Month: September 2023

For two weeks in September, we had a visit from Johanna Kranz, a PhD student from TU Dresden. Johanna (3rd from left in the back row, below) is working on the PhenoFeedbacks project under the guidance of J. Prof. Dr. Matthias Forkel. Johanna gave a presentation in the Ecoinformatics seminar, and interacted with faculty and students across campus. She also explored many of our local scenic wonders, including Walnut Canyon, the Grand Canyon, Red Mountain, and Sunset Crater. Before leaving town, Jacob and Jen took Johanna to the Lava River Cave northwest of Flagstaff for a below-ground (non-technical) spelunking adventure. Afterwards, Johanna wrote “Visiting Andrew’s lab was a great experience meeting other PhD students and postdocs and learning more about their different areas of research. I look forward to staying in touch and collaborating in the future!” Thank you for your visit, and your kind words, Johanna!

The Logic Supply 2013 AU140 computer (pictured below) that had been the brains of our Bartlett data collection system for over 10 y was recently the subject of a blog post. Check it out!

Congratulations to SICCS T3 Fellowship and NSF GRFP awardee Natasha Wesely, who passed her Comprehensive Exam on September 13. Andrew, Mariah Carbone (Biological Sciences) and David Auty (School of Forestry, and SICCS affiliate) comprised the examination committee. A Building 7 celebration of the successful defense followed later in the day. The picture shows visiting PhD student Johanna Kranz (TU-Dresden), and lab members Mostafa, Jacob, and Natasha all arriving at the off-campus location, where they were joined by a dozen or more additional friends, colleagues, and a few random interlopers and party-crashers.

Although he couldn’t make the installation trip to California, Andrew recently assembled a solar-powered instrument package that includes a data logger, temperature and relative humidity measurements, a PhenoCam and a cell phone modem. George Koch and Drew Peltier hauled the gear to the top of an 80 m. giant Sequoia (Sequoiadendron giganteum) tree near the famed Mariposa Grove in Yosemite National Park. The installation was completed over two days in mid-September. Andrew hopes to visit the site later this autumn. Near-real-time images are available through the PhenoCam web page.

Former Post-Doc Eric Beamesderfer’s paper, “The role of surface energy fluxes in determining mixing layer heights,” has just been published in the AFM special issue on land-atmosphere interactions. Eric’s study used continuous point-based ceilometer- and radiosonde-derived measurements of MLH at surface flux tower sites to identify the surface influence on MLH dynamics. Mean MLH was the highest at all sites during the summer, while the highest annual mean MLH was found at the warm and dry sites, dominated by high sensible heat fluxes. At daily time scales, surface fluxes of sensible heat, latent heat, and vapor pressure deficit had the largest influence on afternoon MLH. These results highlight the difficulty in using single-point observations to explain MLH dynamics but should encourage the use of ceilometers or similar atmospheric measurements at surface flux sites in future studies.