F-DEWS Deployments, Instruments, and Data

Students were required to fill-out a ‘Mission Summary’ form with essential details of the IOP including instruments deployed, locations, etc. (see Appendix F). Given the number of instruments, most of the IOPs involved about a dozen students.

After some coordinated effort, all of the DOW-7 data were ‘reprocessed’ to an Integrated Data Viewer (IDV) friendly format via the NCAR SOLO software. The process involves rewriting the data as a ‘new’ DORADE file that is compatible with the latest version of IDV (5.2).   As required within the the two courses (MET4233/5233 and ENS5903) students have begun to integrate the aforementioned data sets. In addition to the DOW-7, students in MET4233 were assigned to specific instrument teams that included a research-grade lidar (Zephyr 300), 4 rain gauges (two total/two tipping bucket with Campbell Scientific data loggers), iMet radiosonde, TLE camera, and an electric field mill (Fig. 3). In addition to these data, we have also archived supplementary data sets including the National Lightning Detection Network (NLDN) and the Kennedy  Space  Center  Lightning  Detection  and  Ranging  (LDAR)  system.  The  latter  also contains data from the KSC CGLSS (Cloud-to-Ground Lightning). During the 12 day visit, there were 6 IOPs as the weather was quite active. Our department (Marine and Environmental Systems) paid for a university van rental ($30/day, Fig. 3) for the duration of the project. The van transported up to 11 students to and from the various IOP data collection locations. Of the 6 deployments, one was ‘remote’ – on the north shore of Lake Okeechobee (6 September 2015). A summary of each of the IOPs follows.

Fig. 3a. FIT “chase van” with students at the north shore of Lake Okeechobee.
Fig. 3b. Graduate students and Post-Doc setting up the electric field sensor. 
Fig. 3c. Foreground – Zephyr 300 lidar. 
Fig. 3d. Students measure the rainfall collected during the 31 August 2015 IOP.

Monday August 31
The DOW-7  (with  four MET4233  students)  was  parked  at  Eastern  Florida State College (EFSC) at the Palm Bay Florida campus (Fig. 4). The van chase team (8 students), with precipitation gauges, travelled south (about 30 miles) to Vero Beach and headed west on route 60 – west of I-95.  There was heavy rain (~1.5” in the gauges, Fig. 4) and frequent lightning as well. This event was very “tropical” with high precipitable water values associated with the remnants of tropical storm Erica (an inverted trough). The thunderstorm of interest moved north toward radar but collapsed before arriving there. Given that this was the first IOP, Students were trained in the art of setting up rain gauges and are shown leveling a gauge just prior to the deluge (Fig. 4).

Fig. 4a. The DOW-7 sitting on the Palm Bay campus of Eastern Florida State College.
Fig. 4b. Students assist Professor Mike Splitt with the leveling of a rain gauge. 
Fig. 4c. The storm approaches rapidly from the south before overtaking the chase van on the evening of 31 August 2015.
Fig. 4d. The storm approaches rapidly from the south before overtaking the chase van on the evening of 31 August 2015.

As previously mentioned, the data are now viewable in IDV. This platform is conducive for integrating  different  data  sources, runs in either a Windows or Linux  environment, and is being used, by the PI, here at FIT in several courses including MET4233 and MET1999. An example of its capabilities is shown in Fig. 5. Here, we’ve combined NLDN CG data over a 5 min window that corresponds, in time, to the DOW-7 reflectivity (3 degree tilt) at 2223 UTC 31 August 2015 (IOP 1). The polarity of the strikes are shown as ‘+’ and ‘-‘. The storm to the south of the radar (for which the chase van and precipitation gauge was deployed, see Table 1)  is  electrically  active  at  this time. Several of the graduate student led research teams are examining the dual—pol products from this storm. In particular, graduate student Jeff Colvin has been looking at “areas” of negative KDP as a proxy for indicating vertically aligned hydrometeors within the electric field. A 5 degree tilt shows areas  of  negative KDP on the order of –8 to –6 in the core reflectivity south and southwest of the radar (Fig. 6). The DOW-7 polarization data will form the background of several of the student research projects (see Section 1).

Fig. 5. DOW-7 reflectivity (dBZ, 3 degree tilt) valid 2223 UTC 31 August 2015 (color filled). Also shown are the 5 min window of NLDN cloud-to-ground lightning locations (with polarity).
 
Fig. 6. DOW-7 KDP valid 2248 UTC 31 August 2015. Image provided by meteorology graduate student Jeff Colvin.

Friday September 4
The second IOP caught the end of an active convective event during the early evening hours. A radiosonde  was  launched  on  campus  at the High Bay area at the Olin Physical Science building. The DOW  went west on route 192 between Holopaw and I-95 (Fig. 7). The precipitation (chase) team also went west. We recorded primarily light anvil precipitation with one rain gauge pair (one total/one tipping bucket) placed on campus and one pair near the radar (see Table 1 for gauge locations). 15 students   participated  in this IOP including those travelling with the DOW, working with the LIDAR, installing precipitation gauges, and the radiosonde launch (Fig. 8).

