A new uninterrupted 14‑month-long forecast produced using a recent version of ECMWF’s Integrated Forecasting System (IFS Cycle 43r1) is available to researchers. Such a forecast is known as a ‘Nature Run’ (NR) and is commonly used for Observing System Simulation Experiments (OSSEs). The new NR, called ECO1280, starts at 00:00 UTC on 30 September 2015 and includes the rapid intensification of Hurricane Joaquin. The ECO1280 uses the TCo1279L137 configuration of the IFS, which has a grid spacing of about 9 km and 137 vertical layers.
An NR is used to represent the atmosphere in simulation experiments including OSSEs. Ideally the NR is generated by a state‑of-the‑art numerical model and realistically represents all phenomena that affect the new observing system. Since no forecast system is perfect, there should be realistic differences between the NR model and the model used for assimilation and forecasting. For researchers, the value of the new ECMWF NR is that the ECMWF model is very advanced, complete and accurate.
All ECO1280 variables are archived every three hours. During the first month, data are archived every hour. Storage required for one month of data at three-hour archiving is about 4 TB. Instructions for downloading, converting, and interpolating the ECO1280 are given on the ECO1280 web page: https://www.cira.colostate.edu/imagery-data/ecmwf-nature-run/
Use and access
The ECO1280 may be used for any research purpose. Interested researchers should acquire the ECO1280 by contacting the Cooperative Institute for Research in the Atmosphere at Colorado State University (CIRA/CSU) to describe planned usage and to obtain data access instructions. Resulting publications or presentations must acknowledge ECMWF and CIRA/CSU. A useful aid to the design and interpretation of OSSEs is the OSSE checklist available at http://www.aoml.noaa.gov/qosap/osse-checklist/.