Spatial and temporal variation of phenological growing season and climate change impacts in temperate eastern China

Abstract

Using phenological and normalized difference vegetation index (NDVI) data from 1982 to 1993 at seven sample stations in temperate eastern China, we calculated the cumulative frequency of leaf unfolding and leaf coloration dates for deciduous species every 5 days throughout the study period. Then, we determined the growing season beginning and end dates by computing times when 50% of the species had undergone leaf unfolding and leaf coloration for each station year. Next, we used these beginning and end dates of the growing season as time markers to determine corresponding threshold NDVI values on NDVI curves for the pixels overlaying phenological stations. Based on a cluster analysis, we determined extrapolation areas for each phenological station in every year, and then implemented the spatial extrapolation of growing season parameters from the seven sample stations to all possible meteorological stations in the study area.Results show that spatial patterns of growing season beginning and end dates correlate significantly with spatial patterns of mean air temperatures in spring and autumn, respectively. Contrasting with results from similar studies in Europe and North America, our study suggests that there is a significant delay in leaf coloration dates, along with a less pronounced advance of leaf unfolding dates in different latitudinal zones and the whole area from 1982 to 1993. The growing season has been extended by 1.4-3.6 days per year in the northern zones and by 1.4 days per year across the entire study area on average. The apparent delay in growing season end dates is associated with regional cooling from late spring to summer, while the insignificant advancement in beginning dates corresponds to inconsistent temperature trend changes from late winter to spring. On an interannual basis, growing season beginning and end dates correlate negatively with mean air temperatures from

Deriving a light use efficiency model from eddy covariance flux data for predicting daily gross primary production across biomes

“…Some authors have also stressed the role of soil temperature as the prime factor determining the timing of the onset of boreal, deciduous forests and temperate conifer photosynthesis (Schwarz et al, 1997;Jarvis and Linder, 2000;Baldocchi et al, 2005). Chen et al (2005) found that the spatial patterns of beginning and end dates of growing season correlated significantly with the spatial patterns of mean air temperatures in spring and autumn, respectively, in temperate eastern China, and temperature during the growing season usually did not reach the level that incurred strong negative temperature effects on photosynthesis. In our study, temperature index had little impact on GPP during the growing season, in agreement with field observations (Polley et al, 1992;Bassow and Bazzaz, 1998).…”

Trends of the thermal growing season in China, 1951–2007

“…Zheng et al (2002) showed that the response of phenophase advance (or delay) to temperature change was nonlinear, and that phenophase advance differs between northern and southern China. Similarly, by combining NDVI and meteorological data in temperate eastern China from 1983 to 1992, Chen et al (2005) found that the GS was extended by 1.4-3.6 days/year north of 32°N, but shorter south of that latitude. Schwartz and Chen (2002) noted no apparent change in the onset of spring growth in China over the period .…”

Advances in first bloom dates and increased occurrences of yearly second blooms in eastern China since the 1960s: further phenological evidence of climate warming

“…Phenological studies by Chinese researchers using remotely sensed data have since confirmed that growing seasons are lengthening by 1.4-3.6 days per year in the north part of eastern China, and by 1.4 days per year across the entire eastern China on average from 1982 to 1993 (Chen et al 2005). Observed phenological data have proved there are different response patterns of Electronic supplementary material The online version of this article (doi:10.1007/s11284-011-0830-7) contains supplementary material, which is available to authorized users.…”