ECMWF new model cycle (IFS cycle 43r3) will contain a number of meteorological changes (provisional implementation date 20th June 2017):

Assimilation

• • Improved humidity background error variances directly from the EDA like for all other variables.
  • Revised wavelet filtering of background error variances and revised quality control of drop-sonde wind observations in 4DVAR to improve tropical cyclone structures.

Observations

• • Increased use of microwave humidity sounding data by adding new sensors (SAPHIR, GMI 183 GHz channels).
  • Activation of 118 GHz channels over land from MWHS-2 instrument on-board FY-3C.
  • Harmonised data usage over land and sea-ice for microwave sounders (adding MHS channel 4 over snow, adding some ATMS channels, lower observation errors for MHS data over land).
  • Improved screening of infrared observations for anomalously high atmospheric concentrations of hydrogen cyanide (HCN) from wildfires.
  • Improved quality control for radio occultation observations and radiosonde data.

Model

• • New, more efficient radiation scheme with reduced noise and more accurate longwave radiation transfer calculation.
  • New aerosol climatology based on ‘tuned’ CAMS aerosol re-analysis including dependence on relative humidity.
  • Increased super-cooled liquid water at colder temperatures (down to -38C) from the convection scheme.
  • Visibility calculation changed to use ‘tuned’ CAMS aerosol climatology.

For more detailed information and timescale visit Implementation of IFS cycle 43r3