Impacts of diffuse radiation on light use efficiency across terrestrial ecosystems based on Eddy covariance observation in China.
Ecosystem light use efficiency (LUE) is a key factor of production models for gross primary production (GPP) predictions. Previous studies revealed that ecosystem LUE could be significantly enhanced by an increase on diffuse radiation. Under large spatial heterogeneity and increasing annual diffuse radiation in China, eddy covariance flux data at 6 sites across different ecosystems from 2003 to 2007 were used to investigate the impacts of diffuse radiation indicated by the cloudiness index (CI) on ecosystem LUE in grassland and forest ecosystems. Our results showed that the ecosystem LUE at the six sites was significantly correlated with the cloudiness variation (0.24 ≤ R(2) ≤ 0.85), especially at the Changbaishan temperate forest ecosystem (R(2) = 0.85). Meanwhile, the CI values appeared more frequently between 0.8 and 1.0 in two subtropical forest ecosystems (Qianyanzhou and Dinghushan) and were much larger than those in temperate ecosystems. Besides, cloudiness thresholds which were favorable for enhancing ecosystem carbon sequestration existed at the three forest sites, respectively. Our research confirmed that the ecosystem LUE at the six sites in China was positively responsive to the diffuse radiation, and the cloudiness index could be used as an environmental regulator for LUE modeling in regional GPP prediction.
Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China.
Kun
K
Huang
Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China.
Shaoqiang
S
Wang
Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China.
Lei
L
Zhou
Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China.
Huimin
H
Wang
Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China.
Junhui
J
Zhang
South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China.
Junhua
J
Yan
Northwest Plateau Institute of Biology, Chinese Academy of Sciences, Xining 810001, China.
Liang
L
Zhao
University of Chinese Academy of Sciences, Beijing 100049, China.
Yanfen
Y
Wang
Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China.
Peili
P
Shi
D002244:Carbon / Q000378:metabolism; D057486:Carbon Cycle / Q000502:physiology*; D057965:Carbon Sequestration; D002681:China; D002980:Climate; D065928:Forests; D065948:Grassland; D008027:Light; D008962:Models, Theoretical; D010788:Photosynthesis / Q000502:physiology*; D011827:Radiation; D012621:Seasons
D002244:Carbon