Model information

The MM5 (version 3.72) with Polar Mods (Polar MM5) and the Noah Land Surface Model (LSM) setting is used in the real-time numerical weather predictions over North America and Eurasia. The Polar Mods were developed by the Byrd Polar Research Center at The Ohio State University to better handle Arctic/Antarctic conditions for forecasting purposes. In its basic configuration, the model consists of 150x150 and 180x180 grid points with a horizontal resolution 60 km over North America and Eurasia domains, respectively. In vertical, the model has 28 terrain-following levels, and the top pressure is set to 10 hPa.

The Polar MM5 runs are non-hydrostatic and contain the following parameterization schemes:

• Grell cumulus parameterization scheme
• Reisner's mixed-phase explicit moisture scheme
• MRF planetary boundary layer scheme
• RRTM longwave scheme

The land surface model is a one-dimesional model of energy, momentum,water and CO2 exchange between the atmosphere and land, accounting for ecological difference among vegetation types, hydraulic and thermal differences among soil types within a grid cell. In coupling to the Polar MM5, the land surface model provides to the Polar MM5 surface albedos, upward longwave radiation, sensible heat flux and latent heat flux at every time step. The Polar MM5 provides to the LSM at every time step, incident solar radiation, incident longwave radiation, convective and large-scale precipitation and lowest model level temperature, specific humdity, pressure and height (about 50 m above the surface).

The coupled model starts at 0000 UTC as its initial times every day and produces a 48-hour prediction for North America and Eurasia domains, respectively. The initial and boundary conditions are interpolated from the daily 0000 UTC run of the Aviation model forecasts (AVN) issued by the National Centers for Environmental Prediction (NCEP), and obtained from the NECP website: ftp://ftpprd.ncep.noaa.gov.

Model output information

The following real-time model outputs are placed on the website:

• Spatial Plots:

• Near surface: 2m temperature, 10m wind and sea level pressure
• 850 hPa temperature, wind and height
• 700 hPa temperature, wind and height
• 500 hPa temperature, wind and height
• 6 hour total precipitation
• 1000 to 500 hPa thickness and sea level pressure
• 700 hPa relative humidity, wind and height
• 500 hPa relative vorticity, wind and height
• 300 hPa isotachs, wind and height

• Skew-T/Log-P Diagrams: at 22 selected stations

• Time Series Plots: at 22 selected stations

Any comments or questions about the real-time numerical weather prediction for North America and Eurasia. Please mail to bromwich@polarmet1.mps.ohio-state.edu.