Fig. 7. FIT undergraduate students Tia Harris and Michael Barnett disembark from the DOW-7 parked off of highway 192 west of Melbourne FL.
Fig. 8a. FIT students inflate a weather balloon in the Physics High Bay in support of the 4 September 2015 DOW-7 IOP. 
Fig. 8b. Students prepare the balloon to be launched.

Sunday September 6
This IOP turned out to be our longest excursion as the van and radar travelled south towards the north shore of Lake Okeechobee. During early September, the sea breeze begins to wane – but the lake generally continues to enhance convection. This outing was in part designed to support the proposed convective initiation work. This was the only day the field mill (Fig. 9) was taken out in the field (note that the field mill was on top of the Physics building on campus for the other IOPs). Eleven students participated and meteorologist Dr. Pallav Ray also went out with chase crew.

Fig. 9a. Graduate students, Dr. Lazarus (holding the iMet radiosonde receiver) and Dr. Ray gazing upwards at the ascending balloon. 
Fig. 9b. Students watch as the balloon is released. 
Fig. 9c. Setting up the field meter as the storm approaches.

Fig. 9d. Field meter data as storm passed overhead.

There was a well-defined lake breeze (Fig. 10) around the entire lake. Although the convection was somewhat anemic – with no reports of lightning there were several well-observed gust fronts. The data from this day will form part of the project work proposed by Graduate student Bryan Holman. As an example, an IDV-generated image at one degree tilt from the DOW-7 is shown in Fig. 11 (provided by graduate student Bryan Holman). A couple of fairly prominent outflow boundaries are present both south and east of the radar during this IOP. Bryan is examining the structure of gust fronts that occurred during the course of the IOPs.

Fig. 10. Panorama looking east-to-west along the north shore of Lake Okeechobee on 6 September 2015. The sky over the lake is clear with cumulus (congestus) along the shoreline.

Precipitation data (~0.5”) were collected about 15 miles NW of radar (see Fig. 9). The DOW, which was parked on the levy on the north side of the lake, had a great view of the lake generated breeze.  A successful radiosonde launch (from the north shore of the lake) recorded data up to around 11.0 km (Fig. 9).

Tuesday September 8
This was an intense convective event (a severe thunderstorm warning was issued for Melbourne) unfortunately the DOW-7 (parked at Eastern Florida State College in Palm Bay) was having technical problems during the storm peak.  This was an electrically active storm that had a well-defined gust front which passed directly over the FIT campus during the late afternoon. The lidar data for the gust front passage indicates peak wind speeds between 50 and 80 m above the surface sustained near 13 m s-1  (Fig. 12) as precipitation measurements with two of the gauges  deployed in  SE Palm  Bay and two gauges on campus. A balloon was launched from campus out ahead of the storm – with the storm overrunning the sonde as  the balloon reached an altitude of 10.5 km. The Melbourne WSR88D will serve as a DOW proxy for this day. About a dozen students participated during this IOP including 4 with the radar (Fig 13).

Fig. 11. DOW-7 reflectivity (1 degree tilt) valid 1840 UTC 6 September 2015. The radar was parked on a levy along the north shore of Lake Okeechobee. Several gust front boundaries are visible in this image (courtesy of graduate student Bryan Holman).
Fig. 12. Lidar wind profiles (min, max, and mean in m/s) from 8 September 2015 gust front passage in Melbourne.
Fig. 13a. Students inflate balloon in preparation for a radiosonde launch on 8 September 2015.
Fig. 13b. FIT undergraduate students on board the DOW-7 with technician Alycia Gilliland. 
Fig. 13c. The severe storm approaches.
 

Wednesday September 9
This was a relatively short IOP (~ 2 h) with the DOW-7 parked over at Eastern Florida State College. Mid-to-late afternoon weak short-lived  convection formed in NW Melbourne. The chase van pursued the storms off of I-95 and Eau Gallie Boulevard in Melbourne. This storm had some lightning with it and did have some back building/pulse convection for about an hour period (Fig. 14).

Fig. 14a. Sophomore meteorology student on the DOW-7 9 September 2015. 
Fig. 14b. RHI scan of the convection.
Fig. 14c. Photo taken near the time of the image.
 

Thursday September 10
A small cell developed directly over campus, with nearby lightning strikes. We attempted to launch a field mill however there was only a small window of opportunity where there was an enhanced electric field (~5-10 min) and thus we did not get the mill launched. The radiosonde, which was to be piggy-backed with the mill, will also not launched.  There were precipitation gauges deployed on campus only. Both reflectivity and differential reflectivity are shown below in Figure 15. The elevated ZDR is likely associated with large rain drops.

Fig. 15a. 3 degree tilt valid 1810 UTC 10 September 2015. Reflectivity (dBZ). 
Fig. 15b. 3 degree tilt valid 1810 UTC 10 September 2015. Differential reflectivity (dB).

 

Table 1: Precipitation gauge locations for the 6 IOPs. Also shown are the start/stop time for the data collection and the DOW-7 location.

 

Appendix F