Some Thoughts on Shifts in Biome Seasonality

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Some Thoughts on Shifts in Biome
Seasonality Geoff Henebry, South Dakota State
University We need to unpack this new phrase
1) Shifts implies an observable baseline
against which to quantify a change and further
implies that the shift is significant 2) Biome
implies an emergent vegetation-climate
association 3) Seasonality implies
quasi-periodic abiotic phenomena
What about phenology?
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Phenology has been defined as the study of the
timing of recurring biological events, the causes
of their timing, their relationship to biotic and
abiotic forces, and the inter-relations among
phases of the same or different species. J.Y.
Ewusie, 1992
Source Ewusie, J.Y. 1992. Phenology in Tropical
Ecology. Accra Ghana Universities Press. 109 pp.
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• Some Useful Distinctions
• Phenology has traditional been linked to species
• Land Surface Phenologies (LSPs) are the seasonal
  spatio-temporal patterns of the vegetated land
  surface as observed by synoptic sensors at
  spatial resolutions and extents relevant to
  meteorological processes in the atmospheric
  boundary layer (de Beurs and Henebry, 2004 RSE
  2005 GCB 2005 IJRS 2008 JClim).
• NASA Community White Paper on Phenology (Friedl
  et al. 2006) describes the concept of LSPs and
  stresses that LSPs are intrinsically mixtures of
  biotic abiotic signals
• Strong latitudinal altitudinal controls on LSPs
• Various shades of LSPs
• Spring-green
• Rain-green
• Ever-green
• Never-green

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• What are some aquatic aspects of
  phenology/seasonality?
• Various shades of aquatic Inland vs. Coastal vs.
  Bluewater
• Inland distinctions wetlands, lakes, reservoirs,
  perennial vs. intermittent streams, rivers
  their floodplains
• Aquatic phenomena Lake ice on/off, onset of
  meltwater flows, flood-pulse events,
  algal/cyanobacterial blooms, ...
• What is common to terrestrial aquatic
  phenologies and/or seasonalities?
• Human modulation (LCLUC, ag mgmt, pollution,
  invasive introduced species, etc.)
• Atmospheric modulation (ENSO, NAM, PDO, etc.)
• Solar modulation?

Kryjov, VN, and C-K Park. 2007. Solar modulation
of the El Niño/Southern Oscillation impact on the
Northern Hemisphere annular mode. GRL 34L101701
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• What are key challenges?
• Multiplicity of Methods Multiplicity of
  Targets Confusion
• The nomenclature void must be addressed !
• Land Surface Phenology Variable Intercomparison
  Project initiated by Mike White, USU, and Kirsten
  de Beurs, VT, at 2007 AGU phenology sessions.

• What are appropriate spatial units for
  characterizing phenology/seasonality? Pixels?
  Ecoregions? Ad-hoc units? MAUPmodifiable areal
  unit problem
• What are appropriate temporal units for
  characterizing phenology/seasonality? Calendar
  time? Compositing periods? Thermal time?
• What are appropriate methods to characterize
  shifts and assess their significance? Step
  changes vs. Trends (accumulations of
  insignificant changes)

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Changes in LSP following the collapse of the
Soviet Union are not uniform across Kazakhstan
(de Beurs and Henebry 2004, 2005).
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CENTRAL ASIA Trends in MODIS NBAR NDVI (C4
CMG) 2001-2006 DOY 65-241 Revealed using
the Seasonal Mann-Kendall nonparametric trend
test corrected for autocorrelation (de Beurs and
Henebry 2004 GRSL) Red SMK lt
0 Green SMK gt 0 Blue mean NDVI
White Countries Blue Rivers Yellow Coastlines
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CENTRAL ASIA Trends in MODIS NBAR NDVI (C4
CMG) 2001-2006 DOY 65-241 Revealed using
the Seasonal Mann-Kendall nonparametric trend
test corrected for autocorrelation (de Beurs and
Henebry 2004 GRSL) Red SMK lt
0 Green p le 0.01 Blue mean NDVI
White Countries Blue Rivers Brown Coastlines
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CIRCUM-POLAR Trends in MODIS NBAR NDVI (C4
CMG) 2000-2006 DOY 97-257 Red
1-(p le 0.01) Green mean NDVI ge 0.1 Blue
SMK trend test gt 0
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• Significant opportunities for the research theme
• Shifts in Biome Seasonality
• Blending of datastreams from multiple
  sensors/platforms
• Active microwave
• Passive microwave
• Thermal and mid-IR (3-5 ?m)
• Geostationary optical
• Polar orbiting optical
• to develop a comprehensive suite for
  characterizing land surface phenologies
  seasonalities in different biomes/ecoregions.
• Useful for monitoring, change analysis, impacts
  assessment, modeling (carbon, water, nutrients,
  weather, climate, land use, habitat,), and
  ecological forecasting.