EGU General Assembly 2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

Outgoing Long Wave Radiation Dipole of Tropical Cyclones

Mohan Smith and Ralf Toumi
Mohan Smith and Ralf Toumi
  • Imperial College London, RCS, Physics, United Kingdom of Great Britain and Northern Ireland (

Remote (r ≤ 1800km) outgoing longwave radiation (OLR) fields are investigated in observations, the ECMWF ensemble forecast and reanalysis data. A large scale dipole pattern of low and high fluxes are found in both the observations and model. Low OLR regions are positioned within the cyclone circulation and high OLR regions are found 500-1500km to the north west of the TC. The position of the high OLR region rotates anticlockwise about the TC center as the TC motion vector rotates clockwise from westward to eastward. There is a strong association between the low level wind divergence fields and the high OLR remote region. We propose this remote high OLR region is of interest regarding TC track forecasts. Sub-ensembles selected upon the location of the remote high OLR region improved track forecasts improved by 15\% at 6hrs lead time. This technique out performs those sub-ensembles selected by the inner 750km TC OLR signal, however the best skill improvement in the study selects sub-ensembles by a 3600x3600km TC centered OLR field.

How to cite: Smith, M. and Toumi, R.: Outgoing Long Wave Radiation Dipole of Tropical Cyclones, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-20341,, 2020


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