U.S. and global in situ datasets for the analysis of climate variability and change

Attention to the issue of human-induced climate change has never been greater, resulting in even greater reliance on observational data by numerous and diverse groups in attempts to determine the extent to which the Earth's climate has, and continues, to change. NOAA's National Climatic Data Center (NCDC) has been the source of many in situ data sets used to assess global and regional climate change in reports such as the 2009 report on Global Climate Change Impacts on the United States and the Intergovernmental Panel on Climate Change Fourth Assessment Report which was released in 2007. Ongoing efforts at NCDC to enhance the quality and size of U.S. and global climate data sets for climate change research have resulted in improvements in several in situ data sets that are essential to continued growth in climate change science. These data sets support ongoing climate monitoring efforts and, along with others from the international community, are expected to make essential contributions to future national and international climate change studies. This presentation provides an overview of recent improvements to the Global Historical Climatology Network-Monthly (GHCN-M), Global Historical Climatology Network-Daily (GHCN-D), the US Historical Climatology Network-Version 2 Monthly (USHCN-V2m), and U.S. Hourly Precipitation Data (HPD) data sets. The global data sets contain records for as many as 45,000 stations with observations from the 1800s through the present. While temperature and precipitation data are provided by the greatest number of stations, snowfall and snow depth data are also included for thousands of stations. Recent advances in quality control processes and adjustment algorithms for removing artificial changes (inhomogeneities) in the US. and global temperature record also have greatly improved the overall quality of these data. In addition to an overview of the recent advances in these data sets, the application of GHCN-D data for the analysis of global hazards is included as an example of new uses for these data in the study of climate change.