Site classifications, definitions, and updates to Landnet K. Thome NASA WGCV Plenary # 44 EUMETSAT, Darmstadt, Germany August 28-31, 2018

Historical Background - Need for Global, Integrated Network of Calibration Sites User communities were increasingly relying on information products from multiple satellite sensors Better calibration should result from more post launch calibration, involving standardized measurement protocols, instrumentation, and processing Field measurements are resource-intensive activities Less expensive complementary approaches should provide more frequent calibration updates and enable the monitoring of sensor performance trends, even without surface measurements

Historical Background The effort led to the concept of a web-based test- site catalog - Landnet

Historical Background Effort was made to: Agree scope of Test site definition Identify characteristics of sensors which can benefit from test sites Agree desirable list of site characteristics/descriptors Define key “classification characteristics” (discriminators) per application First pass review to classify real sites Discussion on implementation, maintenance, review Resulting catalog Provided a list of prime candidate terrestrial targets for consideration as benchmark sites for the post-launch radiometric calibration of space-based optical sensors Online test site catalog provided public Web site access Incompleteness of available information on prime test sites indicated more coordination and documentation were needed

Historical Background Future Plan for Landnet was: Refine the selection of recommended primary sites Establish traceability chain for primary site data Gather complete site characterization data and information Acquire and archive imagery of all primary sites –this was done well Define core measurements (eg. Instruments) Develop online calibration data access infrastructure – came close Develop guidelines and establish endorsements mechanisms for meeting calibration standards Endorse and advocate compliance with calibration standards Difficulties encountered achieving all of these plans Never clearly defined a mechanism to update the site list

More history – At WGCV-42 we discussed what to do with Landnet Improve definitions of the purpose of Landnet Opted to try and use the RadCalNet Admission Panel to help evaluate Landnet status on a yearly basis Identify sites that are no longer active Yearly email to site administrator receives no response No published results within a three-year period Evaluate proposals from sites wanting to be added to LandNet Five years of demonstrated use for a single application or sensor Use of site for a minimum of three sensors, one of which provides globally-available products

CEOS activities since WGCV-42 point toward including other factors in how we address Landnet Original Landnet sites are now not useful for the community Users want sites with more widely available data collected on more regular schedules Sites with multiple applications preferred by satellite sensor teams Push for interoperable and analysis ready data sets is increasing the importance of test sites Numbers of sites and uses continues to expand and maintaining a comprehensive and current list may not be feasible at WGCV level Concept of a test site is changing Not necessarily a well defined geographic location May not be in the same location over time Cross-calibration techniques are defining sites based on joint acquisitions

Propose a WGCV Test Site list Supersite discussion between LPV and IVOS after WGCV-43 shows that there are common features to test sites allowing a single site collecting many of the sites Create a website entry point at WGCV level that lists several key WGCV test sites General purpose description of how site is used, its location, and links to more detail Sites would be representative of types and purposes for cal/val Content would be aimed towards data product users, project managers, satellite conops teams Links would point cal/val experts to information more suitable to their interests Crude example shown on following page

Established traceability chain Online calibration data access WGCV test sites are used for activities ranging from sensor calibration to data product validation. The table below lists a range of representative sites currently in use that meet key features of WGCV test sties: Established traceability chain Online calibration data access Compliance with calibration standards Each of WGCV’s subgroups maintains a list of sites meeting the above and specific to each group’s activities. Detailed descriptions of the sites, measurements at the sites, and access to data archives can be found at the links in the table. Test site label Center coordin ate Key site propertties Primary purpose Secondary purposes More detailed description Railroad Valley 38.5 N 115.7 W High reflectance bare soil surface at high elevation, low aerosol loading Radiometric calibration Surface reflectance validation www.ivos_sites.org

Raises multiple questions Does WGCV push the responsibility of maintaining a website list of test sites to the subgroups? Would hierarchy of a WGCV website be test site centric or application centric? Table listed by test site names or by usage? Does WGCV wish to continue Landnet or reboot/restart the concept within a broader WGCV test site concept? Path forward should lead to a revised test site list by WGCV-45 regardless of what path we choose Is there a clear next step to continue moving this effort forward? Responsible party? Priority of test site list versus other WGCV/subgroup web updates