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A strategic programme for NERC Lowland catchment research
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New methods to estimate catchment evaporation: summary

A fuller description of this project is also available.

Aims

This study tested the hypothesis that: while field scale measurements may be most accurate at the point of measurement, the errors introduced by their extrapolation when looking at the catchment as a whole, outweigh the errors involved in applying remote sensing techniques.  More about the aims of this project

Main findings and outputs

  • There is considerable variability of evaporation across the landscape linked to land cover, soils and meteorology.
  • Uncertainties in our estimates of evaporation tend to reduce as we go to catchment averages.
  • There is considerable potential to estimate catchment average evaporation using available gridded data sets.
  • The LOCAR data set is proving extremely powerful - for the first time (in the UK at least) we have simultaneous measurements of soil moisture, evaporation and hydrological measurements.
  • Successful ground-truthing of satellite-derived net radiation estimates for clear skies has been achieved.  More about the main findings of this project

Description of activities

Newly available satellite measurements were combined with conventional and novel surface measurements, using geographic information system (GIS) techniques. An important facet of the study was a thorough analysis of error at every stage that allowed a quantitative assessment of techniques.

Related and future work

Development of a longwave algorithm to estimate the downwelling longwave radiation at the surface is continuing as part of the NERC funded project NE/C52038X/1 which focuses on the impact of Saharan dust aerosol on the surface radiation budget.

Scintillometry work is continuing with the development of a microwave instrument (which measures evaporation directly) under NERC grant number NE/B506143.

Researchers' details

Principal Investigator:

Co-investigators:

More researchers who worked on this project More researchers who worked on this project

Publications

All publications from this and other LOCAR projects are listed in the publications database.

Selected publications from this project are listed below. The full list of publications and recommended reading can be viewed in the full description page for this project Full publication list for this project

Selected publications

Blyth, E.M., Evans, J.G., Finch, J.W., Bantges, R. and, Harding, R.J., 2006. Spatial variability of the English agricultural landscape and its effect on evaporation. Agricultural and Forest Meteorology, 138, 19-28

Evans, J.G., Bantges, R ,Finch, J.W., Blyth, E.M., Harding, R.J and Murray,T., 2005 Large Aperture Scintillometry over Complex Terrain:Results from Chalk Down-land. European Meteorological Society Conference 2005.

Full list of publications resulting from this project Full publication list for this project

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