Figure 1.
Seasonal variation in daily average temperature (Ta) and vapor pressure deficit (VPD), and daily precipitation (PPT) and daily average soil water content (SWC) throughout the study period.
Soil water content data from 6 April to 23 May were omitted because of a malfunction in the connecting cable between the soil moisture sensor and the data logger.
Table 1.
Comparison of environmental conditions in temperate desert steppe, Inner Mongolia, during 2008 to 2010.
Figure 2.
Seasonal dynamics of leaf area index (LAI) in 2008 and 2009.
Figure 3.
Seasonal variations in daily integrated net ecosystem carbon exchange (NEE), gross primary production (GPP), and ecosystem respiration (Reco) over the course of the study.
Negative NEE denotes the net carbon uptake of the ecosystem.
Table 2.
Comparison of carbon fluxes in temperate desert steppe, Inner Mongolia, during 2008 to 2010.
Figure 4.
Yearly cumulative net ecosystem carbon exchange (NEE), gross primary production (GPP), ecosystem respiration (Reco), and precipitation (PPT) in the Inner Mongolia temperate desert steppe from 2008 to 2010.
Negative NEE indicates that the ecosystem is gaining carbon.
Table 3.
Mean soil water content and the parameters used to describe the rectangular hyperbolic response of daytime net ecosystem CO2 exchange to photosynthetically active radiation during May to September of the three measured years as described in Eq. 7.
Figure 5.
Temporal variations in canopy surface conductance (gc) from May to September.
Figure 6.
Exponential relation between canopy surface conductance (gc and soil water content (SWC).
Data were obtained from May to September of each of the three study years. Rainy days were excluded from the analysis.
Figure 7.
Linear relation between daily gross primary production (GPP) and canopy surface conductance (gc).
Data were obtained from May to September of each of the three study years. Rainy days were excluded from the analysis.
Figure 8.
Responses of gross primary productivity (GPP) and ecosystem respiration (Reco) to soil water content (SWC).
GPP and Reco data from May to September were averaged with a bin width of 1% for SWC. Error bars represent one standard error. Rainy days were excluded from the analysis.
Table 4.
The regression equations between gross primary productivity and soil water content, and between ecosystem respiration and soil water content in the three years.
Table 5.
Regression coefficients as described in Eqs. 8–9, lower than 25°C.
Figure 9.
Ecosystem respiration (Reco) responses to gross primary production (GPP) in a linear manner.
Figure 10.
Relationships between daily net ecosystem CO2 exchange (NEE), daily gross primary production (GPP), and leaf area index (LAI).
NEE, GPP, and soil water content (SWC) data represent the seven-day mean that is centered on the day samples for LAI. Error bars represent one standard error.