EGU 2019

Here are some of the interesting points I saw during EGU 2019 in Vienna.

Monday: NWP, DA and Ensembles (AS1.1)

  • Florian Pappenberger outlined plans for future work at ECMWF. Cycle 46R1 will be introduced in June 2019. Which will include the ENS being initialized from 50 member ensemble DA system. There will be web presentation on 46R1 on the 15th and 16th of May.
  • Pall August Porarinsson presented work on the use of 750m resolution runs of HARMONIE for forecasting Iceland. Compared to the operational 2.5km resolution model, the 750m forecasts offered better forecasts in areas of complex topography (such as fjords) but produced a worse temperature forecast.

Atmospheric Boundary Layer (AS2.2)

  • Domingo Munoz-Esparza presented on work using LES simulation to forecast turbulence for UAVs (aka drones). In an effort to make these simulation fast enough to be operational they have developed GPU based LES code called FastEddy.
  • Clara Garcia-Sanchez presented work using WRF with the Fitch turbine wake scheme to estimate losses from hypothetical windfarms in central USA. WRF was run at 3km as a resource assessment tool. It was found that as wind farms get larger and larger (beyond realistic scales) the energy density asymtotically reduces towards 1 W/m^2.

Convection Permitting modelling (CL5.04/AS1.28)

  • Daniel Argüeso presented work on using WRF simulations to forecast rainfall over the Maritime Continent. He ran WRF at a variety of resolutions: 32, 16, 8, 4 and 2km with and without a cu_physics scheme. It was found that explicity resolving convection allowed production of stronger rainfall events and a more accurate diurnal cycle as the convection scheme did not allow CAPE to build to large enough values.

Energy Meteorology (ERE2.1/AS1.11)

  • Frederik Kurzrock discussed using WRF to forecast incoming shortwave radiation on La Réunion. Two different WRF experiments were conducted, one with an updating cycle and WRF-DA of satellite observations and another one which was simply downscaling GFS driving data. He used spatial averaged SW to compare forecast values to observations, citing Lara-Fanego. It was found that the setup with data assimilation did not produce an improvement in overall skill although it did reduce the occurrence of large errors. More frequent cycling might be tested to see if the DA setup can be improved.
  • Adrian Acevedo presented work relating to the use of WRF downscaling and PCA analysis for forecasting for renewable at a coastal location in northern Spain. He downscaled both CFS (reanalysis) and GFS (forecast) using WRF 9km – 3km – 600m. And compared the WRF-forecast to observations and also compared the WRF-forecast to the WRF-reanalysis, treating the WRF-reanalysis as truth. He also did some post-processing stuff with PCA but I didn’t follow.
  • Jan Wohland presented work on the use of century-long reanalyses for wind resource assessments, looking at 20CR (NOAA), ERA-20C and CERA-20C (both ECMWF). It was found that these ECMWF reanalyses have spurious trends caused by the assimilation of ocean winds which can be corrupted by changes to observing system. When the trend is removed, it reveals some significant low-frequency (multi-decadal) variability in wind speed and that the period since the late seventies (the satellite-era and starting point for most global reanalyses) is during a period of faster than average wind speeds. Therefore the use of this 30-40 year period for resource assessment might not be as representative as we think. Not relevant to my work at all but was a very interesting talk.

I also presented a poster on the influence of PBL schemes in the WRF model on wind speed forecast skill over Ireland, looking at both 10m from synop stations and mast observations from wind farms.