Validation of the Atmospheric Forcing of ISLSCP Initiative I CD-ROM and Outputs from the JMA-SiB Using FIFE Observations

[摘要] The site-averaged data, compiled by the First International Satellite Land Surface Climatology Project (ISLSCP) Field Experiment (FIFE) from 1987 to 1988, are compared with the output from a simple biosphere model introduced by the Japan Meteorological Agency (JMA-SiB), and with the atmospheric forcing archived in the ISLSCP Initiative I CD-ROM.In the JMA-SiB output, 1988 soil moisture below a depth of 5cm is systematically underestimated, due to budget calculation errors from autumn 1987 to spring 1988. The total precipitation during this period exhibits close agreement between the observed and the one used as the atmospheric forcing. In the observation, the precipitation directly leads to an increase in soil moisture, while in the JMA-SiB, most of the forcing precipitation is consumed by evapotranspiration. Reasons for this discrepancy in spring 1988 can be summarized as follows: (1) The near surface mixing ratio is systematically underestimated in winter, which does not reflect the evapotranspiration in the JMA-SiB. (2) The atmospheric forcing underestimates the intense precipitation concentrated over the last 11 days, just prior to the resumption of soil moisture observations.Since the characteristics of the observations and those of the atmospheric forcing are found to be fairly different, simulated soil moisture should not be directly compared with that observed. It appears necessary to carry out an another validation experiment using the site-averaged FIFE data as the atmospheric forcing for the JMA-SiB.

[学科分类] 大气科学