Seasonal mean daily D-values and their standard deviations are estimated at the 700-mb level (about 10,000 ft above mean sea level) over the northern hemisphere, and presented in maps and tables. Linear interpolation between these data and similar data for sea level, as presented in technical Memorandum 243-54- 51, is then used to estimate seasonal D-values and their standard deviations at the 5000-ft level. (auth)