## 4 Discussion  
### Monthly Dynamics of Ecological Parameters in China  
The growth of vegetation is a gradual process, necessitating the monitoring of ecological parameters with consideration of monthly dynamics. Figure 12 illustrates the inter-monthly fluctuations of ecological parameters across different LUTs, while Figure 13 presents a comprehensive analysis of the data from Figure 12, focusing solely on the range and coefficient of variation. Initially, the study discussed the changing characteristics of ecological parameters in various LUTs in vegetation regions. Forest exhibited the highest lower and upper limits of ecological parameters. The peak ecological parameters for cultivated land were observed in August, whereas for forest and grassland, they were in July. The coefficient of variation for ecological parameters was lowest in forests, followed by grasslands, and highest in cultivated lands. Subsequently, when comparing the changing characteristics of various LUTs in non-vegetation regions, it was noted that, except for LAI, the ecological parameters of water bodies were lower than those of built-up areas. The coefficient of variation for NDVI and EVI in water bodies was the highest, indicating significant inter-monthly variation. Specific changes in the NDVI and EVI were observed in water bodies and unutilized land. The monthly dynamics of ecological parameters between grasslands and constructive land were found to be similar. However, a distinct observation was made regarding the trend of both LUTs from May to July. As depicted in Figure 12, the trend of ecological parameters in grasslands from May to July appears smoother compared to constructive land. This smoother trend was primarily due to a more gradual increase in various ecological parameters from May to June, followed by a more rapid increase from June to July. Figure 11: The coupled degree of ecological parameters between alternate years of LULC changes in China in 2001–2020. Relationship between Climatic Factors and Ecological Parameters of Various LUTs in China and Its Sub-Regions  
In the context of climate change, there are obvious regional and vegetation-type variances in how distinct meteorological factors impact vegetation growth [36; 65; 66; 67; 68; 69]. Previous research has tended to treat all vegetation types collectively, examining the relationship between ecological parameters and climate variables by averaging values across the study area, thereby overlooking the impact of land use variations on this correlation. Based on  
Figure 12: The inter-monthly fluctuations of ecological parameters of various LUTs in China in 2001–2020. Figure 13: The range and coefficient of variation of inter-monthly ecological parameters of various LUTs in China in 2001–2020. our previous studies, the mean values of temperature and precipitation in China from 2001 to 2018 were 7.93 \({}^{\circ}\)C and 672 mm, with rates of change of -0.0242 \({}^{\circ}\)C-(10a)\({}^{-1}\) and 17.32 mm-(10a)\({}^{-1}\), respectively, when the meteorological factors were ignored for the study of various land types (Figure 14). The average annual temperature of cultivated land (12.14 \({}^{\circ}\)C), forest (10.65 \({}^{\circ}\)C), and constructed land (15.41 \({}^{\circ}\)C) exceeded 10 \({}^{\circ}\)C, while unutilized land recorded the lowest temperature (4.78 \({}^{\circ}\)C). Solely the average annual precipitation of forests surpassed 1000 mm (1093 mm), followed by constructed land (981 mm), with unutilized land exhibiting the least annual precipitation (225 mm). Regarding the trend in meteorological parameter changes, except for grassland and unutilized land, the temperature of other LUTs exhibited an upward trajectory. Precipitation levels increased across all LUTs, albeit with obvious differences.