Coffee Hour on ICESat-2 | Bacastow appointed to board | Research on ice and fire

IMAGE OF THE WEEK

ICESat-2 image

NASA’s Ice, Cloud and land Elevation Satellite-2 (ICESat-2) was launched in September 2018 and became the highest-resolution laser altimeter ever operated from space. The satellite is now measuring the height of Earth’s surfaces in remarkable detail. A forested hillside in Mexico is visible in the elevation measurement above, acquired on October 19, 2018, by the Advanced Topographic Laser Altimeter System (ATLAS) on ICESat-2. For reference, the orbital path is laid over a natural-color image acquired on January 11, 2017, by the Operational Land Imager (OLI) on Landsat 8. Learn more about ICESat-2 at Coffee Hour on Friday, Sept. 11, with our speaker, Penn State Geography alumna Kaitlin Harbeck.

GOOD NEWS

The undergraduate clubs in the Department of Geography, GIS Coalition, Gamma Theta Upsilon, and UnderDoGS are holding combined meetings on Zoom this semester. The next meeting is on Monday, Sept. 14 at 7:30 p.m.

Alumna Sheryl Kron Larson-Rhodes, who earned a bachelor of science in 1985, received a State University of New York (SUNY) Chancellor’s Award for Excellence in Librarianship. The Chancellor’s Awards are “honors conferred to acknowledge & provide recognition for consistently superior professional achievement & to encourage the ongoing pursuit of excellence.” Larson-Rhodes is among nine librarians from SUNY’s 64 campuses to receive the Chancellor’s Award for the 2019–2020 academic year. She serves as the First Year Experience Librarian at SUNY Geneseo, & among the college departments she supports is (of course!) Geneseo’s Department of Geography, which in 2018 received the Award for Bachelors Program Excellence from the American Association of Geographers.

COFFEE HOUR

Coffee Hour with Kaitlin Harbeck
ICESat2 – Measuring the Height of the Earth One Photon at a Time

NASA’s next generation laser altimeter mission, the Ice, Cloud and Land Elevation Satellite-2 (ICESat-2), launched on 15 September 2018, carrying the Advanced Topographic Laser Altimeter System (ATLAS) as its sole payload. ATLAS is a photon-counting lidar that directs laser beams (532 nm) at the Earth’s surface, fires a stream of light 10,000 times per second, and measures the distance between the illuminated ground surface and the instrument by precisely measuring individual photon times of flight.

NEWS

Bacastow appointed to US Geospatial Intelligence Foundation board of directors

Todd Bacastow, teaching professor in the College of Earth and Mineral Sciences at Penn State, has been appointed to the board of directors of the United States Geospatial Intelligence Foundation (USGIF) for a three-year term.

USGIF is a non-profit organization dedicated to promoting geospatial intelligence training and education and building a stronger community of interest across industry, academia, government, professional organizations and individual stakeholders. Since 2007, Bacastow has also served as a member of USGIF’s Academic Planning Committee.

RECENTLY PUBLISHED

Woody plant diversity changes of Abies-Tsuga forests during the natural regeneration of arrow bamboo (Bashania faberi) in the Wolong Nature Reserve

Zhu, T., Jinyan, H., Dian, L., Taylor, A.H., Hemin, Z.
Chinese Journal of Applied and Environmental Biology
DOI: 10.19675/j.cnki.1006-687x.2019.05002
We examined the response of woody plants to internal forest disturbance during subalpine succession and its underlying driving mechanism by comparing changes in woody plant diversity of Abies-Tsuga forests after the flowering and die-back of arrow bamboo (Bashania faberi). We calculated species diversity indices (a-diversity and β-diversity) for the survey data from six fixed plots in the area of the Wolong Nature Reserve, Sichuan Province, from 1984 and 2013 to understand changes in flora and species diversity over time, including the pro-phases and post-phases of the bamboo regeneration and restoration. The results showed that species and the diversity indices of the trees in the Abies-Tsuga forests did not change significantly before or after the regeneration and restoration of arrow bamboo but maintained relatively stable state (P > 0.05). In contrast, species diversity and the importance values of shrubs changed significantly between the pro-phase and postphase of the regenerative and restorative periods, and the species composition and diversity indices of the Abies-Tsuga forests slightly increased (P < 0.05). Variation was seen in woody plant tree diversity patterns, as changes in the tree species of the sample plots below 3000 m above sea level were small, but a significant change was seen in the sample plots above 3000 m above sea level. In contrast, the diversity of shrubs was significantly different among all plots and showed a slight increasing trend. At the same time, there were no significant differences in the tree species diversity of the Abies-Tsuga forests between different sites before or after the regeneration and restoration of arrow bamboo. Shrubs were significantly different with each other during the early stage. Only several plots and several indices were significantly altered during the later stage, and the rest presented no significantly statistical effects. In a word, these results reflect the stability of the species composition in climax communities, the variability of the species diversity of Abies-Tsuga forests during the process of bamboo regeneration and restoration, and the adaptation of diverse types of plants (e.g., tree species and shrubs) to environmental changes. This provides a basis for developing strategies for biodiversity conservation and the ecological restoration of wild giant panda habitats.

