Wednesday, March 25, 2015

Determining Rayleigh Scatter Lidar Temperatures Using an Optimal Estimation Method

Middle atmosphere temperature profile retrieved using an OEM (red curve) compared to the traditional analysis using 2 detector channels (blue and green curves).
  • A lay summary of the paper is available at the Optical Society of America’s Spotlight on Optics.
We have recently published a paper in Applied Optics detailing a new method for retrieving temperature from Rayleigh lidar measurements using an optimal estimation method (OEM). The OEM allows a full systematic and random uncertainty budget to be done for each retrieval, specifies the height to which the retrieval is insensitive to the a priori temperature profile and gives the vertical resolution of the retrieval as a function of height. The ability to determine the full uncertainty budget is particularly important for using the Rayleigh-lidar temperature measurements for determining long-term changes, particularly for multi-instrument networks like NDACC or GRUAN. The method uses a free community-supported OEM solver developed by P. Eriksson and colleagues (qpack, part of the ARTS retrieval software package). 

We encourage you to try this method, and we are available to help answer your questions as you implement it. 

Bob and Alexander 


Monday, November 10, 2014

Canadian SciSat Finds a Delay in Ozone Recovery from The Globe...





Canadian SciSat Finds a Delay in Ozone Recovery


from The Globe and Mail: Ozone-destroying chemical making comeback


Good news, bad news:


bad news: changes in circulation are causing “old” air with high levels of ozone-destroying hydrogen chloride to persist in the stratosphere, slowing ozone recovery due to CFCs.


good news: the Canadian SCISAT made the measurements that enabled this study, yet another success from this mission. Congratulations to Profs. Kaley Walker, Tom McElroy, Peter Bernath and the SCISAT team.


more on SCISAT from the Canadian Space Agency


via https://dayone.me/10rczmL





Thursday, October 30, 2014

Changing Luminosity in Saturn’s Rings Kudo to Crow Shannon, a...





Changing Luminosity in Saturn’s Rings


Kudo to Crow Shannon, a co-author in a recent study published in Icarus about the changing luminosity of Saturn’s F ring. This exciting research story was recently reported in the LA Times. You can read the article here.


OK Shannon now it is time to go back to the chaos at Echo Base ;-)


Image Credit: NASA/JPL-Caltech/SSI


via https://dayone.me/Ys1zXQ





Monday, August 4, 2014

The Crows at Summer Camp


The Crows at Summer Camp on Flickr.
the young crows recently enjoyed a week at the Connaught Summer Institute in Arctic Science.




Saturday, June 14, 2014

A Vertical Sundial

The photo below shows a new take (for me) on the a sundial, mounted vertically on a building instead of horizontally. You can see from the shadow that is was around noon. Also indicated (I think) are zodiacal positioning, at least that’s what the symbols looked like. And to top it off look carefully and you can see that now only did a Crow snap the picture, a Crow posed in it!


Location: Murtenhof, Mürten, Switzerland