Relative increase of record high maximum temperatures compared to record low minimum temperatures in the U.S.
Article first published online: 1 DEC 2009
Copyright 2009 by the American Geophysical Union.
Geophysical Research Letters
Volume 36, Issue 23, December 2009
How to Cite
2009), Relative increase of record high maximum temperatures compared to record low minimum temperatures in the U.S. Geophys. Res. Lett., 36, L23701, doi:10.1029/2009GL040736., , , , and (
- Issue published online: 1 DEC 2009
- Article first published online: 1 DEC 2009
- Manuscript Accepted: 20 OCT 2009
- Manuscript Revised: 13 OCT 2009
- Manuscript Received: 28 AUG 2009
- climate change;
- temperature records;
- global warming
 The current observed value of the ratio of daily record high maximum temperatures to record low minimum temperatures averaged across the U.S. is about two to one. This is because records that were declining uniformly earlier in the 20th century following a decay proportional to 1/n (n being the number of years since the beginning of record keeping) have been declining less slowly for record highs than record lows since the late 1970s. Model simulations of U.S. 20th century climate show a greater ratio of about four to one due to more uniform warming across the U.S. than in observations. Following an A1B emission scenario for the 21st century, the U.S. ratio of record high maximum to record low minimum temperatures is projected to continue to increase, with ratios of about 20 to 1 by mid-century, and roughly 50 to 1 by the end of the century.