集成多源遥感与模型估算森林变化的水热碳影响

[Objective]Forest cover change influences the spatiotemporal dynamics of carbon sinks and impacts regional and global climates by altering surface heat,water,and material cycles.[Method]This study utilizes the 30-meter resolution China Land Cover Dataset(CLCD)for the years 2000,2010,and 2020,alongside data on Land Surface Temperature(LST),temperature,precipitation,carbon storage,evapotranspiration(ET),albedo,and net radiation(NR).By employing moving window strategies and spatiotemporal analysis,the study quantitatively assesses the effects of forest changes on water-heat-carbon dynamics(including surface temperature,air temperature,precipitation,and carbon storage)and their biophysical mechanisms(such as evapotranspiration,albedo,and net radiation).Linear regression and structural equation modeling were used to analyze the relationships between hydrothermal carbon effects and the biophysical mechanisms of forest change,constructing a spatiotemporal response model of forest change and its impacts on hydrothermal carbon and biophysical mechanisms.[Result]The results showed that the effects of afforestation and deforestation on water-heat-carbon and biophysical mechanisms in Hangzhou and Zhaoqing had consistent positive and negative effects.The mean cooling effect(-2.59±0.27 °C and-1.29±0.2 °C)and warming effect(2.42±0.42 °C and 1.24±0.43 °C)of afforestation and deforestation on LST from 2000 to 2020 were significantly greater than those on Tem(cooling:-0.18±0.07 °C and-0.1±0.03 °C;Temperature:0.17±0.04 °C and 0.09±0.04 °C).Afforestation and deforestation led to changes in positive and negative carbon stocks,with afforestation in Zhaoqing leading to a slight increase in total carbon stocks,while deforestation in Hangzhou led to a decrease in total carbon stocks.The increase of precipitation caused by afforestation in the two cities was significantly stronger than that of deforestation(13.2±4.66 mm and 2.68±5.09 mm.2.88±1.24 mm and 0.62±1.45 mm).From 2010 to 2020,the biophysical mechanism of afforestation on the two cities increased evapotranspiration,decreased albedo and increased net radiation,while deforestation was the opposite.The evapotranspiration and net radiation effects of afforestation in Hangzhou were more significant(0.33±1.12 W/m2 and 0.91±0.79 W/m2),while the evapotranspiration and net radiation reductions were more significant in Zhaoqing(-2.01±1.69 W/m2 and-0.03±1.12 W/m2).For albedo,afforestation exhibits a slight negative effect,while deforestation does the opposite.The changes and correlations of the variables brought about by afforestation and deforestation in the two cities were basically consistent with the respective impact trends.The degree of influence on LST in the biophysical mechanisms was ET>NR>Albedo;The effect of biophysical mechanism on precipitation was stronger in Hangzhou,while it had a stronger effect on temperature in Zhaoqing.The impact of climate factors on carbon storage in Hangzhou is greater than that in Zhaoqing.[Conclusion]The decrease of forest area is an important reason for the decrease of carbon storage in the two cities,and the rapid development of urbanization leads to the trend of decreasing total carbon storage year by year.Forest change affects the dynamic changes of hydrothermal carbon changes and biophysical processes,but the analysis results of the two cities are different due to the differences in geographical location,sea and land location and other factors.In general,rational planning of forest area and scientific urbanization process are conducive to carbon sequestration and sequestration in Hangzhou and Zhaoqing,and stabilize the regional climate,thereby contributing to the implementation of the"dual carbon"policy.