these critical loads. In addition, CLAD is seeking information to support two additional critical loads in the database:

  • surface water critical loads for nutrient enrichment
  • nutrient nitrogen critical loads for forested ecosystems

While data that is national in scope is desired, regional critical load information is also welcome.

Data Submission

Critical load data and supporting information can be submitted using the Excel file CLAD_CL_Data_10-1-2014.xlsx. This file includes instructions and separate tables for the various types of critical loads. The variables contained in each table are listed on the following pages. It is expected that submissions will include a completed Table 1, Site Info, in addition to the appropriate table for the specific critical load of interest. Contributors are welcome to add columns for new variables as needed.

To submit critical load data, please e-mail data files to If a file is too large for e-mail, data files can be uploaded to the Call-for-data folder on the NADP-University of Illinois Box file sharing account. Jason Lynch will provide instructions on request.

Data submission is always welcome and we encourage you to participate in this effort and submit your critical loads to the national database.

Downloadable files

Announcement and Metadata Description
Submission File (CLAD_CL_Data_10-1-2014.xlsx)

For more information:

Please contact Jason Lynch if you have any questions.

Jason Lynch
NCLD Manager