Research Highlights: August 2018

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Advanced Model Inversion Approach Used to Describe High Latitude Ecosystem Response to Climate Chang

Qingyuan Zhang K.F. Huemmrich. E.M. Middleton D.R Landis

(Biospheric Sciences NASA GSFC)

Figure 1
Inversions of the LVS3 model provide physically-based descriptions of fPARchl, the amount of light absorbed by chlorophyll, from MODIS images. Summertime fPARchl, near Utqiagvik (Barrow), AK shows a greening trend but the ecosystem has not yet reached a tipping point and can still return to its original state.

Name: Qingyuan Zhang, USRA
E-mail: qingyuan.zhang-1@nasa.gov
Phone: 301-614-6672

References:

Technical Description of Figures

Scientific significance, societal relevance, and relationships to future missions:

How are high latitude ecosystems responding to high rates of climate change? Previous work has examined time change in the spectral index NDVI. However, NDVI, particularly for high latitude ecosystems, is affected by a number of non-vegetation factors, including: frequently small solar elevation angles, variations in viewing angles, varying amounts of snow, water, and bare ground cover, and relatively large proportions of non-green materials (e.g., standing dead vegetation) in the canopy. We used inversions of the LVS3 model to provide physically-based descriptions of fAPARchl, the amount of light absorbed by chlorophyll, a descriptor of photosynthetic potential, from MODIS imagery. This approach utilizes spectral information from all MODIS land bands, instead of only two bands used by the NDVI, and explicitly addresses solar and view angles as well as determining water cover, snow cover, and bare ground cover, all factors that affect NDVI. The images show significant differences between NDVI and fAPARchl for the area around Utqiagvik (Barrow), AK.

Summertime fAPARchl shows a general greening trend, with increasing fAPARchl over the period from 2001 to 2014. However, from 2013 to 2014 the fAPARchl dropped from its largest to its smallest value over the study period, indicating that while responding to warming conditions this ecosystem has not yet reached a tipping point and can still return to its original state.


Snowmelt runoff in High Mountain Asia

B. Osmanoglu1, R. Hock2, R. Lammers3, S. Nicholls4, P. Montesano5, A. Prusevich3, D. Grogan3, D. Rounce2, M.J. Jo6, S. Frolking3, C. Neigh1

(1: NASA GSFC, 2: University of Alaska Fairbanks, 3: University of New Hampshire, 4: JCET/UMBC- NASA GSFC, 5: SSAI,NASA GSFC, 6: USRA/GSFC)

Figure 1
Variation of snow melt discharge modeled using the University of New Hampshire Water Balance Model, which is capable of tracking snow and glacier runoff separately. The results not only show the seasonal variation of available snow melt in the rivers, but also how much water is used up-stream.

Name: Batu Osmanoglu, Biospheric Sciences Lab. (618), NASA GSFC
E-mail: batuhan.osmanoglu@nasa.gov
Phone: 301-614-6690

References:

Data Sources:

Technical Description of Figures

Scientific significance, societal relevance, and relationships to future missions:

Through our High Mountain Asia (HMA) project, we study the region in a wholistic pattern to better understand the dynamics of HMA glaciers, and how a changing climate will impact the downstream regions that are dependent on the glacier and snowmelt runoff. Through this effort we can model what the water availability in the future will be like, and how it will impact the agricultural activities downstream. Our preliminary results indicate an increase in water availability up to year 2050 or so, after which the water resources become less available due to reduced glacier area.