• On the measurement of the surface energy budget over a land surface during the summer monsoon

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      Permanent link:
      https://www.ias.ac.in/article/fulltext/jess/117/06/0911-0923

    • Keywords

       

      Surface fluxes; energy budget; land experiment; summer monsoon; atmospheric sciences; climate; experiments.

    • Abstract

       

      The measurement of surface energy balance over a land surface in an open area in Bangalore is reported. Measurements of all variables needed to calculate the surface energy balance on time scales longer than a week are made. Components of radiative fluxes are measured while sensible and latent heat fluxes are based on the bulk method using measurements made at two levels on a micrometeorological tower of 10 m height. The bulk flux formulation is verified by comparing its fluxes with direct fluxes using sonic anemometer data sampled at 10 Hz.Soil temperature is measured at 4 depths. Data have been continuously collected for over 6 months covering pre-monsoon and monsoon periods during the year 2006. The study first addresses the issue of getting the fluxes accurately.It is shown that water vapour measurements are the most crucial. A bias of 0.25% in relative humidity,which is well above the normal accuracy assumed by the manufacturers but achievable in the field using a combination of laboratory calibration and field intercomparisons, results in about 20 W m−2 change in the latent heat flux on the seasonal time scale. When seen on the seasonal time scale,the net longwave radiation is the largest energy loss term at the experimental site. The seasonal variation in the energy sink term is small compared to that in the energy source term.

    • Author Affiliations

       

      G S Bhat1 S C Arunchandra1

      1. Center for Atmospheric and Oceanic Sciences, Indian Institute of Science, Bangalore 560 012, India.
    • Dates

       
  • Journal of Earth System Science | News

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