Parallel Experiments

1. CNTL MLS v1.5 MLS NRT CNTL MLS v1.5 MLS NRT SBUV/2 fcst MLS v1.5+SBUV/2 fcst MLS NRT+SBUV/2 fcst Parallel Experiments Analysis Control run – SBUV/2 (N-16 and N-17) Experiment – MLS v1.5 + SBUV/2 (MLS profile 215 – 0.46 hPa) Experiment – NRT MLS + SBUV/2 (MLS profile 215 – 0.46 hPa) Model – T382L64, GSI Period – 41days (2006/09/21/00z ~ 2006/10/31/00z) Test Results from Assimilation of NRT MLS Ozone Profile Data in the NCEP GFS Craig Long Shuntai Zhou, Russ Treadon - craig.long@noaa.gov NOAA/NWS/NCEP • NCEP is testing the viability of NRT MLS ozone products. Here we compare results of assimilating the NRT MLS data for the period Sept 21-Oct 31, 2006 at T382L64 with similar tests using the MLS v1.5 data Included in these runs are the SBUV/2 v6 ozone data. We present the similarities and differences between the MLS v1.5 and NRT runs and a control run which is just using the SBUV/2 data. (The v2.2 data was not available when these runs were made.) • Results: • - The MLS v1.5 and NRT data have finer vertical resolution than the SBUV/2 v6. • MLS v1.5 data improves the 5-day ozone forecast at most latitudes. • NRT MLS data only improves the 5-day ozone forecast in the tropics. • - NRT MLS ozone hole forecasts are not as good as MLS v1.5. • MLS v1.5 has neutral or very slight positive impact on 1000, 850, 500, 200 temps and winds. • NRT MLS has neutral of very slight negative impact on 1000, 850, 500, 200 temps and winds. Figure 3. Comparison of 5-day forecasts of the Antarctic ozone hole (validated at Oct. 22, 2006). Usage of MLS v1.5 data (middle) results in a larger and deeper ozone hole forecast than just using the SBUV/2 v6 data (left). Using the NRT MLS data (right) does not result in as low ozone values in the center of the ozone hole. Figure 6. 500 hPa height anomaly correlations for the control, MLS v1.5 and NRT MLS runs for the NH (top) and SH (bottom). The AC are broken into waves 1-3, 4-9, 10-20, and all waves. Tropical 200 hPa wind (U) RMS errors CNTL MLS v1.5 MLS NRT Figure 4. 2006 ozone hole size comparisons between an analysis using just the SBUV/2 (black), a 5-day forecast using SBUV/2 (blue), and a 5-day forecast using MLS+SBUV/2 (red), and a 5-day forecast using NRT MLS+SBUV/2 (orange). Figure 1. Comparison of vertical resolution of the NCEP GFS L64 model, the SBUV/2 v6 ozone profile, and the MLS profile. Mean Ozone F-A Differences Tropical 200 hPa wind (V) RMS errors CNTL MLS v1.5 MLS NRT SBUV/2 MLSv1.5+SBUV/2 Figure 7. 200 hPa u (top) and v (bottom) tropical wind component RMS errors for the control, MLS v1.5 and NRT MLS runs. NRT MLS+SBUV/2 Figure 2. Comparison of 5-day forecast of ozone profile at 30E, 80S (validated at Oct. 22, 2006). Note that near 70 hPa ozone is almost completely deleted. Without MLS data the GFS forecast could not catch this feature. Figure 5. Ozone Forecast–Analysis differences for the control (SBUV/2 only) (top left), the MLSv1.5+SBUV/2(top right), and the NRT MLS+SBUV/2 (bottom). Inclusion of MLSv1.5 reduces forecast errors at most latitudes. Inclusion of NRT MLS reduces forecast errors only in the tropics and in the low and middle stratosphere.