Strong Legacy Effects of Prior Burn Severity on Forest Resilience to a High-Severity Fire.

Harris, L.B., Drury, S.A. & Taylor, A.H.
Ecosystems
https://doi.org/10.1007/s10021-020-00548-x
Legacy effects from one disturbance may influence successional pathways by amplifying or buffering forest regeneration after the next disturbance. We assessed vegetation and tree regeneration in non-serotinous Sierra lodgepole pine (Pinus contorta var. murrayana) stands after a 1984 wildfire which burned with variable severity and again after a high-severity subsequent fire in 2012. The legacy effects of the 1984 fire were amplified; seedlings and saplings were abundant in areas initially burned at low severity (1267 stems ha−1) despite high reburn severity, but regeneration was low in areas twice burned at high severity (31 stems ha−1). Our results suggest that the severity of the 1984 fire may have influenced post-2012 tree regeneration by creating variable fuel loading, which may have affected soils, litter cover and shade after the 2012 fire and therefore affected seedling establishment and survival. A canopy seed bank of unburnt cones from trees killed by the 2012 fire potentially contributed to a strong effect of prior burn severity on regeneration after the 2012 fire despite a lack of serotinous or resprouting tree species, although the influence of this canopy seedbank was likely limited to the year following the fire. Our results suggest that a low- to moderate-severity fire increases forest resilience relative to a high-severity fire even when the next fire burns at high severity.

Quantifying spatiotemporal variability of glacier algal blooms and the impact on surface albedo in southwestern Greenland

Shujie Wang, Marco Tedesco, Patrick Alexander, Min Xu, and Xavier Fettweis
The Cryosphere
https://doi.org/10.5194/tc-14-2687-2020
Albedo reduction due to light-absorbing impurities can substantially enhance ice sheet surface melt by increasing surface absorption of solar energy. Glacier algae have been suggested to play a critical role in darkening the ablation zone in southwestern Greenland. It was very recently found that the Sentinel-3 Ocean and Land Colour Instrument (OLCI) band ratio R709 nmR673 nm can characterize the spatial patterns of glacier algal blooms. However, Sentinel-3 was launched in 2016, and current data are only available over three melting seasons (2016–2019). Here, we demonstrate the capability of the MEdium Resolution Imaging Spectrometer (MERIS) for mapping glacier algae from space and extend the quantification of glacier algal blooms over southwestern Greenland back to the period 2004–2011. Several band ratio indices (MERIS chlorophyll a indices and the impurity index) were computed and compared with each other. The results indicate that the MERIS two-band ratio index (2BDA) R709 nmR665 nm is very effective in capturing the spatial distribution and temporal dynamics of glacier algal growth on bare ice in July and August. We analyzed the interannual (2004–2011) and summer (July–August) trends of algal distribution and found significant seasonal and interannual increases in glacier algae close to the Jakobshavn Isbrae Glacier and along the middle dark zone between the altitudes of 1200 and 1400 m. Using broadband albedo data from the Moderate Resolution Imaging Spectroradiometer (MODIS), we quantified the impact of glacier algal growth on bare ice albedo, finding a significant correlation between algal development and albedo reduction over algae-abundant areas. Our analysis indicates the strong potential for the satellite algal index to be used to reduce bare ice albedo biases in regional climate model simulations.

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