The U.S. global climate observing system (GCOS) program: an update on continuing efforts to implement reference climate observation sites

The U.S. GCOS Program [http://www.ncdc.noaa.gov/oa/usgcos/index.htm] at NOAA's National Climatic Data Center (NCDC) is involved in implementing a sustainable and robust GCOS observing network for international atmospheric, oceanographic, and terrestrial climate observing. U.S. GCOS support is provided in a three-tiered approach involving a series of international, regional, and bi-lateral projects. The support for GCOS in developing nations fits in with plans for possibly extending the capability of the U.S. Climate Reference Network (USCRN) [http://www.ncdc.noaa.gov/crn] into a larger effort for establishing an international surface reference monitoring effort aligned with GCOS. Finally, the U.S. GCOS Program is a prime sponsor of a new reference observing activity for upper air observations in a developing system known as the GCOS Reference Upper Air Network (GRUAN). GRUAN planning is progressing on a global scale, and from a U.S. standpoint, a total of 7 candidate sites will potentially contribute to the overall GRUAN effort [see http://www.gruan.org] and an update on activities here will be included as well.

The first Synthesis and Assessment product produced by the U.S. Global Climate Research Program, Product 1.1. Temperature Trends in the Lower Atmosphere: Steps for Understanding and Reconciling Differences, April 2006, has specific recommendations related to GCOS with particular emphasis on the need for reference climate observing sites. That report is posted at http://www.climatescience.gov/Library/sap/sap1-1/finalreport/default.htm NCDC is interested in developing partnerships for installing a network of USCRN sites which could be used as part of a global long-term climate reference network to be used in data sparse high elevation and high latitude locations (e.g., the American Cordillera, Arctic, and Antarctic regions). The scope of this extension will depend on the availability of resources for sustained maintenance and operations. In concert with the International Polar Year (IPY), in August 2009 a CRN site was installed in Tiksi, Russia, in concert with the IPY's International Arctic Systems for Observing the Atmosphere project. Data from the Southern Hemisphere, high elevation, and tropical sites are also critically important, so locations in the Antarctic, isolated island locations in the Southern Ocean, high elevation glacier locations in South America, as well as tropical research stations operated by the Smithsonian Institution are sought as additional possible sites. The goal is to partner with other national meteorological services and agencies in these areas that can assist with on-going maintenance and operations expenses.