Spatial Representativeness Error in the Ground-Level Observation Networks for Black Carbon Radiation Absorption

Wang, Rong ; Andrews, Elisabeth ; Balkanski, Yves ; Boucher, Olivier ; Myhre, Gunnar ; Samset, Bjørn Hallvard ; Schulz, Michael ; Schuster, Gregory L [Point of Contact] ; Valari, Myrto ; Tao, Shu

关键词: RADIATION ABSORPTION;    SOLAR RADIATION;    RADIATIVE FORCING;    SPATIAL RESOLUTION;    CARBON;    AEROSOLS;    POLLUTION TRANSPORT;    OPTICAL THICKNESS;    SATELLITE OBSERVATION;    ERROR ANALYSIS;   

RP-ID  :  NF1676L-29444

学科分类：地球科学(综合)

美国|英语

来源: NASA Technical Reports Server

【 摘 要 】

There is high uncertainty in the direct radiative forcing of black carbon (BC), an aerosol that strongly absorbs solar radiation. The observation-constrained estimate, which is several times larger than the bottom-up estimate, is influenced by the spatial representativeness error due to the mesoscale inhomogeneity of the aerosol fields and the relatively low resolution of global chemistry-transport models. Here we evaluated the spatial representativeness error for two widely used observational networks (AErosol RObotic NETwork and Global Atmosphere Watch) by downscaling the geospatial grid in a global model of BC aerosol absorption optical depth to 0.1° × 0.1°. Comparing the models at a spatial resolution of 2° × 2° with BC aerosol absorption at AErosol RObotic NETwork sites (which are commonly located near emission hot spots) tends to cause a global spatial representativeness error of 30%, as a positive bias for the current top-down estimate of global BC direct radiative forcing. By contrast, the global spatial representativeness error will be 7% for the Global Atmosphere Watch network, because the sites are located in such a way that there are almost an equal number of sites with positive or negative representativeness error.