## 3 Results
### Effects of Climate Factors on Ecosystem Carbon Fluxes
All analyses indicated that such drought events led to more adverse results in the grassland than in the forest ecosystem. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Vegetation Type** & **Carbon Fluxes** & **Rg (W m\({}^{-2}\))** & **Ta (\({}^{\circ}\)C)** & **VPD (hPa)** & **Pre (mm d\({}^{-1}\))** \\ \hline \multirow{6}{*}{Forest} & GPP & \multirow{2}{*}{0.770 **} & \multirow{2}{*}{0.864 **} & \multirow{2}{*}{0.646 **} & \multirow{2}{*}{0.223 **} \\  & (g C m\({}^{-2}\) d\({}^{-1}\)) & & & & \\ \cline{2-5}  & Re & & & & \\ \cline{2-5}  & (g C m\({}^{-2}\) d\({}^{-1}\)) & & & & \\ \cline{2-5}  & NEE & & & & \\ \cline{2-5}  & (g C m\({}^{-2}\) d\({}^{-1}\)) & \(-0.632\) ** & \(-0.559\) ** & \(-0.310\) ** & \(-0.179\) ** \\ \hline \multirow{6}{*}{Grassland} & GPP & \multirow{2}{*}{0.711 **} & \multirow{2}{*}{0.643 **} & \multirow{2}{*}{0.520 **} & \multirow{2}{*}{\(-0.042\)} \\  & (g C m\({}^{-2}\) d\({}^{-1}\)) & & & & \\ \cline{1-1} \cline{2-5}  & Re & & & & \\ \cline{1-1} \cline{2-5}  & (g C m\({}^{-2}\) d\({}^{-1}\)) & & & & \\ \cline{1-1} \cline{2-5}  & NEE & & & & \\ \cline{1-1} \cline{2-5}  & (g C m\({}^{-2}\) d\({}^{-1}\)) & \(-0.212\) ** & \(-0.007\) & \(-0.044\) & \(0.087\) \\ \hline \hline \end{tabular}  
* The correlation is significant at the 0.01 level.  
\end{table} 
Table 1: The Pearson correlation analysis between climate factors and ecosystem carbon fluxes at the forest and grassland sites for each weekly period, respectively. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline  & \multirow{2}{*}{**Variables**} & \multicolumn{3}{c}{**Forest Site**} & \multicolumn{3}{c}{**Grassland Site**} \\ \cline{3-6}  & & **Multi-Year Means** & **Dropout 2003** & **Multi-Year Means** & **Dropout 2003** \\ \hline \multirow{10}{*}{Climate factors} & Rg & 150.53 & 163.04 & 135.1 & 149.2 \\  & (W m\({}^{-2}\)) & \multicolumn{3}{c}{8.3\%} & \multicolumn{3}{c}{10.4\%} \\ \cline{2-6}  & Ta & 4.22 & 4.72 & 9.23 & 9.56 \\ \cline{2-6}  & (\({}^{\circ}\)C) & \multicolumn{3}{c}{11.8\%} & \multicolumn{3}{c}{3.6\%} \\ \cline{2-6}  & VPD & 3.13 & 4.01 & 2.83 & 4.54 \\ \cline{2-6}  & (hPa) & \multicolumn{3}{c}{28.1\%} & \multicolumn{3}{c}{60.4\%} \\ \cline{2-6}  & Pre & 862.1 & 663.2 & 1276.5 & 890.3 \\ \cline{2-6}  & (mm y\({}^{-1}\)) & \multicolumn{3}{c}{\(-\)23.1\%} & \multicolumn{3}{c}{\(-\)30.3\%} \\ \hline \multirow{10}{*}{Carbon fluxes} & GPP & 1541.96 & 1614.05 & 2003.24 & 1647.57 \\  & (g C m\({}^{-2}\) y\({}^{-1}\)) & \multicolumn{3}{c}{4.68\%} & \multicolumn{3}{c}{\(-\)17.8\%} \\ \cline{2-6}  & Re & 1534.76 & 1835.67 & 1530.43 & 1378.82 \\ \cline{2-6}  & (g C m\({}^{-2}\) y\({}^{-1}\)) & \multicolumn{3}{c}{19.6\%} & \multicolumn{3}{c}{\(-\)9.9\%} \\ \cline{2-6}  & NEE & \(-\)10.76 & 218.8 & \(-\)441.3 & \(-\)157.3 \\ \cline{1-1} \cline{2-6}  & (g C m\({}^{-2}\) y\({}^{-1}\)) & \multicolumn{3}{c}{\(-\)2133.5\%} & \multicolumn{3}{c}{\(-\)64.3\%} \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Relative deviations of changes in climate and ecosystem carbon fluxes between the multi-year means during the adjacent normal years and the drought 2003 at the forest (CH-Dav) and grassland (CH-Oe1) sites, respectively. Figure 6: Relationships between VPD and ecosystem carbon fluxes, namely GPP (**a**,**b**), Re (**a**,**b**), and NEE (**c**,**d**), at the forest (**Left**) and grassland (**Right**) sites for each weekly period.