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GIScCE. 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

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slide1
GIScCE

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?

slide2
GIScCE

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.

slide3
GIScCE
  • Some Useful Distinctions
  • Phenology has traditional been linked to species
  • Land Surface Phenologies (LSPs) are the seasonalspatio-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
slide4
GIScCE

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 34:L101701

slide5
GIScCE

What are key challenges?

  • Multiplicity of Methods + Multiplicity of Targets = Confusion

The nomenclature void must be addressed !

  • Land Surface Phenology Variable Intercomparison Projectinitiated 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?MAUP=modifiable 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)
slide6
Changes in LSP following the collapse of the Soviet Union are not uniform across Kazakhstan (de Beurs and Henebry 2004, 2005).
slide7
GIScCE

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

slide8
GIScCE

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

slide9
GIScCE

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

slide10
GIScCE
  • 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.
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