Scientific Theme: Advanced Modeling and Observing Systems

Complementary Research: Faculty Fellows Research
Lidar Remote Sensing and Laser Spectroscopy for Atmospheric Sciences
Xinzhao Chu
Funding: NSF Aeronomy, MRI, and CEDAR Programs
To advance our understanding and knowledge of global atmosphere composition,
temperature, and dynamics, as well as climate change issues, it is essential to develop new
generation lidar remote sensing instruments so that we can acquire crucial atmosphere data
globally to improve atmospheric models and theories. The major efforts of the Chu Research
Group in the last 12 months were spent on the revolution of lidar technology, and two
milestones were reached.
First, a Major Research Instrumentation (MRI) proposal led by Dr. Xinzhao Chu for developing a mobile Feresonance/Rayleigh/Mie
Doppler lidar received all excellent reviews and was funded by the National Science
Foundation MRI program in August 2007. This MRI lidar integrates the state-of-the-art technologies of lasers, novel
laser spectroscopy, advanced electro-optics, and sensors into a single system to produce a powerful and robust tool
with unmatched measurement capability throughout the middle and upper atmosphere. The chirp-free and ditherfree
frequency locking and saturation-free Fe layer resonance result in a bias-free estimate of winds and
temperatures, which is revolutionary for resonance Doppler lidar.
Second, a Consortium of Resonance and Rayleigh Lidars (CRRL) was funded by the National Science Foundation
in August 2006, and Dr. Xinzhao Chu began to establish a national lidar Consortium Technology Center at CIRES,
aiming to consolidate lidar expertise and advance the middle- and upper-atmosphere lidar technology to meet new
science challenges. During the 2006-2007 winter break, Dr. Chu and her team conducted research on novel Dopplerfree
spectroscopy and created new ideas of achieving accurate pulsed-laser frequency calibration for lidar, which
significantly contributed to the MRI proposal. The MRI lidar will be developed for the science community and
become part of the CRRL.
In addition, Dr. Xinzhao Chu received the Faculty Early Career Development (CAREER) award from the National
Science Foundation in April 2007 and is leading her team to study global middle-atmosphere thermal and dynamic
structures using lidar, satellite data, and atmospheric models.
The Chu Research Group recruited one research scientist (Dr. Wentao Huang), three Ph.D. students, one master‘s
student, and one undergraduate student in the last 16 months. Though the team is still very young, they continue to
make good progress. They established a lidar and laser laboratory at CIRES, and established a lidar observatory (T-
2) at NOAA‘s Table Mountain facility in collaboration with Dr. Mike Hardesty (CIRES-NOAA/ESRL) and his
team. Dr. Chu brought a lidar container from Rothera, Antarctica to CU, and it is now residing beside T-2 and will
host the MRI lidar transmitter for future mobile deployment.
The LabView-software-based servo loop and real-time
signal inquiry/processing that the team is developing, if
successful, will significantly improve CRRL lidar frequency
accuracy and stability. Traditionally, lidar system
parameters were not recorded routinely, which put the
measurement accuracy into question. The new computerbased
system will enable automatic control, measurement,
and recording of lidar parameters to improve accuracy and
stability.
With the lidar data collected from Antarctic and equatorial
regions, the Chu Research Group did scientific
investigations on stratospheric gravity waves, polar
stratospheric clouds, polar mesospheric clouds, and middle
atmosphere temperatures. The interesting results obtained
from these studies further motivated the team to develop the
best lidar instruments, make global observations to collect
more data, and conduct further investigations on global
atmosphere composition, thermal structure, and dynamics.
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CU mobile lidar container (front) and lidar
observatory (back) at NOAA Table Mountain.
The container will host the MRI lidar
transmitter.