Evaluation of Surface Fluxes Over a Paddy Field in Tropical Environment: Some findings from a preliminary observation of GAME

Abstract

A preliminary observation for the GEWEX Asian Monsoon Experiment (GAME) was carried out at one of the observation sites of GAME near Sukhothai, Thailand in the summer of 1996, in order to assess the performance of prototype stations for measuring surface fluxes and soil moisture as well as to evaluate relative merits of the methods of determining fluxes. The data sets from three observation systems yielded turbulence statistics and the surface flux values by applying the eddy correlation method, the bandpass covariance method, the Bowen ratio method, the profile method and the bulk method. Intercomparisons of the resulting values indicate that the turbulence statistics are of high quality but the algorithm for evaluating bandpass covariance needs further improvement. It was also found that an accurate evaluation of energy storage in water body is essential in the application of energy balance approaches at paddy field. Overall, all stations performed satisfactory during the experiment in a hot, humid environment. However, a better protection against a strong rainfall appears to be needed for long term observations in this area.