PARENT SESSION
Poster Session: Human Influences on Landscape and Hydrological Processes

Analyzing Land Cover Change in Kazakhstan: Land Surface Phenology, Climatic Variation, and Sensor Artifacts. ^*DE BEURS, KIRSTEN M. and HENEBRY, GEOFFREY M. , ¹ CALMIT, School of Natural Resources, Lincoln, NE, USA

ABSTRACT- The collapse of the economic and political institutions of the Soviet Union in the early 1990s led to widespread agricultural de-intensification, land abandonment, and decreased grazing pressure. Were the land cover changes in Kazakhstan following independence in 1991 of sufficient magnitude to alter the land surface phenology at resolutions relevant to climate models? To explore this question we used the Pathfinder AVHRR Land (PAL) dataset, which consists of global 10d maximum NDVI composites from 7/1981 to 9/2001 at 8 km resolution. To what extent are the PAL data affected by sensor artifacts that may mask other kinds of change? We evaluated 19 subsets of 1600sq km, one for each ecoregion of Kazakhstan as delineated by the World Wildlife Fund. We pursued two complementary aspects of change analysis: detection of trends within each sensor's tenure and detection of trends and discontinuities across the entire observational period. Seasonal polynomial models of NDVI phenology were developed to relate accumulated growing degree-day with NDVI. Application of the statistical framework to the "Central Asian Southern desert" revealed no significant differences between NOAA-9 and NOAA-14 nor significant trends within the sensor periods. All other ecoregions displayed distinct land surface phenologies which could be explained by a review of available socio-economic literature. The results show that (1) PAL NDVI data can be a credible data source for land cover change research and (2) straightforward parametric and nonparametric statistical methods, when properly implemented, can distinguish variation due to weather and sensors from changes in land surface phenology.

KEY WORDS: institutional change, land cover change, phenology, agroecosystem, central asia