洱海湖滨农田下垫面大口径闪烁仪与涡动相关仪测量的湍流热通量对比分析

Comparison of Sensible and Latent Heat Fluxes over Farmland Underlying Surface of Erhai Lakeside Region Measured from Large Aperture Scintillometer and Eddy-covariance System

利用大理国家气候观象台大口径闪烁仪(LAS)和涡动相关仪(EC)在洱海湖滨农田下垫面的同步观测资料,比较分析了两种仪器测量湍流感热和潜热通量的差异特征。结果表明,LAS测得的湍流感热和潜热通量与EC测得的均有较高的相关性,相关系数分别为0.85和0.90。两种仪器测量结果差异均存在显著的昼夜和季节变化。昼夜变化表现为白天时段LAS的平均感热(潜热)通量比EC的偏小15.6 W·m-2(偏大94.6 W·m-2);夜间时段则相反,LAS比EC的偏大9.3 W·m-2(偏小40.6 W·m-2)。季节变化表现为湿季(5-8月、10月)LAS的平均感热通量比EC的偏小6.9 W·m-2,干季(4月)LAS的平均潜热通量比EC的偏小2.1 W·m-2,其他月份则相反,LAS比EC测得的感热(潜热)偏大5.7(18.1)W·m-2。

The sensible and latent heat fluxes were determined with a Large Aperture Scintillometer（ LAS）which was set up over farmland underlying surface of Erhai Lakeside region with a path length of 1938 m. These large-scale sensible and latent heat fluxes were compared with local-scale Eddy-covariance System（ EC） measurements. The results showed excellent agreement for the sensible and latent heat fluxes measured by LAS and EC with the correlation coefficient up to 0. 85 and 0. 90,respectively,and revealed clear diurnal variation and season change for the difference of heat fluxes. The diurnal variation demonstrated that sensible heat flux measured by LAS was 15. 6 W ·m-2lower than that by EC and latent heat flux measured by LAS was 94. 6 W ·m-2higher than that by EC in daytime,however,it was contrary in nighttime. The season change displayed that monthly mean sensible heat flux measured by LAS was 6. 9 W ·m-2lower than that by EC in wet season（ M ay to August,October） and monthly mean latent heat flux measured by LAS was 2. 1 W ·m-2lower than that by EC in dry season（ April）,but other month was on the contrary.