1-, 3-, 5-, and 7-day periods of extreme high dry-bulb temperature and enthalpy

摘要

Data are presented and comparisons made between single-hour design conditions vs. averages from extreme and near-extreme 1-, 3-, 5- and 7-day periods using 30 years of hourly weather data. Design data examined include dry bulb temperature and enthalpy for 218 U.S. locations. Based upon the average of the 218 locations investigated, it was found that the average temperature for the most extreme 7-day period is within 2.3 deg C of the average dry-bulb temperature of the most extreme 1-day (range: 0.3to 7.3 deg C). The average of the differences for each location between the 0.4 percent single-hour design dry-bulb temperature and the 1-day extreme period was 2 deg C (range: single-hour value 4.1 cooler to 7.4 deg C warmer) and between the 0.4 percent single-hour design dry-bulb temperature and the 7-day extreme period was 4.3 deg C (range: single-hour value 1.1 to 9.7 deg C warmer). The average (over 218 stations) of the difference between the 0.4 percent single-hour design dry-bulb temperature values and the 2 percent hottest one-day periods was 6.7 deg C (range 2.4 to 10.9 deg C). Thus 98 percent of the 1 day periods fora location can be expected to be at least 6.7 deg C cooler than the 0.4 percent single-hour design dry-bulb temperature value.The most extreme enthalpy 1- and 3-day sequences were more extreme than the 0.4 percent single-hour design enthalpy value by an average of 2.8 and 0.4 kJ/kg respectively (range 10.0 to -3.6 and 9.1 to -8.3).