[Analysis of vegetation dynamics over Liaoning province based on remote sensing data].

In the present paper, the authors used normalized difference vegetation index (NDVI) data derived from NOAA AVHRR sensor to analyze spatial heterogeneity and temporal dynamics of Liaoning province during the past two decades. A set of 2 292 spatially distributed NDVI values were analyzed to investigate obvious deviations by the mean-monthly values from 1982 to 2001. Various statistical analyses including minimum, mean and maximum values, coefficient of variation (CV), standardized anomalies (Z-scores), and 36-month running mean were used for monthly NDVI values to research spatial and temporal variations in vegetation. In Liaoning province, the authors found the strong seasonal oscillations during plants growing period, the maximum value of NDVI appeared in July-August, and seasonal variation ranged from 6% to 14% of CV value. Vegetation greenness kept upward trend from 1984 to 1990, but showed downward trend from 1991 to 1998. Vegetation greenness followed an interannual oscillation period of 7-8 years. The authors also found that the variation of NDVI peak along latitude direction was 20%-25% greater in 1991-1999 than in 1982-1990 in dry season across Liaoning province. The conclusions of this paper suggest that the patterns of vegetation variability in Liaoning province were caused by enhanced aridity occurring over the last decade of the 20th century.