Mar 23, 2020
This tool is an interactive map of the Chesapeake Bay watershed that provides gridded estimates of percent changes in projected future (2011-2099) freeze-thaw days, compared to a modeled historic baseline (1981-2010).
This tool is excerpted from Chesapeake Bay Watershed Climate Impacts Summary and Outlook for Summer 2019.
Selecting time periods and temperature thresholds: To view average annual number of days above various thresholds and periods of time, select 30-year time increments on the right side of the map, as well as three different temperature thresholds and two future greenhouse gas emission scenarios. Hover over a location on the map to see a pop-up window of average annual days above a given threshold for that location.
LOCA or Localized Constructed Analogs is a downscaled climate data product available at 1/16th degree (6 km) resolution over the continental United States. LOCA datasets include the 32 climate models available in the CMIP5 archive, for two future greenhouse gas concentration trajectories—a low emissions future, RCP 4.5,1 and a high emissions future, RCP 8.5.2 For this study, we utilized LOCA data over the Chesapeake Bay watershed from 1981–2100 (or 2099 for some models). Access LOCA datasets and learn more about the methodology.
Extreme high temperature was determined for each year by summing all extreme temperature days (above 90°F, 95°F, 100°F) that occurred in each year. We calculated extreme high temperature days for each year and the averaged values across 30-year periods—1981–2010, 2011–2040, 2041–2070, 2071–2100 for LOCA data for RCP 4.53 and RCP 8.5.4 To average across climate models for each grid cell in the LOCA dataset, we employed a weighted average provided by the Northeast Regional Climate Center. The LOCA datasets were masked to the boundaries of the Chesapeake Bay watershed before calculating extreme high temperature days.