EMD-WRF On-Demand ICING

Introduction

EMD-WRF OD ICING is the name of EMD’s icing model. The model is driven by an icing configuration of the standard EMD WRF [1] On-Demand service [2]. The model is run with a spatial resolution of 3x3 km with an hourly temporal resolution and using the ERA-5 reanalysis data from ECMWF as global boundary data [3]. The Thompson microphysics scheme is used for parameterization of the cloud physics and the MYJ scheme for the planetary boundary layer physics [4], [5]. The median volume diameter (MVD) by [6] is used, with a constant droplet concentration (Nc) of (default) 100 cm-3 and the liquid water content (LWC) in kg/m3 [7]. The atmospheric data feeds into the standard cylinder-based model [8], [9] including melting and shedding [10]. The WRF grid point (latitude, longitude) closest to the at mast location or site location is used as a default. The grid point holds a certain elevation above sea level and icing is modelled as a default for 15 heights in the vertical direction above ground level (agl.).

The modelled ice load (kg) is used to identify hours of instrumental icing based on the industry standard thresholds of 10 g [11]. And similar from the modelled ice accretion rate (g/h), hours of meteorological icing [12] is found using the threshold of 10 g/h [9]. The final step of EMD’s modelling chain, is an estimate of the expected production loss of a site which is found by using the IEA Ice Classification system seen in Table 1.

TABLE HERE

The complete list of parameters are seen in the Table 2 further below.

The EMD-WRF OD ICING is available as a time-series product, please see more here: Time-Series - On-Demand.
Please also see the technical note and results from recent validation study on EMD-WRF OD ICING for more information. (add link to note)

How to order?

To get pointwise-timeseries data, you need meso-credits (one credit is worth one month of data). Credits can be ordered here: http://www.emd.dk/windpro/online-ordering/ Please note, that a time period of 10 years will include the complete icing analysis, whereas shorter time periods include only raw timeseries. Complete icing analysis includes:

• Icing reports as pdfs at three hub-heights - 100m, 150m and 200m
  • Including predicted AEP loss
• Icing maps at three hub-heights - 100m, 150m and 200m
  • IEA ice class, IEA Ice loss (% AEP) and modelled meteorological icing (icing rate > 10 g/h)
• The possibility to use your icing results and timeseries directly in your windPRO project
• Monthly, yearly and seasonal icing analysis and bin-sector analysis as csv-files
• Timeseries of raw WRF data and modelled icing

Data Availability

All EMD-WRF OD ICING is available with global spatial coverage. The temporal availability and update frequency depends on a number of factors such as availability from the boundary data providers, bandwidth and download times, as well as availability on EMD high-performance computing and storage systems. EMD-WRF OD ICING is availability with the ERA5 only, see table below.

Dataset	First date	Most recent date
EMD-WRF OD (ERA5)	1999.01.01	2-3 months from present day