|
|
|
| Simulation analysis and verification of surface CO2 flux over Pearl River Delta, China |
|
|
|
|
Abstract Carbon dioxide is the primary greenhouse gas involved in climate change. This gas is responsible for 85% of the increase in radiative forcing over the past decade and 81% over the last five years. Accurate estimations of strength and spatiotemporal distributions of surface sources and sinks of CO2 are thus of great interest to the scientific community and policy makers. The CO2 measurement and modeling system developed by the National Oceanic and Atmospheric Administration and called the Carbon Tracker-2010 (CT-2010) was used to analyze the seasonal and spatial distributions of net CO2 flux and CO2 sink characteristics of terrestrial ecosystems in the Pearl River Delta (PRD) region. Prior to doing simulations, the CT-2010 model was validated using in situ observations from the Panyu meteorological site (PYQXJ), the Dongguan site (DG), and the Ding Hushan site (DHS), which are representative of grassland, urban green space, and forest ecosystems in the PRD region, respectively. Net fluxes from the CT-2010model compared with observations from the three sites well. Hourly, daily, and diurnal residuals were less than 2.0 μmol/(m2?s) and correlation coefficients were greater than 0.60 (P<0.01). The CT-2010 model captured well the seasonal patterns of CO2fluxes over the PRD region. However, the magnitude of the simulated fluxes was generally greater than that of the observed fluxes. Annual residuals were 2.056, 0.964, and 2.100μmol/(m2?s) at the PYQXJ, DG, and DHS sites, respectively. From June 2004to May 2005, the mean surface net flux over the PRD region was 3.43μmol/(m2?s). In summer, fall, winter, and spring, mean surface net fluxes were 0.18, 0.51, 1.4, and 1.35 μmol/(m2?s), respectively. The mean terrestrial flux in the PRD was -6.5×10-3 PgC. The region during this time was dominated by crops (42.01%), grassland/shrubs (31.46%), and mixed (coniferous/broadleaf) forest (26.53%).
|
|
Received: 17 February 2014
|
|
|
|
|
|
|
