scatterings from the Purple Crow Lidar    About    Archive    Feed

Last Report from the Crow's Nest for now from #agu11. Safe travels homepeeps.


The morning was spend at my own poster. Well, actually the poster is the work of Crow Jaya who was not able to attend. And much of the work’s inspiration was due to Tom McElroy. I quick review of the poster: much of our temperature information in the middle atmosphere comes from measurements by lidars using the Rayleigh scatter technique, e.g. elastic scattering. The standard analysis used since (at least) the 80’s is a top down integration of the lidar returns for temperature. The problem with this method is you have to pick a pressure to start the integration. It turns out you then have to throw out the first 10 to 15 km of your retrieval. To get this 10 to 15 km back would require you to increase the lidar’s sensitivity by 4x, which would typically mean getting laser you couldn’t afford, a telescope you couldn’t afford or both.

We were able to get a non-linear inversion to work which allows the lidar returns to be integrated from the bottom up. The sensitivity to the initial pressure is not quite small, and the returns are useful over the entire height range.

Crow Robin had his poster showing off the capabilities of our system and our new observatory, Echo Base. He put a tremendous amount of work into moving the system and the rest of the team can’t thank him enough!

Ozone 2011 revisited

I did get to set in on Gloria Manney’s talk in the northern hemisphere ozone depletion section tying together the various measurements and meteorology to explain the record lost of Arctic ozone this spring.

It is interesting how this ozone destruction was not due to the temperatures being record cold but to the duration of temperature below the chlorine activation point and intensity of the vortex that caused the large ozone lost.

I also stayed for Rodica Linenmaier’s talk about the [CANDAC] ( measurements. CANDAC operates the Polar Enviroment Atmospheric Research Laboratory (PEARL) in Eureka. She did a great job summarizing the measurements and contrasted them to the 15 years of measurements prior to this winter, again highlighting the importance of supporting long term measurements particularly in the polar regions.

Better go check a few more posters (and remember to pick up mine :–) but I think my fingers are done for AGU 2011.

Use this link to share with your followers or follow me on Twitter!