Michael Pollock

‌‌Michael Pollock - m.d.pollock@ncl.ac.uk

 

PhD Title:

Improving the Accuracy of Point-Scale Rainfall Measurements in the UK

 

PhD Project Details:

Accurate measurement of rainfall is a fundamental requirement in many applications.  Rainfall data are often falsely assumed to be sufficiently accurate so as to be fit for purpose.

 

The effective management of flooding and water resources depend upon ‘good’ input data in the form of correct measurements.  If these are not achievable, a fall-back position should be adopted whereby there is an awareness of the extent of the inaccuracy, and therefore an opportunity to quantify the uncertainty of the resulting additional risk.

 

This study aims to improve the understanding of rainfall measurement inaccuracy, and present a method of dealing with rain underestimation at local scales.  The most significant cause of this problem is the ‘wind-induced undercatch’, where environmental wind conditions around the gauge cause an acceleration of the airflow, distorting precipitation particles and causing an underestimate.  Previous studies have conducted work on this topic, such as Sevruk and Hamon (1984), Nešpor and Sevruk (1999) and Colli et al. (2015).  This research builds on such studies and uses a multi-site approach with high resolution field data, coupled with Computational Fluid Dynamic (CFD) modelling of rain gauges, to solve a fundamental problem in hydrology and meteorology.  This PhD will:

 

  • Create experimental designs and carry out equipment installations at four UK sites
  • Run and maintain field experiments throughout the project
  • Review and use CFD approaches to improve knowledge of the wind-induced undercatch
  • Time series modelling of all input data, using Python and ‘R’
  • Develop a correction procedure for one rain sensor, based on experimental and statistical data analysis
  • Prototype a new instrument

 

References

Sevruk, B. & W. Hamon. 1984 International Comparison of National Precipitation Gauges with a Reference Pit Gauge, Secretariat of the World Meteorological Organization.

 

Nešpor, V., & Sevruk, B. (1999) ‘Estimation of Wind-Induced Error of Rainfall Gauge Measurements using a Numerical Simulation’, Journal of Atmospheric and Oceanic Technology, 16(4), 450-464.

 

Colli, M., R. Rasmussen, J. M. Theriault, L. G. Lanza, C. B. Baker & J. Kochendorfer (2015) ‚An Improved Trajectory Model to Evaluate the Collection Performance of Snow Gauges‘, Journal of Applied Meteorology and Climatology, 54, 1826-1836.

 

(Image - A time-averaged CFD visualisation showing the stream-wise vertical view of the air velocity magnitude (Um in m/s). The uniform inflow velocity coming from the left of the picture is 5 m/s. Red indicates acceleration; blue, deceleration)

 

Supervisors:

Dr Paul Quinn

Professor Chris Kilsby

Mark Wilkinson

 

Sponsors:

EML

NERC

 

Partners:

James Hutton Institute

University of Dundee

University of Genoa

WMO-CIMO Lead Centre on Precipitation Intensity

 

Related Outputs:

Paper presented at WMO technical conference on meteorological and environmental instruments and methods of observation, St. Petersburg, July 2014

 

Biography:

Michael studied for a BEng in Civil Engineering at Newcastle University (2007-2011), before undertaking an MSc in Hydrology and Climate Change (2011-2012) at the same institution. 

 

In June 2013 he started a three year Knowledge Transfer Partnership (KTP), working with Newcastle University and Environmental Measurements Ltd (EML).  This involves managing a project to deliver a new product through a collaborative process of research and development.

 

http://research.ncl.ac.uk/proactive/

http://www.emltd.net/technical-papers