TY - JOUR
T1 - ECMWF and GFS model forecast verification during DYNAMO
T2 - Multiscale variability in MJO initiation over the equatorial indian ocean
AU - Kerns, Brandon W.
AU - Chen, Shuyi S.
N1 - Funding Information:
We have benefited from discussions with Jon Gottschalck, Martin Miller, Chidong Zhang, Augustin Vintzileos, and Falko Judt during the course of this study. Constructive comments and suggestions from the three anonymous reviewers helped improve the manuscript significantly. The ECMWF model forecast fields were provided in real time by the ECMWF in support of the DYNAMO field campaign. These data are available through the NCAR Earth Observing Laboratory at http://www. eol.ucar.edu/field_projects/dynamo. The NCEP GFS data were obtained via the NCAR Research Data Archive at http://rda.ucar.edu (data set number 335.0). The TRMM data were obtained from the NASA Goddard Space Flight Center FTP server at ftp://pps.gsfc.nasa. gov/pub/trmmdata/ByDate/V07/. The TRMM product number is 3B42. This research was supported by grants from NOAA (NA11OAR4310077), NSF (AGS1062242), and the ONR LASP DRI (N000141110562).
PY - 2014/4/16
Y1 - 2014/4/16
N2 - Improving understanding and prediction of the initiation of the Madden-Julian Oscillation (MJO) over the equatorial Indian Ocean (IO) was a main objective of the Dynamics of the MJO (DYNAMO) field campaign. This study evaluates the European Centre for Medium-Range Weather Forecasts (ECMWF) and the National Centers for Environmental Prediction Global Forecast System (GFS) operational global model forecasts of MJO-2 in DYNAMO (November–December 2011). The model rainfall and 850 hPa zonal winds are compared with the Tropical Rainfall Measurement Mission (TRMM) rainfall and operational analysis in the equatorial IO. The ECMWF forecasts of the total equatorial rainfall were more consistent with TRMM observations. The GFS did not accurately predict the onset of equatorial convection beyond 5 day lead time. Instead, the GFS rainfall was mainly off the Equator in the Intertropical Convergence Zone (ITCZ). The GFS did not capture synoptic scale systems that bring in dry air intrusions from the subtropics and disrupt convection in the ITCZ which is favorable for equatorial convection associated with the MJO initiation. DYNAMO observations suggest that multiscale interactions among convection, synoptic systems, and the MJO large-scale circulations were important for the initiation of MJO-2. The model forecasts and analysis of 850 hPa zonal wind are decomposed into mesoscale, synoptic, and large-scale flows. Results show that (1) both models have good initial conditions and 1–2 day forecasts and (2) the ECMWF has significantly better skill than the GFS in terms of forecasting equatorial convection, synoptic systems, and the large-scale MJO circulation at 5–15 day lead times.
AB - Improving understanding and prediction of the initiation of the Madden-Julian Oscillation (MJO) over the equatorial Indian Ocean (IO) was a main objective of the Dynamics of the MJO (DYNAMO) field campaign. This study evaluates the European Centre for Medium-Range Weather Forecasts (ECMWF) and the National Centers for Environmental Prediction Global Forecast System (GFS) operational global model forecasts of MJO-2 in DYNAMO (November–December 2011). The model rainfall and 850 hPa zonal winds are compared with the Tropical Rainfall Measurement Mission (TRMM) rainfall and operational analysis in the equatorial IO. The ECMWF forecasts of the total equatorial rainfall were more consistent with TRMM observations. The GFS did not accurately predict the onset of equatorial convection beyond 5 day lead time. Instead, the GFS rainfall was mainly off the Equator in the Intertropical Convergence Zone (ITCZ). The GFS did not capture synoptic scale systems that bring in dry air intrusions from the subtropics and disrupt convection in the ITCZ which is favorable for equatorial convection associated with the MJO initiation. DYNAMO observations suggest that multiscale interactions among convection, synoptic systems, and the MJO large-scale circulations were important for the initiation of MJO-2. The model forecasts and analysis of 850 hPa zonal wind are decomposed into mesoscale, synoptic, and large-scale flows. Results show that (1) both models have good initial conditions and 1–2 day forecasts and (2) the ECMWF has significantly better skill than the GFS in terms of forecasting equatorial convection, synoptic systems, and the large-scale MJO circulation at 5–15 day lead times.
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U2 - 10.1002/2013JD020833
DO - 10.1002/2013JD020833
M3 - Article
AN - SCOPUS:84924948462
VL - 119
SP - 3736
EP - 3755
JO - Journal of Geophysical Research: Atmospheres
JF - Journal of Geophysical Research: Atmospheres
SN - 2169-897X
IS - 7
ER -