Past and Current Research Locations
Select Research Projects - Past and Present
View NASA HyspIRI California Airborne Campaign Sites in a larger map
Fig 1. From Serbin et al., (2012). Variation in nutritional, morphological, and metabolic leaf traits for trembling aspen (white boxes) and eastern cottonwood (grey boxes), summarized by night- time/daytime glasshouse temperatures. Traits are nitrogen concentration (Nmass, %), leaf mass per area (Marea, g m-2), and maximum rates of RuBP carboxylation (Vcmax, umol m-2 s-1) and regeneration (Jmax, umol m-2 s-1). The box plots display the median for each trait by group (dark horizontal line), the interquartile range (IRQ, boxes), the range (whiskers), and the extreme observations (black dots).
Fig 2. From Serbin et al., (2012). The observed versus predicted values from the final PLS leave-one-out (LOO) cross-validation procedure for glasshouse leaf Nmass, Marea, Vcmax, and regeneration Jmax. Note that the color scale for Nmass (a) depicts corresponding variation in Marea, while those for Marea (b), Vcmax (c), and Jmax (d) depict variation in Nmass. Each plot has a total of 53 observations and the symbols correspond to the three temperate regimes.
NASA HyspIRI California Airborne Campaign
(2013 - Present)
Description: Using the ER-2 flight transects for the ongoing 2013-2014 NASA HyspIRI California Airborne field campaign we are comprehensively assessing the potential to make spatially explicit estimates of two important parameters characterizing leaf and canopy photosynthetic capacity: the maximum rate of CO2 carboxylation by RuBisCo (Vcmax), and the maximum rate of electron transport required for the regeneration of RuBP needed in Calvin Cycle processes (Jmax). These variables are typically determined using measures of leaf gas exchange, but we have identified an approach to estimate Vcmax and Jmax using reflectance spectroscopy (Ainsworth et al., 2013; Serbin et al., 2012). The project relies on the simultaneous acquisition of hyperspectral and thermal infrared imagery, as estimates of canopy temperature will be crucial for an accurate characterization of Vcmax and Jmax . The research is being conducted across two climate-elevation gradients in California (see map), and spans a vegetation gradient from coastal sage and chaparral to oak woodlands and closed-canopy conifer forests, as well as key agro-ecosystems in the Central and Coachella Valleys. The resulting estimates of Vcmax and Jmax are being evaluated against those derived from eddy flux-based observations of gross primary productivity (GPP). If successful, this activity will demonstrate a unique capacity of the proposed HyspIRI mission. This research specifically addresses three HyspIRI science questions:
VQ2. Ecosystem Function, Physiology and Seasonal Activity;
VQ3. Biogeochemical Cycles; and especially
CQ4. Ecosystem Function and Diversity.
NASA HyspIRI: http://hyspiri.jpl.nasa.gov/
NASA AVIRIS: http://aviris.jpl.nasa.gov/
Fig 1. From Serbin et al., (2009). Daily FIPAR from the 1994 burn site during the 2006 growing season. Fitted line is the phenological trajectory for this site.
Fig 2. From Serbin et al., (2009). Seasonal patterns in the overstory and understory plant area index (Le) for the chronosequence sites. Error bars represent the standard error of the site mean (combined well- and poorly-drained stands). Bars with similar lettering at not significantly different at the a = 0.05 level.
Fig 3. From Serbin et al., (2013). Post-fire photographs from the 2003 wildfire study site one year following fire (A) and two years post-fire (B & C) illustrating the degree of fire severity and the patchiness of the herbaceous layer recovery. Pre- and post-fire MODIS MOD09 red reflectance, NIR reflectance, and NDVI seasonal trajectories, with the pre-fire and post-fire NDVI trends superimposed (green line) to highlight the quasi-stable maximum pre-fire values as well as the rapid recovery in NDVI following the fire.
NASA MODIS Validation Project
(2004 - 2007)
Description: Info forthcoming
Remote Sensing of Environment (2013)
Agricultural and Forest Meteorology (2009)
Remote Sensing of Environment (2008)
Fig 4. From Serbin et al., (2013). Comparisons between the MODIS C4 and C5 FPAR seasonal trajectories and in situ FPAR during the 2006 growing season. The gray shaded area represents the ±one standard deviation of the mean LI-191SA daily FPAR values, while the vertical bars represent the ±one standard deviation of the mean LAI-2000 or MODIS FPAR values for each period. Note that the LAI-2000 values represent the transect means (±one standard deviation) for each measurement period.
Fig 5. From Serbin et al., (2013). The seasonal pattern of MODIS C4 and C5 LAI compared to observed values for years 2005 and 2006. Note the MODIS data are averaged by year and compositing period. The error bars represent the ±one standard deviation of the mean MODIS or in situ LAI observation during the composite period.