Nowcasting Trajectory Analysis Project (NTAP)

Nowcasting presentation


Experiment 1

I have a preliminary code running GOES-sounder ob trajectories. The animation provided is of GOES-8 sounder locations that have been projected 6 hours into the future using the 300 hPa wind field from 12UTC 30 Aug 2000. The grid is AWIPS 236 (native RUC) on P surfaces that we have downloaded from the SP frontend. Every third wind vector is displayed. You can see some convergence/divergence in the trajectories.


Experiment 2

In this experiment I used hourly wind updates to project the 12UTC GOES-8 sounder locations. The animation provided is of GOES-8 sounder locations that have been projected 6 hours into the future using hourly 300 hPa wind field from 12UTC and 15UTC RUC cycles from 30 Aug 2000. The grid is AWIPS 236 (native RUC) on P surfaces that we have downloaded from the SP frontend. An animation comparing the 6 hour projections from Experiment 1 and 2 is provided.


Experiment 3

In this experiment I used hourly wind updates to project the 12UTC GOES-8 sounder locations. The animation provided is of GOES-8 sounder locations that have been projected 6 hours into the future using hourly 700, 500, 300 hPa wind field from 12UTC and 15UTC RUC cycles from 30 Aug 2000. The grid is AWIPS 236 (native RUC) on P surfaces that we have downloaded from the SP frontend. You can see the observations moving in response to the vertical shear.


Experiment 4

Hourly projections of the 12UTC 30Aug00 GOES-8 retrievals are validated against an analysis of the retrieved GOES-8 thetaE for each hour. This was done at 850, 700, and 500hPa. The GOES-8 sounder locations that have been projected 6 hours into the future using hourly 850, 700, 500 hPa wind field from 12UTC and 15UTC RUC cycles from 30 Aug 2000.

Note: The GOES 3x3 retrievals use the 18UTC analysis as the background at 18UTC. The previous retrievals use fields time interpolated from 12UTC.

Here is an animation of the locations of the GOES-8 retrievals at 850hPa and the corresponding analysis.

Here is an animation of the locations of the projected pseudo obs at 850hPa and the corresponding analysis.

Here is an animation of the scatter diagram comparing the trajectory obs (y-axis) to the GOES-8 thetaE analysis (x-axis) at 850hPa.

Here is an animation of the locations of the GOES-8 retrievals at 700hPa and the corresponding analysis.

Here is an animation of the locations of the projected pseudo obs at 700hPa and the corresponding analysis.

Here is an animation of the scatter diagram comparing the trajectory obs (y-axis) to the GOES-8 thetaE analysis (x-axis) at 700hPa.

Here is an animation of the locations of the GOES-8 retrievals at 500hPa and the corresponding analysis.

Here is an animation of the locations of the projected pseudo obs at 500hPa and the corresponding analysis.

Here is an animation of the scatter diagram comparing the trajectory obs (y-axis) to the GOES-8 thetaE analysis (x-axis) at 500hPa.

The statistics plotted below correspond to the scatter plots above.

Here is a plot of the observation count for each hour after 12UTC 30Aug00. The trajectory ob count decreases slightly because some of the obs are projected off the domain. The GOES-8 retrieval ob count decreases because of the formation of clouds, reducing the number of clear fields-of-view (FOV).

Here is a plot of the root mean square difference between the trajectory obs and an analysis of the GOES-8 retrievals for each hour after 12UTC 30Aug00. The accuracy of the trajectory obs degrade with time.

Here is a plot of the bias (trajectory obs minus GOES-8 retrieval) The largest changes in the bias occur at 850hPa. Little change occurs at 500hPa.

Statistics were also computed by analyzing the trajectory observations onto the grid and validating them against the actual thetae retrievals from GOES-8. The stats are slightly different because the GOES-8 retrievals have sequentially decreasing observation counts due to clouds. Here is a plot of the root mean square difference between gridded GOES-8 thetae and trajectory obs (solid) and gridded trajectory obs and GOES-8 retrievals (dashed) at the 850hPa, 700hPa, and 500hPa levels. The comparisons match quite well in time. Here is a plot of the bias (Same as above). The biases at 700hPa and 850hPa are slightly better when verifying the GOES-8 thetae grid against the trajectory obs.


Experiment 5

Hourly projections of the 12UTC 30Aug00 GOES-8 thetaE retrievals are computed for 2 levels at a time. The levels are differenced (upper minus lower) to assess the thermodynamic stability. Only the 12UTC 30Aug00 GOES-8 thetaE retrievals are used. Hourly forecast winds from the RUC are used to project the retrievals.

Here is an animation of the differences of 500hPa thetaE (K) minus 700hPa thetaE.

Here is an animation of the differences of 670hPa thetaE (K) minus 920hPa thetaE.

Here is an animation of the differences of 700hPa thetaE (K) minus 920hPa thetaE.

Here is an animation of the differences of 850hPa thetaE (K) minus 950hPa thetaE.

Here is an animation of the differences of 620hPa thetaE (K) minus 850hPa thetaE.

Here is an animation of the differences of 700hPa thetaE (K) minus 850hPa thetaE.


Experiment 6

Hourly projections of the 12UTC 30Aug00 GOES-8 retrievals of mixing ratio are validated against an analysis of the retrieved GOES-8 mixing ratio for each hour. This was done at 920, 850, and 700hPa. The GOES-8 sounder locations that have been projected 6 hours into the future using hourly 920, 850, and 700 hPa wind field from 12UTC and 15UTC RUC cycles from 30 Aug 2000.

Here is an animation of the 920 hPa mixing ratio, trajectory obs minus GOES retrievals.

Here is an animation of the scatter plot comparing the 920 hPa mixing ratio trajectory obs and the GOES retrievals.

Here is an animation of the 850 hPa mixing ratio, trajectory obs minus GOES retrievals.

Here is an animation of the scatter plot comparing the 850 hPa mixing ratio trajectory obs and the GOES retrievals.

Here is an animation of the 700 hPa mixing ratio, trajectory obs minus GOES retrievals.

Here is an animation of the scatter plot comparing the 700 hPa mixing ratio trajectory obs and the GOES retrievals.


Please refer questions or comments to the ITAPMaster: Robert.Aune@noaa.gov