The impact of diffuse sunlight on canopy light-use efficiency, gross photosynthetic product and net ecosystem exchange in three forest biomes

2007 ◽  
Vol 13 (4) ◽  
pp. 776-787 ◽  
Author(s):  
P. B. ALTON ◽  
P. R. NORTH ◽  
S. O. LOS
Keyword(s):  
Net Ecosystem Exchange ◽  
Light Use Efficiency ◽  
Photosynthetic Product ◽  
Use Efficiency ◽  
The Impact

Terrestrial CO2 Fluxes, Concentrations, Sources and Budget in Northeast China: Observational and Modeling Studies

2020 ◽  
Author(s):  
Xiaolan Li ◽  
Xiao-Ming Hu ◽  
Changjie Cai ◽  
Qingyu Jia ◽  
Yao Zhang ◽  
...  
Keyword(s):  
Land Surface ◽  
Northeast China ◽  
Ecosystem Respiration ◽  
Mixed Forest ◽  
Net Ecosystem Exchange ◽  
Growth Period ◽  
Rice Paddy ◽  
Light Use Efficiency ◽  
Maximum Light ◽  
Use Efficiency

<p>CO<sub>2</sub> fluxes and concentrations are not well understood in Northeast China, where dominant land surface types are mixed forest and cropland.  Here, we analyzed the CO<sub>2</sub> fluxes and concentrations using Eddy Covariance (EC) measurements, satellite observations, and the Weather Research and Forecasting model coupled with the Vegetation Photosynthesis and Respiration Model (WRF-VPRM).  We also used WRF-VPRM outputs to examine CO<sub>2</sub> transport/dispersion, and to quantify the biogenic and anthropogenic contributions to atmospheric CO<sub>2</sub> concentrations.  Finally, we investigated the uncertainties of simulating CO<sub>2</sub> fluxes related to four VPRM parameters (including maximum light use efficiency, photosynthetically active radiation half-saturation value, and two respiration parameters) using offline ensemble simulations with randomly selected parameter values.  The results indicated that mixed forests acted as a larger CO<sub>2</sub> source and sink than rice paddies on average in 2016 due to a longer growth period and stronger ecosystem respiration, although the minimum EC-measured daily mean net ecosystem exchange (NEE) was smaller at rice paddy (-10 μmol m<sup>-2</sup> s<sup>-1</sup>) than at mixed forest (-6.5 μmol m<sup>-2</sup> s<sup>-1</sup>) during the growing season (May through September).  The monthly fluctuation of column-averaged CO<sub>2</sub> concentrations (XCO<sub>2</sub>) exceeded 10 ppm in Northeast China during 2016.  Biogenic contribution (large negative in summer and insignificant in other months) offset about 70% of anthropogenic contribution of XCO<sub>2</sub> in this region.  WRF-VPRM modeling successfully captured seasonal and episodic variations of NEE and CO<sub>2</sub> concentrations, however, the NEE in mixed forest was overestimated during daytime, mainly due to the uncertainties of VPRM parameters, especially maximum light use efficiency.</p>

scholarly journals Does the Construction and Operation of High-Speed Rail Improve Urban Land Use Efficiency? Evidence from China

Land ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 303
Author(s):  
Xinhai Lu ◽  
Yifeng Tang ◽  
Shangan Ke
Keyword(s):  
Economic Growth ◽  
Land Use ◽  
High Speed ◽  
Urban Land ◽  
Urban Land Use ◽  
Western China ◽  
High Speed Rail ◽  
Land Use Efficiency ◽  
Use Efficiency ◽  
The Impact

The construction and operation of high-speed rail (HSR) has become an important policy for China to achieve efficiency and fairness and promote high-quality economic growth. HSR promotes the flow of production factors such as labor and capital and affects economic growth, and may further affect urban land use efficiency (ULUE). To explore the impact of HSR on ULUE, this paper uses panel data of 284 cities in China from 2005 to 2018, and constructs Propensity Score Matching-Differences in Differences model to evaluate the effect of HSR on ULUE. The result of entire China demonstrates that the HSR could significantly improves the ULUE. Meanwhile, this paper also considers the heterogeneity of results caused by geographic location, urban levels and scales. It demonstrates that the HSR has a significantly positive effect on ULUE of Eastern, Central China, and large-sized cities. However, in Western China, in medium-sized, and small-sized cities, the impact of HSR on ULUE is not significant. This paper concludes that construction and operation of HSR should be linked to urban development planning and land use planning. Meanwhile, the cities with different geographical locations and scales should take advantage of HSR to improve ULUE and promote urban coordinated development.

Labour-use Efficiency of Assam Gramin Vikash Bank: Branch- and District-level Analysis

2021 ◽  
pp. 232102222110243
Author(s):  
Mohuya Deb Purkayastha ◽  
Joyeeta Deb ◽  
Ram Pratap Sinha
Keyword(s):  
Efficiency Score ◽  
Significant Variable ◽  
Data Envelopment ◽  
Tobit Regression ◽  
Second Stage ◽  
Time Period ◽  
Use Efficiency ◽  
The Mean ◽  
The Impact ◽  
Observation Period

The present study estimated labour-use efficiency of 48 branches of Assam Gramin Vikash Bank at its branch level, covering three districts of Barak Valley, which falls under Silchar region of the bank for the time period from 2010–2011 to 2017–2018. The study applied data envelopment analysis for estimating labour-use efficiency. In the second stage, the study applied censored Tobit regression for determining the impact of several contextual variables on efficiency. The study reveals that the mean labour-use efficiency score of the selected branches is 76% when averaged for the in-sample branches over the observation period. Results of the Tobit regression identified cluster 2 and total business of the branches as the significant factors for determining efficiency and the number of employees as a significant variable influencing inefficiency. JEL Classifications: G2, G20, G21, J3

Enhanced light interception and light use efficiency explain overyielding in young tree communities

2021 ◽  
Author(s):  
Laura J. Williams ◽  
Ethan E. Butler ◽  
Jeannine Cavender‐Bares ◽  
Artur Stefanski ◽  
Karen E. Rice ◽  
...  
Keyword(s):  
Light Interception ◽  
Light Use Efficiency ◽  
Young Tree ◽  
Tree Communities ◽  
Use Efficiency

scholarly journals A common garden experiment examining light use efficiency and heat sum to explain growth differences in native and exotic Pinus taeda

2018 ◽  
Vol 425 ◽  
pp. 35-44 ◽  
Author(s):  
Timothy J. Albaugh ◽  
Thomas R. Fox ◽  
Chris A. Maier ◽  
Otávio C. Campoe ◽  
Rafael A. Rubilar ◽  
...  
Keyword(s):  
Pinus Taeda ◽  
Common Garden ◽  
Light Use Efficiency ◽  
Common Garden Experiment ◽  
Use Efficiency ◽  
Growth Differences
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