CALIFORNIA INSTITUTE OF TECHNOLOGY
King-Fai Li
DIVISION OF GEOLOGICAL AND PLANETARY SCIENCES
PASADENA, CALIFORNIA 91125 TELEPHONE (626) 395-3992
February 11, 2009
Dear PNAS Editor:
We would like you to consider an article entitled “A 27-day solar cycle in the
middle atmosphere from MLS/Aura measurements” by King-Fai Li, Mao-Chang Liang,
Charles D. Camp and Yuk L. Yung. In this manuscript, we analyzed a 27-day solar cycle
signal in middle atmospheric temperature using recent measurements from the
MLS/AURA observations.
The 11-year solar cycle has been used to test the climate sensitivity of general
circulation models in, e.g., the IPCC 4th Assessment Report. Their effects on climate are
expected to be enhanced in the middle atmosphere via solar heating due to stratospheric
ozone absorption. However, the current data (~50 years) are too short to draw any
statistically significant conclusions. On the other hand, the 27-day solar cycle, although
smaller in amplitude, offers more cycles for better statistics. With the advance in
technology, the 27-day solar cycle signal in the atmosphere can now be observed from
space.
Two new statistical tools were used to test the robustness of the 27-solar cycle
signal in temperature in both space and time. The correlation between the signal and the
solar cycle forcing has been established. Thus we were able to obtain, for the first time, a
two-dimensional temperature response to the 27-day solar cycle. The results certainly
provide a basis for calibrating climate models and have public interests. Furthermore, the
combined statistical approach is novel and will have great potential of applications to
other data analysis.
This submission includes one manuscript and 6 figures. The text of the
manuscript is 5400 words. The figure takes up approximately one and a half pages.
If the paper is accepted, we wish to see it published back to back with a related
paper that is submitted to PNAS, entitled “Quasi 27-day oscillation in the atmosphere as
a tool for calibrating climate models” by Mao-Chang Liang.
We hope that you are willing to consider our manuscript for publication and look
forward to your response.
Sincerely, and for my co-authors,
King-Fai Li
Division of Geological and Planetary Sciences
California Institute of Technology
PASADENA, CALIFORNIA 91125 TELEPHONE (626) 395-3992
CALIFORNIA INSTITUTE OF TECHNOLOGY
King-Fai Li
DIVISION OF GEOLOGICAL AND PLANETARY SCIENCES
PASADENA, CALIFORNIA 91125 TELEPHONE (626) 395-3992
List of three members of the Editorial Board:
Mark H. Thiemens (mthiemens@ucsd.edu)
University of California, San Diego
Christopher B. Field (cfield@ciw.edu)
Carnegie Institution of Washington
James P. Kennett (kennett@geol.ucsb.edu)
University of California, Santa Barbara
List of three NAS members:
J. Mike Wallace (wallace@atmos.washington.edu)
University of Washington
Richard Goody (goody@huarp.harvard.edu)
Harvard University
Susan Solomon (ssolomon@al.noaa.gov)
National Oceanic and Atmospheric Administration
List of potential referees (in alphabetical order):
The response of the atmosphere to solar variability:
Prof. L. J. Gray (forbes@colorado.edu)
Department of Meteorology
University of Reading, UK
Stratospheric response due to solar variability:
Dr. Lon Hood (lon@lpl.arizona.edu)
Lunar and Planetary Lab
University of Arizona
Statistical study of atmospheric variability:
Dr. Alexander Ruzmaikin (Alexander.Ruzmaikin@jpl.nasa.gov)
Jet Propulsion Laboratory
Temperature retrieval of MLS instrument:
Dr. Michael Schwartz (michael@mls.jpl.nasa.gov)
Jet Propulsion Laboratory
Climate change due to solar cycle forcing:
Prof. Ka-Kit Tung (tung@amath.washington.edu)
Department of Applied Mathematics
University of Washington
PASADENA, CALIFORNIA 91125 TELEPHONE (626) 395-3992