We are pleased to release a major revision to the USGS National Climate Change Viewer (NCCV). The NCCV includes the historical (1950-2005) and future (2006-2099) climate and water balance projections derived from 20 downscaled CMIP5 climate models for the RCP4.5 and RCP8.5 emissions scenarios.
The major changes to the application are:
- We replaced the NASA NEX-DCP30 data set with the MACAv2-METDATA, which is based on more advanced methods of bias correction (Abatzoglou, J. T., 2011) and downscaling (Abatzoglou, J.T. and Brown T.J., 2012). Previous work (Alder & Hostetler, 2019) recommended MACAv2-METDATA due to its underlying use of dynamic PRISM temperature lapse rates, especially in high-elevation and snow-dominated regions. The MACAv2-METDATA are on a 4 km by 4 km grid over the contiguous U.S. (CONUS). Twenty Global Climate Models (GCMs) are included in the MACAv2-METDATA.
- We used air temperature and precipitation from the 20 CMIP5 models as input to our simple water-balance model to simulate changes in the surface water balance from 1950 through 2099 on the 4 km CONUS grid.
- The NCCV allows users to visualize projected changes in climate (maximum and minimum air temperature, precipitation, vapor pressure deficit) and the water balance (snow water equivalent, runoff, soil water storage, and evaporative deficit) for any state, county and USGS Hydrologic Units (HUC4 and HUC8) using a variety of graphics and tools.
- We provide monthly time series and averages for the historical period (1981-2010) and four future time periods (2025-2049, 2050-2074, and 2075-2099).
- As in the previous version, the NCCV provides useful tools for characterizing climate change including maps, climographs (plots of monthly averages), histograms that show the distribution or spread of the model simulations, time series plots, and tables that summarize projected changes. The application also provides access to comprehensive, summary reports in PDF format and CSV files for the climate and water balance variables for each geographic area.
- In addition to monthly and annual averages, the application now displays seasonal averages (Winter: December, January, February; Spring: March, April, May; Summer: June, July, August; Fall: September, October, November).
- Statistical significance of future changes for each region are added to the data table and model agreement charts.
- The new downloadable PDF reports include national and regional maps for each variable and scenario. The climatology and time series plots in the PDF reports have been expanded.
Erratum: A coding error was found in the Monthly Water Balance Model (MWBM) that affected the runoff variable in some situations in the previous version of the viewer. This error caused the net water balance not to close (equal zero) in some circumstances. The snow, soil storage, and evaporative deficit variables were not affected. The coding error is corrected in the new version of the viewer.