In response to global climate change, many important earth-systems-oriented science
programs have been established in the past. One such program, the Fluxnet program, studies
the response of world forests and other natural ecosystems by measuring biospheric fluxes of
carbon dioxide (CO2), water vapour, and energy with eddy-covariance (EC) techniques to
assess the role of world ecosystems in offsetting increases in CO2 emissions and related
impacts on global climate. The EC methodology has its limitations particularly when
weather is inclement and during system stoppages. These limitations create non-trivial
problems by creating data gaps in the monitored data stream, diminishing the integrity of the
dataset and increasing uncertainty with data interpretation.
This Thesis deals with the development of a parsimonious, semi-empirical approach
for gap filling of net ecosystem productivity (NEP) data. The approach integrates the effects
of environmental controls on diurnal NEP. The approach, because of its limited number of
parameters, can be rapidly optimized when appropriate meteorological, site, and NEP target
values are provided. The procedure is verified by applying it to several gap-filling case
studies, including timeseries collected over balsam fir (Abies Balsamea (L.) Mill.) forests in
New Brunswick (NB), Canada and several other forests along a north-south temperaturemoisture
gradient from northern Europe to the Middle East. The evaluation showed that the
model performed relatively well for most sites; i.e., r2 ranged from 0.68-0.83 and modelling
efficiencies, from 0.89-0.97, demonstrating the possibility of applying the model to forests
outside NB. Inferior model performance was associated with sites with less than complete
input datasets.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:UNB.1882/1053 |
| Date | January 2007 |
| Creators | Zisheng, Xing |
| Contributors | Bourque, C. P. A. |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Thesis or Dissertation |
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