1. Passive Microwave Data @ Report to the Polar DAAC Advisory Group PoDAG XXII, June 2-4, 2004 Boulder, CO

2. Overview Material originally compiled in response to a request from Waleed to host a workshop. This presentation is intended to provide a summary of activities and share information that may be used for future planning and decision making.

3. Activities Undertook two primary activities to gather information for the workshop:  Development of a bibliography  Statistics to determine how many users and what products were accessed

4. Bibliography Conducted a limited search and compiled results from 2 different databases (Engineering Village 2 and Web of Science) 545 citations were returned All names contained in a reference were compared to user list. If at least one name appeared on our list, the reference was categorized as a 'yes' for NSIDC User. The user list used for comparison totaled 1488 individuals 434 citations or 80% were identified as NSIDC Users

5. Summary: Bibliography The bibliography can be a useful indication of usage of data sets and be a useful product for the user community The bibliography in this presentation is only partial based on two reference search services It is time consuming and resource intensive to compile and maintain

6. Products NSIDC NASATeam (NNT) & NSIDC Bootstrap (NBT) DMSP Daily and Monthly Sea Ice Concentrations http://nsidc.org/data/nsidc-0002.html GSFC NASATeam (GNT) Sea Ice Concentrations from Nimbus-7 SMMR and DMSP SSM/I Passive Microwave http://nsidc.org/data/nsidc-0051.html GSFC Bootstrap (GBT) Bootstrap Sea Ice Concentrations from Nimbus-7 SMMR and DMSP SSM/I http://nsidc.org/data/nsidc-0079.html

7. Products and Distribution Methods NNT & NBT Sea Ice  Pre-packaged CD-ROMs o Can determine how many users and who they are o Can't determine which algorithm used  Switched to FTP o Can determine which algorithms, # hosts, # of files and volume distributed o Can't determine how many users or who they are

8. Products and Distribution Methods GBT Sea Ice  Distributed via FTP only o Can determine algorithm, # hosts, # of files and volume distributed o Can't determine how many users or who they are GNT Sea Ice  Distributed on CD-ROM only o Can determine algorithm used o Can determine how many users and who they are

9. User Statistics: Data Request Tracking System Based on data request tracking system ( does not incorporate ftp logs ):  1376 individual users  1605 requests (including subscriptions)  Tb data requests o 490 users, 575 requests  Sea Ice data requests o 965 users, 1323 requests o Not possible to identify algorithm used

10. User Statistics: FTP The following chart illustrates the total number of files and volume of all of the passive microwave products by fiscal year Number of files and volume affected by how the data are organized and whether or not compressed. Different data sets organized differently over time Shows a steady increase due to updates, transition in distribution methods (CD to FTP) and new products released

11. Total Files 391,163 Total Mbytes 180,889

12. Statistics: FTP The following chart illustrates a comparison of FTP statistics for the NSIDC-produced sea ice products with the GBT sea ice data for the period April 2001 - February 2004 GNT data were distributed on CD-ROM during this time period and had 77 requests for the data set, 210 in total since the product was released The larger number of files distributed associated with the NNT algorithm is attributed to differences in the way the data are organized.

13. There were 77 requests for the GNT CD-ROMs during this time period.

14. Summary: Digital Data Our conclusion is that there is fairly evenly distributed use of the four products by the user community based on the information that we have available

15. Summary: Digital Data It is difficult to determine access to the data based on algorithm because of differing or changing distribution methods It is difficult to distinguish between products, though we have recently implemented a system that should make it easier to report in the future