Journal of Geographical Sciences ›› 2014, Vol. 24 ›› Issue (4): 579-592.doi: 10.1007/s11442-014-1107-1

• Research Articles •     Next Articles

Estimation of diffuse photosynthetically active radiation and the spatiotemporal variation analysis in China from 1981 to 2010

Xiaoli REN1,2(), Honglin HE1, Li ZHANG1,*(), Guirui YU1   

  1. 1. Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, CAS, Beijing 100101, China
    2. University of Chinese Academy of Sciences, Beijing 100049, China
  • Received:2013-12-20 Accepted:2014-01-27 Online:2014-04-20 Published:2015-07-09
  • Contact: Li ZHANG E-mail:xlren_lydia@hotmail.com;li.zhang@igsnrr.ac.cn
  • About author:

    Author: Ren Xiaoli (1984-), PhD, E-mail: xlren_lydia@hotmail.com

  • Supported by:
    Research on the key technology of effectiveness evaluation and standardized construction of National Nature Reserve, No.201209028.“Strategic Priority Research Program-Climate Change: Carbon Budget and Relevant Issues” of the Chinese Academy of Sciences, No.XDA05050600.Key Projects in the National Science & Technology Pillar Program during the Twelve Five-year Plan Period, No.2013BAC03B03

Abstract:

Photosynthetically active radiation (PAR) is the energy source of plant photosynthesis, and the diffuse component can enhance canopy light use efficiency, thereby increasing the carbon uptake. Therefore, diffuse PAR is an important driving factor of ecosystem productivity models. In this study, we estimated the diffuse PAR of over 700 meteorological sites in China from 1981 to 2010 using an empirical model based on observational data from Chinese Ecosystem Research Network (CERN) and China Meteorology Administration. Then we derived the spatial data set of 10 km monthly diffuse PAR using ANUSPLIN software, and analyzed the spatiotemporal variation characteristics of diffuse PAR through GIS and trend analysis techniques. The results showed that: (1) The spatial patterns of annual average diffuse PAR during 1981-2010 are heterogeneous across China, lower in the northeast and higher in the west and south. The nationwide average value for 30 years ranges from 6.66 mol m-2 d-1 to 15.27 mol m-2 d-1, and the value in summer is the biggest while the value in winter is the smallest. (2) There is an evident increasing trend of annual diffuse PAR during recent 30 years, with the increasing amplitude at 0.03 mol m-2 d-1/10a. But a significant declining trend is shown in the first 10 years, and obvious anomalies can be seen in 1982, 1983, 1991 and 1992. And there is a downtrend in spring and an uptrend in all the other seasons. (3) The spatial distribution of temporal variation rates of diffuse PAR is inhomogeneous across the country, generally decreasing in the north and increasing in the south.

Key words: photosynthetically active radiation (PAR), diffuse fraction, diffuse PAR, spatiotemporal variations